Improved visual outcome in familial retinoblastoma with late preterm

or early term delivery after prenatal RB1 mutation identification.

Sameh E. Soliman, M.D.1,2,3, Helen Dimaras, Ph.D.2,3,4, Vikas Khetan,

M.B. B.S.5, Elise Héon, M.D., F.R.C.S.C.2,3,4, Helen S.L. Chan, M.B. B.S.,

F.R.C.S.C., Brenda L. Gallie, M.D., F.R.C.S.C.

1Ophthalmology Department, Faculty of Medicine, Alexandria

University

2The Department of Ophthalmology & Vision Sciences, University of

Toronto.

3The Hospital for Sick Children, Toronto, Canada.

4The Division of Visual Sciences, Toronto Western Research Institute,

Toronto, Canada

5Sankara Nethralya Hospital, Chennai, India.

Pediatrics (H.S.L.C.), Molecular Genetics and Medical Biophysics

(B.L.G.), University of Toronto, Toronto, Ontario, Canada; the Division

of Hematology/Oncology (H.D., H.S.L.C.) and Departments of

Ophthalmology & Vision Sciences (E.H., B.L.G., V.K.) and Pediatrics

(H.S.L.C.),; (H.D., B.L.G.);, Toronto, Canada.

Address reprint requests to Dr. Brenda Gallie at the Department of

Ophthalmology and Vision Sciences, the Hospital for Sick Children,

525 University Avenue, Toronto, ON M5G 2L3, Canada, or at

brenda@gallie.ca.

Running Head: early delivery of familial RB.

Key Words: prenatal retinoblastoma, Retinoblastoma gene mutation,

RB1, molecular testing, late pre-term delivery, near-term delivery,

amniocentesis

Submitted as Original Article to JAMA Ophthalmology.

Abstract ( /350)

Importance: The abstract should begin with a sentence or 2 explaining the clinical (or other) importance of the study question.

Objective: State the precise objective or study question addressed in the report (eg, “To determine whether…”). If more than 1 objective is addressed, the main objective should be indicated and only key secondary objectives stated. If an a priori hypothesis was tested, it should be stated.

Design: Describe the basic design of the study. State the years of the study and the duration of follow-up. If applicable, include the name of the study (eg, the Framingham Heart Study). As relevant, indicate whether observers were masked to patient groupings, particularly for subjective measurements.

Setting: Describe the study setting to assist readers to determine the applicability of the report to other circumstances, for example, general community, a primary care or referral center, private or institutional practice, or ambulatory or hospitalized care.

Participants: State the clinical disorders, important eligibility criteria, and key sociodemographic features of patients. The numbers of participants and how they were selected should be provided (see below), including the number of otherwise eligible individuals who were approached but refused. If matching is used for comparison groups, characteristics that are matched should be specified. In follow-up studies, the proportion of participants who completed the study must be indicated. In intervention studies, the number of patients withdrawn because of adverse effects should be given. For selection procedures, these terms should be used, if appropriate: random sample (where random refers to a formal, randomized selection in which all eligible individuals have a fixed and usually equal chance of selection); population-based sample; referred sample; consecutive sample; volunteer sample; convenience sample.

Objective: State the precise objective or study question addressed in the report (eg, “To determine whether…”). If more than 1 objective is addressed, the main objective should be indicated and only key secondary objectives stated. If an a priori hypothesis was tested, it should be stated. To study the ocular and visual outcomes of infants with familial retinoblastoma when they are prenatally diagnosed and

safely delivered preterm to initiate treatment, and compare to outcomes of those diagnosed postnatally.

Objective: To determine overall outcomes of infants with familial retinoblastoma diagnosed

prenatal and delivered preterm compared to infants diagnosed postnatal.

Design: Describe the basic design of the study. State the years of the study and the duration of follow-up. If applicable, include the name of the study (eg, the Framingham Heart Study). As relevant, indicate whether observers were masked to patient groupings, particularly for subjective measurements.

MethodsDesign: A retrospective, observational study of Sickkids medical records documented

children born between 1 June 1996 and 1 June 2014 with familial retinoblastoma cared for , seen at

Sickkids SickKids, followed till April 2015because of relation to a retinoblastoma proband.

Setting: Describe the study setting to assist readers to determine the applicability of the report to other circumstances, for example, general community, a primary care or referral center, private or institutional practice, or ambulatory or hospitalized care.

Setting: This study was conducted at the SickKids academic institutional retinoblastoma referral

center.

Participants: State the clinical disorders, important eligibility criteria, and key sociodemographic features of patients. The numbers of participants and how they were selected should be provided (see below), including the number of otherwise eligible individuals who were approached but refused. If matching is used for comparison groups, characteristics that are matched should be specified. In follow-up studies, the proportion of participants who completed the study must be indicated. In intervention studies, the number of patients withdrawn because of adverse effects should be given. For selection procedures, these terms should be used, if appropriate: random sample (where random refers to a formal, randomized selection in which all eligible individuals have a fixed and usually equal chance of selection); population-based sample; referred sample; consecutive sample; volunteer sample; convenience sample.

Participants: All children with familial retinoblastoma treated at SickKids were included. All children

remain under care at Sickkids.

Intervention(s) for Clinical Trials or Exposure(s) for observational studies: The essential features of any interventions or exposures should be described, including their

method and duration of administration. The intervention or exposure should be named by its most common clinical name, and nonproprietary drug names should be used.

Exposure(s): Infants shown on amniocentesis to carry the parent’s RB1 mutant allele were planned

for early pre-term delivery, compared to normal term delivery and postnatal RB1 testing. All children

received treatments for eye tumors.

Main Outcome Measure(s): Indicate the primary study outcome measurement(s) as

planned before data collection began. If the manuscript does not report the main planned outcomes of a

study, this fact should be stated and the reason indicated. State clearly if the hypothesis being tested was

formulated during or after data collection. Explain outcomes or measurements unfamiliar to a general

medical readership.

Main Outcome Measures: The hypothesis prior to data collection was that preterm delivery of

infants at near 100% risk of bilateral retinoblastoma safely optimizes visual outcome and minimizes use

of invasive treatments. Primary study outcome measurements were gestational age and ocular location of

first and subsequent tumors; treatments given; eye classification and staging; visual outcome; number of

anesthetics; pregnancy or delivery complications; and estimated overall cost of care.

International Intraocular Retinoblastoma Classification of each eye; laterality; Tumour Node

Metastasis staging; date of last follow-up; and visual outcome.. Patients who inherited their family’s RB1

mutation were included in this study. Data collected included: relation to proband; sex; gestational age at

birth; pregnancy or delivery complications; date of RB1 molecular testing, type of sample tested and

result; timing and location of first and all subsequent tumor appearance(s) in each eye; treatment history;

International Intraocular Retinoblastoma Classification of each eye; laterality; Tumour Node Metastasis

staging; date of last follow-up; and visual outcome.

Intervention(s) for Clinical Trials or Exposure(s) for observational studies: The essential features of any interventions or exposures should be described, including their method and duration of administration. The intervention or exposure should be named by its most common clinical name, and nonproprietary drug names should be used.

Main Outcome Measure(s): Indicate the primary study outcome measurement(s) as planned before data collection began. If the manuscript does not report the main planned outcomes of a study, this fact should be stated and the reason indicated. State clearly if the hypothesis being tested was formulated during or after data collection. Explain outcomes or measurements unfamiliar to a general medical readership.

Results: The main outcomes of the study should be reported and quantified, including baseline characteristics and final included/analyzed sample. Include absolute numbers and measures of absolute risks (such as increase/decrease or absolute differences between groups), along with confidence intervals (for example, 95%) or Pvalues. Approaches such as number needed to treat to achieve a unit of benefit may be included when appropriate. Measures of relative risk also may be reported (eg, relative risk, hazard ratios) and should include confidence intervals. Studies of screening and diagnostic tests should report sensitivity, specificity, and likelihood ratio. If predictive value or accuracy is reported, prevalence or pretest likelihood should be given as well. All randomized clinical trials should include the results of intention-to-treat analysis, and all surveys should include response rates.

Results: The main outcomes of the study should be reported and quantified, including baseline

characteristics and final included/analyzed sample. Include absolute numbers and measures of absolute

risks (such as increase/decrease or absolute differences between groups), along with confidence

intervals (for example, 95%) or Pvalues. Approaches such as number needed to treat to achieve a unit of

benefit may be included when appropriate. Measures of relative risk also may be reported (eg, relative

risk, hazard ratios) and should include confidence intervals. Studies of screening and diagnostic tests

should report sensitivity, specificity, and likelihood ratio. If predictive value or accuracy is reported,

prevalence or pretest likelihood should be given as well.

Conclusions and Relevance: Provide only conclusions of the study

that are directly supported by the results, along with implications for

clinical practice or health policy, avoiding speculation and

overgeneralization. Indicate whether additional study is required

before the information should be used in usual clinical settings. Give

equal emphasis to positive and negative findings of equal scientific

merit. Also, provide a statement of relevance indicating implications

for clinical practice or health policy, avoiding speculation and

overgeneralization. The relevance statement may also indicate

whether additional study is required before the information should be

used in clinical settings.

Results: Of 21 infants shown to carry their parent’s RB1 mutation, 12 had been tested prenatally and

9 after birth. Of the infants tested prenatally, 9 were induced at 36-38 weeks gestation and 3 were born

spontaneously preterm. Immediate postnatal examination revealed vision-threatening tumors present only

in 25% (3/12) of infants prenatally diagnosed, compared to 67% (6/9) of those diagnosed postnatally. All

patients eventually developed tumors in both eyes. Good vision was maintained in all prenatally

diagnosed patients; treatments included focal therapy (all); later systemic chemotherapy (5), enucleation

and stereotactic radiation (1). Full-term infants received focal therapy (all), systemic chemotherapy (4),

stereotactic radiation (2), and enucleation of one eye (4), with poorer visual outcome.

Conclusions and Relevance: Provide only conclusions of the study that are directly supported by the results, along with implications for clinical practice or health policy, avoiding speculation and overgeneralization. Indicate whether additional study is required before the information should be used in usual clinical settings. Give equal emphasis to positive and negative findings of equal scientific merit. Also, provide a statement of

relevance indicating implications for clinical practice or health policy, avoiding speculation and overgeneralization. The relevance statement may also indicate whether additional study is required before the information should be used in clinical settings.

Conclusions and RelevanceConclusion: Prenatal diagnosis of retinoblastoma followed by

late preterm and near-term delivery facilitated eExpedient intervention and optimal outcomes were

facilitated by Prenatal molecular detection coupled with safe late preterm and near term delivery.

Word Count ( /350)

Introduction

Retinoblastoma, the most common primary ocular malignancy in children, is initiated when both

alleles of the RB1 tumor suppressor gene are inactivated in a precursor retinal cell, and progresses when

mutations in other specific genes occur.1,2 Both alleles may be lost only in the somatic cell from which the

tumor arises, however, in about 50% of children, a germline mutation predisposes to the development of

multiple retinal tumors during childhood, and other cancers later in life. Ten percent of patients display a

family history of disease, inheriting a family-specific mutation from a parent.1,3

Familial retinoblastoma tends to be discovered earlier during the first six months if properly

screened and cChildren with RB1 germline null alleles might may already have retinoblastoma tumor(s)

already at birth, which are often in the posterior pole of the eye where they threaten vision.4-8 Preservation

of vision with treatment of these small tumors is often difficult, because focal treatment in proximity to

the optic nerve and macula may damage vision. Most of these children will develop more tumors in the

first year of life, which tend to be located more peripherally. The preservation of vision with treatment of

these small tumors is often difficult, because focal treatment in proximity to the optic nerve and macula

may damage vision. The child is bilaterally affected in either simultaneous or sequential involvement. 4,7

Low penetrance mutations (10% of casesfamilys)3 and mosiacism can cause low burden of disease

withresult in fewer tumors and higher more unilaterally affected children9. The timing of first tumors after

birth has not been studied.

It is recommended that iInfants in families with a family history of retinoblastoma are recommended

to be screened as soon as possible after birth, and then repeatedly for the first few years of life, including

under anaesthesia, aiming at early diagnosis when tumors are small and easy to treat with ocular and

visual salvage.7,10 6,7,10

Preterm birth is defined as a live birth occurring before completion of 37 weeks gestation.

Subcategories of preterm birth include: extremely preterm (<28 weeks gestation), very preterm (28 to <32

weeks) and moderate-to-late preterm (32 to <37 weeks). Full term birth is generally defined as a live birth

occurring at 40 weeks gestation. Infants born after completion of 37 and before 39 weeks gestation are

technically considered early term. (8-9). 11,12 The main concern with late preterm or early term delivery is

its reported effect on neurological and cognitive development and later school performance ,13-15 but visual

dysfunction from a larger macular tumor can cause similar neurocognitive defects due to blindness16

despite never studied in a comparative manner.

We now present the first report of prenatal genetic screening and late preterm or early term delivery

for treatment of retinoblastoma for children demonstrated to carry the RB1 mutant allele of a parent. We

show that for children at 50% risk to inherit a germline RB1 mutant allele, prenatal molecular diagnosis

and preterm delivery allowed detection and treatment of small, early tumors, resulting in lower treatment

morbidity, better tumor control and visual outcome, compared to those children born full term at 39-40

weeks.

Methods

Study DesignResearch ethics board approval (REB approval number 1000028725) was obtained from The

Hospital for Sick Children (SickKids) for a. A retrospective review of medical records of all children with

familial retinoblastoma seen at SickKids, and born between 1 June 1996 and 1 June 2014, with relation

to a retinoblastoma proband. Data collected included: relation to proband; laterality of retinoblastoma in

proband; sex; gestational age at birth; age; pregnancy, prenatal abdominal ultrasound if done; delivery or

perinatal complications; type of genetic sample tested and result; penetrance of RB1 mutaion; timing age

and location of first and all subsequent tumor (s) in each eye; treatments used; number of anaesthetics;

International Intraocular Retinoblastoma Classification17 of each eye (IIRC); Tumor Node Metastasis

(TNM) staging for eyes and child18; treatment date ofduration last treatment; date of last follow-up; and

visual outcome at last follow-up in Snellen and LogMAR values. RB1 mutation testing was performed by

Retinoblastoma Solutions before 2013, and Impact Genetics after 2013, as previously described.19

The corrected age for gestation for each child was calculated (taking 39 weeks as full term). Eyes

with Vision threatening tumors were defined as in close toany tumor threatening the optic nerve or

macular area (IIRC17 Group B or worse, in posterior pole. Treatment burden was evaluated by an impact

score (Figure 1) based on i) duration of active treatment (time from diagnosis to last treatment), ii) use of

systemic chemotherapy or radiation, and iii) number of examinations under anesthesia (EUAs). Treatment

success was defined as avoidance of enucleation or external beam irradiation. Good visual outcome was

defined as visual acuity > 20/200 (>0 in 1-LogMAR scale) (cut edge of legal blindness). A blind child is

defined as best eye visual acuity < 20/200 (<0 in 1-LogMAR scale).

StatisticsBasic descriptive statistics (student t-test, chi square test and Fisher exact test) were used for all

comparisons between patients who underwent prenatal testing and preterm delivery (Cohort 1) and those

who were diagnosed post-natal (Cohort 2)ly.

Results

Patient DemographicsThe records of 21 familial retinoblastoma children were reviewed (11 males, 10 females)

(Supplementary Table 1). Diagnosis was by observation of prenatal retinoblastoma tumor (child #9) or

postnatal tumor (child #8) or postnatal testing for the parental RB1 mutation for Cohort 1: 6 were

delivered full term and 3 late preterm because of pregnancy-induced hypertension (#7), fetal ultrasound

evidence of retinoblastoma20 (#9) or spontaneous (#8). Twelve children (57%) (Cohort 2) were prenatally

diagnosed to carry an RB1 mutation and planned for late preterm or early term delivery: 3 were

spontaneously premature (#10, 13, 15; 28-37 weeks gestation) and 9 were referred to a high-risk

pregnancy unit for elective late preterm or early term delivery (36-38 weeks gestation).

Molecular diagnosisAll study subjects were offspring of retinoblastoma probands. Nineteen probands were bilaterally,

and 2 were unilaterally affected (mother #8, father #19). The familial RB1 mutations were previously

detected except for the unilaterally affected parent of #8, who was never testsed and understood that her

children had no risk since she was unilaterally affected. whose mutation was identified after finding her

son’s mutation as she was tested previously and considered to be a non germline mutation. Cohort 1

children (#1-9) were tested postnatal on blood; Cohort 2 children (#10-21) were tested prenatal on

amniocentesis at 16-33 weeks gestation.

Null RB1 mutations were present in 16 families; 5 had low penetrance RB1 mutations (whole gene

deletion #19; weak splice site mutations #15, 18, 21; and C712R19). No proband in this study was mosaic

for the RB1 mutation. All study subjects were eventually bilaterally affected. No tumors were detected at

birth (IIRC17 Group 0) in 7/15 (47%) infants and 17/30 (57%) eyes with null RB1 mutations, and in 5/5

(100%) infants and 10/10 (100%) eyes with low penetrance mutations (p=0.04* for patients, p=0.02* for

eyes; Fisher exact test) (Table 1).

The age at first tumor in either eye was significantly younger for those with null mutations (mean

89, median 74 days), than those with low penetrance mutations (mean 134, median 119 days) (P=0.04*,

Mann Whitney test). However, the gestational age at first tumor for those with null mutations (mean 77,

median 43 days) was not significantly different than for those with low penetrance mutations (mean 110,

median 81 days) (P=0.24*, Mann Whitney test). (Child #8 was excluded from these calculations as the

child was first examined at 3 months of age with Group A/D tumors, so age at first diagnosis is

unknown.)

Stage of Tumors at Birth

Thirty-three percent (3/9) of Cohort 1 and 75% (9/12) of Cohort 2 were free of visible tumor at birth

(Table 1a, Figure 1) (p=0.09). We assumed that child #8 had tumor at birth since he had a group D IIRC17

eye at 3 months of age. Of eyes, 79% (19/24) of Cohort 1 eyes were tumor-free at birth, compared to 33%

(6/18) of Cohort 2 eyes (p=0.026*, Chi Square test), excluding the IIRC17 Group A eye of child #8 (Table

1b).

All patients eventually developed tumors in both eyes regardless of whether their RB1 mutation was

full or low penetrance. Tumors emerged first in the macular and peri-macular region (IIRC17 Group B), as

previously described21. The median gestational age of diagnosis of 24 IIRC17 A eyes (< 3mm and away

from optic nerve and fovea) was 103 days, and of 16 IIRC17 B eyes (all threatening optic nerve and fovea,

6 also >3 mm) was 38 days, significantly younger reflecting the early development of visually threatening

tumors (Table 3?). Bilateral IIRC17 Group A eyes were present at initial diagnosis (optimal situation for

achieving good vision with minimally invasive therapy) in 2/9 (22%) children in Cohort 1 and 7/12 (58%)

in Cohort 2 (Table 2a). IIRC17 Group A was the initial diagnosis of 9/18 (50%) eyes in Cohort 1, and

11/22 (68%) eyes in Cohort 2 (p=0.15, Table 2b).

Treatment Course All infants were frequently examined from birth onwards (except child #8 who presented at age 3

months) as per the National Retinoblastoma Strategy Guidelines for Care.10 Cohort 1 patients were treated

with focal therapy (all), chemotherapy (4), stereotactic radiation (2), and enucleation of one eye (4)

(Supplementary Table 1, Figures 1, 3). Cohort 2 patients were treated with focal therapy (all); later

systemic chemotherapy (5), enucleation of one eye and stereotactic radiation (1) (Figure 1, 2). Successful

treatment by focal therapy alone (avoidance of systemic chemotherapy or EBRT) was possible in 2/9

(22%) of Cohort 1 and 7/12 (58%) of Cohort 2 (PVALUE?) (Table 3, , Figure 2).

The treatment burden showed no statistical significant difference between Cohort 1 and 2

(percentage of patients requiring systemic therapy and active treatment duration). The mean active

treatment duration was 579 days (0-2101 days) in Cohort 1 compared to 473 days (0-971 days) in Cohort

2.

REPLACE WITH (TREATMENT?) IMPACT SCORE……..AS DEFINED…….ABOVE

OutcomeThere were no adverse effects associated with induced or natural preterm or early term birth, and no

pregnancy, delivery or perinatal complications reported for any of the infants. Overall mean Follow up

(years) was overall mean 8 years ((median 5.6) years), Cohort 1 mean x (median y), and Cohort 2 mean x

years (median y) (Supplementary Table 1).

Treatment success92% of prenatally diagnosed mutation patients didn’t require Neither enucleation or external beam

irradiation were required (defined as success) in in comparison to 44% in of Cohort 1 and 92% of Cohort

2 the postnatally diagnosed mutation patients (P=0.046*, Fisher exact test). Kaplan Meier ocular survival

graph for Cohort 1 was 67% prenatal versus postnatal diagnosis is shown in figure it is estimated at 67%

in postnatal cohort compared to 92% in the prenatal cohort at 4 yearsfor Cohort 2 (Figure x). No child ne

of the cases developed extra ocular or metastatic disease; and all of them are alive and well at the end of

the studylast followup.

Visual outcomeVisual outcomes were good As per eyefor 56% of eyes in Cohort 1 and , 92% of eyes in Cohort 2 of

the prenatal detection and planned earlier delivery were of good visual outcome compared to 56% of eyes

in the postnatal detection; a difference found to be statistically significant (P=0.010*, Fisher exact test).

Children were legally blind (visual acuity less than 20/200 both eyes) in As per child, 22% of children in

the postnatal detection Cohort 1 and 0% of Cohort 2were considered blind (visual acuity less than 20/200

both eyes) in comparison none of the patients in the prenatal detection Cohort (p=0.174, Fisher exact test)

Treatment success (avoidance of enucleation and/or stereotactic radiation) accompanied with

resultant good vision was documented for 88% (21/24) eyes in the prenatal diagnosis cohort, compared to

50% (9/18) of eyes from the postnatal diagnosis cohort with significant difference (p=0.014*, Fisher

exact test) (Table 2b, Figure 1). A negative correlation was found between gestational age and final visual

outcome (r=-0.24) with better visual outcome in earlier deliveries. (Figure )

Discussion

In the first study of its kind, we report that prenatal molecular diagnosis of familial retinoblastoma

was possible, and that elective late-preterm or early term delivery allowed monitoring and treatment of

tumors as they emerged, resulting in better ocular and visual outcomes. Our cases illustrate well that the

risk of visual loss from delayed therapy for macular retinoblastoma tumors outweighs the risks associated

with induced late preterm delivery (Figure 1).

With the most current technologies, it is practical to identify 96% of the germline mutations in

bilaterally affected probands, and to identify the 10% of unilateral probands who carry a germline gene

mutation by studying the tumor .10 When the family's unique mutation is identified in the proband,

molecular testing of family members can determine who else carries the mutation and is at risk of

developing the disease. We reported on in utero testing that identified 12 mutation carriers, but did not

include the number of infants tested who did not inherit their family’s mutation. These infants can go to

full term and do not need examination to detect retinoblastoma tumors, since they are at no greater risk of

developing the disease than the general population. Without molecular information, repeated retinal

examination is essential for all first degree relatives until the age of 7 years, the first 3 years under general

anesthesia.10 Such repeated screening can be a great burden on patients and their families, finances, time

and resource utilization than the one-time-only molecular genetic testing that would conclusively

determine their risk.4 Also multiple studies22-24 showed the deleterious effects of multiple anesthesias in

early infancy on the neurocognitive development of the child.

Optimal treatment for retinoblastoma today includes combined therapeutic modalities to optimize

vision and minimize morbidity of treatment, while achieving tumor control; the relative ease or difficulty

of this task is affected by the age and the degree of tumor burden at diagnosis.25 Retinoblastoma treatment

in the first 3 months of life represents a challenge as most of the therapeutic modalities as systemic

chemotherapy, chemosurgery or radiation therapy can’t be used. The only treatment options at this age

are focal therapy (laser and cryotherapy) and periocular chemotherapy.26 Consistent with previous

reports,5 we showed that 62% of children with a germline gene mutation already have tumors at birth.

This percentage reduces to 31% when the germline mutation is prenatally detected and earlier delivery

(late preterm or early term) was planned.

The earliest tumors commonly involve the macular or paramacular region, dangerously risking loss

of central vision, while tumors that develop later on are usually peripheral, where they have less visual

impact.5,26-29 In our cohort, the risk of having a vision threatening tumor dropped from 39% to 17% by

prenatal mutation detection and planned earlier delivery.

Macular and paramacular tumors are difficult to manage by laser therapy or application of a

radioactive plaque, since these will damage the optic nerve or central vision. Systemic chemotherapy

effectively shrinks tumors such that focal therapy can be applied with minimal visual damage. In our

setting, the Toronto Protocol using high dose, short duration cyclosporine to counteract multidrug

resistance30,31 has allowed many retinoblastoma tumors to be treated with combination chemotherapy and

focal therapy without resorting to radiation. In our experience, infants as young as 30 days tolerate the

Toronto Protocol with cyclosporine A, 30,31 however systemic chemotherapy in neonates has other

associated morbidities. We recognize the conventional recommendation to reduce chemotherapy dosages

by 50%, particularly for infants in the first three months of life, to offset the immaturity of their liver and

kidneys,32-34 but note that this also breeds the optimal conditions for cancer cells to develop multidrug

resistance, making later recurrence difficult to treat. The development of periocular topotecan for

treatment of small-volume retinoblastoma35 also assisted in the number of patients that were able to be

treated by focal therapy alone, avoiding systemic modalities on the young infants, and a greater rate of

eye salvage with good visual outcome (Table 2).

Imhof et al7 in the Netherlands screened 135 children at risk of familial retinoblastoma 1-2 weeks

after birth without molecular diagnosis and discovered 17 cases of familial RB (13% of screened children

at risk) and 70% of them had RB in at least one eye at first examination and 41% of eyes had vision

threatening tumor to the macula. 41% (7/17) of patients had failure of treatment (EBRT or enucleation)

and one case of metastasis. 73.5% of eyes (27/34) had good visual acuity (defined by vision >20/100) that

will reduce to 56% (19/27) if we consider eyes with EBRT as failure. These results correspond to our

postnatal screening cohort showing similar results. On the contrary, the prenatal diagnosis and planned

earlier delivery cohort showed less vision threatening tumors (17%), less treatment failure (8%) and better

visual outcome (88%).

Early screening of at risk infants with positive family history as soon an possible after birth is the

internationally accepted model (whether intensive screening is utilized or not).7,36 Here we propose the

prenatal screening of the known mutation in the probands by amniocentesis in the second half of

pregnancy where the risks of miscarriage are minimal (0.1-1.4%).37,38 For those who are confirmed to

have the mutation; planned late preterm or early term delivery at 36-38 weeks of gestation and as a result

a smaller tumor with less macular involvement leading to better visual outcome is anticipated. there was

no difference between the two Cohorts in the treatment burden and the systemic chemotherapy usage as

we didn't change the treatment course by early delivery but changed the treatment outcome by catching

the tumors at earlier stage also multiple focal treatments in both Cohorts were for small new tumors that

occurred due to the nature of the germline tumor and not related to early delivery or prenatal detection.

The main concern with late preterm or early term delivery is its reported effect on neurological and

cognitive development and later school performance (30-32),13-15 but visual dysfunction from a larger

macular tumor can cause similar neurocognitive defects due to blindness16 despite never studied in a

comparative manner. So, earlier delivery must be discussed thoroughly through the team of neonatologist

ophthalmologist and oncologist to reach the best timing for better outcome25 so rather than focusing on

the combination of treatments to tackle burdensome disease, we showed safe preterm delivery resulted in

a decreased tumor burden at birth that was significantly easier to treat (Figure 2, Table 2). Safe preterm

delivery resulted in more infants born tumor-free, facilitating frequent surveillance to detect tumors as

they emerged, and focal therapy of smaller, easier to control masses, causing minimal damage to vision

(Figure 1,2).

Counseling on reproductive risks is imperative for families affected by retinoblastoma even in

unilateral probands. In developed countries; where current therapies result in extremely low mortality,

most retinoblastoma patients will survive to have children. Prenatal diagnosis in the published literature

has been cited as useful in preimplantation genetics (to ensure an unaffected child) or to inform parents

who wish to terminate an affected pregnancy39. There have been two prior reports indicating pre-natal

molecular testing for retinoblastoma; in one, the fetus sibling of a proband was found not to carry the

sibling’s mutation40, and in the other, 3 of 5 tested fetuses of a proband were terminated once molecular

testing confirmed the mutation in the offspring.41 We are first to report that elective safe late-preterm

delivery of prenatally diagnosed infants with retinoblastoma results in improved outcomes. It is our

experience that for retinoblastoma survivors and their relatives who understand fully the underlying risks,

they are more interested in early diagnosis to optimize options for therapy in affected babies rather than to

consider termination of pregnancy. We also surmise that since germline mutations predispose to future,

second cancers in affected individuals, perhaps it is worth investigating the role of cord blood banking

infants that are prenatally molecularly diagnosed with retinoblastoma. A long-term study could show the

impact of such an approach to patient outcomes in their adulthood. We conclude that since infants with

familial retinoblastoma are likely to develop vision-threatening macular tumors, prenatal molecular

diagnosis and safe, late-preterm delivery will increase the chance of good visual outcome with decreased

treatment associated morbidity.

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3. Lohmann DR, Gallie BL. Retinoblastoma. In: Pagon RA, Adam MP, Ardinger HH, et al., eds. GeneReviews(R). Seattle (WA)2000.

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