chest wall toxicity in sabr : predictors and contouring of chest wall

Dr Vimoj J. Nair, SABR Fellow, Department of Radiation Oncology, The Ottawa Hospital Cancer Centre, ON, Canada

Chest Wall Toxicity In Stereotactic Ablative Body

Radiotherapy (SABR): Current Evidence

Dr Vimoj J NairSABR Fellow

http://www.ottawahospital.on.ca/wps/portal/Base/TheHospital/!ut/p/c5/04_SB8K8xLLM9MSSzPy8xBz9CP0os3gXC3MPd08TIwMLXxcXA89AZwt3Jw8XQwMDE_2CbEdFACuHzB0!/

Dr Vimoj J. Nair MBBS MD Department of Radiation Oncology, The Ottawa Hospital Cancer Centre, ON, Canada

Introduction

• Despite the increasing popularity of SBRT, concern persists regarding late normal tissue toxicity.

• Reports of increased frequency of rib fracture and chest wall pain after SABR treatment of peripherally located lesions compared to conventionally fractionated therapy


MAJOR CLINICAL TRIALS NO RIB CONSTRAINTS


Incidence of Chest wall Syndrome/Toxicity

Modality Incidence

Conventional radiotherapy 1-6%

Hypofractionated RT [Overgaard et al]

19%

SABRSevere chest wall pain 5-33%

rib fractures – 2-21%

Thoracotomy ~30-50%,

VATS None / mild 63%

Severe 6%

McKenna RJ, Houck W, Beeman Fuller C. Video-assisted thoracic surgery lobectomy: experience with 1,100 cases. The Annals of Thoracic Surgery, February 2006. 81(2):421-426.


Chest wall toxicity

• Dermatologic (erythema, ulceration and fibrosis)

• Chest wall pain – focal or neuropathic

• Rib fracture– symptomatic and

asymptomatic


Spectrum of CW toxicity

CTCAE v 3.0

Grade

Short name

1 2 3 4 5

Pain Mild pain not interfering with function

Moderate pain, pain or

analgesics interfering with

function, but not with ADL

Severe pain, pain or

analgesics severely

interfering with ADL

Disabling -

Fracture Asymptomatic, radiographic findings

only (e.g. Asymptomatic rib

fracture on plain x-ray, pelvic insufficinecy, fracture on MRI, etc)

Symptomatic, but not

displaced; immobilization

indicated

Symptomatic and displaced or open wound with bone exposure;

operative intervention

indicated

Disabling, amputation indicated

Death


• 61% Rib # asymptomatic, revealed ONLY through imaging• 19% of all episodes of CW pain coincided with a documented

rib fracture.

Andolino et al, IJROBP 2011


CHEST WALL CONTOURING


Studies Pros/Retr

o

N chest wall

{CW} lesion

definition

Chest wall Contouring

criteria

Dose fractionati

on

Median f/u

{mths}

Chest wall [Toxicity Pain and Fracture]

rates

Median Time of toxicity {mths}

1 Dunlap et al, Virginia/Colorado,

ASTRO 2008, IJROBP 2010

Retro

60 < 2.5 cm from CW OR Dmax >20 Gy

CW 3cm 60 Gy/30Fr

11 21% pain and 8% fractures

7.1

2 Voroney et al, Alberta,/PMH J

Thor Oncol 2009

Retro

42 NA NA 54-60 Gy /3 Fr

NA 21% rib #, 26% CW pain 1.5 to

5% rib .

17

3 Petterssen et al, Sweden,

Radiother Oncol, 2009

Retro

33 NA Individual Ribs

45Gy/3Fr 29 13 rib fractures 8.8

4 Welsh et al , MDACC, Astro 2009,

IJROBP 2010

Retro

265 (268 TX)

NA All soft tissue minus lungs

50Gy/4Fr 10.3 22% pain, 3% fractures

6

5 Stephans et al , Cleveland, IJROBP

2011

Retro

134 NA Unspecified arc of tissues

60Gy/3 18.8 7% chest wall toxicity ; # not

reported

8.8

6 Andolino et al, Indiana, IJROBP

2011

Retro

347 [203 CW]

CW within ≥

50% isodose

CW3cm + ribs

separately

54-60 Gy/ 2-5 Fr

19 CW 21%, NCW 3.5%

10% CW required

Prescription

8

7 Mutter et al, MSKCC, NY, 2011

Pros 126 NA CW2cm, CW 3cm

compared; 1.2 cm sup/inf

40-60Gy/3-5Fr

16 4% rib #, 51% grade 2 pain

9

Studies on chest wall toxicity in SABR

CW2cm correlated with toxicity



• 2-cm expansion in the LAT/ANT & POST from the lung edges

• Exclude lung volume, mediastinal soft tissue, and anterior vertebral body

• Include intercostal muscles and exclude other muscles and skin.

• To avoid cumbersome contouring of the entire rib/chest wall, one can define the rib contours arbitrarily within a 3-cm limit from the PTV.



2cm


CHEST WALL TOXICITY PREDICTORS AND PARAMETERS: CURRENT EVIDENCE


Studies Pros/Retro

N chest wall {CW} vs NCW

lesion definition

Dose fraction

ation

1 Dunlap et al, Virginia/Colorado,

ASTRO 2008, IJROBP 2010

Retro 60 < 2.5 cm from CW OR Dmax

>20 Gy

60 Gy/30Fr

•Volume threshold of 30 cm3 •Recommended V30Gy < 30cc

2 Voroney et al, Alberta,/PMH J

Thor Oncol 2009

Retro 42 NA 54-60 Gy /3 Fr

•Median dose to # site 46-50 Gy

3 Petterssen et al, Sweden, Radiother Oncol,

2009

Retro 33 NA 45Gy/3Fr •Risk of # : 5% if D2CC =27Gy ; 50% if D2CC = 50Gy • 37 % if V40 Gy >2cc

4 Welsh et al , MDACC, Astro 2009,

IJROBP 2010

Retro 265 (268

TX)

NA 50Gy/4Fr •V30 Gy relevant •BMI >29 Doubles risk of c/c pain

5 Stephans et al , Cleveland,

IJROBP 2011

Retro 134 NA 60Gy/3 •V30 ≤ 30cc & V60 ≤ 3cc ~ ≤10-15% risk of late chest wall toxicity

6 Andolino et al, Indiana, IJROBP

2011

Retro 347 [203

CW]

CW within ≥ 50% isodose

54-60 Gy/ 2-5

Fr

•10% if V30 Gy ≥ 15 cc and V40 Gy ≥ 5cc•30% risk of toxicity when V30 ≥ 40cc & V40 ≥ 15 cc. •Dmax >50Gy significant increase in pain and fracture.

7 Mutter et al, MSKCC, NY, 2011

Pros 126 < 2.5 cm from CW

40-60Gy/3-

5Fr

•CW2 V30 ≥ 70cc, significant correlation with Grade 2 CW pain

Studies on chest wall toxicity in SBRT


• Prospective . 126 pts with primary, clinically node-negative NSCLC received 40–60 Gy / 3-5 # of SBRT

• DVH dosimetry of CW3cm vs CW2cm.

• Results: Median f/u 16 months, the 2-year estimated actuarial incidence of Grade 2 CW pain : 39%.

• Median time to onset of Grade 2 CWpain was 9 months.

• CW2cm consistently enabled better prediction of CW toxicity.

• CW volume receiving 30 Gy (V30) as one of the strongest predictors (p < 0.001).

• Physical dose of 30 Gy was received by >70cc -significant correlation with Grade 2 CW pain (p =

0.004) so keep V30<70cc

• Only 19/126 pts met previous cutoff V30<30Gy


VUmc DATA

• Prospective • 500 pts with T1-2N0 (2003-2009)• Median f/u 33 Months

Chest wall toxicity following risk-adapted stereotactic radiotherapy for early stage lung cancer E. M. Bongers, C. J. Haasbeek, F. J. Lagerwaard, B. Slotman, S. Senan


• Results will be presented in ASTRO 2011/IJROBP (in press)


Conclusion

• Tumor size and distance from chest wall is correlated to risk of chest wall toxicity.

• Contour 2cm expansion upto 3 cm cranio-caudally.

• V30Gy : useful as a guideline for estimating the likelihood of chest wall toxicity– <70cc optimum– <30 cc ??? feasible

• Dmax 50Gy ~ above which pain and fracture increase.

• Longer f/u needed – Late toxicity


CONCLUSION: STRATEGIES FOR CHEST WALL TOXICITY MANAGEMENT

• Reducing the total tumor dose

• ? Risk adapted fractionation/ increase no of Fr

• Increasing the number of noncoplanar beams• Patient selection is vital• Tumor coverage and other normal tissue

constraints should NOT be compromised.


HOWEVER THERE ARE SOME TOXICITIES THAT WE CAN’T AVOID


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chest wall toxicity in sabr : predictors and contouring of chest wall

Education

chest wall toxicity

pain mild pain

fibrosis chest wall

asymptomatic rib fracture

episodes of cw pain

sabr severe chest wall

rib fractures

documented rib fracture