impact of overall treatment time and dose escalation on local control in locally advanced cervical...
TRANSCRIPT
Impact of overall treatment time and dose escalation on local control in locally advanced cervical cancer
treated by chemo-radiation and image-guided adaptive brachytherapy
Renaud Mazeron# 57608 (abstract 1827)DPD 06. Digital Poster Discussion - GYN
GUSTAVE ROUSSY Mazeron R ASTRO GYN PD6
Background
Image-guided adaptive brachytherapy (IGABT) is becoming a standard in the treatment of locally advanced cervical cancer
Local control rates reported in monocentric series are high, about 90% (Pötter et al., Nomden et al., Mazeron et al.)
Objective: Identifying the prognosis factors for local control in a cohort a patients treated with concomitant chemo-radiation followed by IGABT
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GUSTAVE ROUSSY Mazeron R ASTRO GYN PD6
Material and Methods
Consecutive patientsLocally advanced cervical cancer (IB2-IVA)Curative intentGEC-ESTRO recommendations appliedAt the beginning of our experience, patients with
stage I-II lesions went throughout post radiation hysterectomy. For them, local failure was considered in case of macroscopic remnant (1 cm in width) or in case of local relapse during their follow-up.
In patients treated with definitive radiotherapy, local failure was defined as any relapse in the cervix, vagina, parametium, or uterus during the follow-up.
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GUSTAVE ROUSSY Mazeron R ASTRO GYN PD6
Note: Post radiation hysterectomy
Patients included to warrant consecutive patientsTreated at the beginning of our experience, with
doses lower than nowadays. Important to study dose-response effect.
1cm as cutoff: strong prognosis factor reported in the literature
Prognostic factors were analyzed using a linear regression model. Additional dose / effect correlations were done using the logit model.
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Statistics
GUSTAVE ROUSSY Mazeron R ASTRO GYN PD6
Results
Tumor width at diagnosis (> 5 cm), initial tumor volume (>50 cm3), D90% of the HR-CTV (high risk, > 85 Gy), the HR-CTV volume (> 30 cm3) and overall treatment time (OTT, > 55days) appeared significantly correlated with local control in univariate analysis, but treatment duration remained the only significant factor in multivariate analysis (p=0.022, odds ratio=2.44).
Logit models: positive for OTT, D90 HR and IR-CTV
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GUSTAVE ROUSSY Mazeron R ASTRO GYN PD6
Figure 1
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GUSTAVE ROUSSY Mazeron R ASTRO GYN PD6 7
GUSTAVE ROUSSY Mazeron R ASTRO GYN PD6
Take home messages
OTT remains important with a loss of 0,5% of local control probability beyond 55 days
This is less than reported 10 years ago (1%) but significant
A dose-response for both HR-IR CTV has been shown similar to that demonstrated by Dimopoulos et al. for HDR brachytherapy, supporting the dose escalation concept (see oral presentation by Kari Tanderup)
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