Tumor shrinkage during chemoradiation in locally advanced cervical cancer patients: prognostic significance, and impact for image-guided adaptive brachytherapy

Publication date: Available online 18 June 2018
Source:International Journal of Radiation Oncology*Biology*Physics
Author(s): Antoine Schernberg, Sophie Bockel, Pierre Annede, Ingrid Fumagalli, Alexandre Escande, Fabien Mignot, Manon Kissel, Philippe Morice, Enrica Bentivegna, Sebastien Gouy, Eric Deutsch, Christine Haie-Meder, Cyrus Chargari
ObjectiveTo study the prognostic value of gross tumor volume (GTV) shrinkage and its dosimetric implication in a large cohort of cervical cancer patients receiving definitive chemoradiotherapy plus image—guided adaptive brachytherapy (IGABT).Materials and MethodsClinical records of consecutive patients treated in our Institution between February 2004 and November 2015 by concurrent chemoradiotherapy (45Gy in 25 fractions +/- lymph node boosts) followed by a magnetic resonance imaging (MRI)-guided adaptive pulse-dose rate brachytherapy were included. The prognostic value of GTV and its evolution after chemoradiotherapy were examined first on initial staging MRI and then at time of brachytherapy. All measures and measurement cutoff were selected using time-dependent Area Under the Curve for 3-year progression-free survival (PFS).ResultsGTV evolution between diagnosis and the time of brachytherapy was assessed in 247 patients. After chemoradiotherapy, complete response was observed in 75 patients (28%). Optimal cutoffs were GTV=55cc at diagnosis, GTV=7.5cc at brachytherapy, and GTV reduction ≥90%. All patients with volume above or reduction below these cutoffs had significant reduced overall survival (OS), PFS, local control (LC) and distant metastasis control (DMC) (p<0.001). Patients with anemia at diagnosis had a lower tumor volume response rate (p<0.001). In multivariate analysis, incorporating the FIGO stage, N+ stage, anemia, and dosimetric parameters for IGABT, GTV optimal volume reduction after chemoradiotherapy was independently associated with improved OS, PFS, LC, and DMC (p<0.001).ConclusionThese results could provide a rationale for dose de-escalation studies in brachytherapy for patients displaying optimal GTV volumetric reduction after chemoradiotherapy, and may reinforce the need for dose escalation in poor responding patients.

Teaser

The prognostic value of GTV and its evolution after chemoradiotherapy, assessed in 247 patients were examined first on initial staging MRI and then at time of brachytherapy. In multivariate analysis, GTV optimal volume reduction was independently associated with improved overall survival and local control (p<0.001). Patients with optimal GTV reduction had no significant benefit from dose escalation D90 CTVHR ≥80Gy (p>0.3) while patients without optimal GTV reduction may have (p<0.05).


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