ESTRO38 Congress Report

Clinical

2. RECTAL Organ preservation after chemoradiotherapy for rectal cancer: 5-year results of the GRECCAR2 trial (E38-1982)

Véronique Vendrely, Philippe Rouanet, Jean-Jacques Tuech, Alain Valverde, Bernard Lelong, Michel Rivoire, Jean-Luc Faucheron, Jafari Mehrdad, Guillaume Portier, Eric Frison, Julien Asselineau, Quentin Denost, Eric Rullier

Bordeaux University Hospital (France) and the GRECCAR

Context of the study Rectal preservation, using a local excision (LE) or an observational strategy has been increasingly debated for good responders after neoadjuvant CRT to decrease surgical morbidity and increase quality of life. The French GRECCAR 2 trial was the first phase III trial investigating this strategy. Although LE was not superior to TME due to a high rate of completion surgery, which increasedmorbidity and side-effects at 2 years, this trial highlighted the good pathological response with no positive mesorectal node. Further follow-up was needed to validate the oncological safety of the strategy: here are presented the 5-year results FromMarch 2007 to September 2012, 148 patients clinically good responders after CRT for T2T3 rectal cancer, size ≤ 4 cm, were randomized in 74 LE vs. 74 TME, 3 were excluded and 145 analyzed. In the LE group, 26 had a completion TME for ypT2-3, which was part of the protocol. Kaplan-Meier and Cox regressions were used to estimate and compare local and metastatic recurrence and survival at 5 year What were the three main findings of your research? 1. Overall (84% vs. 82%; HR=0.92, p=0.845) and disease- free (70% vs. 72%; HR=0.87, p=0.682) survivals were not different between the LE and the TME groups at 5 years 2. Moreover, there was no difference either regarding local recurrence (7% vs. 7%; hazard ratio (HR)=1.41, p=0.599) nor metastatic recurrence (18% vs. 19%; HR=0.86, p=0.734) between the LE and the TME group at 5 years. 3. Interestingly, in both groups themetastatic risk remained high (almost 20%) even for good responders with initial small tumors such as T2-3 rectal cancers less than 4 cm in diameter. What impact could your research have? The 5-year results of the GRECCAR 2 trial confirm the oncological safety of the rectal preservation strategy in a selected population of good responders after RCT for small T2-3 rectal cancers. Further questions have been raised regarding evaluation, accurate selection of patients and place of complementary TME that lead to build a new randomized trial: GRECCAR 12. This randomized phase 3 trial is designed to test the hypothesis that adding neoadjuvant chemotherapy to CRT will optimize the tumor response and increase the number of patients who will benefit from organ preservation. Moreover, given the need for improved response evaluation, this trial will focus on MRI response evaluation and its correlation with clinical and pathological response. of the GRECCAR 2 trial. Overview of abstract

Is this research indicative of a bigger trend in oncology? Most of ongoing trials focus currently on the optimization of tumor response in order to increase the chance of rectal preservation. There are several options to increase the response rate: radiotherapy dose escalation using contact-therapy or HDR brachytherapy, intensification of concomitant chemotherapy, neoadjuvant chemotherapy before irradiation or additional chemotherapy after irradiation. Finally, accurate evaluation of tumor response remains a major issue regarding rectal preservation.

CLINICAL | Congress report

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