Abstract 431P
Background
JCOG1007 trial failed to demonstrate the superiority ofprimary tumor resection (PTR) before chemotherapy (CTX) to CTX alone in overall survival (OS) of colorectal cancer (CRC) patients (pts) with asymptomatic primary tumor and synchronous unresectable metastases due to futility at the first planned interim analysis (median follow-up, 22.0 months, cut-off date for the analysis June 5, 2019). The hazard ratio (HR) for OS was 1.10, and the predictive probability that the OS of PTR plus CTX would be superior to that of CTX alone was as low as 12.3%. We report updated results with a cut-off date of Nov 2019.
Methods
Eligibility criteria included colon and upper rectal adenocarcinoma, cT1-4 without involvement of other organs, presence of three or less unresectable factors confined to either liver, lungs, distant lymph nodes, or peritoneum, aged 20-74, no symptoms due to primary tumor and PS 0-1. Patients were randomized to either PTR followed by CTX or CTX alone. CTX regimens were declared before study entry; options included mFOLFOX6 plus bevacizumab or CapeOX plus bevacizumab. The primary endpoint was the OS. The planned sample size was 140 pts per arm, with one-sided alpha of 5%, and 70% power detecting a median OS difference of 8 months (24 months vs. 32 months).
Results
Between Jun 2012 and Sep 2019, 165 patients were randomized. 81 pts were allocated to PTR plus CTX, and 84 pts to CTX alone. At the data cut-off date, 56% of required events (126/227) were observed, with median follow-up for all randomized patients of 22.1 months, median OS was 25.9 months (95% CI 19.9-31.7) in PTR plus CTX and 26.4 months (95% CI 21.9-32.1) in CTX alone. The HR of OS was 1.11 (95% CI 0.78 – 1.58) and the superiority of PTR plus CTX was not demonstrated (one-sided p = 0.72). Median PFS was 10.4 (8.3-13.4) with PTR plus CTX and 12.1 (9.5 – 13.2) with CTX alone (HR 1.12 [0.81-1.55]).
Conclusions
The updated results confirmed that PTR followed by CTX has no survival benefit over CTX alone. PTR is not recommended for CRC patients with asymptomatic primary tumor and synchronous unresectable metastases.
Clinical trial identification
UMIN000008147.
Editorial acknowledgement
Legal entity responsible for the study
Japan Clinical Oncology Group.
Funding
National Cancer Center Research and Development Fund and Grants-in-Aid for Cancer Research from the Ministry of Health, Labour and Welfare of Japan.
Disclosure
Y. Kanemitsu: Honoraria (self): Chugai Pharma; Advisory/Consultancy: Coviden; Honoraria (self): Ethicon; Honoraria (self): Intuitive Surgical. All other authors have declared no conflicts of interest.