413P - Primary tumor resection (PTR) in metastatic colorectal cancer (mCRC) patients (pts) treated with upfront chemotherapy (CT) + bevacizumab (BEV): A pooled analysis of TRIBE and TRIBE2 studies

Background

In mCRC treatment, the management of primary tumor still represents a complex and challenging issue for oncologists, especially in case of asymptomatic pts and during therapy with antiangiogenic drugs. The aim of the present analysis was to focus on the role of PTR in a pooled analysis of two randomized phase III studies (TRIBE and TRIBE2).

Methods

This pooled-analysis included pts enrolled in the phase III TRIBE (NCT00719797) and TRIBE-2 (NCT02339116) studies that compared upfront FOLFOXIRI + BEV to FOLFIRI or FOLFOX + BEV, respectively. Association between PTR and adverse events experienced during 1^st-line therapy was analyzed by χ2 test or Fisher’s exact test, as statistically appropriate. Survival curves were estimated with Kaplan-Meier method and compared by log-rank test.

Results

In our analysis, 1175 pts were included. Of them, 680 (58%) underwent PTR at baseline. Pts with resected primary tumor had more often a metachronous disease (p <0.001), a right sided colon cancer (p = 0.001), an ECOG PS 0 (p = 0.025), and a liver only metastatic disease (p = 0.006); moreover, they had more frequently received an adjuvant CT (p <0.001). Better progression-free survival (PFS) and overall survival (OS) were observed in pts who underwent PTR compared to those with unresected primary: 11.5 vs. 10.0 months (p <0.001) and 28.2 vs. 22.4 (p <0.001), respectively. In multivariate analysis, PTR was confirmed as an independent prognostic factor for better PFS (p = 0.05) together with triplet CT + BEV (p <0.0001), ECOG PS 0 (p <0.0001), RAS/BRAF wild-type cancer (p = 0.01) and liver-only metastatic disease (p = 0.02). About adverse events during 1^st-line CT + BEV, in the group of pts with resected vs unresected primary tumor, diarrhea was more often observed (p = 0.028), whereas anemia (p = 0.044), perforation (p = 0.008), and gastrointestinal and surgical serious adverse events (p <0.0001) were less frequent. No statistically significant differences were noted in incidence of bleeding (p = 0.427).

Conclusions

PTR impacted positively on prognosis of mCRC pts, and it was associated with less incidence of serious gastrointestinal and surgical adverse events during upfront CT plus BEV.

Clinical trial identification

Editorial acknowledgement

Legal entity responsible for the study

The authors.

Funding

Has not received any funding.

Disclosure

All authors have declared no conflicts of interest.