617P - Predictive and prognostic impact of primary tumor location on sequential treatment with regorafenib and trifluridine/tipiracil at third line and beyond in metastatic colorectal cancer: A real-world multicenter retrospective analysis

Background

Primary tumor location (PTL) has a confirmed prognostic and predictive effect in colorectal cancer first-line therapy, but its effect during the refractory stage is uncertain.

Methods

Clinical data of patients diagnosed with mCRC who received regorafenib (R) and/or trifluridine/tipiracil (T) between July 2012 and March 2022, were collected from 13 Italian cancer institutes retrospectively. Patients were divided into two groups based on whether they presented right (RCC) or left colon cancer (LCC). Our aim was to evaluate the impact of PTL on overall survival (OS), progression-free survival (PFS), and disease control rate (DCR) in R or T treatment groups in a real-world setting.

Results

866 patients were included. Of these, 146 (16.8%) received T followed by R (T/R), 116 (13.3%) the reverse sequence (R/T), 325 (37.5%) received T alone, and 279 (32.5%) R alone. M/F=504/362; median age was 68 (30-87); median duration of follow-up was 7.2 months. We focused on patients who were sequentially treated with T and R and with the reverse sequence. Among 262 patients, we identified 52 RCC and 94 LCC in the T/R group, compared to 34 RCC and 82 LCC of the reverse sequence. In LCC patients, we found an OS advantage, with a median of 16.8 months in the R/T group vs. 14.7 months in the T/R group (p=0,0569). PFS was statistically significantly longer for the LCC patients who received the R/T sequence (11.7 vs. 9.1 months of the reverse sequence) (p=0,0022). PTL had no effect on disease control rate: we identified the best DCR (34.8%) in LCC patients in both T/R and R/T sequences (p=0.4904).

Conclusions

In our real-world analysis, PTL appears to have a prognostic impact in patients with refractory metastatic colorectal cancer who have received R and T in a sequential way. In fact, treatment with the sequence R/T seemed to us significantly correlated with better outcomes in terms of OS and PFS in patients with left-sided primary cancer. In terms of DCR, we cannot state that PTL is a predictive factor. We advise conducting additional research with sequential R and T treatment. Prospective clinical investigations, we believe, are required in this context.

Clinical trial identification

Editorial acknowledgement

Legal entity responsible for the study

C. Signorelli.

Funding

Has not received any funding.

Disclosure

All authors have declared no conflicts of interest.