Impact of tumor location on outcomes in patients with metastatic colorectal cancer (mCRC) treated with regorafenib (REG): An interim analysis from the prospective, observational CORRELATE study

3567 Background: The anatomical location of the primary tumor has been associated with outcomes in mCRC, with left-sided (L) tumors having a better prognosis than right-sided (R) tumors and location predicting response to treatment. REG significantly improved overall survival (OS) vs placebo in patients with mCRC who progressed on available treatments in 2 randomized, phase 3 trials (CORRECT, CONCUR). This exploratory analysis evaluated outcomes by primary tumor location in patients with mCRC treated with REG in the CORRELATE study. Methods: CORRELATE is an observational study designed to characterize the safety and effectiveness of REG in unselected patients for whom the decision to treat with REG has been made by the treating physician according to the local health authority label. Primary L tumors were located in the rectum, splenic flexure, recto-sigmoid, descending, or sigmoid colon; R tumors were in the appendix, hepatic flexure, cecum, or ascending colon. OS was analyzed by the Kaplan–Meier method and comparisons were by a 2-sided log-rank test. Results: Primary tumor location was available for 474 patients (L, n = 375 [79%]; R, n = 99 [21%]). Median time from initial diagnosis and from diagnosis of metastatic disease to treatment was slightly longer in L vs R tumors (32 vs 28 months and 25 vs 22 months, respectively). A higher proportion of patients with L vs R tumors, respectively, had prior radiotherapy (34% vs 13%) and a lower proportion had a partial colectomy (40% vs 70%). Best response to prior systemic therapy (partial response + stable disease) was 72% for L tumors and 68% for R tumors with a median duration of treatment of 26 and 22 months, respectively. REG treatment duration was similar in the 2 groups. Median OS (95% CI) was 6.7 months (6.1, 7.7) for L tumors vs 6.3 months (4.9, 8.1) for R tumors (P = 0.3); median progression-free survival (95% CI) was 2.8 months (2.6, 3.0) vs 2.6 months (2.4, 3.0) (P = 0.5), respectively. Conclusions: Interim results from this observational study suggest that OS is similar in patients with R and L tumors treated with REG. Clinical trial information: NCT02042144.