Differences in survival for metastatic colorectal cancer patients by lines of therapy received.

Abstract

e14016 Background: Improvements in survival for advanced-stage CRC patients who receive chemotherapy have been reported. We compared survival rates for patients with 3+ vs. <3 lines of therapy. Methods: Adult patients with a diagnosis of CRC between 01/01/05 and 05/31/10 were identified from the Impact Intelligence Oncology Management (IIOM) registry. Patients with either stage 4 CRC at original diagnosis or development of metastasis were included. Registry data included original stage and date of diagnosis. Linked healthcare claims from the Life Sciences Research Database, a large US health insurance database affiliated with OptumInsight, were used to identify lines of therapy after metastases and patient characteristics. Death data were obtained from the Social Security Administration’s master death file. Patients were categorized by number of lines of therapy received (0, 1, 2, 3+) and original stage at diagnosis (0-2, 3, 4, unknown). Survival following metastases was evaluated using Cox proportional hazards models controlling for lines of therapy received, stage, and other patient characteristics. Results: 598 patients, followed for a mean of 653 days after becoming metastatic, were included. Mean unadjusted length of follow-up was lowest among patients who received no chemotherapy (516 days) or only 1 line (511 days), and increased to 627 days for those with 2 lines and 930 days for those with 3+ lines. However, multivariate analysis indicated that patients with 3+ lines had comparable survival vs. those with 0 (HR=0.79), 1 (HR=1.59), or 2 (HR=1.15) lines of therapy (p>0.05 for all comparisons). Compared to patients who presented with stage 4 CRC, those who progressed from stage 0-2 (HR=1.22), stage 3 (HR=0.83), or unknown stage (HR=1.18) had similar survival after metastases (p>0.05 for all comparisons). After excluding 94 patients who didn’t receive chemotherapy, patients treated with an oxaliplatin-based regimen (HR=1.28; p=0.24) in first line had similar survival compared to patients treated with an irinotecan-based or anti-EGFR regimen in first line. Conclusions: Lines of therapy received and initial stage were not associated with survival after development of metastases.