Patterns of Treatment Sequences in Chemotherapy and Targeted Biologics for Metastatic Colorectal Cancer: Findings from a Large Community-Based Cohort of Elderly Patients

BACKGROUND: Over the last decade, multiple chemotherapies/targeted biologics have been approved for metastatic colorectal cancer (mCRC). However, evidence is limited with regards to the array of treatments received by mCRC patients. OBJECTIVE: This study examines treatment sequences (first- to third-line chemotherapy/targeted biologics) and the factors associated with first-line targeted biologics and common treatment sequences for elderly mCRC patients treated in a community setting. METHODS: A retrospective cohort study was conducted in mCRC patients diagnosed from January 2004 through December 2009 using the Surveillance, Epidemiology and End Results Medicare-linked database. The treatment sequences administered to elderly mCRC patients were empirically identified. RESULTS: Of 4418 mCRC patients who received treatment, 1370 (31 %) received first, second, and third line; 1164 (26 %) received first and second line; and 1884 (43 %) received only first line. The most common first line of treatment for mCRC patients was 5-fluorouracil/leucovorin + oxaliplatin (FOLFOX) + bevacizumab (23 %) and FOLFOX (23 %). 5-fluorouracil/leucovorin + irinotecan (FOLFIRI)-based regimens were commonly (22 %) administered in second line. The most common treatment sequence was first-line oxaliplatin or irinotecan followed by second-line oxaliplatin or irinotecan + bevacizumab followed by a third-line targeted biologic. Of patients who received first-line therapy, 47 % also received a targeted biologic, and the factors associated were age, comorbidity score, cancer site, geographic location, and year of diagnosis. CONCLUSION: Elderly mCRC patients receive a multitude of treatments in various sequences. Further exploration of the comparative effectiveness of treatment sequences may yield important information for improving mCRC survival. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s40801-015-0059-9) contains supplementary material, which is available to authorized users.