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INTRODUCTION: Patterns and trends in the use of modern chemotherapeutic regimens, primary tumor resection, and the relative timing of chemotherapy and resection in older patients with stage IV colorectal cancer (CRC) have not been evaluated.
METHODS: We used Texas Cancer Registry-Medicare linked data (2001-2007) to identify patients 66 and older with stage IV colorectal cancer (N=3,343). Time trends in resection of the primary tumor and receipt of chemotherapy were determined. We defined chemotherapy regimens as "standard" (5-fluorouracil (5-FU)/leucovorin (LV)) or "modern" (oxaliplatin or irinotecan plus 5-FU/LV or bevacizumab).
RESULTS: The mean age of patients was 76.9 ± 7.2 years, 53.3% were female, and 80.9% were white. 87.7% of cancers were in the colon and 25.7% of tumors were poorly differentiated histologically. Liver metastases, lung metastases, and carcinomatosis were documented in 72.8%, 32.3% and 36.3% of patients, respectively. 37.4% were treated with both chemotherapy and resection, 26.4% had resection only, 11.8% had chemotherapy only, and 24.4% had no treatment. Resection of the primary tumor was performed in 63.8% of patients, of which 24.3% were emergent. After excluding emergent procedures, resection decreased from 59.9% to 53.0% between the early (2001-2002) and late (2006-2007) study periods (P=0.007). In patients undergoing elective resection and chemotherapy (N=1015), resection was done prior to chemotherapy in 88.5% of patients. 30-day post-operative mortality for all patients undergoing resection of the primary tumor was 13.5% and 10.7% for elective resection. Chemotherapy was given to 49.2% of patients and was stable over time. However, in patients who received chemotherapy, the use of oxaliplatin or irinotecan plus 5-FU/LV increased from 53.3% in 2001 to 89.7% in 2007 (P<0.0001). After approval of bevacizumab for metastatic CRC in 2004, its use increased from 0.5% to 30.8% from 2001-2004 and from 30.8% to 55.8% from 2004-2007 (P<0.0001).
CONCLUSIONS: In patients with stage IV colorectal cancer, modern chemotherapeutic regimens have been rapidly adopted over the last decade. Concomitantly, there has been a decrease in resection rates. Given the increased effectiveness of modern chemotherapeutic regimens and the high operative mortality in this population, further studies are needed to evaluate the role of and timing of resection of the primary tumor.