Comparison of rectal and colon cancer outcomes: A population based analysis

Abstract

4040 Background: Rectal cancer has previously been associated with inferior five year survival in comparison to colon cancer. Total mesorectal excision (TME) and adjuvant therapy have reduced locoregional recurrence and, in some studies, improved rectal cancer survival. Therapy and outcomes of colon and rectal cancer were compared among 3 patient cohorts referred to the British Columbia Cancer Agency (BCCA) between 1990 and 2002. Methods: Patients with resected, pathological stage II or III colorectal cancer referred to BCCA in 1990, 1995/96, and 2001/02 were included. For those patients receiving long-course preoperative radiation, the higher of clinical or pathological stage was used. Kaplan Meier method was used for survival analysis. Results: 1,851 patients were included with a median age range of 64–69 and follow up time of 15.7 [1990], 10.8 [1995/96] and 5.3 [2001/02] years. Between 1990 and 2001/02 the use of adjuvant chemotherapy increased significantly for rectal cancer from 14.7% to 68.5% (p<0.001) and for colon cancer from 32.9% to 54% (p<0.001). The use of preoperative radiation therapy (RT) (p<0.001) and total mesorectal excision (TME) (p<0.001) in rectal cancer also significantly increased. 5 year overall survival (OS) was numerically inferior for rectal compared to colon cancer in 1990 and similar to colon cancer in the later cohorts (Table). The analysis was limited by small sample size and an expanded cohort will be presented. 5 year OS significantly improved for both rectal (p<0.001) and colon cancer (p=0.025) between 1990 and 2001/02. Conclusions: In this population based study, 5 year OS for stage II/III rectal and colon cancer significantly improved between 1990 and 2001/02, with similar outcomes now apparent for both sites. With respect to rectal cancer, improved outcomes are likely related to increased use of TME technique, preoperative RT and adjuvant chemotherapy. Improved outcomes for colon cancer likely reflect increased use of adjuvant chemotherapy. 5 year overall survival for colon and rectal cancer Year N 5 Y Overall Survival (%) Rectal Cancer 5 Y Overall Survival (%) Colon Cancer P-Value 1990 236 43.8 [34.9, 54.9] 53.7 [46.0, 62.7] 0.0969 Stage II 83 55.2 [39.7, 76.6] 63.6 [51.8, 78.2] 0.3954 Stage III 153 38.8 [28.7, 52.4] 47.7 [38.2, 59.5] 0.2088 1995–96 563 59.3 [53.1, 66.3] 61.7 [56.7, 67.2] 0.5607 Stage II 233 68 [58.3, 79.2] 72.3 [65.3, 80] 0.4675 Stage III 330 54.4 [46.6, 63.4] 53.5 [46.8, 61.2] 0.8654 2001–02 1052 63.7 [58.5, 69.4] 66.2 [62.4, 70.1] 0.4543 Stage II 430 70.6 [63.1, 78.9] 77.1 [71.9, 82.7] 0.158 Stage III 622 58.4 [51.4, 66.4] 59.1 [54.2, 64.4] 0.8818 No significant financial relationships to disclose.