Treatment patterns and outcomes of patients with pT3N0 rectal cancer in a population-based setting

Abstract

4039 Background: Adjuvant radiation (R) and chemotherapy (C) is generally recommended for patients (pts) with pT3N0 rectal cancer. Patterns of adjuvant therapy and outcomes among pts with pT3N0 rectal cancer referred to the British Columbia Cancer Agency (BCCA) were determined. Methods: The BCCA Colorectal Cancer Outcomes Unit database was used to identify referred pts with pT3N0 rectal carcinoma diagnosed between 2000–2004. During this period, “short course” R (25Gy/5, surgery within 10 days) was recommended for resectable cT3 tumors followed by 6 months of C. If not treated pre-operatively (pre-op), guidelines specified post-op “long course” (45Gy/25) R and C. Three treatment groups were identified: Surgery alone (S), S and R (SR), and S, R and C (SRC). Eligible pts had complete surgical resection with or without Total Mesorectal Excision (TME). Pts treated with “downstaging” pre-op long course R, with S and C only (13 pts) or with R2 resection were excluded. Locoregional Recurrence (LR) and Distant Recurrence (DR) rates determined. Reasons for non-treatment were determined by chart review. Results: 303 pts were identified, with median follow-up of 33.5 months. Significant differences in age, tumor height, grade, and R therapy existed between groups ( Table I ). TME status, R status and Radial Margin positivity were similar. LR rates were 15% (S), 2% (SR) and 1.4% (SRC). DR rates were 11.7% (S), 7.9% (SR) and 8.5% (SRC). Median Overall Survival (OS) and Disease Free Survival (DFS) was not reached. Conclusions: Treatment of pT3N0 rectal cancer was variable and significant heterogeneity existed between groups receiving S, SR and SRC. Nevertheless, LR rates were very low in pts receiving R and substantially higher in pts who did not. DR rates were similar across groups, irrespective of C history. Reasons for not receiving R or C were primarily patient related (medical/post- operative considerations, patient refusal). Potential physician related factors (non-referral) accounted for 28% of lack of C treatment in the SR group. [Table: see text] No significant financial relationships to disclose.