Net survival of patients with colorectal cancer: a comparison of two periods

Background: The purpose of our analysis was to compare the results of treatment in patients who underwent resection for colorectal carcinoma. Methods: In the period from 1/1/1991 to 31/12/2000 1478 patients with colorectal carcinoma underwent potentially curative resection. We divided them into two 5-year period groups according to different treatment regimes. The 5-year net survival rate was estimated, where the net survival is the probability of survival derived solely from the cancer-specific hazard. Results: In a 10-year period, we resected 1478 patients. The 5-year net survival rate for R0-resected patients with colon cancer increased from 76.3 to 85.2% between the periods 1991–1995 and 1995–2000. The 5-year net survival rate for R0-resected patients with rectal cancer also increased from 67.5 to 73% in the same period. Conclusion: A comparison of the 5-year net survival rate for R0-resected patients with colorectal cancer increased in the last period from 1995 to 2000 compared with the period from 1991 to 1995. In multivariate analysis, early stage at diagnosis and adjuvant chemotherapy was both associated with better net survival after surgery with curative intent. The improvement of net survival is potentially the result of combination of better surgical and adjuvant therapy.