Purpose: To investigate the prognostic significance of smoking in addition to established risk factors in patients with Dukes stage B and C colorectal cancer (CRC).
Methods: 291 consecutive non-selected CRC patients were studied retrospectively. Twenty-three variables were examined using a regression statistical model to identify relevant prognostic factors related to disease free survival (DFS) and overall survival (OS).
Results: On multivariate analysis DFS was found to be negatively affected in patients with a smoking history of ≤10 pack-years vs. non-smokers (p<0.016). Additionally, performance status (PS)<90 (p<0.001), Dukes stage C (p<0.001) and elevated tumor markers (p<0.001) at the time of diagnosis were found to adversely affect DFS. Smoking also had a significant association with relapse. Patients with a smoking history of ≤10 pack-years had 2.45 (p<0.018) higher risk of recurrence compared to patients with no smoking history. OS was influenced by Karnofsky performance status (PS), Dukes stage, and elevated tumor markers. In particular patients with PS< 90 had a 4.69-fold higher risk of death (p<0.001) than patients with better PS. Stage C disease was associated with 2.27-fold higher risk of death (p<0.001) than stage B disease, and patients with elevated tumor markers at the time of diagnosis had 2.74-fold higher risk of death (p<0.014) when compared to those whose tumor markers were normal at presentation.
Conclusion: Our study associates smoking and relapse incidence in non-clinical- trial CRC patients and reiterates the prognostic significance of PS, stage and tumor markers at the time of diagnosis.