Gender aspects of survival after surgical treatment for rectal cancer.

ABSTRACT

AIM: Longer survival in women than men after rectal cancer surgery has been reported. Our hypothesis was that after correction for their longer life expectancy a survival benefit for women would still remain. METHOD: We studied 2792 patients diagnosed with rectal cancer in the southern part of Sweden between 1996 and 2006. The following parameters were included in a prespecified multivariable Cox regression analysis: age at diagnosis, gender, preoperative radiotherapy, stage, year and type of surgery. In addition to overall survival, relative survival was calculated using the Hakulinen approach utilizing an age-, gender- and calendar year-matched Swedish control cohort. RESULTS: Female patients were significantly older, received neoadjuvant treatment less often and were more often operated on by local excision. Overall survival was significantly longer in women. In the multivariable analysis of relative survival, controlling for neoadjuvant treatment, Dukes stage and year and type of surgery, no significant effect of gender [hazard ratio (HR) 1.10 for men, P = 0.114] was found, whereas an improved relative survival with increased age (HR 0.96 per year, P < 0.001) was seen. In contrast, using the same multivariable model with no correction for underlying mortality in the population, male gender (HR 1.38, P < 0.001) and greater age (HR 1.05 per year, P < 0.001) increased the risk of death. CONCLUSION: The results show that after correction for the underlying longer survival in women and some known confounders, survival after surgical treatment for rectal cancer appears to be gender neutral.