Recognized factors that increase a woman’s lifetime risk of vaginal cancer include younger age at coitarche, greater number of lifetime sexual partners, smoking, in utero diethylstilbestrol exposure, and human papillomavirus (HPV) infection, write Chirag A. Shah, MD, MPH, from the University of Washington in Seattle, and colleagues. The cause of vaginal cancer is closely linked to cervical cancer, and HPV infection seems to be a necessary cofactor in most cases.
The goal of this study was to assess the current effect on mortality of demographic factors, pathologic characteristics of the tumor, and choice of treatment in women with vaginal cancer. The investigators identified 2149 women diagnosed with primary vaginal cancer between 1990 and 2004, using data from 17 population-based cancer registries participating in the Surveillance, Epidemiology, and End Results program. Cox proportional hazards modeling was used to determine the association between various demographic factors, tumor characteristics, and treatments and risk for vaginal cancer mortality.
At diagnosis, mean age was 65.7 ± 14.3 years, and approximately two thirds were non-Hispanic whites. However, African American women had the highest incidence of vaginal cancer (1.24 per 100,000 person-years). Higher stage predicted lower 5-year disease-specific survival duration, which was 84% for stage I, 75% for stage II, and 57% for stage III/IV. The risks for mortality were increased for tumor size greater than 4 cm (hazard ratio [HR], 1.71) and for advanced disease (HR, 4.67), as determined in a multivariate adjusted model.
Women with vaginal melanoma had a 1.51-fold increased risk for mortality vs those who had squamous cell carcinomas (95% confidence interval, 1.07 – 2.41). In treatment modality, surgery alone had the lowest risk for mortality. Compared with women diagnosed from 1990 to 1994, those diagnosed after 2000 had an adjusted 17% decrease in their risk for death, suggesting a decrease in risk of mortality with time.
Stage, tumor size, histology, and treatment modality significantly affect a woman’s risk of mortality from vaginal cancer, the study authors write. There seems to be a survival advantage that is temporally related to the advent of chemoradiation.
Limitations of this study include observational design, use of data that had already been collected, missing data on tumor size for more than half of cases, lack of data on chemotherapy, and possible residual confounding by unmeasured predictors.
When possible in early stage disease, surgery seems to confer a survival advantage, the study authors conclude. The decision on treatment modality must still be made in the context of the individual patient, because it is unlikely that prospective trials will be undertaken to answer this specific question. In the future we may be able to see if the trend of decreased mortality with modern treatment continues; but presently, it seems there may be an ongoing reduction in the risk of mortality associated with the use of chemoradiation in women with vaginal cancer.
