Survival superiority of females with melanoma. A multivariate analysis of 6383 patients exploring the significance of gender in prognostic outcome
K. R. Stidham, J. L. Johnson and H. F. Seigler
Duke University Medical School, Durham, NC.
OBJECTIVE: To evaluate the effects of gender on prognostic outcome of
patients with melanoma. DESIGN: Retrospective cohort study, including 20
years of follow-up. SETTING: Duke University Melanoma Clinic, Durham, NC, a
referral center for patients with melanoma. PATIENTS: Patients with
melanoma (N = 6383), consisting of 45% females and 55% males, obtained from
a referred sample. Eligibility requirements were nonocular melanomas and
white race. MAIN OUTCOME MEASURES: Time to metastases and survival.
RESULTS: Females with melanoma demonstrated a superior prognostic outcome
over males, with a 34% survival advantage and a 28% disease-free advantage.
When each of the variables of age, site, Clark's level, histologic type,
and tumor thickness was explored for possible influences on prognostic
outcome, female survival advantage persisted, although modified by
independent variables. The greatest influence came from the variables of
site, Clark's level, and Breslow's thickness. Age, specifically in
premenopausal vs postmenopausal age groups, was not significant in altering
females' prognostic advantage. A multivariate analysis combining the
effects of all the variables resulted in females still maintaining a 22%
survival advantage and a 17% disease-free advantage. CONCLUSIONS: Females
with melanoma have a significant prognostic advantage over their male
counterparts that cannot be fully explained by influences from the
variables of age, site, Clark's level, histology, and Breslow's thickness.
This superior prognostic outcome does not appear to be associated with
menstrual status. Evidence does suggest that the protective factor for
females occurs at the level of metastases.
