Nevus Density May Affect Melanoma Survival
Michael D Reyes, Kathleen L Reyes, Susan Paine, Raymond Barnhill, Marianne Berwick. University of New Mexico, Albuquerque, NM; Hôpital Saint-Louis, Université Paris VII, Paris, France
Background: Individuals with large numbers of nevi (>100) are at increased risk of developing melanoma, even in the absence of atypical nevi. Despite this knowledge, the association between number of nevi and survival with melanoma remains to be investigated.
Design: In our population based study of number of nevi and survival with melanoma, eligibility criteria included a diagnosis of non-metastatic primary invasive cutaneous melanoma. A questionnaire assessed patient characteristics, while a single dermatopathologist recorded histologic features of melanoma. Nevi were counted on the arms and backs of participants. Statistical analysis included simple frequencies, contingency tables and cross-tabulations, univariate models, and finally multivariate models. Covariates with statistically significant relationships to number of nevi or death were included in a multivariate analysis with death as the primary outcome.
Results: Our study assesses the survival of melanoma patients with a large number of nevi (approximately top 20th percentile), which corresponds to >30 nevi on the arms and back. Of all recorded variables only skin type, anatomic site, and skin spouse or self examination were found to have a statistically significant (p<0.05) association with number of nevi. None of these variables showed a significant association with death from melanoma. A multivariate analysis assessing survival was performed with pertinent patient and tumor variables. In the multivariate model, six factors showed a statistically significant relationship with survival (p<0.05), of which one was >30 nevi.
|Variable||Hazard ratio (95% confidernce interval)||P value|
|Number of nevi|
|Sex (forced into model)|
|Age at diagnosis (1 year increase)||1.0 (1.0-1.0)||.03|