ORLANDO – Malignant melanomas of the scalp behave differently from melanomas arising at other body sites, and are associated with poor disease-free and overall survival compared with other head and neck melanomas, investigators reported here.
A retrospective study of more than 11,000 patients with malignant melanomas showed that 5-year melanoma-specific survival was 65% for patients with lesions on the scalp, compared with 78% for patients with tumors on the trunk or elsewhere on the head, face, neck, or ear (P = .0003), said Dr. Junko Ozao-Choy, a fellow at the John Wayne Cancer Institute in Santa Monica, Calif.
Dr. Junko Ozao-Choy
Five-year overall survival for patients with melanomas of the scalp was 58%, compared with 72% for those with head, face, neck, or ear lesions, 74% for those with trunk lesions, and 77% for those with tumors on an extremity (P less than .0001), Dr. Ozao-Choy reported at a symposium sponsored by the Society of Surgical Oncology.
Melanomas of the scalp may account for the poor prognosis of head and neck melanoma relative to tumors originating at other body sites, Dr. Ozao-Choy and her colleagues suggested.
"Scalp melanomas may warrant further studies to ascertain whether biology or anatomy contributes to their worse clinical course," she said, adding that the results indicate "scalp melanomas may need closer clinical follow-up."
Compared with melanomas originating at other body sites, scalp melanomas tend to occur in older patients, predominantly men, according to the investigators. The lesions tend to have higher Breslow thickness, advanced nodal stage and overall stage, and more ulceration.
Dr. Ozao-Choy and her colleagues based their findings on a database review of 11,396 patients presenting for treatment within 4 months of diagnosis from 1971 through 2010. In univariate analysis controlling for sex, they found that 80% of the 799 patients with melanoma originating on the scalp were men (P = .0001).
The mean age at presentation was 54 years for those with scalp lesions and 55 for those with head, neck, or ear tumors. Taken together, the mean age at diagnosis for patients with scalp and head melanomas was higher than for patients with lesions on the trunk (age 47 years) or extremities (age 51 years, P less than .0001).
Scalp tumors had greater Breslow thickness, at a mean of 2.5 mm compared with 1.7 mm for other head and neck melanomas, 1.8 mm for trunk tumors, and 1.9 mm for lesions on an extremity (P less than .0001).
Looking at 5-year overall survival by stage, the authors found that patients with stage I/II scalp lesions had worse survival than those with stage I/II lesions at other sites (P less than .0001). Similarly, stage III scalp primary tumors were associated with worse survival than other stage III tumors (P = .009).
Multivariate analysis controlling for age, male sex, Breslow thickness, lymph node status, and ulceration revealed that patients with scalp tumors had worse 5-year disease-free survival, at 47%, compared with 61% for other head and neck tumors, 66% for trunk tumors, and 69% for extremity melanomas (hazard ratio, 1.8; P less than .0001).
In the question and answer session, an audience member commented that the worse prognosis for head and neck melanomas may be related to the greater frequency of aggressive NRAS and BRAF mutations in tumors originating at those sites.
The study was internally funded. The authors had no disclosures.