The prognostic significance of recall antigen testing in melanoma patients

A quantitative assessment of the long-term prognostic value and clinical usefulness of recall antigen reactions in patients with malignant melanoma is not available. The authors evaluated longitudinal observations of survival made in 846 patients over a 12-year period. Each patient was initially studied with Mantoux-type recall antigen skin tests. The patients were categorized with respect to the following: high (>5 mm) or low (≤5 mm) averaged skin test reaction diameters at 48 hr; Clark level; tumor stage (I = localized tumor, II = local extension and/or region lymph node metastasis, III = systemic metastasis); ulceration; site of primary; histologic type; age; and sex. The percentage of high reactors in Stages I, II, and III were 44.3%, 37.4%, and 25%, respectively. Survival was evaluated with the Cox-Mantell hazard function model and the Cox regression model. The significant (chi-squared; probability) risk factors detected were tumor stage (94.58; ≤0.0001), Clark level (19.37; ≤0.0001), sex (16.97; ≤0.0001), and skin test reactivity (7.48; ≤0.0062). A significant relationship also was detected between skin test reactor status and the tumor stage (p ≤ 0.0330). When evaluated within each stage of disease, skin test reactivity predicted survival only in Stage II patients (p ≤0.0080). Five-year survival estimates among Stage II patients were 58% among high reactors and 38% among low reactors. Despite this interesting difference, the amount of independent information about survival provided by recall skin tests was small in comparison to the other clinically available risk factors. This suggests that recall antigen skin tests are not likely to be helpful in the evaluation of the individual patient.