DNCB reactivity and prognosis in 419 patients with malignant melanoma.

Delayed cutaneous hypersensitivity to 2,3-dinitrochlorobenzene (DNCB) was tested in 419 patients with malignant melanoma to determine whether DNCB reactivity was associated with prognosis. At the time of definitive surgery, a positive DNCB test was seen in 82% of the patients in State I (regional lymph node histologically negative) and in 81% of patients in Stage II (regional lymph node positive). A positive DNCB test, obtained at the time of staging in patients with more advanced disease, was seen in 70% of patients in State III (metastases in, at most, on internal organ) and in 68% of patients in Stage IV (metastases in more internal organ). Using the chi 2 test, the trend of a decrease in DNCB reactivity from Stage I to Stage IV is significant (P less than 0.04). In regard to DNCB reactivity and prognosis, the following statistical differences (P less than 0.05) were obtained: In Stage II, the recurrence distribution for DNCB-positive patients is more favorable than for DNCB-negative patients (estimated median time to recurrence 16 vs. 7 months); the survival distribution again in Stage II was more favorable for DNCB-positive patients tha DNCB-negative patients (estimated survival time 31 vs. 18 months). When the group of State II patients was divided into subgroups with different prognoses (state of primary at the time of lymphadenectomy), a survival advantage was seen in all substages but was statistically significant (P less than 0.05) only in Stage II d (regional lymph node involvement diagnosed more than two months after resection of primary melanoma). The results of DNCB tests in patients with malignant melanoma correlate with stage of disease and, in Stage II, with prognosis.