Recurrent malignant melanoma is a clinical entity that behaves distinctly differently from the primary disease. The purpose of this study was to determine whether there are significant trends in the prognostic factors or in the timing and sites of recurrence. We reviewed 250 patients with recurrent malignant melanoma from the Sydney Melanoma Unit in Australia who were followed in their Tumor Registry between 1960 and 1981 (median follow-up was 7 years). Fifty-two percent of all first recurrences were to regional nodes, 17 percent were local recurrences, 8 percent were in-transit metastases, and 23 percent of all first recurrences were to a distant organ. We found that 67 percent of all recurrences were diagnosed within 24 months and 81 percent were diagnosed by 36 months after the primary melanoma.
Regional nodal recurrences were diagnosed earlier (with 63 percent at 18 months and 74 percent at 24 months). Local recurrences and in-transit metastases were comparable (with 55 percent of each at 18 months and about 66 percent of each at 24 months), and systemic recurrences were diagnosed later (52 percent at 24 months and 71 percent at 36 months). Of significant interest was the fact that survival after the diagnosis of recurrence was independent of thickness of the primary tumor or duration of disease-free interval (local, in-transit, or regional nodal).
Only the diagnosis of distant organ metastasis correlated with shorter survival; local recurrence, in-transit metastasis, and regional nodal metastasis were all associated with comparable survivals. Finally, based on these findings, we believe that in assessing the benefits of any particular surgical adjuvant in melanoma by disease-free interval, 3 years of follow-up should be valid for a meaningful conclusion of the presence or absence of any benefit of treatment.