The Changing Kinetics of Advanced Melanoma

Abstract

The current issue of JAMA Dermatology contains 3 articles that attempt to describe some aspect of disease kinetics of selected subsets of patients with melanoma.The first of these studies, from von Schuckmann and colleagues 1 in Australia, attempts to describe factors predictive of early recurrence (within 2 years) among patients who presented for treatment of clinically localized T1b to T4b melanoma in Queensland.Patients were recruited prospectively from a number of hospital and private clinic sources. Of 1245 patients identified and invited to participate, 700 (56%) were included in the analysis. Most of the follow-up was obtained as a patient-reported binary recurrence status (yes/no) every 6 months. In the event of patients lost to follow-up, local hospital records and Queensland Cancer Registry data were reviewed. All recurrences were verified insofar as possible by medical record review. Factors identified predicting recurrence within 2 years were not surprising and included the presence of ulceration, an increased mitotic index, increasing T stage, and head and neck location. Descriptive statistics were provided comparing outcomes by the seventh and eighth editions of the AJCC Staging Manual, and describing the initial sites of recurrence.The biggest challenge in interpreting the significance of this study is the heterogeneity of the patient data set, a data set that included 442 patients with clinical T1b to T4b who did not undergo sentinel lymph node biopsy (SLNB), 213 patients with pathologic T1b to T4b who had a negative SLNB result, and 38 patients with at least stage IIIa after a positive SLNB result (the SLNB numbers do not quite add up to 700 in Table 1). This heterogeneity recalls that of the AJCC7 data set, where pathologic staging of clinically localized melanomas was not required. The A JCC8 has addressed this shortcoming by including only patients who underwent SLNB, 2 thus describing more homogeneous T-stage subsets. Excluding the patients with T1a disease, the AJCC8 data set depicted describes the dynamic kinetics of outcome in 10 466 patients with pathologic T1b to T4b melanomas. As expected, more advanced tumors generally recur more frequently and earlier. Importantly, the AJCC8 data set demonstrated that most events in this cohort of patients are expected to occur after the 2-year threshold described in the study by von Schuckmann et al, 1 with continued attrition out to at least 10 years. Thus, the second concern: the 2-year interval, although entirely practical for a prospective study such as this, may not be entirely reflective of the true biology of this heterogeneous cohort.