Relationship between sentinel lymph node status and regression of primary malignant melanoma

The prognostic significance of spontaneous regression of primary melanoma is a controversial issue. Studies on sentinel lymph node status and circulating tumour cells may represent a step towards a better understanding. The clinical details of 269 melanoma patients who underwent sentinel lymph node biopsy were analysed. Correlation was sought between the parameters of the primary tumour, particularly tumours showing a partial intermediate level of regression, and sentinel lymph node status. The presence of circulating tumour cells was studied by reverse transcription-polymerase chain reaction for tyrosinase messenger RNA preoperatively in 94 patients. Of the examined tumours, 27.8% showed histological features of a partial intermediate level of regression. Regressive tumours were localized predominantly on the trunk (P=0.006), were significantly thinner (P<0.0000) and were less frequently ulcerated (P=0.003) than tumours without regression. Moreover, the majority of regressive melanomas were of the superficial spreading type (P<0.0000) and their sentinel node status was more favourable (P=0.026). We demonstrated the presence of circulating tumour cells in five of 26 (19.2%) regressive and 19 of 68 (29.4%) non-regressive tumours. The difference was not significant (P=0.32). By multivariate analysis, however, the Breslow thickness and ulceration of the primary tumour were predictors of the sentinel lymph node status, in agreement with literature data. A partial intermediate level of regression of the primary tumour did not affect unfavourably the sentinel lymph node status in our study. We failed to demonstrate a significant relationship between the presence of circulating tumour cells and either primary tumour regression or the sentinel lymph node status.