Epidemiology, Diagnosis and Treatment Outcomes of Skin Melanoma in the Republic of Belarus

Abstract

The primary incidence of skin melanoma in the Republic of Belarus over 25 years (from 1991 through 2015) has increased 3.3-fold (from 2.6 to 9.0 per 100,000 population). A higher level of urban population incidence, a large proportion of people affected at the employable age. In 2015 the proportion of prognostically unfavourable pT3-pT4 neoplasms was 38.2%. Metastatic disease was detected in 12.4% of the patients. Methodology: Material of the paper is based on the data of Belarusian Cancer Registry using the principles of data collection, monitoring and processing recommended by the IARC. Results: The proportion of stage IB neoplasms made up almost one third of the cases assigned to stage I. Of the cases assigned to stage II, the proportion of neoplasms with a high prognostic index of metastatic spread (T3b-T4b) was more than 70%. The recurrence rate is 15.1% even at melanoma invasion depth of up to 1 mm (with ulceration), while it rises to 32.4% at pT2b. The cumulative 5-year disease-specific survival of all patients in 2005 was 54.1 ± 1.5%, and in 2015 it was 64.0±2.2%. Conclusion: A strong correlation is observed between survival of patients and the extent of invasion and ulceration of the primary focus. For metastasis-free pT1a melanoma, the 5-year survival was 92.2%, for T1b – 79.9%, for pT2b – 72.5%, for pT3b – 55.1%, for pT4b – 49.1%. According to the Cancer Registry data, ulceration of the primary neoplasm is frequently observed: it amounts to 41.1% of the cases with melanoma invasion depth up to 2 mm (pT2), to 55.9% with 2-4 mm (pT3) and to 76.3% with the tumor thickness of more than 4 mm (pT4).