Clinicopathological predictors of recurrence in nodular and superficial spreading cutaneous melanoma: A multivariate analysis of 214 cases

Background Nodular melanoma (NM) accounts for most thick melanomas and because of their frequent association with ulceration, fast growth rate and high mitotic rate, contribute substantially to melanoma-related mortality. In a multicentric series of 214 primary melanomas including 96 NM and 118 superficial spreading melanoma (SSM), histopathological features were examined with the aim to identify clinicopathological predictors of recurrence. Methods All consecutive cases of histopathologically diagnosed primary invasive SSM and NM during the period 2005-2010, were retrieved from the 12 participating Italian Melanoma Intergroup (IMI) centers. Each center provided clinical and pathological data such as gender, age at diagnosis, anatomical site, histopathological conventional parameters and date of excision and first melanoma recurrence. Results Results showed that NM subtype were significantly associated with Breslow thickness (BT) at multivariate analysis: [BT 1.01-2 mm (OR, 7.22; 95% CI, 2.73 -19.05), BT 2.01-4 mm, (OR, 7.04; 95% CI, 2.54 -19.56), and BT > 4 mm (OR, 51.78; 95% CI, 5.65. -474.86), (p<0.0001)]. Furthermore, mitotic rate (MR) was significantly correlated with NM histotype: [(MR 3-5 mitoses/ mm2 (OR, 2.62; 95% CI, 1.01 - 6.83) and MR >5 mitoses/ mm2 (OR, 4.87; 95% CI, 1.77 -13.40), (p=0.002)]. The risk of recurrence was not significantly associated with NM histotype while BT [BT 1.01-2.00 mm (HR, 1.55; 95% CI, 0.51-4.71), BT 2.01-4.00 mm (HR, 2.42; 95% CI, 0.89-6.54), BT > 4.00 mm. (HR, 3.13; 95% CI, 0.95-10.28), (p=0.05)], mitotic rate [MR > 2 mitoses/mm2 (HR, 2.34; 95% CI, 1.11 - 4.97), (p=0.03)] and the positivity of lymph node sentinel biopsy (SNLB) (HR, 2.60; 95% CI, 1.19-5.68), (p=0.007) were significantly associated with an increased risk of recurrence at multivariate analysis.