25. The prognostic importance of tumour-infiltrating lymphocyte grade in patients with primary cutaneous melanoma

Abstract

Aim To determine whether tumour-infiltrating lymphocyte (TIL) grade is an independent predictor of survival and sentinel lymph node (SLN) status in patients with localised primary cutaneous melanoma. Methods From the Melanoma Institute Australia database, 1865 patients with a single primary melanoma >0.75 mm in thickness were identified. The associations between clinical and pathologic factors, melanoma-specific survival and SLN status were analysed. Results The majority of patients had either no (grade 0, 35.4%) or few (grade 1, 45.1%) TILs, with a minority showing moderate (grade 2, 16.3%) or marked (grade 3, 3.2%) TILs. Tumour thickness, mitotic rate and Clark level were inversely correlated with TIL grade (each p p p p = 0.0004), ulceration ( p =0.0002), tumour thickness ( p = 0.001) and presence of satellitosis ( p = 0.02). TIL grade was the strongest predictor of SLN positivity after age. The 5-year survival was 82.9% and the recurrence-free survival was 86.9% (median follow-up 43 months). Tumour thickness ( p p p = 0.0002), mitotic rate ( p = 0.024) and TIL grade ( p Conclusion Patients with a marked TIL infiltrate have an excellent prognosis. TIL grade is an important independent predictor of survival and SLN status in melanoma patients and should be included in pathology reports of primary cutaneous melanoma.