(HealthDay News) — Tumor-infiltrating lymphocyte (TIL) grade is an independent predictor of melanoma-specific survival and sentinel lymph node (SLN) status in patients with localized primary cutaneous melanoma, according to a study published online June 18 in the Journal of Clinical Oncology.
To investigate whether the density and distribution of TILs independently predicts SLN status and survival, Farhad Azimi, of the Melanoma Institute Australia in Sydney, and colleagues reviewed data from 1,865 patients with a single localized primary cutaneous melanoma ≥0.75 mm in thickness.
The researchers observed an inverse association between TIL grade and tumor thickness, mitotic rate, and Clark level. Sixty-one percent of patients underwent a SLN biopsy and 22.1 percent were positive. SLN positivity decreased with increasing TIL grade, ranging from 27.8 percent for TIL grade 0 to 5.6 percent for TIL grade 3 (P < 0.001). Decreasing age, decreasing TIL grade, ulceration, increasing tumor thickness, satellitosis, and increasing mitoses were significant predictors of SLN positivity. Independent predictors of melanoma-specific survival were tumor thickness, ulceration, satellitosis, mitotic rate, TIL grade, and sex. Survival was 100 percent in those with TIL grade 3.
“Ultimately, a greater understanding of the mechanisms controlling TILs in melanoma may provide avenues for developing important new immunotherapeutic strategies for patients with melanoma,” the authors write.