LVI AND REGRESSION AS PROGNOSTIC FACTORS IN THIN MELANOMAS

In a European study reported in the Journal of Clinical Oncology, Maurichi et al identified lymphovascular invasion and regression as important prognostic factors in thin melanoma. They developed a nomogram including age, mitotic rate, ulceration, lymphovascular invasion, regression, and sentinel node status that accurately predicted 12-year overall survival.

Study Details

The study involved data from 2,243 patients with thin melanoma (≤ 1 mm) from prospectively maintained databases at six European centers. Median follow-up was 124 months, 12-year overall survival was 85.3%, and median times to local, regional, and distant recurrence were 79, 78, and 107 months.

Predictors of Relapse and Overall Survival

Relapse was significantly associated with age, Breslow thickness, mitotic rate, ulceration, lymphovascular invasion, and regression (all P < .001). Incidence was lower and subgroup differences were reduced for distant metastasis vs regional relapse. The worst prognosis categories were age > 60 years, Breslow thickness > 0.75 mm, mitotic rate ≥ 1/ mm2, ulceration, lymphovascular invasion, and regression ≥ 50%. Breslow thickness > 0.75 mm, mitotic rate  ≥ 1/mm2 , ulceration, and lymphovascular invasion were also significantly associated with positive sentinel node status (all P <.001).

On multivariate analysis, independent predictors of overall survival consisted of lymphovascular invasion (hazard ratio [HR] = 1.81, P = .002) and regression ≥ 50% (HR = 3.32, P < .001), as well as increased age (HR = 3.88, P < .001, for 3rd vs 1st quartile), mitotic rate ≥ 1/mm2 (HR = 1.58, P = .026), ulceration (HR = 3.81, P < .001), and positive sentinel node status (HR = 2.97, P < .001).

A nomogram constructed from these factors to predict 12-year overall survival was well calibrated and had good discriminative accuracy, with a C statistic of 0.88.

The investigators concluded, “Our findings suggest including [lymphovascular invasion] and regression as new prognostic factors in the melanoma staging system. The nomogram appears useful for risk stratification in clinical management and for recruiting patients to clinical trials.”

Andrea Maurichi, MD, from the Istituto Nazionale dei Tumori, Milan, is the corresponding author for the Journal of Clinical Oncology article.