Depth of invasion analysis to predict acral melanoma outcomes.

BACKGROUND: Acral melanoma is a subtype with worse outcomes. The Breslow micrometric measurement is the most critical parameter in planning treatment and predicting outcomes. However, for acral lentiginous melanoma, the value of the Breslow thickness is a matter of debate. Depth of Invasion (DOI) is a well-established measure for staging oral squamous cell carcinoma. OBJECTIVE: This study compared DOI and Breslow thickness for predicting acral melanoma outcomes. METHODS: We performed a retrospective cross-sectional study of 71 acral melanoma lesions subjected to sentinel lymph node biopsy at one Brazilian referral center. RESULTS: Cox model univariate analysis showed that both DOI and Breslow thickness predicted melanoma specific survival (HR 1.12; p = 0.0255 and HR 1.144; p = 0.0006, respectively), although Kaplan Meier curve was only significant for Breslow (χ2 = 5.792; p = 0.0161) and not for DOI (χ2 = 0.2556; p = 0.6132). Sentinel lymph node status and presence or absence of ulceration also predicted specific survival in patients with acral melanoma (χ2 = 6.3514; p = 0.0117 and χ2 = 4.2793; p = 0.0386, respectively). Multivariate analysis, however, demonstrated that Breslow depth was the only independent parameter for predicting acral melanoma specific survival (HR 1.144; p = 0.0006). CONCLUSION: Even though Breslow thickness remains the main predictor for survival in acral melanoma, it is not a perfect parameter. The introduction of DOI in this context opens new perspectives for predicting acral melanoma outcomes.

Proposal for the applicability of modified Breslow (measured from the basal membrane) as a predictor of survival and sentinel lymph node outcome in patients with cutaneous melanoma.

BACKGROUND: Cutaneous melanoma is a neoplasm with a high mortality rate and risk of metastases to distant organs. The Breslow micrometric measurement is considered the most important factor for evaluating prognosis and management, measured from the granular layer to the deepest portion of the neoplasm. Despite its widespread use, the Breslow thickness measurement has some inaccuracies, such as not considering variations in the thickness of the epidermis in different body locations or when there is ulceration. OBJECTIVE: To evaluate the applicability of a modified Breslow measurement, measured from the basal membrane instead of from the granular layer, in an attempt to predict sentinel lymph node examination outcome and survival of patients with melanoma. METHODS: A retrospective and cross-sectional analysis was carried out based on the evaluation of slides stained with hematoxylin & eosin from 275 cases of melanoma that underwent sentinel lymph node biopsy from 2008 to 2021 at a reference center in Brazil. RESULTS: Analysis of the Cox model to evaluate the impact of the Breslow measurement and the modified Breslow measurement on survival showed that both methods are statistically significant. Logistic regression revealed a significant association between both measurements and the presence of metastasis in sentinel lymph nodes. CONCLUSION: Measuring melanoma depth from the basal membrane (modified Breslow measurement) is capable of predicting survival time and sentinel lymph node outcome, as well as the conventional Breslow measurement.