Primary cutaneous melanoma with regression does not require a lower threshold for sentinel lymph node biopsy

Area of Science:

• Oncology
• Dermatology
• Surgical Pathology

Background:

• Histological evidence of tumor regression (RG) occurs in 35% or fewer cutaneous melanoma cases.
• Some clinicians suggest a lower threshold for sentinel lymph node (SLN) biopsy in patients with RG.

Purpose of the Study:

• To evaluate the impact of histological tumor regression on sentinel lymph node biopsy positivity and recurrence rates in cutaneous melanoma.
• To determine if RG influences the risk stratification for melanoma patients.

Main Methods:

• Retrospective analysis of 1,349 patients with clinically localized cutaneous melanoma (1995-2004).
• Compared outcomes for 344 patients with histological RG versus 1,005 patients with no regression (NRG).
• Analyzed SLN biopsy rates, positivity, and recurrence based on Breslow depth and RG presence.

Main Results:

• Patients with RG had a lower median Breslow depth (1.1 mm) than those with NRG (1.5 mm).
• SLN biopsy rates were lower in RG patients (64%) vs NRG patients (72%).
• SLN positivity was significantly lower in RG patients (10%) compared to NRG patients (18%).
• Recurrence rates were lower in RG patients (12%) than NRG patients (21%).

Conclusions:

• Histological tumor regression in primary cutaneous melanoma does not predict sentinel lymph node positivity when stratified by Breslow depth.
• The presence of RG does not increase the risk of recurrence compared to melanomas without regression (NRG).
• Breslow depth remains a critical factor in melanoma staging and risk assessment, irrespective of regression status.