Is 0.75 mm Breslow thickness the correct cut-off point for performing sentinel node biopsy in patients with melanoma?

Currently, in patients with malignant melanoma there is no clear cut-off point of Breslow thickness in order to avoid unnecessary lymph node excision surgery, without missing metastatic nodes. We retrospectively studied a cohort of 64 patients, with pathologically proven malignant melanoma, who underwent lymph node scintigraphy and surgical resection of the sentinel node, during the last two years. The patients were divided into 5 groups: Group 1: Ten patients, mean age 46 ± 6 years (range 40-55 years), with Breslow thickness of the lesion 0.51-0.75 mm. Group 2: Eleven patients, mean age 41 ± 9 years (range 31-61 years), with Breslow thickness 0.76-1mm. Group 3: Twelve patients, mean age 59 ± 12 (41-76 years), with Breslow thickness 1.01-1.25 mm. Group 4: Fourteen patients, mean age 61 ± 8 (38-74 years), with Breslow thickness 1.26-1.5mm. Group 5: Seventeen patients, mean age 56 ± 10 (32-71 years), with Breslow thickness >1.5mm. We found only seven infiltrated sentinel lymph nodes. From these, 3 patients belonged to the 5th group (Breslow>1.5mm), two patients to the 4th group (Breslow 1.26-1.5mm), one patient in the 3rd group (Breslow 1.01-1.25 mm) and one patient to the 2nd group (Breslow 0.76-1mm). Since there was no positive sentinel lymph node in any patient with Breslow thickness less than < 0.75 mm, we conclude that sentinel lymph node biopsy in patients with Breslow thickness less than < 0.75 mm may not be useful and might not be carried out, except in high risk cases such as melanomas with ulceration, high mitotic rate and vertical growth phase.