Radio-Guided Occult Lesion Localization technique for biopsy of non-palpable subcutaneous lesions in suspect metastatic melanoma

In patients with history of melanoma the risk of recurrence depends on the initial stage. Patients who first present with a more advanced disease are more likely to recur. Instead, patients who have a lesser advanced disease will progress slowly and are less likely to recur. The aim of this study is to evaluate the utility of a minimally invasive and targeted technique as a diagnostic and therapeutic tool for the excision of non-palpable lesions suspected as melanoma metastases. Between February 2018 and April 2022, we evaluated 21 patients with stage IIB - IIC – III melanoma (following the 8th Edition AJCC - American Joint Committee on Cancer - melanoma staging system). These patients showed subcutaneous non-palpable lesions with a high risk of malignancy in PET/CT scan during oncological follow-up. To guide the biopsy, we used Radio- Guided Occult Lesion Localization (ROLL) technique by an intralesional injection of [99mTc] albumin macroaggregates (MAA) the day before surgery. During surgery a hand-held gamma probe was used to locate the lesions. Surgical localization of radiolabeled lesions was achieved in all cases. Relapse melanoma was histologically confirmed in 13 patients. This technique proved to be a simple, safe, and effective method to detect and biopsy non-palpable or difficult to locate lesions in suspect metastatic melanoma. The main advantage is disease restaging, from stage II to III, allowing patients to access adjuvant therapies not approved as early-stage melanoma treatment.