The present monocentric prospective phase 2 study aims to reproduce the results obtained at NIRS thus offering the possibility of obtaining a promising rate of progression-free survival (PFS) and local control (LC) in patients diagnosed with mucosal melanoma of lower genital tract. Systemic treatment with immunotherapy is not the subject of this study but is allowed both in the neoadjuvant and sequential regimens.

Melanomas have always been considered poorly radiosensitive. It is now accepted that high LET (Linear Energy Transfer) particle beams, such as carbon ions, can offer a biological advantage, compared to photons treatment, in radio-resistant neoplasms treatment, thanks to their higher biological efficacy (RBE) against tumours with a low α/ ß ratio. In addition, carbon ions have the physical advantage of an inverted depth deposition profile compared to photons, allowing then a steep dose gradients that ensure increased sparing of adjacent healthy organs at risk (OARs).

Patients with primary gynaecological melanoma, non-metastatic, non-suitable for surgery, and not previously subjected to conventional radiotherapy can be enrolled in the trial, according to selection criteria. After requested baseline exams, the patient undergoes to simulation phase for the carbon ion radiation therapy, according to study constraints. The patient will then receive immunotherapy not concomitant to CIRT. The response is evaluated through RECIST criteria.

PFS is the primary endpoint, calculated from the end of CIRT to date of disease progression or death or last follow up.

Inclusion Criteria:

• Histological diagnosis
• Absence of skin extension
• N + (only if confined to the groin and pelvis)
• Age between 20-80 years
• ECOG 0-2
• No evidence of metastasis
• At least 5 mm away with rectum and bladder wall
• No previous RT
• Written informed consent
• Patient's ability to understand the characteristics and consequences of the clinical trial
• Molecular characterization/ mutational state
• Disease staging (baseline exams)

Exclusion Criteria:

• Hip prosthesis, or metal prostheses or any other condition that prevents adequate imaging to identify the target volume and calculate the dose in the treatment plan
• Psychic or other disorders that may prevent informed consent
• Previous invasive tumor unless patient has been disease free for at least 3 years
• Contraindication to MRI
• Pregnancy or breastfeeding in progress

gynecological disease