This multicenter, phase III randomized controlled trial evaluates whether omitting re-excision after complete primary excision of cutaneous melanoma affects patient outcomes. A total of 1,749 patients with pT1b-pT4b cutaneous melanoma without evidence of metastases will be randomized to either standard re-excision according to current guidelines or no re-excision. Sentinel lymph node biopsy and adjuvant systemic therapy will be performed as indicated in both groups.

The primary objective is to compare relapse-free survival (RFS) between the two groups. Secondary objectives include comparisons of overall survival (OS), local recurrence rates, recurrence of in-transit and lymph node metastases, distant metastasis-free survival (DMFS), surgical morbidity, quality of life, and health economic outcomes.

This multicenter, phase III randomized controlled non-inferiority trial evaluates the oncologic safety and clinical impact of omitting re-excision after complete diagnostic excision of primary cutaneous melanoma. Although current guidelines recommend re-excision with margins of 1-2 cm depending on Breslow thickness, the clinical benefit of this procedure in all patients remains uncertain.

Patients with histologically confirmed pT1b-pT4b (AJCC 8th edition) cutaneous melanoma who have undergone complete primary excision with tumor-free margins and show no evidence of regional or distant metastases will be randomized in a 1:1 ratio to either standard re-excision according to local protocols (control arm) or omission of re-excision (experimental arm). Sentinel lymph node biopsy (SLNB) will be performed according to current guidelines and local practice, and may be omitted in selected patients at the discretion of the treating physician. Randomization will be stratified by tumor T stage and SLNB status and adjuvant systemic therapy is permitted according to national guidelines.

Re-excision, when performed, should take place within 12 weeks of the initial diagnostic excision and follow standardized surgical principles, including documentation of surgical margins and pathological assessment of the specimen. Patients will be followed for up to 5 years according to current clinical guidelines. Recurrences will be categorized as local, in-transit, nodal, or distant, and histological confirmation will be obtained whenever feasible. Management of recurrences and use of systemic therapies will be at the discretion of the treating physicians and recorded throughout the study.

In addition to oncologic outcomes, the study evaluates surgical morbidity, including postoperative complications classified according to the Clavien-Dindo system and the need for reconstructive procedures. Patient-reported outcomes will be collected longitudinally to assess health-related quality of life and scar-related outcomes using validated questionnaires. Health economic evaluation will include cost-effectiveness and cost-utility analyses from healthcare and societal perspectives, incorporating resource use, productivity losses, and quality-adjusted life years over a lifetime horizon using model-based approaches.

The trial is designed as a non-inferiority study to compare relapse-free survival between re-excision and no re-excision. The sample size is sufficient to detect non-inferiority with respect to a predefined margin, corresponding to an acceptable absolute decrease in 5-year relapse-free survival of 5%. Time-to-event endpoints will be analyzed using Kaplan-Meier methods and Cox proportional hazards models adjusted for stratification factors, with hazard ratios and 90% confidence intervals reported. The primary analysis will follow the intention-to-treat principle, with a supportive per-protocol analysis. Secondary endpoints will be analyzed using appropriate regression methods for time-to-event and binary outcomes, and longitudinal patient-reported outcomes will be evaluated using mixed-effects models. Sensitivity analyses will assess the potential influence of adjuvant systemic therapy on outcomes. An interim analysis for futility is planned after a subset of events has occurred.

Inclusion Criteria:

• Patients must be 18 years or older at time of consent

• Patients must have an ECOG performance score between 0 and 2

• Histologically confirmed, stage pT1b - pT4b (TNM AJCC 8th edition) cutaneous primary melanoma

• Histological subtypes that are eligible are:

  • Superficial Spreading Melanoma (SSM)
  • Nodular Melanoma (NM)

• The primary melanoma must have been removed by diagnostic excision and must have at least a minimum of 1 mm tumor free margin for invasive melanoma AND any in situ melanoma

• Patient must provide informed consent and comply with the treatment protocol and follow-up plan

• Life expectancy of at least 5 years from the time of diagnosis, not considering the melanoma in question, as determined by the investigator

• A survivor of prior cancer is eligible provided that ALL of the following criteria are met and documented:

  • The patient has undergone potentially curative therapy for all prior malignancies
  • Life expectancy should be at least 5 years and
  • The patient is deemed by their treating physician to be at low risk of recurrence from previous malignancies.

Exclusion Criteria:

• Non-cutaneous melanoma (uveal, mucosal)
• Acral melanoma
• Lentigo malignant melanoma (LMM)
• Desmoplastic melanoma
• Neurotropic melanoma
• Spitz melanoma/malignant Spitz tumor melanoma
• Satellites, in-transit melanomas or macroscopic melanoma metastases
• Uncertain diagnosis of melanoma i.e. so-called 'melanocytic lesions of unknown malignant potential' (MELTUMP or STUMP)
• Other non-SSM or NM subtypes
• Melanoma removed by shave excision, excogliation or core biopsy
• Patient has already undergone a local flap reconstruction of the defect after excision of the primary
• History of previous or concurrent (i.e., second primary) invasive melanoma
• Multiple melanomas
• Patient has undergone surgery on a separate occasion to clear the lymph nodes of the probable draining lymphatic field, except for previous SLNB
• Any additional solid tumor or hematologic malignancy during the past 5 years with a life expectancy of less than 5 years
• History of organ transplantation