Sentinel node biopsy is the standard staging procedure for melanoma patients, and sentinel node status is the most important prognostic factor for disease outcome in AJCC stage I/II disease. However, the therapeutic value of the sentinel node procedure followed by early completion lymph node dissection is still controversial.
If a patient has a positive sentinel node, they will usually be offered a completion lymph node dissection to remove all lymph nodes from that nodal basin. Yet just 15 – 20% of all sentinel node positive patients have further lymph node metastases detected at this time. This means that around 80 – 85% of all sentinel node positive patients could be subjected to unnecessary surgery. At the same time, it is not clear whether the 15 – 20% minority of patients who do have additional nodal involvement detected at completion lymph node dissection, actually realize a survival benefit from this procedure.
Indeed, an early analysis of a randomized, phase III, noninferiority trial conducted in Germany by the Dermatologic Cooperative Oncology Group has shown that patients with melanoma and a positive sentinel lymph node biopsy gained no survival benefit by having complete lymph node dissection compared with patients in an observation group (J Clin Oncol 33, 2015 (suppl; abstr LBA9002)).
The EORTC Melanoma Group conducted the largest retrospective analysis (1080 patients were included between 1993 and 2008, van der Ploeg et al. J Clin Oncol 2011), which seems to indicate that patients with minimal sentinel node tumor burden have similar prognostic factors and outcome to sentinel node negative patients.
The EORTC 1208 (MiniTub) study will address these issues. MiniTub is a prospective registry for patients with minimal sentinel node tumor burden who undergo completion lymph node dissection or nodal observation only.
Dr. Alexander van Akkooi of the Netherlands Cancer Institute-Antoni Van Leeuwenhoekziekenhuis in Amsterdam and coordinator of this study says, “MiniTub is a registry. Enrolled patients will be managed with serial nodal observation or completion lymph node dissection based only on their own decision, after consultation with their treating physician, which is the current standard practice across Europe and Worldwide. The goal of MiniTub is to determine whether the melanoma patients with minimal sentinel node tumor burden managed only by serial nodal observation have a 5-year Distant Metastasis Free Interval comparable to those patients who opted for completion lymph node dissection. We also plan to compare their outcome to patients who had a negative sentinel node biopsy.”
This EORTC prospective registry will be the first to address these treatment issues by targeting patients with minimal sentinel node tumor burden in melanoma. Over a five year period, MiniTub expects to register 243 patients with T2-T3 primary tumors (Breslow thickness 1.01-4 mm) and minimal sentinel node tumor burden (≤ 0.4 subcapsular and/or ≤ 0.1 mm any location), who choose serial nodal observation. Patients will be followed up for ten years. In addition, for descriptive analyses, patients with T1 or T4 tumors, and with minimal sentinel node tumor burden, will be allowed to be entered.
MiniTub is coordinated by the EORTC Melanoma Group and will be conducted in 29 hospitals in ten countries: Belgium, France, Germany, Italy, Portugal, Slovenia, Spain, Switzerland, The Netherlands, and The United Kingdom.
This study is supported by the EORTC Melanoma Group.
John Bean, PhD
EORTC, Medical Science Writer