Top Line: Can inguinal lymph node dissection be omitted in women with early stage vulvar cancer and positive sentinel node biopsy?
The Study: The GROINS-V trial demonstrated that groin dissection can be safely omitted in women with early stage, clinically node negative vulvar cancer who have negative sentinel lymph node biopsy (SLNB) with an isolated groin recurrence rate of 2%. This is important as inguinal node dissection can have significant morbidity, especially when followed by radiation when there are 2+ nodes positive or ECE. So, the question is whether women with a positive SLNB need full groin dissection and radiation or whether radiation alone suffices. In GROINS-V II women with early stage vulvar cancer (< 4cm and clinically node negative) underwent primary excision and sentinel lymph node biopsy. If the SLNB was positive, radiation (50 Gy in 25-28 fractions) was delivered to the ipsilateral or bilateral (discretionary) inguinal and distal external iliac nodes. The protocol was paused early on as there were more isolated groin recurrences in the first 91 patients than expected. Most of those had macrometastases (> 2mm). So, the protocol then changed to RT alone for SLNB micro mets and ILND for macromets with radiation if 2+ mets or ECE. Of all patients enrolled prior to surgery, 21% were SLNB+ with half of those having micromets and half having macromets. The rate of isolated groin recurrence for micromets was 4% at 2 years and only 1.6% for those who received per-protocol radiation (12% for those who didn’t). This rate was comparable to the 2.7% rate seen in SLNB- patients and the 3.6% rate seen in GROINS-V I. Among those with macrometastases, roughly a third had radiation alone while ⅔ had ILND (followed by radiation in 56%.) At 2 years, isolated groin recurrences were significantly higher with radiation alone (22%) than with ILND +/- radiation (7%). Lymphedema at 12 months was seen in 4% after SLNB alone, 11% after SLNB and RT, and 23% after ILND.
TBL: For women with early stage vulvar cancer and sentinel lymph node micromets (≤2mm), adjuvant radiation alone results in an isolated groin recurrence rate similar to ILND with less morbidity. In women with SLN macromets (>2mm), radiation alone is inferior to ILND with respect to isolated groin recurrence. | Oonk, J Clin Oncol 2021