# GROINSS-V II: radiotherapy versus inguinofemoral lymphadenectomy for vulvar cancer with sentinel node micrometastases

Source: https://onco.cc/key-papers/paper-groinss-v-ii-radiotherapy-vulvar-micrometastases-jco-2021/  
OnCo record `paper-groinss-v-ii-radiotherapy-vulvar-micrometastases-jco-2021` (Key paper). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

When the sentinel node in the groin held only a tiny deposit of vulvar cancer, radiotherapy to the groin was a safe alternative to removing all the nodes; when the deposit was larger, radiotherapy alone was not enough.

## Summary

Prospective multicentre phase 2 study of 1,535 women with early vulvar squamous cell carcinoma who had a sentinel node procedure; those with a positive node received inguinofemoral radiotherapy (50 Gy) instead of lymphadenectomy.

Among women with micrometastases (2 mm or less), the isolated groin recurrence rate at two years was about 1.6 percent with radiotherapy. Among those with macrometastases (over 2 mm), recurrence with radiotherapy alone was unacceptably high (about 22 percent), a stopping rule was triggered and lymphadenectomy was reinstated for that group.

## Fields

- Kind: Key paper
- Last checked: 2026-09-18
- Journal: Journal of Clinical Oncology
- Year: 2021
- DOI: 10.1200/JCO.21.00006
- Authors: Oonk MHM, Slomovitz B, Baldwin PJW, et al.
- Findings: Isolated groin recurrence at two years about 1.6 percent after radiotherapy for sentinel node micrometastases of 2 mm or less.; About 22 percent groin recurrence with radiotherapy alone for macrometastases over 2 mm, so lymphadenectomy remains the standard for those women.
- What it means: The size of the deposit in the sentinel node now decides treatment: radiotherapy for micrometastases, full groin dissection (with or without chemoradiotherapy) for macrometastases.
- Caveats: Not randomised; the comparison is with historical outcomes after lymphadenectomy.; Long-term lymphoedema and other late effects of groin radiotherapy are still being followed.

## Sources

- J Clin Oncol 2021: https://doi.org/10.1200/JCO.21.00006
- PubMed: https://pubmed.ncbi.nlm.nih.gov/34432481/

## Connected records

- cancers: [HPV-associated vulvar squamous cell carcinoma](https://onco.cc/cancers/hpv-associated-vulvar-cancer/), [HPV-independent vulvar squamous cell carcinoma (p53-mutant)](https://onco.cc/cancers/hpv-independent-vulvar-cancer/)
- journals: [Journal of Clinical Oncology](https://onco.cc/journals/jco/)

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