Vaginal cancer and vaginal intraepithelial neoplasia (VaIN): FIGO staging, the HPV association, radiotherapy-dominant management and survival by stage

A 58-year-old woman presents with three months of postcoital bleeding and a small ulcerated plaque on the upper posterior vaginal wall; her cervix is normal and her last cervical screen was normal six months ago. This is not "atrophic vaginitis" — it is primary vaginal squamous cell carcinoma until a punch biopsy proves otherwise. Your job is to confirm it is primary (not a cervical or vulvar recurrence), stage it with FIGO, route her to radiotherapy rather than a surgery that cannot achieve a clear margin, and explain why HPV drives both the lesion and her surveillance. The FIGO staging, the HPV field effect, and the radiotherapy-dominant management are the three things a fellowship candidate must defend.[1][2][3]

Overview and definition

Primary vaginal cancer is a malignant epithelial tumour arising in the vagina. It is rare — fewer than 1 per cent of all female cancers, with an estimated 17,500 new cases globally in 2020 — and the five-year survival across all stages ranges from 50 to 70 per cent.[2][9] The FIGO definition of a primary vaginal cancer is strict: a tumour involving the cervix or vulva, or a cervical or vulvar cancer within the previous five years, is classified as that cancer, not as vaginal. This rule exists because the lower genital tract shares an HPV field, and a lesion at the cervicovaginal junction is far more likely to be a cervical primary with vaginal extension than a true vaginal primary.[1][2]

Squamous cell carcinoma comprises about 80 per cent of primary vaginal cancers, adenocarcinoma 5 to 10 per cent (including the diethylstilbestrol-related clear cell adenocarcinoma), with melanoma, sarcoma and embryonal rhabdomyosarcoma (sarcoma botryoides, in children) as rarer subtypes.[2][5]