Vaginal cancer and VaIN — structured SAQ (15 marks)

(a) The FIGO definition before staging (2 marks)

• 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. ^[1]
• Why: 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. Her cervix is normal and her screen was recent, which supports a primary vaginal cancer — but the rule is applied before staging.^[2]

One mark for the rule, one mark for the rationale. ^[2]

(b) FIGO staging reproduced verbatim (4 marks)

One mark per stage. ^[1][2]

• Stage I — limited to the vaginal wall.^[1]
• Stage II — invading paravaginal tissues, but not to the pelvic sidewall.^[1]
• Stage III — extending to the pelvic wall and/or the lower one third of the vagina and/or causing hydronephrosis or non-functioning kidney; with or without inguinal lymph node metastases.^[1]
• Stage IV — extending beyond the true pelvis and/or involving bladder or rectal mucosa and/or distant metastases; with or without nearby lymph node metastases.^[1]

(c) Management and the primary modality (5 marks)

Two marks for the primary modality with rationale; one mark for brachytherapy; two marks for the narrow surgical role and its criteria. ^[2][3]

• Radiotherapy is the primary treatment — external beam radiotherapy combined with brachytherapy, with a combined dose above 70 Gy, plus concurrent cisplatin 40 mg per square metre weekly. The rationale is that the vagina lies against bladder, urethra and rectum, so surgery rarely achieves clear margins.^[2][3]
• Brachytherapy is essential — SEER and NCDB data show an independent survival benefit; omitting it costs survival.^[3]
• Surgery is reserved for small (2 cm or less) stage I tumours of the proximal vagina in women who have not had prior pelvic radiotherapy, where local excision or partial vaginectomy with lymph node assessment may be considered. Pelvic exenteration is for central recurrence after radiotherapy.^[3]

(d) The HPV association and surveillance (4 marks)

One mark per point, maximum four. ^[2][4]

• Around four in five (75 to 85 per cent) vaginal squamous cell carcinomas are HPV-associated, predominantly HPV 16 and 18, mirroring the cervix through a VaIN-to-cancer sequence.^[2]
• The HPV field effect — any woman with VaIN, CIN or VIN may have a second lesion; examine the cervix and vulva at every assessment.^[2][4]
• HPV positivity is favourable for squamous cell carcinoma.^[2]
• Surveillance requires lifelong lower-genital-tract monitoring for the field effect, with cytology and HPV testing, and smoking cessation and HPV vaccination where appropriate.^[4]