Vulvar cancer with a focal ulcer on lichen sclerosus — structured SAQ (15 marks)

(a) FIGO 2021 stage and depth of invasion (3 marks)

• Stage: Stage IB (a tumour over 2 cm in size or with stromal invasion over 1 mm, confined to the vulva with negative nodes). This tumour is 2.5 cm (over 2 cm) with invasion of 4 mm (over 1 mm). ^[1]
• Depth of invasion (FIGO 2021): measured from the basement membrane of the deepest, adjacent, dysplastic, tumour-free rete ridge (or nearest dysplastic rete peg) to the deepest point of invasion. ^[1]
• This is a change from the older method of measuring from the most superficial dermal papilla, and correlates better with outcome. ^[1]

(b) Surgical management — primary and groin (5 marks)

• Primary tumour: wide local excision (radical local excision) with a 1 to 2 cm clinical margin through healthy tissue to the deep fascia. Radical vulvectomy is reserved for large, multifocal or locally advanced disease. ^[1]
• Groin nodes: sentinel lymph node biopsy is the standard for early-stage, unifocal, node-negative disease. For a lesion over 1 cm from the midline, ipsilateral sentinel biopsy suffices; this lesion is lateralised on the right labium majus. ^[2]
• Inguinofemoral lymphadenectomy is performed only if the sentinel node is positive. ^[2]
• Stage IA (invasion up to 1 mm) would need no groin dissection — but this tumour invades 4 mm, so node assessment is mandatory. ^[1]

(c) GROINSS-V evidence (3 marks)

• GROINSS-V (Te Grootenhuis 2016) enrolled 377 women with unifocal T1 squamous cell carcinoma under 4 cm who underwent the sentinel node procedure, with inguinofemoral lymphadenectomy only for sentinel metastases. ^[2]
• At a median follow-up of 105 months, the isolated groin recurrence rate was 2.5 percent at 5 years for sentinel-node-negative patients. ^[2]
• Disease-specific 10-year survival was 91 percent for sentinel-negative versus 65 percent for sentinel-positive patients. This is the safety evidence that made sentinel biopsy the standard. ^[2]

(d) Morbidity: sentinel versus inguinofemoral (2 marks)

• Per the Rahm 2022 population-based study: persisting lymphoedema about 3.8 percent after sentinel biopsy versus about 38.6 percent after inguinofemoral lymphadenectomy; infection about 15 percent versus about 36 percent. ^[4]
• Lymphoedema is near-ubiquitous when adjuvant groin radiotherapy follows a full lymphadenectomy — the double hit. ^[4]

(e) Radiotherapy indications (2 marks)

• Positive or close surgical margins that cannot be re-resected. ^[1]
• Positive lymph nodes (especially extracapsular spread or multiple nodes); primary chemoradiation for locally advanced disease; and recurrent disease not amenable to surgery. ^[1]

Common errors that lose marks

• Staging this as Stage IA — it is over 1 mm invasion and over 2 cm, so Stage IB. ^[1]
• Recommending a full bilateral inguinofemoral lymphadenectomy for an early-stage node-negative lateralised lesion — sentinel biopsy is the standard. ^[2]
• Quoting the old depth-of-invasion method (from the dermal papilla). ^[1]
• Omitting the GROINSS-V 2.5 percent groin recurrence figure. ^[2]
• Treating differentiated VIN by ablation alone — it demands excision and lichen sclerosus treatment. ^[3]

Examiner notes

A high-scoring candidate stages this Stage IB, states the FIGO 2021 depth-of-invasion definition (from the adjacent dysplastic rete ridge), recommends wide local excision plus ipsilateral sentinel node biopsy, quotes the GROINSS-V 2.5 percent groin recurrence and the lymphoedema morbidity difference (about 4 percent versus about 39 percent), and lists the radiotherapy indications. ^[1][2][4]