Vulval Cancer

Introduction

Vulval cancer is a rare gynaecological malignancy, predominantly affecting older, postmenopausal women, with an average age at diagnosis in the 60s-70s. Squamous cell carcinoma accounts for the great majority of cases (around 90%), with melanoma, Bartholin's gland carcinoma, basal cell carcinoma and sarcoma making up the remainder.¹

Diagnosis is often delayed - symptoms can overlap substantially with common benign vulval skin conditions (particularly lichen sclerosus), and both patients and clinicians can be slow to investigate persistent vulval symptoms, whether from embarrassment, misattribution to a benign cause, or under-recognition of vulval cancer as a differential. Any persistent, unexplained vulval symptom deserves careful examination and a low threshold for biopsy.

Aetiology: two distinct pathways

Vulval squamous cell carcinoma arises via two distinct pathogenic routes, which behave differently and affect different populations - understanding this split makes sense of the risk factors and precursor lesions.²

This split mirrors, but is distinct from, the pattern seen in cervical cancer (uniformly HPV-driven) - vulval cancer is unusual among gynaecological cancers in having this genuinely dual aetiology, which is a frequently tested point of distinction.

Risk factors

• Lichen sclerosus: the strongest risk factor for HPV-independent disease, carrying roughly a 4-5% lifetime risk of progression to vulval SCC (see the lichen sclerosus article)
• Persistent high-risk HPV infection: the driver of HPV-associated disease, with shared risk factors to cervical HPV exposure (smoking, immunosuppression, multiple partners)
• Lichen planus: another chronic inflammatory vulval condition associated with increased risk
• Smoking: increases risk, particularly for HPV-associated disease
• Immunosuppression: HIV, transplant recipients - impairs clearance of HPV and increases risk
• Increasing age
• Previous cervical or vaginal intraepithelial neoplasia/cancer: reflects a shared HPV-driven field effect across the lower genital tract

Clinical features

Presentation is often insidious, with symptoms that can be mistaken for, or coexist with, a benign vulval skin condition - one reason presentation and diagnosis are so often delayed.³

• Persistent vulval itch or soreness, often longstanding and not responding as expected to standard treatment for a presumed benign cause
• A vulval lump or mass: may be raised, warty, ulcerated, or plaque-like
• Vulval ulceration that does not heal
• Bleeding or discharge from a vulval lesion
• Pain, though some lesions are painless and found incidentally
• A palpable groin lump: enlarged inguinal lymph node(s) from metastatic spread, sometimes the presenting feature

Examination should assess the site, size and character of any lesion, and specifically palpate the groins for lymphadenopathy, since nodal involvement is central to both staging and prognosis.

Differential diagnosis

• Lichen sclerosus or lichen planus without malignant change - the most common reason for chronic vulval symptoms
• Vulval intraepithelial neoplasia (VIN): the pre-invasive precursor - itself needs biopsy and specialist management to exclude/detect early invasion
• Bartholin's cyst or abscess: typically more acutely painful and fluctuant
• Genital warts (condylomata acuminata): benign HPV-related lesions, usually multiple and soft
• Vulval psoriasis or eczema
• Melanoma: a pigmented vulval lesion needs the same urgency as cutaneous melanoma elsewhere

Investigations

Biopsy

The essential investigation for any suspicious vulval lesion, providing histological diagnosis and distinguishing invasive cancer from VIN or a benign process. Vulvoscopy (colposcopic examination of the vulva) can help identify the most representative area to biopsy, particularly with multifocal disease.

Staging investigations

Once cancer is confirmed, groin ultrasound ± fine needle aspiration assesses clinically or radiologically suspicious inguinal nodes. MRI pelvis assesses local extent and depth of invasion, and CT chest/abdomen/pelvis or PET-CT assesses for more distant nodal or metastatic spread in higher-risk disease.

Staging and spread

Vulval cancer uses surgical-pathological FIGO staging. Spread occurs primarily by direct local extension to adjacent structures (vagina, urethra, anus) and by lymphatic spread to the inguinofemoral lymph nodes, with the risk of nodal involvement rising with depth of invasion and lesion size.⁴

Inguinofemoral lymph node status is the single strongest prognostic factor in vulval cancer, more so than local tumour stage alone - this is the central reason nodal assessment is such a core part of both staging and management.

Management

Management is individualised by lesion size, depth of invasion, and nodal status, planned via a specialist gynaecological oncology MDT.¹

Surgery

Wide local excision with an adequate tumour-free margin is the mainstay for localised disease, aiming to preserve as much normal anatomy and function as possible. Radical vulvectomy (more extensive excision) is reserved for larger or multifocal tumours.

Groin (inguinofemoral) node management

• Sentinel lymph node biopsy: for early-stage, unifocal tumours with clinically node-negative groins, identifying and removing only the first draining node(s) to reduce the morbidity of full lymphadenectomy while still providing nodal staging
• Inguinofemoral lymphadenectomy: full groin node dissection for larger tumours, multifocal disease, or where sentinel node biopsy is not suitable/available, or confirms nodal involvement

Chemoradiotherapy

Used for locally advanced disease not amenable to primary surgical resection without unacceptable functional loss, for close/involved surgical margins, or for confirmed nodal involvement (as adjuvant treatment), often combining external beam radiotherapy with concurrent chemotherapy.

Complications

• Lymphoedema of the lower limb(s) following inguinofemoral lymphadenectomy - a common and often long-term complication
• Wound breakdown or infection after vulval surgery
• Sexual dysfunction and altered body image following vulvectomy
• Urinary or defecatory dysfunction if the tumour or its treatment involves the urethra or anus
• Lymphocyst formation in the groin after lymphadenectomy
• Psychological impact, which is often underestimated given the sensitive anatomical site involved

Prognosis

Prognosis for early-stage, node-negative vulval cancer is good, with high survival rates after adequate surgical excision. Prognosis falls substantially once inguinofemoral lymph nodes are involved, and falls further with an increasing number of involved nodes - reinforcing why accurate nodal assessment shapes both the treatment plan and the prognostic conversation with the patient. Given the association with lichen sclerosus, ongoing surveillance of women with this condition, and prompt biopsy of any new or changing lesion, remains an important opportunity for earlier detection.