Vulvar cancer

Nodal drainage
Superficial and deep inguinal nodes
Cloquet's node: superior-most deep inguinal node; lives under the inguinal ligament

Epidemiology
3700 cases, 900 deaths per year in US

Risk factors
The usual suspects: HPV, immune suppression, herpes simplex, prior vaginal/cervical cancer
Diabetes
Hypertension
Low SES
Smoking
Working in dry cleaning
Vulvar intraepithelial neoplasia, leukoplakia
Vulvar cancer associated with a higher incidence of non-gynecologic malignancy as well

Pathology
Labia most common site
Precursor lesion = lichen sclerosis
85% are squamous cell, 10% melanoma
Paget's disease of vulva: associated with underlying invasive cancer in 20-30%
Confluent lesions - highly invasive
Compact lesions - usually well differentiated
Fingerlike lesions - usually infiltrative with high rates of LVSI

Clinical
75% of palpable inguinal nodes are positive upon dissection
30% of patients with positive inguinal nodes have positive pelvic nodes
Prognostic factors: nodes are most important; tumor size and depth of invasion determine nodal risk; others include tumor grade, LVSI, age.

Therapy
Almost all patients require inguinal node dissection (can only omit if the tumor is less than 1mm deep)
Margins should be at least 1cm in fresh specimens, 8mm in fixed
There are two famous trials in vulvar cancer:
1) Patients who already had known inguinal disease after inguinal dissection were randomized to pelvic and bilateral groin RT to 50Gy. RT improved overall survival at two years (68 vs 54%). The largest advantage to RT was seen in patients with at least 2 nodes or fixed/ulcerated nodes.
2) Patients with clinically negative groins were randomized to radical vulvectomy with inguinal dissection vs. radical vulvectomy with inguinal RT to 50Gy.  The trial was stopped early due to better survival in the surgery group (88 vs 63% at 3 years).  There was a 0% risk of groin failure in the surgery group and an 18% risk in the RT group.  This trial has been roundly criticized for the fact that the fields were prescribed to a depth of 3cm which is not deep enough to adequately cover the inguinal nodes in most women.  Furthermore, if patients had + nodes on surgery, RT was given (20% of women).