Prognostic factors include lymph node metastases. Inguinal lymph node metastatases is accompanied by a 50% reduction in long term survival. Pelvic nodal metastastases portend worse survival probabilities.
An analysis of 1124 patients treated with radical vulvectomy alone and inguinal radiation reported the following risk factors:
The GOG found two risk factors in their study on vulva cancer: tumor size > 4 cm and lymphatic space involvement. If either risk factor was present, the risk of recurrence after vulvectomy was 20% and if neither factor was present, the risk was 9%. The depth of invasion did not appear to affect outcomes.
Heaps reported a sharp rise in the risk of local recurrence with < 8 mm. Heaps suggests that this corresponds to a 1 cm surgical margin in unfixed tissue.
Surgery is the standard of care for early lesions. Radiation therapy is used for definitive treatment when lesions are in close proximity ot the urethra, clitoris or anus. Post-operative radiation therapy has been used for disease close to thes structures which are deemed unresectable without substantial additional morbidity.
Post operative radiation is offered when limited surgery has been performed for organ preservation, such as clitoris, urethra or anus. Post-operative radiation is also used with adverse risk factors:
Patients with nodal adverse features should receive adjuvant radiation to both groins and teh pelvis:
If positive margins are present, re-excision should be considered prior to radiation, if the resection margins are not in close proximity ot the uretrha, clitoris or anus. Selected patients without clinically involved nodes and at very low risk of nodal involvement (i.e. negative sentinel nodes and imaging) may be treated to the vulvar area lone using electrons or low energy photons. A generous margin around the primary should be used, and bolus may be indicated to avoid underdosing the surface of the tumor.
Dana Farber reported significant relations between post-operative margins of ≤ 5mm with the risk of localrecurrence. The vulvar relapse hazard for close margins was 3.03 (margins < 1 cm), and for positive margins was 7.02. Postoperative radiation doses of > 57 Gy reduced the risk of recurrence when compared with 50.4 Gy or less.