Vulvar cancer: Sentinel node biopsy

17 Mar 2008

Sentinel node biopsy can reduce surgical complications in vulvar cancer

Sentinel node biopsy should become standard treatment for selected patients with early stage vulvar cancer, concludes an observational study published in The Journal of Clinical Oncology. The research, representing the largest study ever performed on surgical techniques in vulvar cancer, demonstrates that sentinel node biopsy reduces morbidity over routine lymph node removal.

Squamous cell cancer of the vulva is a rare disease, affecting just two to three per 100,000 women per year. Treatment for early stage disease is surgical removal of the cancerous lesion followed by removal of the inguinofemoral lymph nodes that drain the groin. Only 25% to 35% of women with early-stage disease, however, actually have metastases in their lymph nodes making the remainder unlikely to benefit. Undergoing lymph node removal places women at significant risk of complications -in the short term groin wound healing is compromised by infection and breakdown in 20 to 40 % of patients, and in the long term 30 to 70 % of women suffer from lymphedema of the legs, increasing their risk of developing erysipelas (an acute disease of the skin and subcutaneous tissue caused by haemolytic streptococcus).

In the study Ate Van der Zee and colleagues, from the University Medical Centre (Groningen, Holland), set out to investigate the safety of omitting inguinofemoral lymphadenectomy in women who achieved a negative sentinel node result. Sentinel node procedures are routinely used in breast cancer, and malignant melanoma, but for vulvar cancer single institution studies have failed to reach firm conclusions regarding safety and efficacy. The procedure is based on the observation that if the sentinel node is free from cancer, the other nodes in the chain will also be free and therefore not require removal. If, however, cancer cells were detected in the sentinel node, the full inguinofemoral lymphadenectomy would need to be performed.

Between March 2000 and June 2006, 403 women with squamous cell cancer of the vulva, of less than 4cm, underwent a sentinel node procedure at 15 participating centres located throughout Europe. A total of 623 procedures were performed. To ensure quality each participating centre needed evidence to show that they had already undertaken 10 successful sentinel node procedures in vulvar cancer patients. The sentinel node procedure involved injecting a radioactive tracer and blue dye in the area around the tumour, then using a gamma detector to locate the first lymph or "sentinel" node that it drains to. The node was surgically removed and if on pathological examination found to be free of cancer cells the patient was left alone with regular observation for the next two years.

Results show that of the 259 patients with unifocal vulvar disease (in a single location) found to have a negative sentinel node in the study, only six groin recurrences were identified over a median follow up of 35 months. The three year survival of this group was 97%. "The groin recurrence rate in sentinel node-negative patients in the current study seems to be at least comparable to that reported for patients with early-stage vulvar cancer treated with formal lymphadenectomy of any type," write the authors.

In the second part of the study the investigators compared short and long term complications between patients who just underwent sentinel node removal, and those found to have a positive sentinel node who went on to have inguinofermoral lymphadenectomy. An analysis of short term morbidity showed that wound breakdown was 11.7 % for those undergoing sentinel node procedures compared to 34 % for those undergoing lymphadenectomy (P<.0001), and cellulites was 4.5 % versus 21.3 % respectively ( P<.0001). An analysis of long-term morbidity s