Tinkering With Regimen Leads to Better Outcomes in Vulvar Cancer

David H. Moore, MD

Investigators in a cooperative group trial reported that modifications in a chemoradiation regimen for locally advanced vulvar cancer boosted both clinical and pathologic complete response rates compared with historical results.

About two-thirds of patients had clinical complete responses and more than half had no evidence of disease on pathologic examination. That compared with 48% of patients who had no gross residual disease in the Gynecologic Oncology Group (GOG) 101 trial, which established a widely used chemoradiation regimen. The new trial, GOG 205, employed a higher dose of radiation but a less-intense fractionation schedule than used in GOG 101, according to details presented at the recent Society of Gynecologic Oncologists meeting in Orlando, Florida.

“Although there is still considerable room for improvement, the results of GOG 205 would indicate that this is a reasonable standard for [the] treatment of locally advanced squamous cell carcinoma of the vulva and should be the treatment program for future comparisons in prospective trials,” said David H. Moore, MD, a gynecologic oncologist at the St. Francis Medical Group in Indianapolis, Indiana.

In response to questions that followed his presentation, Moore declined to call the regimen the standard of care and instead referred to it as a standard.

Investigators in GOG 101 evaluated concurrent preoperative chemoradiation with cisplatin and 5-FU. Patients received a total radiation dose of 4760 cGy, delivered twice daily during chemotherapy. Additionally, patients had a drug holiday between the first and second cycles of therapy.

"Although there is still considerable room for improvement, the results of GOG 205 would indicate that this is a reasonable standard for [the] treatment of locally advanced squamous cell carcinoma of the vulva and should be the treatment program for future comparisons in prospective trials."

—David H. Moore, MD

In GOG 205, patients received a total radiation dose of 5760 cGy administered in single daily fractions. Chemotherapy consisted of weekly cisplatin at a dose of 40 mg/m2. Investigators also eliminated the treatment break. The primary endpoint was pathologic complete response, which occurred in half of the 58 patients enrolled in GOG 205. Additionally, 37 (64%) of the patients had clinical complete responses. The principal toxicities were hematologic adverse events, radiation-related dermatitis, pain, and metabolic disturbances.

Responding to another question, Moore suggested that the increased radiation dose probably accounted for most of the improvement in GOG 205 compared with GOG 101. Elimination of the treatment break also might have made a difference.