C. Tanaka

Outcomes after radiation therapy with concurrent weekly platinum-based chemotherapy or every-3–4-week 5-fluorouracil-containing regimens for squamous cell carcinoma of the vulva

OBJECTIVE To compare outcomes in patients with squamous cell carcinoma (SCC) of the vulva treated with radiation (RT) and concurrent weekly platinum-based or every-3-4-week regimens containing 5-fluorouracil (5-FU). METHODS Records of 44 patients with vulvar SCC treated with concurrent chemotherapy and radiation (chemoRT) from 1988 to 2008 were reviewed. Rates of disease-free survival (DFS), overall survival (OS), locoregional recurrence (LRR), and distant metastases (DM) were estimated using the Kaplan-Meier method. RESULTS The median age was 63 years (range, 44-90), 84.1% of patients had ECOG performance status 0-1, and patients had FIGO Stage II (n=6), III (n=31), or IVA (n=7) disease. Patients were treated preoperatively (n=10), postoperatively (n=10), or without surgery (n=24). The median RT dose to the vulva was 50.2 Gray (range, 22-75). Concurrent chemotherapy regimens included weekly platinum (n=16) or every 3-4 week regimens with 5-FU as the backbone (n=28). With a median follow-up of 31.5 months, there was no significant difference in 2-year OS (74.5% vs. 70.0%; p=0.65), DFS (61.9% vs. 56.0%; p=0.85), LRR (31.3% vs. 32.9%; p=0.93), or DM (6.3% vs. 10.6%; p=0.81) between the weekly platinum and every-3-4-week 5-FU regimens. Twenty patients (45.4%) recurred: 16 LRR, 2 DM, and 2 with both. The clinical and pathologic complete response rates were 58.8% (20/34), and 53.8% (14/26), respectively. There was a higher proportion of grade 3 or higher acute non-skin toxicities in patients receiving every-3-4-week 5-FU (46.1% vs. 13.3%; p=0.07), but more grade 3 or higher skin toxicity in patients receiving weekly platinum (62.5% vs. 32.0%; p=0.01). CONCLUSION OS, response rates, and recurrence rates were not significantly different after RT with concurrent weekly platinum-based versus every-3-4-week regimens containing 5-FU for vulvar SCC.

Prognostic importance of human papillomavirus (HPV) and p16 positivity in squamous cell carcinoma of the vulva treated with radiotherapy

OBJECTIVE HPV status is an important prognostic factor for patients with oropharyngeal, anal and cervical cancers treated with radiotherapy. This study evaluates the association between HPV and p16 status and outcome in a radiation-treated cohort with vulvar squamous cell carcinoma (SCC). METHODS Patients with vulvar SCC who received radiotherapy with or without surgical resection between 1985 and 2011 were identified retrospectively. Immunostaining for p16 and multiplex PCR for HPV genotyping were performed using archival tumor tissue from 57 patients. Actuarial estimates of PFS, OS and in-field recurrence were calculated using the Kaplan-Meier method. Cox proportional hazards models were used for multivariable analysis. Median follow-up was 58months among the 57 patients with an available tumor specimen. RESULTS HPV prevalence was implied in 37% by (diffuse linear) p16 immunostaining and confirmed in 27% by HPV PCR with good agreement (κ=0.7). HPV-16 was identified in 80% of HPV-positive tumors. Women with p16-positive tumors had significantly higher 5-year PFS (65% vs. 16%, p<0.01) and OS (65% vs. 22%, p=0.01) rates, as well as lower in-field relapse rates (19% vs. 75%, p<0.01) compared to those with p16-negative disease. On multivariable analysis adjusted for age and stage, p16 positivity was significantly associated with better PFS (HR 0.4, 95% CI 0.2-0.9) and lower rates of in-field relapse (HR 0.2, 95% CI 0.06-0.6). Results were similar when analyzed by HPV DNA status. CONCLUSION In this study, the presence of HPV or its surrogate of p16 immunostaining was an independent prognostic factor for in-field relapse and survival in women with vulvar SCC treated with radiotherapy. This finding warrants validation in larger cohorts or the prospective setting.