Challenges to delivery and effectiveness of adjuvant radiation therapy in elderly patients with node-positive vulvar cancer

Abstract

Objective To examine adjuvant radiation therapy (RT) use, patterns of RT delivery, and clinical outcomes in older patients with node-positive vulvar cancer. Methods Using SEER-Medicare linked data, we identified 444 patients (age≥66 years) with node-positive squamous cell vulvar carcinoma, without distant metastases, and treated with primary surgery between 1991 and 2009. We used claims to examine RT use and the following delivery metrics: 1) completion of ≥20 fractions, 2) treatment duration <8 weeks, 3) <1 week of intra-treatment break, and 4) treatment interval from surgery to start of RT <8 weeks. We tested associations between RT use and metrics with overall (OS) and cause-specific survival (CSS) using multivariate proportional hazards regression. Results Median age was 78 years (interquartile range [IQR]=74–83). Median follow-up was 17 months (IQR=9–40). Three hundred six patients (69%) received RT. Three delivery metrics were associated with improved outcomes: completion of ≥20 fractions, treatment duration <8 weeks, and <1 week of intra-treatment break. Patients who achieved these 3 metrics demonstrated better disease outcomes compared with surgery alone (OS hazard ratio [HR] for death=0.62, 95% confidence interval [CI]=0.46–0.82, P=0.001; CSS HR=0.58, 95% CI=0.40–0.85, P=0.005). Patients not achieving RT metrics demonstrated marginal improvements in disease outcomes over surgery alone (OS HR=0.73, 95% CI=0.55–0.99, P=0.04; CSS HR=0.76, 95% CI=0.52–1.11, P=0.16). Notably, only 51% of patients who received RT achieved all benchmarks. Conclusions In this cohort of older women with node-positive vulvar cancer, achieving metrics for RT delivery was an important factor for optimizing disease benefits from treatment.

Prognostic Value of the Number of Removed Lymph Nodes in Vulvar Squamous Cell Carcinoma Patients With Node-Positive Disease: A Population-Based Study

“…Adjuvant radiotherapy has been confirmed to improve outcomes in patients with node-positive vulvar SCC in previous research ( 16 – 19 ). A total of 69.7% of the patients in our study underwent adjuvant radiotherapy; however, adjuvant radiotherapy had no effect on survival outcomes of patients, according to the results of multivariate analyses.…”

“…Adjuvant radiotherapy was not an independent predictor in our multivariate analyses. However, several studies have indicated that adjuvant radiotherapy is associated with an improvement of outcomes in patients with node-positive vulvar SCC ( 16 – 19 ). Therefore, we further analyzed the effect of adjuvant radiotherapy on survival outcomes according to the number of RLNs.…”

Vulvar Cancer, Version 1.2017, NCCN Clinical Practice Guidelines in Oncology

“…Adjuvant RT was associated with improved OS over surgery alone in this cohort of older women (HR, 0.71; 95% CI, 0.57-0.88; P=.002) along with a trend toward improved cause-specific survival (HR, 0.79; 95% CI, 0.59-1.05; P=.11). 111 Parameters for RT delivery were important among this cohort; 3-year OS and cause-specific survival were significantly improved in patients who received ≥20 fractions (3-year OS: 34% vs 26%; P=.008, and 3-year cause-specific survival: 48% vs 37%; P=.03).…”

Outcome of Radiation Therapy for Locally Advanced Vulvar Carcinoma: Analysis of Inguinal Lymph Node

“…In our study, most patients received only RT, which explains the relatively poor outcome. Cameron et al (13) observed a 24% 5-year OS following surgery and adjuvant RT. The median patient age of that study was 78 years, similar to our own, so the outcomes are comparable.…”

“…Moore DH et al reported that 4% of T3-T4 patients administered CRT have been recently shown to have a complete CR of the primary tumour (12). In surgery and radiation combination treatment, studies have reported a 3-to 4-year OS of 32%-64% (13)(14)(15). However, differences in therapy make it difficult to compare outcomes.…”