Complication Rates After Intraoperative Radiation Therapy: Do Applicator Size and Distance to Skin Matter?

BACKGROUND: Intraoperative radiation therapy (IORT) has gained popularity for early stage breast cancer treatment. Few studies have examined the relationship between complications and both demographic and technical factors. The objective of the current study was to determine if applicator size or distances to the skin were significant risk factors for complications. METHODS: Data was prospectively collected on patients who underwent lumpectomy followed by IORT from November 1, 2013 to August 31, 2018. Exclusion criteria included any prior radiation exposure or personal history of breast cancer. Comorbid conditions such as body mass index, diabetes, and smoking as well as technical specifications such as applicator size and distances to the skin were included for investigation. Student's t-test, Fisher's exact test, and odds ratios were utilized for statistical analysis. RESULTS: The study was comprised of 219 patients. None developed Clavien-Dindo grade 2 or above complications. Of 21.0% (n = 46) had minor complications. The most common complication was a palpable breast seroma (n = 37). Diabetes was the only comorbid condition with increased risk for complications (OR 3.2; 95% CI1.3-7.5; P = 0.008). The applicator sizes and average skin distances were similar between groups. Surprisingly, the closest skin distance was not a significant risk factor for post-operative complications (1.4 +/- 1.6 versus 1.4 +/- 1.9 cm; P = 1.0). CONCLUSION: Neither applicator size nor the closest skin distance were associated with increased complications. Traditionally described risk factors such as BMI and smoking were not predictive. This data provides support for potentially expanding the utilization for IORT without increasing complications.