Postoperative Radiotherapy in Endometrial Cancer with Comorbidities
A 68-year-old woman with FIGO stage IB grade 2 endometrioid adenocarcinoma underwent total abdominal hysterectomy and bilateral salpingo-oophorectomy with pelvic lymph node dissection. Final pathology shows 60% myometrial invasion, no lymphovascular space invasion, and negative nodes (0/12). She has a history of type 2 diabetes (HbA1c 8.5%), hypertension, and a BMI of 38. She lives 90 minutes from the cancer center. Postoperative imaging shows no residual disease. The multidisciplinary tumor board recommends adjuvant radiotherapy. She is concerned about the time commitment and side effects, especially given her diabetes and obesity.
1. What adjuvant radiotherapy approach would you recommend and why? Include target volumes, dose, and fractionation.
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For stage IB grade 2 endometrial cancer with no other risk factors, adjuvant radiotherapy reduces locoregional recurrence but does not improve overall survival. Given her comorbidities and travel distance, vaginal brachytherapy alone is preferred over pelvic external beam radiotherapy (EBRT) because it provides excellent vaginal control with minimal toxicity and fewer visits. The target volume is the vaginal cuff and upper 3-4 cm of the vagina. A common regimen is high-dose-rate brachytherapy 21 Gy in 3 fractions prescribed to 5 mm depth, or 6 Gy × 5 fractions. Pelvic EBRT (45-50.4 Gy in 1.8-2 Gy fractions) would be considered if she had high-risk features (e.g., LVSI, grade 3, deep invasion), but she does not. Brachytherapy minimizes dose to the bladder and rectum, which is important given her diabetes and obesity. She should be counseled that brachytherapy is associated with fewer GI and urinary side effects compared to EBRT.
2. How would you address her concerns about diabetes and obesity in the context of radiotherapy?
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Diabetes and obesity increase the risk of radiation-induced toxicity, particularly skin reactions, infections, and delayed healing. For brachytherapy, the risk is lower than with EBRT. However, optimizing glycemic control before and during treatment is important; we would coordinate with her primary care physician to improve HbA1c. For brachytherapy, she may need anesthesia or sedation, which carries higher risk with obesity; anesthesia evaluation is warranted. Positioning and setup may be challenging; we would use appropriate padding and monitor skin. She should be advised on skin care and monitored for infection. Given her travel distance, we could consolidate brachytherapy into a short schedule (e.g., 3 fractions over 2-3 days) to minimize trips. We would also involve a dietitian and diabetes educator. If EBRT were needed, she would be at higher risk for moist desquamation and fatigue, requiring close follow-up.