Main Session
Sep
29
PQA 06 - Genitourinary Cancer, Gynecological Cancer, and Health Care Access and Engagement
3787 - Locally Advanced Cervical Cancer Treated with Definitive Chemo and Radiation with Brachytherapy Boost: Dosimetry Comparison of Multi Plan with Single Plan Brachytherapy Approach
Presenter(s)
Suvidya Pachigolla, MD, MS, BS - Northwestern Feinberg School of Medicine, Chicago, IL
S. Pachigolla1, S. Kumaresan2, C. Kumaran Nair3, J. Wong4, and E. D. Donnelly1; 1Department of Radiation Oncology, Northwestern Memorial Hospital, Chicago, IL, 2Northwestern University Feinberg School of Medicine, Chicago, IL, United States, 3Northwestern Memorial Hospital, Chicago, IL, 4Department of Radiation Oncology, Feinberg School of Medicine, Northwestern University, Chicago, IL
Purpose/Objective(s): Standard of care for locally advanced cervical cancer consists of a combination of pelvic external beam radiation therapy, systemic therapy and brachytherapy. High-Dose Rate (HDR) Brachytherapy can be performed as an outpatient through multiple insertions, interdigitated with external beam radiation, or as an inpatient through a single or limited number of insertion(s). In this abstract, we compared the dosimetric impact of a single insertion plan and multi-insertion plans. We hypothesize that due to tumor downsizing and ability to improve brachytherapy adapter geometry, the multi-insertion plan would offer improved tumor coverage and OAR sparing.
Materials/Methods:
This was a single-site, retrospective review of patients with locally advanced cervical cancer treated with definitive chemoradiation and HDR brachytherapy from 2014 to 2024 at a high-volume academic medical center network referral center. Patients were identified from a radiation oncology database of cervical cancer patients. Clinical, pathologic, and treatment characteristics with outcomes were extracted. Dosimetric values including HR-CTV D90, and Bladder/Rectum/Sigmoid/Bowel D2cc, were extracted automatically. Inpatients received a single insertion (SI), and the brachytherapy plan was repeated for each fraction. Outpatients received multi-insertions (MI) and a custom plan for each fraction of brachytherapy. For the outpatient brachytherapy patients, we compared the actual dosimetric values of the sum of the multiple plans with the theoretical sum of the first plan as if treating all 5 fractions in a single insertion.Results:
A total of 141 patients treated with definitive chemoradiation and HDR brachytherapy were included. Overall, 118 (83.7%) were treated with a single insertion as inpatients, 23 (16.3%) were treated as outpatients with multi-insertions. Mean HR-CTV D90 was comparable between MI and SI treatment strategies (87.83 Gy vs 87.08 Gy), indicating equivalent target coverage. There was no significant statistical difference between dosimetric parameters for organs at risk. Bladder D2cc was 70.27 Gy for MI versus 67.63 Gy for SI. Rectum D2cc was 55.48 Gy versus 56.90 Gy. Sigmoid D2cc was 60.75 Gy versus 63.27 Gy. Bowel D2cc was 58.02 Gy versus 54.27 Gy.Conclusion:
Multi-insertion plans demonstrated no dosimetric difference for both tumor volume coverage and organs at risk. Further data evaluating impact on health care resources, cost and patient reported outcomes can influence appropriate brachytherapy regimens when selecting between inpatient and outpatient models.