PO43  Presentation Time: 4:45 PM: Reduced Duration Intracavitary Brachytherapy in Cervix Malignancies: A Comparative Analysis from Single Institute

PURPOSE: The on-going pandemic has impacted the use of anesthesia and the operating room frequency thereby affecting the brachytherapy treatment in various institutions due to the COVID-19 protocols. This has led to single applications of Intracavitary brachytherapy (ICRT) being used to deliver entire treatment boost in cervix cancer. We present our dosimetric and early clinical outcomes comparing traditional weekly three-fractions ICRT with single application/ two-applications ICRT MATERIALS AND METHODS: In this retrospective analysis conducted in our department, a total of 39 cases, treated between January 2021 to January 2022 were evaluated for the study. Of these, 15 cases were treated with the traditional once a week applicator insertion for 3 fractions and 24 cases underwent lesser application - 20 cases underwent 2 insertions and 4 cases single insertion (all receiving total 3 fractions of 7Gy each). The dosimetric parameters were compared including CTV D90 and D95 along with rectum, sigmoid and bladder D2cc, 1cc and 0.1cc respectively. The acute toxicity assessment was done using the RTOG scale. The follow-up was undertaken as per the institutional protocol and Mann-Whitney U-test were applied to compare the cohorts. RESULTS: With a median follow-up of 6 months, the median CTV was D90%: 81.2 vs. 80.9 Gy and the median CTV volume was 44.3 vs 42.9 cc respectively. The 0.1 cm(3) and 2 cm(3) to bladder, rectum, and sigmoid were 105.6 vs 104.2 Gy and 85.5 vs 85.9Gy, 89.4Gy vs 88.7Gy and 69.1 vs 67.8Gy, and 84.7 vs 84.1Gy and 71.7 vs 69.9Gy, respectively suggesting no significant difference in the dosimetric outcomes with the two forms of applications. The less than three applications had a shorter overall treatment time with median OTT of 43 days vs. 55 days (p = 0.02). On completion of treatment and 6 months follow-up, local control was achieved in all patients. There was no significant difference in the acute toxicities in terms of cystitis and proctitis in both forms of the application. CONCLUSION: The single application/ twice application ICRT procedure showed similar outcomes as the traditional three-week duration treatment in terms of dosimetric outcomes and acute toxicities and ultimately leading to shortened overall treatment time. It also helped reduce the anesthesia burden and various resources associated with the procedure.