Single Institution Experience of Using 24 Gy in 3 Fractions High Dose Rate Brachytherapy Once a Week Following Chemoradiation in Cervical Cancer

Purpose: Locally advanced cervical cancer is routinely treated with concurrent cisplatin and pelvic external beam radiation therapy (EBRT) followed by intracavitary (IC) or intracavitary combination interstitial (IC/IS) brachytherapy. There is significant variation regarding the doses per fraction in high dose rate (HDR) brachytherapy for cervical cancer. The fractionation schedule of 24 Gy in 3 fractions (24 Gy/3F) is less-resource intensive and more convenient for patients. We report the clinical outcomes of our single institution experience using EBRT followed by 3 fractions of HDR brachytherapy in the treatment of locally advanced cervical cancer.

Methodology: A retrospective review of 83 consecutive patients with FIGO Stage IA2 – IVB cervical cancer treated with 24Gy/3F CT-guided brachytherapy between April 2017 to October 2020 was conducted. Of these, 41 patients with at least 3 years of follow up were included for outcome analysis. Brachytherapy planning was CT based, and the 8Gy/fraction dose was prescribed to the GEC-ESTRO defined high-risk clinical target volume (HR-CTV). Descriptive statistics were used to summarize patient- and treatment-related variables.

Results: From April 2017 to October 2020, 41 patients with stage IA2-IVB cervical cancer received 24 Gy/3F HDR brachytherapy after external beam radiation of 45Gy/25 fractions over 5 weeks. 87.8% (n = 36) patients received concurrent cisplatin chemotherapy. Median overall treatment time was 53 days (range: 39 – 66). The median age of patients was 52 years (range: 28 – 77). Squamous cell carcinoma was the most common histology (71.4%). The 2018 FIGO stage distribution was: 7 I; 14 II; 17 III; 3 IV. The majority were FIGO Stage III (40.5%). The median HR CTV was 26.37 cc (IQR 21.42-32.83). Median HR CTV D90, Bladder D2cc, Rectum D2cc for all patients was 83.6 (IQR 80.9-86.1), 75.4 (IQR 71.3 – 82.1), 58.2 (IQR 54.7 – 64.8), respectively. At 3 years, 66.7% of patients were alive and 50% of patients remained disease free. Grade 3 or more short-term toxicity was seen in 1 patient (radiation dermatitis). Grade 3 or more late GI/GU toxicity was seen in 0% of the patients.

Conclusions: EBRT followed by 24Gy/3F HDR brachytherapy is a less-resource intensive and more convenient fractionation regimen for patients. Long-term follow up is needed to further assess oncologic outcomes and late toxicity.

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