Toxicities And Recurrences After Co-60 High-Dose-Rate Brachytherapy For Cervical Cancer In A Tertiary Hospital In The Philippines

Abstract

Background

Brachytherapy allows for tumor dose escalation while sparing the organs-at-risk (OARs), such as the bladder and the rectum. When added to external beam radiotherapy (EBRT), brachytherapy improves survival and local control for cervical cancer patients. Despite the rising popularity of high-dose-rate brachytherapy (HDR) and use of Co-60 isotope in the country, local data on brachytherapy outcomes are lacking. The study aimed to review the incidence of recurrence, and gastrointestinal (GI) and genitourinary (GU) toxicities in cervical cancer patients treated with Co-60 intracavitary HDR brachytherapy in a tertiary government hospital in the Philippines.

Methods

Records of biopsy-confirmed, unresected, stage I-III cervical cancer patients who completed EBRT and brachytherapy between September 2016 and September 2018 were reviewed. For the analysis of outcomes and their association with patient- [age, smoking history, body mass index, histology, stage, size of mass] and treatment-related [overall treatment time (OTT), EBRT machine used, brachytherapy fractionation, dose prior to midline shielding/central tumor dose (CTD)] clinical parameters, patients who were unable to comply with institutionally-required 90-day follow-up were excluded.

Results

One hundred sixty-three (163) patient records were initially reviewed for baseline characteristics. Median age at diagnosis was 47 years. Patients were predominantly stage IIB1 (n=93,57.1%) and IIIB (n=50,30.7%). Median OTT was 129 days. For patients who had adequate (≥90 days) follow-up (n=132), median follow-up duration was 389 days. Median EBRT CTD was 46Gy. After brachytherapy, recurrence was noted in 42 patients (31.8%), with 14 (10.6%) occurring locoregionally, 17 (12.9%) distantly, and 11 (8.3%) both locoregionally and distantly. The most commonly involved sites of locoregional and distant recurrence was the uterocervix (n=16,59.3%) and paraaortics (n=42, 31.8%), respectively. Twenty-six (26) patients (19.7%) experienced GI toxicities, while 2 patients (1.5%) experienced GU toxicities. OTT was borderline significantly associated with recurrence (p=0.06), while CTD was significantly associated with toxicities (p=0.03).

Conclusion

We present outcomes of locoregional and distant recurrences, and gastrointestinal and genitourinary toxicities after chemoradiation and Co-60 HDR brachytherapy in a tertiary government hospital in the Philippines. None of the patients were able to finish the recommended OTT of 56 days. Our study suggests that OTT was weakly associated with recurrence, while CTD was significantly associated with incidence of toxicities. To our knowledge, this is the first study in the country to report on institutional brachytherapy outcomes. This study was undertaken to guide future research and policy creation in high- volume centers in the country.