Positron emission tomography versus computed tomography -guided intracavitary brachytherapy for locally advanced...

To compare early clinical outcomes in patients with locally advanced cervical cancer (LACC) treated with positron emission tomography-computed tomography (PET-CT) versus CT-guided intracavitary brachytherapy (ICBT) after external beam radiation therapy (EBRT).

Patients with carcinoma cervix, stage IIB to IIIB, receiving EBRT with concurrent weekly cisplatin were randomized into two arms: PET-CT versus CT-guided ICBT arms. High-risk clinical target volume (HRCTV), rectum, bladder, and sigmoid colon were contoured. Planning, local control (LC), overall survival (OS), and toxicities were evaluated.

Fifty patients (25 in each arm) were recruited from September 2019 to April 2021. The mean dose to HRCTV D90 and D95 was 87.7 Gy (SD 6.1 Gy) and 83.04 Gy (SD 5.5 Gy) in PET-CT and 85.6 Gy (SD 6.4 Gy) and 80.6 Gy (SD 5.7 Gy) in CT arm (P value 0.13). The mean dose to bladder, rectum, and sigmoid colon was 80.3 Gy (SD 8.2 Gy), 70 Gy (SD 6.1 Gy), and 66.2 Gy (SD 7.4 Gy) in PET-CT and 79 Gy (SD 6.9 Gy), 70.2 Gy (SD 7.2 Gy), and 64.9 Gy (SD 6.3 Gy) in the CT arm (P value 0.58, 0.88, and 0.55). On intention to treat analysis, the 6 months LC rate was 79.1% in PET-CT and 72.7% in CT arm (P value 0.3). On per protocol analysis of 46 patients, OS was 82.9% in PET-CT and 89% in CT arm at 2 years (P value- 0.6). No Grade III/IV Bowel/Bladder toxicities were reported.

Results of our study have shown comparable outcomes in terms of LC, OS, and toxicities between both arms; however, LC was slightly better in PET-CT arm, though not statistically significant. Further studies with a larger sample size should be conducted to establish the role of PET-CT-guided ICBT in LACC.