Combination of external beam radiotherapy and Californium (Cf)-252 neutron intracavity brachytherapy is more effective in control of cervical squamous cell carcinoma than that of cervical adenocarcinoma

The objective of this study was to compare the effect of combined external beam radiotherapy (EBRT) and Californium (Cf)-252 neutron intracavity brachytherapy (ICBT) on cervical squamous versus adenocarcinoma. A total of 106 patients with stage IB–IIIB cervical cancer were accrued between January 2005 and May 2011 and divided into squamous cell carcinoma (SCC) and adenocarcinoma (AC) as a pair with 53 patients in each group according to tumor size, stage, age, and hemoglobin level using matched-pair design. The whole pelvic EBRT was performed with 2 Gy/fraction, 4 fractions/week. The total dose was 48–54 Gy (the center of whole pelvic field was blocked by 4 cm in width after 20–36 Gy). Cf-252 neutron ICBT was delivered with 11 and 12 Gy-eq/f with the total dose at point A of 44 and 48 Gy-eq for SCC and AC patients, respectively. The mean follow-up time was 43 months. The 5-year LC, OS, DFS, LAC rates, and mean survival time were 66.0, 56.6, 52.8.0, 17.0 %, and 76.4 ± 6.2 months, respectively, for AC patients, whereas they were 81.1, 69.8, 67.9, 11.3 %, and 93.3 ± 4.3 months, respectively, for SCC patients. Furthermore, the early treatment toxicity was mild in both groups, the late treatment complications were mainly radiation-induced proctitis and cystitis, and there were no grade 3 or higher complications. Although the combination of Cf-252 neutron ICBT and EBRT was effective in both histology types of cervical cancer, a more aggressive strategy is needed to control cervical AC.