Comparing dosimetric and cancer control outcomes after intensity-modulated radiation therapy and tomotherapy for advanced cervical cancer

Concurrent chemoradiation therapy (CCRT) is the standard treatment for locally advanced cervical cancer. The present study aimed to compare the therapeutic responses, toxicities and dosimetric parameters between intensity-modulated radiation therapy (IMRT) and tomotherapy (TOMO) in patients with advanced cervical cancer. This retrospective study included 310 patients with stage IIB-IIIB cervical cancer who underwent CCRT, with 155 patients in each group. Intracavitary brachytherapy was performed after a course of external beam radiation therapy (EBRT), or in the last week of pelvic EBRT. The treatment planning aim at point A (defined as a reference location 2 cm above the vaginal fornix and 2 cm beside the mid axis of the uterus) was >85 Gy in an equivalent dose at 2 Gy. There was no statistical difference with regard to clinicopathological characteristics between the two groups (P>0.05). Improved dose conformity and dose homogeneity (P<0.05) were observed in TOMO planning. TOMO provided more efficacious critical organ sparing than IMRT when assessing the percentage of normal tissue receiving at least 20 Gy (V20) for the bladder, the percentage of normal tissue receiving at least 40 Gy (V40) for the femoral head, and the V40 and V20 for the rectum (P<0.05). TOMO demonstrated a greater ability to protect the ovary (P<0.05). The acute radiation toxicity of proctitis and leukopenia were significantly lower in the TOMO group (P<0.05). The chronic radiation toxicity of radiation enterocolitis and cystitis was lower in the TOMO group (P<0.05). Thus, TOMO provided better critical organ sparing than IMRT. The radiation toxicities were acceptable. Therefore, TOMO appears to be a good option for the treatment of stage IIB-IIIB cervical cancer.