Evidence (low-dose rate vs. high-dose rate intracavitary radiation therapy):
Although low-dose rate (LDR) brachytherapy, typically with cesium Cs 137, has been the traditional approach, the use of high-dose rate (HDR) therapy, typically with iridium Ir 192, is rapidly increasing. HDR brachytherapy provides the advantage of eliminating radiation exposure to medical personnel, a shorter treatment time, patient convenience, and improved outpatient management. The American Brachytherapy Society has published guidelines for the use of LDR and HDR brachytherapy as a component of cervical cancer treatment.[14,15]
In three randomized trials, HDR brachytherapy was comparable with LDR brachytherapy in terms of local-regional control and complication rates.[16,17,18][Level of evidence: 1iiDii]
In an attempt to improve upon standard chemoradiation, a phase III randomized trial compared concurrent gemcitabine plus cisplatin and radiation therapy followed by adjuvant gemcitabine and cisplatin (experimental arm) with concurrent cisplatin plus radiation (standard chemoradiation) in patients with stages IIB to IVA cervical cancer.[Level of evidence: 1iiA] A total of 515 patients from nine countries were enrolled. The schedule for the experimental arm was cisplatin (40 mg/m2) and gemcitabine (125 mg/m2) weekly for 6 weeks with concurrent EBRT (50.4 Gy in 28 fractions) followed by brachytherapy (30-35 Gy in 96 hours) and then two adjuvant 21-day cycles of cisplatin (50 mg/m2) on day 1 plus gemcitabine (1,000 mg/m2) on days 1 and 8. The standard arm was cisplatin (40 mg/m2) weekly for 6 weeks with concurrent EBRT and brachytherapy as described for the experimental arm.
The primary endpoint was progression-free survival (PFS) at 3 years; however, the study found improvement in the experimental arm for PFS at 3 years (74.4%; 95% confidence interval [CI], 68%-79.8% vs. 65.0%; 95% CI, 58.5%-70.7%); overall PFS (hazard ratio [HR], 0.68; 95% CI, 0.49-0.95); and OS (HR, 0.68; 95% CI, 0.49-0.95). Patients in the experimental arm had increased hematologic and nonhematologic grade 3 or 4 toxic effects, and two deaths in the experimental arm were possibly related to treatment.
A subgroup analysis showed an increased benefit in patients with a higher stage of disease (stages III-IVA vs. stage IIB), which suggested that the increased toxic effects of the experimental protocol may be justified for these patients. Additional investigation is needed to determine which aspect of the experimental arm led to improved survival (i.e., the addition of the weekly gemcitabine, the adjuvant chemotherapy, or both) and to determine quality of life during and after treatment, a condition that was omitted from the protocol.