Extended-Field Irradiation Deemed Essential in Treating Selected Cervical Cancer Patients
Ten-year survival data of patients with high-risk cervical cancer emphasize the need for extended-field irradiation, according to
Ten-year survival data of patients with high-risk cervical canceremphasize the need for extended-field irradiation, according tothe Radiation Therapy Oncology Group. The absolute survival was55% for the patients who received the extended-field irradiationvs 44% for patients treated with pelvic irradiation alone, datafrom RTOG protocol 79-20 show.
Patients with stage IB or IIA primary cervical cancers measuring4 cm or greater in diameter and patients with stage IIB cancerswere randomized to receive either standard pelvic irradiationor pelvic plus para-aortic irradiation. There were 337 analyzablepatients in the study. "We believe the reason for the improvedsurvival was patients who completely responded to the extended-fieldtreatment had a lower incidence to distant metastases than theircounterparts treated on the other arm of the study," saysMarvin Rotman, MD, chair of the study. In addition, there wasa significantly better salvage rate in the complete responderswho later failed locally, he says.
Patients on the pelvic irradiation alone arm of the study received40 to 50 Gy to the pelvic area in 4.5 to 6.5 weeks, 5 days a week.Patients treated with para-aortic irradiation received 44 to 45Gy delivered in 4.5 to 5.5 weeks, 5days a week. The pelvis thenreceived 20 Gy and the para-aortic fields were treated with anadditional 15 Gy.
All patients also underwent brachytherapy to a total dose of 4,000to 5, 000 mg/h of radium equivalents.
Disease-free survival was similar in both arms (40% for the pelvicirradiation alone arm and 42% for the pelvic plus para-aorticirradiation arm). Locoregional failure rates also were similar(35% for pelvic and 31% for pelvic plus para-aortic irradiation).
The cumulative incidence of grade 4 and 5 toxicities at 10 yearsin the extended-field arm was 8.4%, as compared with 3.8% in thepelvic irradiation only arm. Complications were found more oftenin patients with prior abdominal surgery, Dr. Rotman says.
