Role of bipedal lymphangiogram in radiation treatment planning for cervix cancer.

Purpose: The role of bipedal lymphangiogram in tailoring radiation portals in radical radiation therapy for Stages II or III cervix cancer is investigated.
Methods and Materials: The records and simulation films of 87 patients with Stage II or III carcinoma of the cervix treated with radical radiation therapy alone have been retrospectively reviewed.
Results: Sixty-two percent of patients who had a bipedal lymphangiogram, subsequently had their radiation fields altered from a "standard portal." The most frequently altered fields were the lateral margin of the postero anterior field and the anterior margin of the lateral fields. In order to cover the lymphatic channels in the pelvis in 90% of cases as outlined by the bipedal lymphangiogram, the lateral margins of the postero anterior fields would need to be 2.5 cm lateral to the pelvic brim and the anterior border of the lateral field, 0.5 cm anterior to the pubic symphysis.
Conclusion: "Standard" fields adequately cover the median distribution of lymphatics, but may result in a geographic miss in some patients. Bipedal lymphangiograms allow a more accurate tailoring of pelvic lymphatic fields.