A comparison of intracavitary versus interstitial irradiation in the treatment of cervical cancer

Objective, Management of locally advanced cervical cancer consists primarily of combination external and internal radiation, In order to investigate the impact of intracavitary brachytherapy versus interstitial brachytherapy on local tumor control, survival, and complications, we retrospectively reviewed the concomitant experience of two institutions, each of which practice exclusively one of these radiotherapeutic techniques. Methods. Between 1979 and 1989, 61 patients with bulky stage II, III, or TVA cervical cancer were treated using a combination of teletherapy and intracavitary brachytherapy at one institution, while 70 similar patients were treated with teletherapy and interstitial brachytherapy at another institution, Patients in both groups were similar with respect to age, FIGO stage, tumor size, surgical stage, and histologic subtype, Patients treated with intracavitary therapy received a mean cumulative dose of 7706 cGy to point A and 5523 cGy to point B using standard Fletcher-Suit techniques, Those who received interstitial irradiation were treated with a mean external dose of 5050 cGy and 2 interstitial implants using a transperineal Syed-Neblett template with a mean tumor dose of 2239 and 1,942 cGy with each application, respectively, Patients treated with chemoradiation were excluded from this review. Results. Although initial rates of local control were not different, prolonged 5-year disease-free survival(50% vs 21%, P = 0.01) and improved 5-year local control (61% vs 32%, P = 0.01) were observed among patients with stage II disease treated with intracavitary irradiation, No statistical differences in survival could be detected among stage III and IVA patients. Women treated with intracavitary irradiation received a larger dose of brachytherapy than those treated with interstitial therapy (4608 vs 3504 radium milligram hours equivalent, P < 0.0001) because a tandem was only used in 17 (24%) interstitial implants. Major complications occurred in 21% of patients in each group. Conclusion. When a tandem is infrequently used during interstitial brachytherapy, the toxicity is similar to that of intracavitary techniques, However, more relapses are observed among patients with stage II lesions treated with interstitial irradiation. (C) 1997 Academic Press.