Prophylactic irradiation of the para-aortic lymph node chain in stage iib and bulky stage ib carcinoma of the cervix, initial treatment results of RTOG 7920

Abstract

From November 1979 to October 1986, 367 patients were entered onto RTOG 7920 and randomized to receive either pelvic irradiation alone or pelvic plus para-aortic radiation. Patients with Stage IIB cervical carcinoma who had not undergone curative surgery and patients with Stages IB and IIA cervical carcinoma who were determined by digital exam to have primary tumors measuring 4 cm or greater in lateral dimension were eligible for this study. Clinically apparent or surgically involved para-aortic nodes were reason for exclusion from the study. Pelvic irradiation consisted of 1.6–1.8 Gy per day for 5 days per week to a total of 40–50 Gy. Para-aortic irradiation delivered 44 to 45 Gy in 1.6–1.8 Gy per day, 5 days per week. Pelvic irradiation was to be completed in 4 1 2 to 6 1 2 weeks and para-aortic irradiation in 4 1 2 to 5 1 2 weeks. Intracavitary brachytherapy delivered a total of 4000–5000 mg hr of radium-equivalents or 30–40 Gy to point A. Patients were stratified prior to random treatment assignment by histology, para-aortic nodal status (negative vs. unevaluated), and FIGO stage. As of June 1, 1989, 30 cases were excluded, including five patients who were inevaluable. Two patients who refused the assigned treatment were also excluded. Therefore, a total of 330 cases were analyzable. At 5 years the estimates of survival, the primary endpoint, for the pelvic only and pelvic plus para-aortic irradiation arms are 55% and 65%, respectively ( p = 0.043). Several secondary endpoints were also analyzed. Estimates for loco-regional control at 5 years are, for pelvic irradiation only, 66%, and for pelvic plus para-aortic irradiation, 75% ( p = 0.21). Distant metastases are estimated in 32% of pelvic irradiation only patients and 25% of pelvic plus para-aortic irradiation patients at 5 years ( p = 0.17). When the first disease failure patterns are examined, more patients fail distally when treated only with pelvic radiation than when using pelvic plus para-aortic fields ( p = .04). In analysis of patients with grade 3 (severe), grade 4 (life-threatening), and grade 5 (fatal complications), 8% of the patients in both groups had grade 3 severe complications. In the pelvic plus para-aortic group, 11 patients had grade 4 and 2 had grade 5 complications, whereas 6 had grade 4 and none had grade 5 in the pelvic only treatment group. In patients with prior abdominal surgery, the pelvic plus para-aortic group had a higher rate of grade 4 and 5 complications ( 11%− 7 62 vs. 2%− 1 49 ). Patients without prior surgery showed no striking complication difference between the two groups. Prophylactic treatment of the para-aortic lymph node chain appears to have a statistically positive impact on the survival rate of women with early cervical cancer. A trend favoring such treatment has also been noted in terms of loco-regional disease control, NED survival, and time to distant metastases.