Carcinoma of the uterine cervix .2. Lack of impact of prolongation of overall treatment time on morbidity of radiation therapy

Purpose: Several reports document a negative impact of prolongation of overall treatment time in a course of irradiation on tumor control and survival. A correlation has been documented of incidence of significant treatment sequelae with increasing doses of irradiation, volume of the specific organ, and dose per fraction. However, no data were found on the potential correlation of overall irradiation treatment time with significant sequelae. Methods and Materials: Records were reviewed of 1269 patients with carcinoma of the cervix (Stage IB to III) treated with definitive irradiation (combination of external beam and two intracavitary insertions). Follow-up was obtained in 97% of patients (median, 12 years; minimum, 3 years; maximum, 28 years). The relationships between overall treatment time and time of brachytherapy and incidence of treatment sequelae were analyzed for each stage. Results: Overall incidence of Grades 2 (moderate) sequelae was 7% and of Grade 3 (severe) sequelae, 11%. There was no significant correlation of various incidences of Grade 2 and 3 sequelae with overall treatment times (8% in patients treated in less than 7 weeks, 9% in 7.1 to 9 weeks, and 12% when treatment time was longer than 9 weeks) (p = 0.08). In patients with Stage IB and IIA tumors, incidence of rectal toxicity (mostly proctitis) was comparable in patients treated in less than 7 or 7.1 to 9 weeks (4.1 and 6%, respectively) and slightly higher in those treated in longer periods (11.5%) (p = 0.24). In patients with Stage IIB and III, the incidence of Grade 2 and 3 small bowel morbidity was 2% in those treated in less than 7 weeks, 6% for 7.1 to 9 weeks, and 4.9% for longer times (p less than or equal to 0.01). This increased morbidity was also correlated with total dose of irradiation to the lateral pelvic wall: 5 of 257 (2%) for less than 60 Gy and 21 of 438 (4.8%) for higher doses (p less than or equal to 0.01). There was no significant correlation between the timing of brachytherapy (usually two low dose rate intracavitary insertions performed within 4.5 to 6.5 weeks of initiation of external beam therapy) and significant treatment sequelae. Conclusions: We observed a varied average incidence of Grade 2 and 3 morbidity in the bladder, rectum, and small intestine with different overall treatment times, without a definite pattern to suggest an impact of prolongation of treatment time on morbidity. Likewise, there was no significant correlation with the timing of intracavitary insertions and morbidity of therapy. Because prolongation of the overall treatment time has a well-documented detrimental effect on pelvic tumor control and survival in carcinoma of the cervix with no significant impact on morbidity, it is imperative to deliver radiation therapy in the shortest possible time and without schedule interruptions.