Abstract:
The adverse effect on treatment outcome for prolongation of overall treatment time (OTT) in radiotherapy has been reported in some studies. This study aimed to clarify the influence of OTT on the efficiency of radiotherapy in cervical cancer. The records of 122 cervical cancer patients with squamous cell carcinoma (stage IIB to IIIB) underwent definitive radiotherapy in year 2009-2013 were retrospective studied. The patients received the totally equivalent dose 2 Gy (EQD2) cumulative dose at point A which consisted of external beam radiotherapy of 44 Gy whole pelvic then midline block to 50 Gy, followed by parametrium boost to 56 Gy and Ir-192 intracavitary brachytherapy with point A dose of 7 Gy for 4 fractions. The patients were separated into 2 groups based on OTT recommended by American Brachytherapy Society, OTT ≤ 56 day (group 1) and > 56 day (group 2). Kaplan-Meier and Log-rank were tested for the difference between 2 groups. Cox regression was used for univariate and multivariate analysis (MVA) to identify the prognostic factor. Chi-square test was used to evaluate the relations between the 2 groups nonparametric.
OTT ranged 44-88 day. EQD2 ranged 83.7-86.1 Gy. Local control rate (p = 0.791), distant metastasis free survival rate (p = 0.978), Disease Free Survival (DFS) (p = 0.980), cause specific survival (p = 0.425) and Overall Survival (OS) (p = 0.991) were not significantly different between 2 groups. MVA identified tumor size as the prognostic factor of DFS (p = 0.009) and stage for OS (p = 0.010). There was no statistical difference in both acute and late complication [skin (p = 1.000,N/A), subcutaneous tissue (p = 0.611, p = 0.849), gastrointestinal system (GI) (p = 0.672, p = 0.601) and genitourinary system (p = 0.670, p = 0.849), respectively]. The EQD2 cumulative rectal dose was further analyzed, < 70 Gy3 (group 1) and ≥ 70 Gy3 (group 2), there were no significance different in acute GI complication (p = 0.647) and late GI complication (p = 0.302).
Our results revealed that no influence of OTT on the treatment outcome, survival and complications. The prognostic factor of DFS was tumor size while stage was the prognostic factor for OS. There was no relation between rectal dose to both acute and late GI complication.