title: Effects of treatment duration during concomitant chemoradiation therapy for cervical cancer.
abstract: OBJECTIVE
  To determine whether extended treatment duration (TD) impacts in-field relapse and survival in the setting of concomitant chemoradiation therapy (CRT) for cervical cancer.
  
  
  METHODS
  A total of 480 consecutive cervical cancer patients treated with radiation therapy (RT) alone or concomitant CRT for curative intent were retrospectively analyzed. Relapse was defined as in-field with respect to external beam radiation therapy fields. The effects of TD on in-field relapse, disease-free survival (DFS), and overall survival (OS) rates were assessed continuously and categorically within the separate RT and CRT cohorts. Covariates included age, histology, stage, and cumulative dose to point A. In-field relapse, DFS, and OS rates were estimated with Kaplan-Meier analysis; comparisons used log-rank statistic. Multivariate analysis used the Cox proportional hazards model.
  
  
  RESULTS
  A total of 372 patients (RT n=206, CRT n=166) were evaluable, with a median follow-up for relapse-free patients of 4.2 years (RT 4.4 years, CRT 4.2 years; P=.807). Treatment duration was longer in the RT cohort (median 55 days; range 35-99 days) versus the CRT cohort (median 51 days; range 35-92 days) (P=.001). In the RT cohort, TD ≥62 days trended to significance for predicting inferior DFS (hazard ratio 1.42, 95% confidence interval 0.86-1.98, P=.086). However, in the CRT cohort, TD assessed continuously or categorically across multiple cutoff thresholds did not predict for in-field relapse, DFS, or OS.
  
  
  CONCLUSIONS
  With RT alone, extended TD ≥62 days may adversely impact treatment efficacy. With the addition of concomitant chemotherapy to RT, however, extended TD has no effect on treatment efficacy.
authors.affiliation: Department of Human Oncology, University of Wisconsin School of Medicine and Public Health, Madison, WI 53792, USA.
authors.forename: Narek
authors.initials: N
authors.lastname: Shaverdian
authors.forename: Vinai
authors.initials: V
authors.lastname: Gondi
authors.forename: Kathryn L
authors.initials: KL
authors.lastname: Sklenar
authors.forename: Emily F
authors.initials: EF
authors.lastname: Dunn
authors.forename: Daniel G
authors.initials: DG
authors.lastname: Petereit
authors.forename: Margaret R
authors.initials: MR
authors.lastname: Straub
authors.forename: Kristin A
authors.initials: KA
authors.lastname: Bradley
mesh_terms: D000367:Age Factors; D000704:Analysis of Variance; D000970:Antineoplastic Agents / Q000008:administration & dosage; D001918:Brachytherapy; D002294:Carcinoma, Squamous Cell / Q000401:mortality* / Q000473:pathology / Q000532:radiotherapy / Q000628:therapy*; D059248:Chemoradiotherapy / Q000009:adverse effects* / Q000401:mortality; D002945:Cisplatin / Q000008:administration & dosage; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local; D013997:Time Factors; D002583:Uterine Cervical Neoplasms / Q000401:mortality* / Q000473:pathology / Q000532:radiotherapy / Q000628:therapy*
chemical_list: D000970:Antineoplastic Agents; D002945:Cisplatin