Impact of overall treatment time on survival and local control in patients with anal cancer: a pooled data analysis of Radiation Therapy Oncology Group trials 87-04 and 98-11.
OBJECTIVE
To determine whether increased duration of radiation therapy (RT) and overall treatment (RX) time has a detrimental effect in anal cancer.


METHODS
Data from Radiation Therapy Oncology Group (RTOG) 87-04 and RTOG 98-11 trials were combined to form three treatment groups: RT/fluorouracil (FU)/mitomycin (n = 472), RT/FU/cisplatin (n = 320), and RT/FU (n = 145). Cox proportional hazards models were used with the following variables: RT duration, RT intensity, RX duration, treatment group, age, sex, Karnofsky performance score (KPS), T stage, N stage, and RT dose.


RESULTS
In the univariate analysis, there was a significant association between RX duration and colostomy failure (CF; hazard ratio [HR] = 1.51; 95% CI, 1.07 to 2.14; P = .02), local failure (HR = 1.52; 95% CI, 1.14 to 2.03; P = .005), locoregional failure (HR = 1.51; 95% CI, 1.15 to 1.98; P = .003), and time to failure (HR = 1.40; 95% CI, 1.10 to 1.79; P = .007). The significance of RX duration was maintained after adjusting for treatment group. In multivariate modeling there was a trend toward an association between RX duration and CF (HR = 1.57; 95% CI, 0.98 to 2.50; P = .06) and a statistically significant association with local failure (HR = 1.96; 95% CI, 1.34 to 2.87; P = .0006). Age, sex, KPS, T stage, N stage, and RT dose, but not RT duration, RT intensity, or RX duration, were found to be statistically significant predictors of OS and colostomy-free survival.


CONCLUSIONS
Total treatment time, but not duration of radiation therapy, seems to have a detrimental effect on local failure and colostomy rate in anal cancer. Induction chemotherapy may contribute to local failure by increasing total treatment time.
Department of Radiation Oncology, University of Michigan, Ann Arbor, MI 48109, USA. edgarb@med.umich.edu
Edgar
E
Ben-Josef
Jennifer
J
Moughan
Jaffer A
JA
Ajani
Marshall
M
Flam
Leonard
L
Gunderson
JonDavid
J
Pollock
Robert
R
Myerson
Rani
R
Anne
Seth A
SA
Rosenthal
Christopher
C
Willett
D000970:Antineoplastic Agents / Q000008:administration & dosage; D001005:Anus Neoplasms / Q000188:drug therapy / Q000401:mortality* / Q000532:radiotherapy*; D002945:Cisplatin / Q000008:administration & dosage; D002986:Clinical Trials as Topic; D003131:Combined Modality Therapy; D005260:Female; D005472:Fluorouracil / Q000627:therapeutic use; D006801:Humans; D008297:Male; D016685:Mitomycin / Q000008:administration & dosage; D016016:Proportional Hazards Models; D011878:Radiotherapy / Q000379:methods*; D011879:Radiotherapy Dosage; D013997:Time Factors
D000970:Antineoplastic Agents; D016685:Mitomycin; D002945:Cisplatin; D005472:Fluorouracil