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.
Ben-Josef
Edgar
E
Department of Radiation Oncology, University of Michigan, Ann Arbor, MI 48109, USA. edgarb@med.umich.edu
Moughan
Jennifer
J
Ajani
Jaffer A
JA
Flam
Marshall
M
Gunderson
Leonard
L
Pollock
JonDavid
J
Myerson
Robert
R
Anne
Rani
R
Rosenthal
Seth A
SA
Willett
Christopher
C
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