Impact of body mass index on outcomes after conformal radiotherapy in patients with prostate cancer.
OBJECTIVE
Several retrospective analyses have suggested that obese men with prostate cancer treated with external beam radiotherapy (EBRT) have outcomes inferior to those of normal-weight men. However, a recently presented analysis for the first time challenged this association between body mass index (BMI) and treatment failure. It is therefore important to provide further data on this issue.


METHODS
This was a retrospective analysis of 564 men treated with risk-adapted conformal EBRT at a single institution. Low-risk patients received EBRT alone, and the other patients received EBRT plus endocrine treatment. In addition, high-risk patients were treated to higher EBRT doses (74 Gy). A rectal balloon catheter for internal immobilization, which can be identified on portal images, was used in 261 patients (46%). Thus, localization did not rely on bony landmarks alone in these cases.


RESULTS
The median BMI was 26, and 15% of patients had BMI≥30. Neither univariate nor multivariate analyses detected any significant impact of BMI on biochemical relapse, prostate cancer-specific survival, or overall survival. The 5-year biochemical relapse rate was 21% and prostate cancer-specific survival 96%.


CONCLUSIONS
The present analysis of a large cohort of consecutively treated patients suggests that efforts to reduce prostate movement and geographic miss might result in comparable outcomes in obese and normal-weight patients.
Geinitz
Hans
H
Department of Radiation Oncology, Klinikum rechts der Isar der Technischen Universität München, Munich, Germany. hans.geinitz@lrz.tu-muenchen.de
Thamm
Reinhard
R
Mueller
Tobias
T
Jess
Kerstin
K
Zimmermann
Frank B
FB
Molls
Michael
M
Nieder
Carsten
C
D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D015992:Body Mass Index; D057785:Catheters; D006801:Humans; D007103:Immobilization / Q000295:instrumentation* / Q000379:methods; D008297:Male; D008875:Middle Aged; D009068:Movement; D009364:Neoplasm Recurrence, Local / Q000097:blood; D009765:Obesity / Q000150:complications; D011467:Prostate; D017430:Prostate-Specific Antigen / Q000097:blood; D011471:Prostatic Neoplasms / Q000097:blood / Q000473:pathology / Q000532:radiotherapy*; D020266:Radiotherapy, Conformal / Q000379:methods*; D012189:Retrospective Studies; D016896:Treatment Outcome
D017430:Prostate-Specific Antigen