Dose-volume histogram parameters and late side effects in magnetic resonance image-guided adaptive cervical cancer brachytherapy.
OBJECTIVE
To evaluate the predictive value of dose-volume histogram (DVH) parameters for late side effects of the rectum, sigmoid colon, and bladder in image-guided brachytherapy for cervix cancer patients.


METHODS
A total of 141 patients received external-beam radiotherapy and image-guided brachytherapy with or without chemotherapy. The DVH parameters for the most exposed 2, 1, and 0.1 cm(3) (D(2cc), D(1cc), and D(0.1cc)) of the rectum, sigmoid, and bladder, as well as International Commission on Radiation Units and Measurements point doses (D(ICRU)) were computed. Total doses were converted to equivalent doses in 2 Gy by applying the linear-quadratic model (α/β = 3 Gy). Late side effects were prospectively assessed using the Late Effects in Normal Tissues-Subjective, Objective, Management and Analytic score. The following patient groups were defined: Group 1: no side effects (Grade 0); Group 2: side effects (Grade 1-4); Group 3: minor side effects (Grade 0-1); and Group 4: major side effects (Grade 2-4).


RESULTS
The median follow-up was 51 months. The overall 5-year actuarial side effect rates were 12% for rectum, 3% for sigmoid, and 23% for bladder. The mean total D(2cc) were 65 ± 12 Gy for rectum, 62 ± 12 Gy for sigmoid, and 95 ± 22 Gy for bladder. For rectum, statistically significant differences were observed between Groups 1 and 2 in all DVH parameters and D(ICRU). Between Groups 3 and 4, no difference was observed for D(0.1cc). For sigmoid, significant differences were observed for D(2cc) and D(1cc), but not for D(0.1cc) in all groups. For bladder, significant differences were observed for all DVH parameters only comparing Groups 3 and 4. No differences were observed for D(ICRU).


CONCLUSIONS
The parameters D(2cc) and D(1cc) have a good predictive value for rectal toxicity. For sigmoid, no prediction could be postulated because of limited data. In bladder, DVH parameters were predictive only for major toxicity.
Georg
Petra
P
Department of Radiotherapy, Medical University of Vienna, Vienna, Austria. petra.georg@akhwien.at
Lang
Stefan
S
Dimopoulos
Johannes C A
JC
Dörr
Wolfgang
W
Sturdza
Alina E
AE
Berger
Daniel
D
Georg
Dietmar
D
Kirisits
Christian
C
Pötter
Richard
R
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001918:Brachytherapy / Q000009:adverse effects* / Q000379:methods; D012809:Colon, Sigmoid / Q000528:radiation effects*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008279:Magnetic Resonance Imaging; D008875:Middle Aged; D058958:Organs at Risk / Q000528:radiation effects; D011446:Prospective Studies; D011832:Radiation Injuries / Q000175:diagnosis*; D011879:Radiotherapy Dosage; D020266:Radiotherapy, Conformal / Q000009:adverse effects*; D012007:Rectum / Q000528:radiation effects*; D047368:Tumor Burden; D001743:Urinary Bladder / Q000528:radiation effects*; D002583:Uterine Cervical Neoplasms / Q000473:pathology / Q000532:radiotherapy*