Serial therapy-induced changes in tumor shape in cervical cancer and their impact on assessing tumor volume and treatment response.
OBJECTIVE
The purpose of this study was to evaluate the patterns and distribution of tumor shape and its temporal change during radiation therapy (RT) in cervical cancer and the effect of tumor configuration changes on the correlation between region of interest (ROI)-based and diameter-based MRI tumor measurement.


METHODS
Serial MRI examinations (T1-weighted and T2-weighted images) were performed in 60 patients (age range, 29-75 years; mean, 53.3 years) with advanced cervical cancer (stages IB2-IVB/recurrent) who were treated with RT at four time points: start of RT, during RT (at 2-2.5 and at 4-5 weeks of RT), and post-RT. Tumor configuration was classified qualitatively into oval, lobulated, and complex based on MR film review. Two methods of tumor volume measurement were compared: ellipsoid computation of three orthogonal diameters (diameter based) and ROI volumetry by delineating the entire tumor volume on the MR workstation (ROI based). Temporal changes of tumor shape and the respective tumor volumes measured by the two methods were analyzed using linear regression analysis.


RESULTS
Most tumors (70%) had a non-oval (lobulated and complex) shape before RT and became increasingly irregular during and after RT: 84% at 2-2.5 weeks of RT (p = 0.037), 86% (p = 0.025) at 4-5 weeks, and 96% post-RT (p = 0.010), compared with 70% pre-RT. Diameter-based and ROI-based measurement correlated well before RT (r = 0.89) but not during RT (r = 0.68 at 2-2.5 weeks, r = 0.67 at 4-5 weeks of RT).


CONCLUSIONS
Most cervical cancers are not oval in shape pretherapy, and they become increasingly irregular during and after therapy because of nonconcentric tumor shrinkage. ROI-based volumetry, which can optimally measure irregular volumes, may provide better response assessment during treatment than diameter-based measurement.
Mayr
Nina A
NA
Department of Radiation Medicine, Division of Radiation Oncology, Arthur G. James Hospital and Solove Research Institute, The Ohio State University, College of Medicine, 300 W 10th Ave., Rm. 080, Columbus, OH 43210, USA. nina.mayr@osumc.edu
Yuh
William T C
WT
Taoka
Toshiaki
T
Wang
Jian Z
JZ
Wu
Dee H
DH
Montebello
Joseph F
JF
Meeks
Sanford L
SL
Paulino
Arnold C
AC
Magnotta
Vincent A
VA
Adli
Mustafa
M
Sorosky
Joel I
JI
Knopp
Michael V
MV
Buatti
John M
JM
D000230:Adenocarcinoma / Q000175:diagnosis / Q000473:pathology / Q000532:radiotherapy*; D000328:Adult; D000368:Aged; D001918:Brachytherapy; D002294:Carcinoma, Squamous Cell / Q000175:diagnosis / Q000473:pathology / Q000532:radiotherapy*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008875:Middle Aged; D011879:Radiotherapy Dosage; D047368:Tumor Burden; D002583:Uterine Cervical Neoplasms / Q000175:diagnosis / Q000473:pathology / Q000532:radiotherapy*