Helical tomotherapy versus conventional intensity-modulated radiation therapy for primary chemoradiation in cervical cancer patients: an intraindividual comparison.
OBJECTIVE
To compare intensity-modulated radiotherapy (IMRT) delivered by helical tomotherapy (HT) with conventional IMRT for primary chemoradiation in cervical cancer patients.


METHODS
Twenty cervical cancer patients undergoing primary chemoradiation received radiation with HT; 10 patients underwent pelvic irradiation (PEL) and 10 extended-field irradiation (EXT). For treatment planning, the simultaneously integrated boost (SIB) concept was applied. Tumor, pelvic, with or without para-aortic lymph nodes were defined as planning target volume A (PTV-A) with a prescribed dose of 1.8/50.4 Gy (28 fractions). The SIB dose for the parametrium (PTV-B), was 2.12/59.36 Gy. The lower target constraints were 95% of the prescribed dose in 95% of the target volume, and the upper dose constraint was 107%. The irradiated small-bowel volumes were kept as low as possible. For every HT plan, a conventional IMRT plan was calculated and compared with regard to dose-volume histogram, conformity index and conformity number, and homogeneity index.


RESULTS
Both techniques allowed excellent target volume coverage and sufficient SB sparing. Conformity index and conformity number results for both PTV-A and PTV-B, homogeneity index for PTV-B, and SB sparing for V45, V50, Dmax, and D1% were significantly better with HT. SB sparing was significantly better for conventional IMRT at low doses (V10).


CONCLUSIONS
Both HT and conventional IMRT provide optimal treatment of cervical cancer patients. The HT technique was significantly favored with regard to target conformity, homogeneity, and SB sparing. Randomized trials are needed to assess the oncological outcome, toxicity, and clinical relevance of these differences.
Marnitz
Simone
S
Charité University Medicine Department of Radiooncology, Berlin, Germany. simone.marnitz@charite.de
Lukarski
Dusko
D
Köhler
Christhardt
C
Wlodarczyk
Waldemar
W
Ebert
Andreas
A
Budach
Volker
V
Schneider
Achim
A
Stromberger
Carmen
C
D002294:Carcinoma, Squamous Cell / Q000188:drug therapy / Q000532:radiotherapy / Q000556:secondary; D003131:Combined Modality Therapy / Q000379:methods; D019583:Dose Fractionation, Radiation; D005260:Female; D006801:Humans; D007421:Intestine, Small / Q000528:radiation effects; D008875:Middle Aged; D058958:Organs at Risk / Q000000981:diagnostic imaging; D011859:Radiography; D050397:Radiotherapy, Intensity-Modulated / Q000009:adverse effects / Q000379:methods*; D047368:Tumor Burden; D002583:Uterine Cervical Neoplasms / Q000188:drug therapy / Q000473:pathology / Q000532:radiotherapy*