title: Which technique for radiation is most beneficial for patients with locally advanced cervical cancer? Intensity modulated proton therapy versus intensity modulated photon treatment, helical tomotherapy and volumetric arc therapy for primary radiation - an intraindividual comparison.
abstract: BACKGROUND
  To compare highly sophisticated intensity-modulated radiotherapy (IMRT) delivered by either helical tomotherapy (HT), RapidArc (RA), IMRT with protons (IMPT) in patients with locally advanced cervical cancer.
  
  
  METHODS
  Twenty cervical cancer patients were irradiated using either conventional IMRT, VMAT or HT; ten received pelvic (PEL) and ten extended field irradiation (EFRT). The dose to the planning-target volume A (PTV_A: cervix, uterus, pelvic ± para-aortic lymph nodes) was 1.8/50.4 Gy. The SIB dose for the parametrium (PTV_B), was 2.12/59.36 Gy. MRI-guided brachytherapy was administered with 5 fractions up to 25 Gy. For EBRT, the lower target constraints were 95% of the prescribed dose in 95% of the target volume. The irradiated small bowel (SB) volumes were kept as low as possible. For every patient, target parameters as well as doses to the organs at risk (SB, bladder, rectum) were evaluated intra-individually for IMRT, HT, VMAT and IMPT.
  
  
  RESULTS
  All techniques provided excellent target volume coverage, homogeneity, conformity. With IMPT, there was a significant reduction of the mean dose (Dmean) of the SB from 30.2 ± 4.0 Gy (IMRT); 27.6 ± 5.6 Gy (HT); 34.1 ± 7.0 (RA) to 18.6 ± 5.9 Gy (IMPT) for pelvic radiation and 26.3 ± 3.2 Gy (IMRT); 24.0 ± 4.1 (HT); 25.3 ± 3.7 (RA) to 13.8 ± 2.8 Gy (IMPT) for patients with EFRT, which corresponds to a reduction of 38-52% for the Dmean (SB). Futhermore, the low dose bath (V10Gy) to the small bowel was reduced by 50% with IMPT in comparison to all photon techniques. Furthermore, Dmean to the bladder and rectum was decresed by 7-9 Gy with IMPT in patents with pelvic radiation and EFRT.
  
  
  CONCLUSIONS
  All modern techniques (were proved to be dosimetrically adequate regarding coverage, conformity and homogeneity of the target. Protons offered the best sparing of small bowel and rectum and therefore could contribute to a significant reduction of acute and late toxicity in cervical cancer treatment.
authors.affiliation: Department of Radiation Oncology, Charité University Hospital, Berlin, Germany. simone.marnitz@charite.de.
authors.forename: Simone
authors.initials: S
authors.lastname: Marnitz
authors.affiliation: Department of Radiation Oncology, Charité University Hospital, Berlin, Germany. waldemar.wlodarczyk@charite.de.
authors.forename: Waldemar
authors.initials: W
authors.lastname: Wlodarczyk
authors.affiliation: Department of Radiation Oncology, Charité University Hospital, Berlin, Germany. oliver.neumann@charite.de.
authors.forename: Oliver
authors.initials: O
authors.lastname: Neumann
authors.affiliation: Department of Gynecology, Charité University Medicine, Berlin, Germany. christhardt.koehler@charite.de.
authors.forename: Christhardt
authors.initials: C
authors.lastname: Koehler
authors.affiliation: Department of Radiation Oncology, Charité University Hospital, Berlin, Germany. mirko.weihrauch@charite.de.
authors.forename: Mirko
authors.initials: M
authors.lastname: Weihrauch
authors.affiliation: Department of Radiation Oncology, Charité University Hospital, Berlin, Germany. volker.budach@charite.de.
authors.forename: Volker
authors.initials: V
authors.lastname: Budach
authors.affiliation: Radiosurgery and Radiotherapy Department, Istituto Clinico Humanitas Cancer Center and Reaserch Hospital, 20100, Rozzano, Italy. luca.cozzi@humanitas.it.
authors.forename: Luca
authors.initials: L
authors.lastname: Cozzi
mesh_terms: D000230:Adenocarcinoma / Q000473:pathology / Q000532:radiotherapy*; D000328:Adult; D000368:Aged; D002294:Carcinoma, Squamous Cell / Q000473:pathology / Q000532:radiotherapy*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008875:Middle Aged; D060787:Neoplasm Grading; D009367:Neoplasm Staging; D058958:Organs at Risk; D010388:Pelvis / Q000528:radiation effects; D017785:Photons / Q000627:therapeutic use*; D011379:Prognosis; D061766:Proton Therapy / Q000379:methods*; D011879:Radiotherapy Dosage; D050397:Radiotherapy, Intensity-Modulated / Q000379:methods*; D012007:Rectum / Q000528:radiation effects; D001743:Urinary Bladder / Q000528:radiation effects; D002583:Uterine Cervical Neoplasms / Q000473:pathology / Q000532:radiotherapy*