title: Integrated peripheral boost in preoperative radiotherapy for the locally most advanced non-resectable rectal cancer patients.
abstract: OBJECTIVE
  Few studies have explored the potential clinical advantages of dose escalation and integrated boosts for patients with non-resectable locally advanced rectal cancer. The possibility of escalating dose to non-resectable regions in these patients was the aim of this study.
  
  
  METHODS
  Seven patients with locally very advanced rectal tumours (sacrum overgrowth or growth into pelvic side walls) were evaluated. Intensity modulated photon and pencil beam scanning proton plans with simultaneously integrated boosts (45 Gy to elective lymph nodes, 50 Gy to tumour and 62.5 Gy to boost area in 25 fractions) were compared.
  
  
  RESULTS
  Target coverage was achieved with both photon and proton plans. Estimated risks of acute side effects put the two patients with the largest tumours at unacceptable risk for intestinal toxicity, regardless of modality. The remaining five patients had beneficial sparing of dose to the small intestine with protons.
  
  
  CONCLUSIONS
  Adding boost to areas where rectal tumours infiltrate adjacent non-resectable organs is an attractive option which appears possible using both photon and proton irradiation. Proton plans reduced dose to organs at risk. Integrated peripheral boosts should be considered more frequently in these very advanced tumours.
authors.affiliation: Department of Radiology, Uppsala University, Uppsala, Sweden. calin.radu@onkologi.uu.se
authors.forename: Calin
authors.initials: C
authors.lastname: Radu
authors.forename: Ola
authors.initials: O
authors.lastname: Norrlid
authors.forename: Morten
authors.initials: M
authors.lastname: Brændengen
authors.forename: Karl
authors.initials: K
authors.lastname: Hansson
authors.forename: Ulf
authors.initials: U
authors.lastname: Isacsson
authors.forename: Bengt
authors.initials: B
authors.lastname: Glimelius
mesh_terms: D000368:Aged; D002277:Carcinoma / Q000000981:diagnostic imaging / Q000473:pathology / Q000532:radiotherapy* / Q000601:surgery; D059248:Chemoradiotherapy; D003131:Combined Modality Therapy; D018450:Disease Progression; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D064847:Multimodal Imaging; D009361:Neoplasm Invasiveness; D049268:Positron-Emission Tomography; D057234:Preoperative Period; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods; D018714:Radiotherapy, Adjuvant / Q000009:adverse effects; D020266:Radiotherapy, Conformal / Q000009:adverse effects / Q000379:methods*; D012004:Rectal Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology / Q000532:radiotherapy* / Q000601:surgery; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome; D047368:Tumor Burden
chemical_list: D019788:Fluorodeoxyglucose F18