title: Quantification and reduction of cardiac dose in radical radiotherapy for oesophageal cancer.
abstract: Chemoradiation is increasingly used in the management of localized oesophageal cancer and has been shown in randomized controlled trials to improve overall survival. Although early toxicity of radiotherapy is well documented, this is not the case for late toxicity. As patients with oesophageal cancer have a high incidence of co-morbidities including cardiac problems, the aim of this paper was to quantify the extent of cardiac radiation and discuss the influence of beam arrangement to reduce this. Eight patients with localized oesophageal cancer treated with radical chemoradiation were selected. The mean cardiac dose and the volumes of heart receiving 30 Gy, 40 Gy and 45 Gy from the conventional two-phase technique were compared with those of single-phase 3-field and 4-field conformal beam arrangements. The 4-field arrangement reduced the mean cardiac dose by at least 3.3 Gy compared with the other two beam arrangements (p=0.01). The mean volume of heart receiving high doses between the three techniques widened as the dose increased in the range 30-45 Gy. There is no statistically significant difference in volumes receiving more than 30 Gy and 40 Gy. 65% of the cardiac volume received more than 45 Gy using a two-phase technique, compared with 57% using three fields and 26% using four fields (p<0.01). With a 4-field beam arrangement, therefore, there is a significant reduction in cardiac dose compared with the other two techniques. Cardiac toxicity and a 4-field beam arrangement should be considered when planning radical radiotherapy for localized oesophageal cancer.
authors.affiliation: Department Clinical Oncology, Royal Marsden Hospital, Sutton, Surrey, UK.
authors.forename: M
authors.initials: M
authors.lastname: Cominos
authors.forename: M A
authors.initials: MA
authors.lastname: Mosleh-Shirazi
authors.forename: D
authors.initials: D
authors.lastname: Tait
authors.forename: A
authors.initials: A
authors.lastname: Henrys
authors.forename: P
authors.initials: P
authors.lastname: Cornes
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000964:Antimetabolites, Antineoplastic / Q000627:therapeutic use; D002294:Carcinoma, Squamous Cell / Q000000981:diagnostic imaging / Q000188:drug therapy / Q000532:radiotherapy*; D003131:Combined Modality Therapy; D004938:Esophageal Neoplasms / Q000000981:diagnostic imaging / Q000188:drug therapy / Q000532:radiotherapy*; D005472:Fluorouracil / Q000627:therapeutic use; D006321:Heart / Q000528:radiation effects*; D006801:Humans; D008875:Middle Aged; D011829:Radiation Dosage; D011832:Radiation Injuries / Q000517:prevention & control; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods*; D020266:Radiotherapy, Conformal / Q000379:methods; D014057:Tomography, X-Ray Computed
chemical_list: D000964:Antimetabolites, Antineoplastic; D005472:Fluorouracil