title: Do all patients of breast carcinoma need 3-dimensional CT-based planning? A dosimetric study comparing different breast sizes.
abstract: Evaluation of dose distribution in a single plane (i.e., 2-dimensional [2D] planning) is simple and less resource-intensive than CT-based 3-dimensional radiotherapy (3DCRT) planning or intensity modulated radiotherapy (IMRT). The aim of the study was to determine if 2D planning could be an appropriate treatment in a subgroup of breast cancer patients based on their breast size. Twenty consecutive patients who underwent breast conservation were planned for radiotherapy. The patients were grouped in 3 different categories based on their respective chest wall separation (CWS) and the thickness of breast, as "small," "medium," and "large." Two more contours were taken at locations 5 cm superior and 5 cm inferior to the isocenter plane. Maximum dose recorded at specified points was compared in superior/inferior slices as compared to the central slice. The mean difference for small breast size was 1.93 (standard deviation [SD] = 1.08). For medium breas size, the mean difference was 2.98 (SD = 2.40). For the large breasts, the mean difference was 4.28 (SD = 2.69). Based on our dosimetric study, breast planning only on the single isocentric contour is an appropriate technique for patients with small breasts. However, for large- and medium-size breasts, CT-based planning and 3D planning have a definite role. These results can be especially useful for rationalizing treatment in busy oncology centers.
authors.affiliation: Department of Radiation Oncology, Tata Memorial Hospital, Parel, Mumbai, Maharashtra, India. anusheel8@hotmail.com
authors.forename: Anusheel
authors.initials: A
authors.lastname: Munshi
authors.forename: Rajeshri H
authors.initials: RH
authors.lastname: Pai
authors.forename: Reena
authors.initials: R
authors.lastname: Phurailatpam
authors.forename: Ashwini
authors.initials: A
authors.lastname: Budrukkar
authors.forename: Rakesh
authors.initials: R
authors.lastname: Jalali
authors.forename: Rajiv
authors.initials: R
authors.lastname: Sarin
authors.forename: D D
authors.initials: DD
authors.lastname: Deshpande
authors.forename: Shyam K
authors.initials: SK
authors.lastname: Shrivastava
authors.forename: Ketayun A
authors.initials: KA
authors.lastname: Dinshaw
mesh_terms: D001943:Breast Neoplasms / Q000000981:diagnostic imaging* / Q000532:radiotherapy*; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008327:Mammography / Q000379:methods*; D009929:Organ Size; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods*; D016896:Treatment Outcome