Prospective Assessment of Optimal Individual Position (Prone Versus Supine) for Breast Radiotherapy: Volumetric and Dosimetric Correlations in 100 Patients

• Published in: International journal of radiation oncology, biology, physics Vol. 84; no. 4; pp. 902 - 909
• Main Authors: Lymberis, Stella C., M.D, deWyngaert, John Keith, Ph.D, Parhar, Preeti, M.D, Chhabra, Arpit M., M.D, Fenton-Kerimian, Maria, N.P, Chang, Jengwha, Ph.D, Hochman, Tsivia, M.S, Guth, Amber, M.D, Roses, Daniel, M.D, Goldberg, Judith D., Sc.D, Formenti, Silvia C., M.D
• Format: Journal Article
• Language: English
• Published: New York, NY Elsevier Inc 15.11.2012; Elsevier
• Subjects: Applied radiobiology (equipment, dosimetry...); Biological and medical sciences; Biological effects of radiation; Breast - anatomy & histology; Breast Neoplasms - diagnostic imaging; Breast Neoplasms - pathology; Breast Neoplasms - radiotherapy; Breast radiotherapy; COMPUTERIZED TOMOGRAPHY; Dose Fractionation; Female; Fiducial Markers; Fundamental and applied biological sciences. Psychology; HEALTH HAZARDS; HEART; Heart - diagnostic imaging; Heart - radiation effects; Hematology, Oncology and Palliative Medicine; Humans; IRRADIATION; Lung - diagnostic imaging; Lung - radiation effects; LUNGS; MAMMARY GLANDS; Middle Aged; MORTALITY; Neoplasm Staging; NEOPLASMS; OAR; Organ Size; Organs at Risk - diagnostic imaging; Organs at Risk - radiation effects; Patient Positioning - methods; PATIENTS; PLANNING; Prone; Prone Position; Prospective Studies; RADIATION DOSES; RADIATION INJURIES; Radiation Injuries - prevention & control; Radiology; RADIOLOGY AND NUCLEAR MEDICINE; RADIOTHERAPY; Radiotherapy Planning, Computer-Assisted - methods; Radiotherapy, Intensity-Modulated - methods; SIMULATION; Supine; Supine Position; Tissues, organs and organisms biophysics; Tomography, X-Ray Computed; Tumor Burden; Prone; OAR; Breast radiotherapy; Supine; Human; Volumetric analysis; Supination; Radiotherapy; Prospective; Cancerology; Treatment; Breast; Dosimetry; Mammary gland; Comparative study
• ISSN: 0360-3016; 1879-355X
• DOI: 10.1016/j.ijrobp.2012.01.040

Purpose Damage to heart and lung from breast radiotherapy is associated with increased cardiovascular mortality and lung cancer development. We conducted a prospective study to evaluate which position is best to spare lung and heart from radiotherapy exposure. Methods and Materials One hundred consecutive Stage 0–IIA breast cancer patients consented to participate in a research trial that required two computed tomography simulation scans for planning both supine and prone positions. The optimal position was defined as that which best covered the contoured breast and tumor bed while it minimized critical organ irradiation, as quantified by the in-field heart and lung volume. The trial was designed to plan the first 100 patients in each position to study correlations between in-field volumes of organs at risk and dose. Results Fifty-three left and 47 right breast cancer patients were consecutively accrued to the trial. In all patients, the prone position was optimal for sparing lung volume compared to the supine setup (mean lung volume reduction was 93.5 cc for right and 103.6 cc for left breast cancer patients). In 46/53 (87%) left breast cancer patients best treated prone, in-field heart volume was reduced by a mean of 12 cc and by 1.8 cc for the other 7/53 (13%) patients best treated supine. As predicted, supine-prone differences in in-field volume and mean dose of heart and lung were highly correlated (Spearman's correlation coefficient for left breast cancer patients was 0.90 for heart and 0.94 for lung and 0.92 for right breast cancer patients for lung). Conclusions Prone setup reduced the amount of irradiated lung in all patients and reduced the amount of heart volume irradiated in 87% of left breast cancer patients. In-field organ volume is a valid surrogate for predicting dose; the trial continued to the planned target of 400.