Significant reductions in heart and lung doses using semi lateral decubitus techniques for left sided breast cancer patients: A comparative dosimetric study with supine techniques

Abstract

Introduction: Various treatment techniques as breath hold techniques have been developed to spare the heart and lung in breast cancer patients receiving adjuvant radiotherapy.
Purpose: to compare the heart and lung dosimetric parameters of semi lateral decubitus technique with and without deep inspiration breath hold with standard supine techniques for left-sided breast cancer patients undergoing breast conservative surgery and adjuvant radiotherapy.
Methods: Fifty patients with left-sided breast cancer were simulated using standard supine, semi lateral decubitus and semi lateral decubitus and deep inspiration breath hold. The three plans carried out using two tangential opposed photon beams were compared.
Results: There was a significant reduction in heart V_5Gy, V_10Gy, V_25Gy, V_30Gy, mean dose & max dose with semi-lateral decubitus and breath hold technique compared to supine technique & semi-lateral decubitus technique (P < 0.001). There was also a significant reduction in the above mentioned heart DVPs with semi-lateral decubitus (P < 0.001) compared to supine technique.
Results: There was a significant reduction in ipsilateral lung V_20Gy and mean dose with semi-lateral decubitus and breath hold technique compared to supine technique (P < 0.001) & semi-lateral decubitus technique (P = 0.003 & 0.006) respectively. There was also a significant reduction in ipsilateral lung V_20Gy and mean dose with semi-lateral decubitus (P < 0.001 & 0.007) compared to supine technique.
Conclusion: Semi-lateral decubitus techniques with and without breath hold for left sided breast cancer patients significantly reduce the dosimetric parameters of the heart and ipsilateral lung compared to supine technique with comparable target dose coverage.