A Dosimetric comparison of IMRT versus 3D–CRT of chest wall in post mastectomy breast cancer patients: A Prospective Study.

Dr. Jayasree Kuna; Dr. Pranabandhu Das; Dr.K.V.Jagannathrao Naidu; Dr. Swapna Jilla; Mrs Sangeetha Mani; Dr. A.Y.Lakshmi; Dr. Amit Chowhan; Dr.V.L.Anusha Konakalla; Dr.B.Sreenivasa Rao; Dr. B.V.Subramanian

Volume : VI, Issue : IX, September - 2017

A Dosimetric comparison of IMRT versus 3D–CRT of chest wall in post mastectomy breast cancer patients: A Prospective Study.

Dr. Jayasree Kuna, Dr. Pranabandhu Das, Dr. K. V. Jagannathrao Naidu, Dr. Swapna Jilla, Mrs Sangeetha Mani, Dr. A. Y. Lakshmi, Dr. Amit Chowhan, Dr. V. L. Anusha Konakalla, Dr. B. Sreenivasa Rao, Dr. B. V. Subramanian

Abstract :

Background

Evidence shows that IMRT leads to better dose distribution than 3DCRT for whole east radiotherapy and for post mastectomy chest wall irradiation with internal mammary nodes . Data on the effect of IMRT of chest wall in post mastectomy east cancer patients without IMN are scarce in literature.

Methods and Material:

For 30 Postmastectomy east cancer patients, 7 field IMRT plan and tangential beam 3D–CRT plan were generated. The dose prescribed to PTV was 50 Gy in 25 fractions. The average values of the PTV parameters namely D_mean, HI, CI, D₂, D₅₀, D₉₈obtained by the two techniques (3DCRT and IMRT) are compared.

Results

On comparison, D_95(%)of PTV (3D–CRT 47.26 Gy; IMRT 48.37 Gy (p<0.01),HI and CI were significantly improved with IMRT. In Left chest wall irradiation, with IMRT V₃₀ of heart was decreased from 23.31% to 18.99% ( p=0.075) and D_mean (14.05Gy 3D–CRT, 19.06Gy IMRT) was increased (p<0.01). V₅ of heart was increased from 6.55% (3D–CRT) to 92.35% (IMRT) (p<0.001). Ipsilateral lung Dmean (21.13Gy 3D–CRT, 18.08Gy IMRT, p=0.07) and V20 (38.22% 3D–CRT, 35.14% IMRT p=0.006) decreased with IMRT. Low dose volumes of lung is increased with IMRT.

Conclusions:

The benefit is marginal in sp� OAR in post mastectomy chest wall without IMN radiation, which is achieved at a cost of increase in low dose volumes of lungs and heart. IMRT can be used in situations where strict constraints to the heart and lungs are not satisfied.