Abstract

To evaluate and compare the dose distribution and dose volume histograms of three dimensional conformal radiation therapy (3D-CRT) versus intensity modulated radiation therapy (IMRT) of the chest wall in post mastectomy breast cancer patients. Material and Methods: Patients were randomized into Arm A (3D-CRT at a dose of 50Gy, delivered in 25# over 5 weeks) or Arm B (IMRT at a dose of 50Gy, delivered in 25# over 5 weeks). The dose-volume histogram (DVH) based analysis for lungs and heart evaluated the percentage volume of ipsilateral lung receiving 20 Gy (mean dose: V20), contralateral lung receiving 5 Gy (V5) and heart receiving 10 and 30 Gy (V10, V30). Results: A total of50 unselected consecutive patients were randomized to Arm A (n=25) or Arm B (n=25). The V20 (p=0.012) and mean dose (p=0.022) of the ipsilateral lung were significantly higher in Arm A as compared with Arm B. The V5 of contralateral lung was significantly (p=0.011) lower in Arm A as compared with Arm B; mean dose was also lower in Arm A, though not significant. For cardiac dose, the V10 (p=0.003) and mean (p=0.000) doses were significantly lower in Arm B versus Arm A; V30 was also lower in Arm A, though not significant. Conclusion: IMRT significantly reduced the mean dose and high dose volumes of ipsilateral lung and heart compared to 3D-CRT in post-mastectomy breast cancer patients, but 3D-CRT provided better results in terms of low dose volume. IMRT provides a better conformity of the plan.

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