Advanced Conformal Radiotherapy versus 3DCRT in Post-mastectomy Breast Cancer Patients: A Comparative Study on Skin Toxicities and Doses to Organs at Risk

Abstract

Introduction: Radiotherapy is an essential modality of treatment after mastectomy. However, toxicities of post-mastectomy radiotherapy are still not well established. This study was aimed at comparing the acute skin toxicities and doses to the organs at risk between conventional and advanced conformal radiotherapy in post-mastectomy breast cancer patients. Materials and Method: A quasi-experimental study was conducted on 60 breast cancer patients after mastectomy from March 2021 to February 2022. Participants were distributed equally into two arms. Arm-A received radiotherapy in conventional conformal technique (3DCRT) and arm-B in advanced conformal techniques (IMRT or VMAT). Patients were evaluated before, during, and after the completion of the treatment. Results: Among the 60 participants, 43% developed skin toxicities of which 18.3% were grade 2 or higher. IMRT and VMAT in comparison to 3DCRT had significantly lower mean dose and maximum dose for heart (4.92 Gy vs. 7.74 Gy, p 0.005 ; 30.95 Gy vs. 45.40 Gy, p 0.0003) and ipsilateral lung (11.93 Gy vs. 17.6 Gy, p 0.0001 ; 37.92 Gy vs. 57.77 Gy, p 0.0001). V5 significantly increased for both. Maximum dose for opposite lung increased significantly (14.14 Gy vs. 7.05 Gy, p 0.001). Mean dose to esophagus was similar in both arms. In case of the spinal cord, mean dose increased in arm-B (3.64 Gy vs. 2.17 Gy, p 0.0004) while maximum dose decreased (15.83 Gy vs. 22.85 Gy, p 0.021). Conclusion: For post-mastectomy patients, advanced conformal radiotherapy techniques are better for minimizing higher dose parameters of organs at risk. Low dose parameters are better in conventional technique. Neither is superior to prevent radiation induced acute skin toxicities.