Postoperative radiotherapy with intensity-modulated radiation therapy versus 3-dimensional conformal radiotherapy in early breast cancer: A randomized clinical trial of KROG 15-03.
PURPOSE
To investigate the safety and efficacy of intensity-modulated radiation therapy (IMRT) for early breast cancer compared with 3-dimensional conformal radiotherapy (3D-CRT) in a prospective and randomized trial.


METHODS AND MATERIALS
From March 2015 to February 2018, 693 patients with pT1-2N0M0 early breast cancer who underwent breast-conserving surgery were enrolled and randomly assigned into IMRT and 3D-CRT. The primary endpoint was 3-year locoregional recurrence-free survival (LRRFS). The secondary endpoints were recurrence-free survival, overall survival, acute toxicity, target coverage index, irradiation dose to organs at risk, and fatigue inventory. The radiation dose for the 3D-CRT arm was 59.4 Gy in 33 fractions for 6.5 weeks. It was 57.4 Gy in 28 fractions with simultaneous integrated boost for 5.5 weeks for the IMRT arm.


RESULTS
Of 693 patients, 349 and 344 patients received 3D-CRT and IMRT, respectively. There was no significant difference in LRRFS between the two arms. Conformity index of planning target volume was significantly superior in the IMRT arm than the 3D-CRT arm (p < 0.001). The mean lung dose and V5-V50 for the ipsilateral lung were significantly lower in the IMRT arm than the 3D-CRT arm (all p < 0.05). The incidence of grade 2 or higher dermatitis was significantly lower in the IMRT arm (p = 0.009).


CONCLUSION
Compared to 3D-CRT, IMRT showed similar results in locoregional tumor control but superior results in planning target volume coverage. When IMRT is used in breast cancer, the irradiation dose to an ipsilateral lung and skin toxicity can be reduced.
['Choi|Kyu Hye|KH|', 'Ahn|Sung Ja|SJ|', 'Jeong|Jae Uk|JU|', 'Yu|Mina|M|', 'Kim|Jin Hee|JH|', 'Jeong|Bae Kwon|BK|', 'Lee|Joo Hwan|JH|', 'Kim|Sung Hwan|SH|', 'Lee|Jong Hoon|JH|']
D001943:Breast Neoplasms D006801:Humans D011446:Prospective Studies D011879:Radiotherapy Dosage D011880:Radiotherapy Planning, Computer-Assisted D020266:Radiotherapy, Conformal D050397:Radiotherapy, Intensity-Modulated
Breast cancer IMRT Toxicity Recurrence