Abstract P1-10-03: A randomized trial of accelerated breast radiotherapy utilizing either 3-dimensional radiotherapy versus intensity modulated radiotherapy

PURPOSE: Primary objective: patient self-assessment of breast pain between 3-dimensional radiotherapy (3D-CRT) versus intensity modulated radiotherapy (IMRT). Secondary objectives: breast cosmesis as well as local-regional recurrence and survival statistics.

METHODS AND MATERIALS: 656 patients (3D-CRT n=325; IMRT n=331) were prospectively randomized to either IMRT or 3D-CRT accelerated partial breast radiotherapy to 38.5 Gy in 10 BID 3.85 Gy fractions. Follow-up was: 1, 4, 8, 12, 16, 20, 24 months then yearly. At follow-up, patients completed a cosmesis/pain self-assessment form and physicians completed a cosmesis and disease-status form.

RESULTS: 636 patients completed treatment (3D-CRT n=316; IMRT n=320). Median age was 62. Mean tumor size was 1.1 cm. Mean margin was 7mm. Histology was: 74.5% IDCA, 7% ILCA, 17% DCIS, 0.5% Tubular, 1% Mucinous. 99% were ER+. HER2/neu status by IHC was 3+ in 16% of patients. Median follow-up is 2 years. Tables 1 and 2 show there is no significant difference in patient-assessed pain and cosmesis between the two treatment arms (p=0.14, =0.68 respectively). Decreasing pain and worsening cosmesis as reported by the patient were significantly related to time (p<0.01, =0.012 respectively). MD assessed cosmesis worsened significantly from baseline in the IMRT compared to 3D-CRT cohort (p=0.045). At 2 years Grade 3 and 4 toxicities were 1.5% and 3.9% respectively for 3D-CRT versus IMRT cohorts. Overall Survival at 2 years were 99.7% for both cohorts. There were 3/319 (0.9%) and 7/328 (2.1%) ipsilateral breast recurrences in the 3D-CRT and IMRT cohorts respectively.

Patient breast pain by follow-up interval12 Months (3D n=167 and IMRT n=163)Rx ModalityNoneMildModerate-Severep value3D50.9%47.3%1.8%0.44IMRT52.1%44.2%3.7% 24 Months (3D n=111 and IMRT n=109)3D52.3%47.7% 0.07IMRT66.1%33.9%  36 Months (3D n=50 and IMRT n=34)3D60.0%40.0% 0.37IMRT58.8%41.2%  48 Months (3D n=12 and IMRT n=123D25.0%75.0% 0.19IMRT58.3%41.7%  Results from mixed model for pain gradeEffectEstimateSELowerUpperp value3D vs IMRT0.0810.055-0.0260.1890.14Visit (Baseline, 12, 24, 36, 48 month-0.1010.019-0.137-0.064<0.01Table 1.

Patient breast cosmesis by follow-up interval12 Months (3D n=162 and IMRT n=158)Rx ModalityNo changeSlight changeObvious changeDrastic changep value3D40.1%38.3%19.1%2.5%0.83IMRT41.8%40.5%15.2%2.5% 24 months (3D n=108 and IMRT n=108)3D38.9%40.7%18.5%1.9%0.30IMRT41.7%29.6%26.9%1.9% 36 Months (3D n=50 and IMRT n=34)3D38.0%34.0%28.0%0%0.37IMRT32.4%35.3%26.5%5.9% 48 Months (3D n=10 and IMRT n=12)3D10.0%30.0%60.0% 0.10IMRT50.0%8.3%41.7%  Patient breast cosmoses by follow-up intervalEffectEstimateSELowerUpperp value3D vs IMRT0.0260.064-0.1000.1530.68All Visit (Baseline, 12, 24, 36, 48 month)-0.0530.021-0.095-0.0120.01Table 2.

Conclusion: T here were no significant differences in patient-assessed pain and cosmesis between the two treatment arms (p=0.14, =0.68 respectively) and no significant increase in pain over time. However, MD assessed cosmesis showed worsening cosmesis in the IMRT cohort compared to the 3D-CRT cohort wen compared to baseline.

Citation Format: Leonard CE, Sobus RD, Fryman S, Sedlacek S, Kercher J, Widner J, Asmar L, Wang Y, Howell K, Barke L, Carter D. A randomized trial of accelerated breast radiotherapy utilizing either 3-dimensional radiotherapy versus intensity modulated radiotherapy [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P1-10-03.