Partial Breast Irradiation Versus Whole Breast Irradiation for Early Breast Cancer Patients in a Randomized Phase III Trial: The Danish Breast Cancer Group Partial Breast Irradiation Trial

Author(s): Birgitte V. Offersen, MD, PhD^1,2;Jan Alsner, MSc, PhD¹;Hanne M. Nielsen, MD, PhD²;Erik H. Jakobsen, MD³;Mette H. Nielsen, MD, PhD⁴;Lars Stenbygaard, MD⁵;Anders N. Pedersen, MD, PhD⁶;Mette S. Thomsen, MSc, PhD⁷;Esben Yates, MSc⁷;Martin Berg, MSc⁸;Ebbe L. Lorenzen, MSc, PhD⁴;Ingelise Jensen, MSc⁹;Mirjana Josipovic, MSc, PhD⁶;Maj-Britt Jensen, MSc¹⁰;and Jens Overgaard, MD, DMSc¹;on behalf of the Danish Breast Cancer Group Radiotherapy Committee

Source: DOI: 10.1200/JCO.22.00451 Journal of Clinical Oncology 40, no. 36 (December 20, 2022) 4189-4197.

Dr. Maen Hussein's Thoughts

For low-risk patients, less radiation is as good, I would love to hear input from Rad Onc. I did notice that the Rad Oncs I work with are adopting this.

PURPOSE

On the basis of low risk of local recurrence in elderly patients with breast cancer after conservative surgery followed by whole breast irradiation (WBI), the Danish Breast Cancer Group initiated the noninferiority external-beam partial breast irradiation (PBI) trial (ClinicalTrials.gov identifier: NCT00892814). We hypothesized that PBI was noninferior to WBI regarding breast induration.

METHODS

Patients operated with breast conservation for relatively low-risk breast cancer were randomly assigned to WBI versus PBI, and all had 40 Gy/15 fractions. The primary end point was 3-year grade 2-3 breast induration.

RESULTS

In total, 865 evaluable patients (434 WBI and 431 PBI) were enrolled between 2009 and 2016. Median follow-up was 5.0 years (morbidity) and 7.6 years (locoregional recurrence). The 3-year rate of induration was 9.7% for WBI and 5.1% for PBI (P = .014). Large breast size was significantly associated with induration with a 3-year incidence of 13% (WBI) and 6% (PBI) for large-breasted patients versus 6% (WBI) and 5% (PBI) for small-breasted patients. PBI showed no increased risk of dyspigmentation, telangiectasia, edema, or pain, and patient satisfaction was high. Letrozole and smoking did not increase the risk of radiation-associated morbidity. Sixteen patients had a locoregional recurrence (six WBI and 10 PBI; P = .28), 20 patients had a contralateral breast cancer, and eight patients had distant failure (five WBI and three PBI). A nonbreast second cancer was detected in 73 patients (8.4%), and there was no difference between groups.

CONCLUSION

External-beam PBI for patients with low-risk breast cancer was noninferior to WBI in terms of breast induration. Large breast size was a risk factor for radiation-associated induration. Few recurrences were detected and unrelated to PBI.

Author Affiliations

¹Department of Experimental Clinical Oncology, Aarhus University Hospital, Aarhus, Denmark ²Department of Oncology, Aarhus University Hospital, Aarhus, Denmark ³Department of Oncology, Lillebaelt Hospital, Vejle, Denmark ⁴Department of Oncology, Odense University Hospital, Odense, Denmark ⁵Department of Oncology, Aalborg University Hospital, Aalborg, Denmark ⁶Department of Oncology, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark ⁷Department of Medical Physics, Aarhus University Hospital, Aarhus, Denmark ⁸Department of Medical Physics, Lillebaelt Hospital, Vejle, Denmark ⁹Department of Medical Physics, Aalborg University Hospital, Aalborg, Denmark ¹⁰Danish Breast Cancer Group, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark

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Hypo- Versus Standard Fractionated Locoregional Radiotherapy of Patients With High-Risk Breast Cancer in the Randomized Phase III Trial: The Danish Breast Cancer Group Skagen Trial 1

Less radiation (40Gy vs 50 Gy) was non inferior in preventing locoregional recurrence and distant mets, also lymphedema rates were not worse. Would love feedback from our rad onc, but it seems less is as good.

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