External beam APBI in early breast cancer - final results of prospective single institution study.
Petr Burkon,
Czech Republic
PO-1277
Abstract
External beam APBI in early breast cancer - final results of prospective single institution study.
Authors: Petr Burkon1,2, Iveta Selingerova3,4, Marek Slavik1,2, Tomas Kazda1,2, Miroslav Vrzal1, Pavel Slampa1,2
1Masaryk Memorial Cancer Institute, Department of Radiation Oncology, Brno, Czech Republic; 2Faculty of Medicine, Masaryk University, Department of Radiation Oncology, Brno, Czech Republic; 3Masaryk Memorial Cancer Institute, Research Centre for Applied Molecular Oncology, Brno, Czech Republic; 4Faculty of Medicine, Masaryk University, Department of Pharmacology, Brno, Czech Republic
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Purpose or Objective
The adjuvant radiotherapy (RT) of the early-stage breast cancer patients is widely established method to cure microscopic residual disease. Nowadays accelerated partial breast irradiation (APBI) is recommended for highly selected patients. This prospective randomized study compares the targeted APBI with commonly used accelerated whole-breast irradiation (WBI) in terms of feasibility, safety, tolerance, and cosmetic effects. Definitive results are presented.
Material and Methods
Early-stage breast cancer patients after partial mastectomy were screened for eligibility. The inclusion criteria were age ˃ 50 years, non-lobular histology, ≤ 2 cm, margins ≥ 2 mm, L0, ER-positive, HER-2 negative. All patients were equally randomized into two arms according to the radiotherapeutic regiment – external APBI (5× 6Gy) and accelerated whole breast irradiation with the boost (15× 2,67Gy + 5× 2Gy). The follow-up visits were planned at the end of RT, 1 month after RT, and then every 3 months. Cosmetics results and toxicity were evaluated using questionnaires, CTCAE criteria, and photodocumentation of the irradiated chest.
Results
The final analysis contains data of 84 randomized patients with he median age 64 years. The tumors were grade 1 in 59 % of patients, the median of 10 mm and 76 % were classified as invasive ductal carcinoma. Toxicity evaluation showed statistically significantly fewer acute adverse events (at the end and 1 month after RT) in the APBI arm in terms of skin erythema, desquamation, skin tenderness, dryness, edema, pigmentation, breast pain and fatigue. Late toxicity (3, 6, 9, and 12 months after RT) was worse in the WBI arm. However, the difference between arms was blurred over time. At the 12 months after RT, a difference in pigmentation was mainly observed. The cosmetic effect (independently evaluated by physician, nurse, and patient) was more favorable in the APBI group.
Conclusion
The external APBI technique demostrated better feasibilty and less toxicity than standard regiment in adjuvant setting in the treatment of early-stage breast cancer patients. The study incerases its evidence for using in in clinical practice. Supported by grant NV19-03-00354 of the Czech Ministry of Health.