Acute and Long-Term Toxicity after Planned Intraoperative Boost and Whole Breast Irradiation in High-Risk Patients with Breast Cancer-Results from the Targeted Intraoperative Radiotherapy Boost Quality Registry (TARGIT BQR)

Lukas Goerdt; Robert Schnaubelt; Uta Kraus-Tiefenbacher; Viktoria Brück; Lelia Bauer; Stefan Dinges; Albert von der Assen; Heidrun Meye; Christina Kaiser; Christel Weiss; Sven Clausen; Frank Schneider; Yasser Abo-Madyan; Katharina Fleckenstein; Sebastian Berlit; Benjamin Tuschy; Marc Sütterlin; Frederik Wenz; Elena Sperk

doi:10.3390/cancers16112067

Acute and Long-Term Toxicity after Planned Intraoperative Boost and Whole Breast Irradiation in High-Risk Patients with Breast Cancer-Results from the Targeted Intraoperative Radiotherapy Boost Quality Registry (TARGIT BQR)

Cancers (Basel). 2024 May 30;16(11):2067. doi: 10.3390/cancers16112067.

Authors

Lukas Goerdt¹, Robert Schnaubelt², Uta Kraus-Tiefenbacher³, Viktoria Brück⁴, Lelia Bauer⁵, Stefan Dinges⁶, Albert von der Assen⁷, Heidrun Meye⁸, Christina Kaiser⁹, Christel Weiss¹⁰, Sven Clausen¹¹, Frank Schneider¹¹, Yasser Abo-Madyan¹¹, Katharina Fleckenstein¹¹, Sebastian Berlit¹, Benjamin Tuschy¹, Marc Sütterlin¹, Frederik Wenz¹², Elena Sperk^{11

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Affiliations

¹ Department of Gynecology and Obstetrics, University Medical Center Mannheim, Medical Faculty Mannheim, Heidelberg University, 68167 Mannheim, Germany.
² Radiation Oncology, MVZ Rheinland Klinikum Neuss, 41462 Neuss, Germany.
³ Department of Radiation Oncology, Krankenhaus Nordwest, 60488 Frankfurt am Main, Germany.
⁴ Breast Center, Asklepios Klinik Barmbek, 22307 Hamburg, Germany.
⁵ Breast Center, GRN Klinik Weinheim, 69469 Weinheim, Germany.
⁶ Department of Radiation Oncology, Städtisches Klinikum Lüneburg, 21339 Lüneburg, Germany.
⁷ Breast Center, Department of Senology, Franziskus Hospital Harderberg-Niels Stensen Kliniken, 49124 Georgsmarienhütte, Germany.
⁸ Department of Radiation Oncology, MVZ Gesundheit Nordhessen, 34125 Kassel, Germany.
⁹ University Medical Center Bonn, Medical Faculty Bonn, Bonn University, 53113 Bonn, Germany.
¹⁰ Department of Medical Biometry, University Medical Center Mannheim, Medical Faculty Mannheim, Heidelberg University, 68167 Mannheim, Germany.
¹¹ Department of Radiation Oncology, University Medical Center Mannheim, Medical Faculty Mannheim, Heidelberg University, 68167 Mannheim, Germany.
¹² University Hospital Freiburg, 79106 Freiburg, Germany.
¹³ Mannheim Cancer Center, University Medical Center Mannheim, Medical Faculty Mannheim, Heidelberg University, 68167 Mannheim, Germany.

Abstract

In the context of breast cancer treatment optimization, this study prospectively examines the feasibility and outcomes of utilizing intraoperative radiotherapy (IORT) as a boost in combination with standard external beam radiotherapy (EBRT) for high-risk patients. Different guidelines recommend such a tumor bed boost in addition to whole breast irradiation with EBRT for patients with risk factors for local breast cancer recurrence. The TARGIT BQR (NCT01440010) is a prospective, multicenter registry study aimed at ensuring the quality of clinical outcomes. It provides, for the first time, data from a large cohort with a detailed assessment of acute and long-term toxicity following an IORT boost using low-energy X-rays. Inclusion criteria encompassed tumors up to 3.5 cm in size and preoperative indications for a boost. The IORT boost, administered immediately after tumor resection, delivered a single dose of 20 Gy. EBRT and systemic therapy adhered to local tumor board recommendations. Follow-up for toxicity assessment (LENT SOMA criteria: fibrosis, teleangiectasia, retraction, pain, breast edema, lymphedema, hyperpigmentation, ulceration) took place before surgery, 6 weeks to 90 days after EBRT, 6 months after IORT, and then annually using standardized case report forms (CRFs). Between 2011 and 2020, 1133 patients from 10 centers were preoperatively enrolled. The planned IORT boost was conducted in 90%, and EBRT in 97% of cases. Median follow-up was 32 months (range 1-120, 20.4% dropped out), with a median age of 61 years (range 30-90). No acute grade 3 or 4 toxicities were observed. Acute side effects included erythema grade 1 or 2 in 4.4%, palpable seroma in 9.1%, punctured seroma in 0.3%, and wound healing disorders in 2.1%. Overall, chronic teleangiectasia of any grade occurred in 16.2%, fibrosis grade ≥ 2 in 14.3%, pain grade ≥ 2 in 3.4%, and hyperpigmentation in 1.1%. In conclusion, a tumor bed boost through IORT using low-energy X-rays is a swift and feasible method that demonstrates low rates in terms of acute or long-term toxicity profiles in combination with whole breast irradiation.

Keywords: IORT; boost; breast cancer; fibrosis; high risk; intraoperative radiotherapy; toxicity; whole breast irradiation.

Grants and funding

This research received no external funding.