Patterns of post-operative irradiation in breast cancer patients submitted to neoadjuvant chemotherapy

 

Patterns of post-operative irradiation in breast cancer patients submitted to neoadjuvant chemotherapy

Kennya Medeiros L. de B. Lima1

Thiago B. de Freitas1

Allan A. Lima Pereira1

Saulo Brito Silva1

Heloisa de Andrade Carvalho2,4

José R. Filassi3

Max S. Mano1,5

Gustavo Nader Marta*1,4

1. Department of Radiology and Oncology – Radiation Oncology Unit; Faculdade de Medicina da Universidade de São Paulo – Instituto do Câncer do Estado de São Paulo (ICESP); Sao Paulo, Brazil.

2. Department of Radiology and Oncology – Radiation Oncology Unit; Faculdade de Medicina da Universidade de São Paulo – Instituto de Radiologia (INRAD); Sao Paulo, Brazil.

3. Department of Gynecology and Obstetrics – Instituto do Câncer do Estado de São Paulo (ICESP), Universidade de São Paulo; Sao Paulo, Brazil.

4. Department of Radiation Oncology – Hospital Sírio-Libanês; Sao Paulo, Brazil.

5. Department of Clinical Oncology – Hospital Sírio-Libanês; Sao Paulo, Brazil.

Conflict of interest: All authors declare that they have no conflicts of interest in relation to the authorship or publication of this contribution

Financial support: This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

Corresponding author*:

Gustavo Nader Marta, MD, PhD

Email: gustavo.marta@hc.fm.usp.br

Address: Department of Radiology and Oncology – Radiation Oncology Unit; Faculdade de Medicina da Universidade de São Paulo – Instituto do Câncer do Estado de São Paulo (ICESP); São Paulo, Brazil.

Ave. Dr. Arnaldo, 251, São Paulo, SP – Brazil – 01246-000

Phone: +55(11) 3893-2619; Fax: +55(11) 3893- 3475

ABSTRACT

INTRODUCTION: The neoadjuvant chemotherapy (NAC) approach can expressively influence radiation therapy indications after breast surgery by theoretically altering the loco-regional relapse risk in accordance with clinical stage features. Precisely, it could reduce this risk for a subgroup of patients with locally advanced breast cancer who achieved a good pathologic response after NAC. Thus, this might raise clinical questions of whether these more favorable subset of patients do benefit from PORT therapy or whether radiation should be performed only for patients with gross residual tumor after neoadjuvant chemotherapy. In addition, there are many uncertainties about the most appropriate radiation therapy fields in patients who received NAC given that all recommendations are usually based on initial clinical and pathological aspects.

OBJECTIVES: The aim of the current study was to assess the radiation therapy fields and survival outcomes in breast cancer patients who underwent (NAC) followed by surgery.

MATERIAL AND METHODS: We performed a retrospective analysis of all non-metastatic breast cancer patients treated between 2008 and 2014 at our institution, who received NAC and post-operative radiation therapy (PORT).

RESULTS: A total of 528 women were included of whom 396 were submitted to mastectomy or adenomastectomy. Most (92.8%) of the patients had locally advanced disease (clinical stage IIB to IIIC). All patients underwent irradiation for breast or chest wall. Most patients received radiation therapy of the supraclavicular and axillary (levels II and III) nodes (87.1% and 86.4% for breast-conserving surgery and 95.1% and 93.8% for mastectomy /

adenomastectomy, respectively). Irradiation of level I axillary and internal mammary nodes was uncommon. The most common radiation therapy schedule was the conventional dose of 50Gy to 50.4Gy in 25 to 28 fractions. The mean overall survival was 66.6 months and the mean disease-free survival was 54.6 months.

CONCLUSION: After NAC, most patients received irradiation of the breast/chest wall and axillary and supraclavicular nodes. Indications were based on initial disease presentation associated with relapse risk factors. In this setting, post-operative radiation therapy to breast/chest wall with or without regional nodal irradiation was effective management that is associated with acceptable survival rates.

Keywords: breast cancer, treatment, neoadjuvant chemotherapy, radiation therapy.