Diagnosing molecular subtypes of breast cancer by means of Raman spectroscopy.

OBJECTIVES: Raman spectroscopy has been used to discriminate human breast cancer and its different tumor molecular subtypes (luminal A, luminal B, HER2, and triple-negative) from normal tissue in surgical specimens. MATERIALS AND METHODS: Breast cancer and normal tissue samples from 31 patients were obtained by surgical resection and submitted for histopathology. Before anatomopathological processing, the samples had been submitted to Raman spectroscopy (830 nm, 25 mW excitation laser parameters). In total, 424 Raman spectra were obtained. Principal component analysis (PCA) was used in an exploratory analysis to unveil the compositional differences between the tumors and normal tissues. Discriminant models were developed to distinguish the different cancer subtypes by means of partial least squares (PLS) regression. RESULTS: PCA vectors showed spectral features referred to the biochemical constitution of breast tissues, such as lipids, proteins, amino acids, and carotenoids, where lipids were decreased and proteins were increased in breast tumors. Despite the small spectral differences between the different subtypes of tumor and normal tissues, the discriminant model based on PLS was able to discriminate the spectra of the breast tumors from normal tissues with an accuracy of 97.3%, between luminal and nonluminal subtypes with an accuracy of 89.9%, between nontriple-negative and triple-negative with an accuracy of 94.7%, and each molecular subtype with an accuracy of 73.0%. CONCLUSION: PCA could reveal the compositional difference between tumors and normal tissues, and PLS could discriminate the Raman spectra of breast tissues regarding the molecular subtypes of cancer, being a useful tool for cancer diagnosis.

Substantial Reduction in Adjuvant Chemotherapy With the Use of the 21-Gene Test to Manage Early Breast Cancer in a Public Hospital in Brazil.

PURPOSE: We evaluated the impact of 21-gene test results on treatment decisions for patients with early-stage breast cancer treated under the public health care system in Brazil, Sistema Único de Saúde. METHODS: Eligible patients treated at Hospital Pérola Byington and Santa Casa de Misericórdia de São Paulo in Brazil were required to have the following characteristics: postsurgery with hormone receptor-positive, human epidermal growth factor 2-negative, node-negative and node-positive, and T1/T2 breast cancer and patients with these characteristics were candidates for adjuvant systemic therapy. Treatment recommendations, chemotherapy plus hormonal therapy (CT + HT) or HT alone, were captured before and after 21-gene test results. RESULTS: From August 2018 to April 2019, 179 women were enrolled. The mean age was 58 years (29-86 years), 135 (76%) were postmenopausal, and 58 (32%) had node-positive breast cancer. Most patients (61%) had a tumor > 2 cm, including 7% with tumors > 4 cm. Using Recurrence Score (RS) result cut points on the basis of the TAILORx trial, 40 (22%) had RS 0-10, 91 (51%) had RS 11-25, and 48 (27%) had RS 26-100. Before 21-gene testing, 162 of 179 (91%) patients were recommended for CT. After testing, 117 of 179 patients (65%) had changes in CT recommendation: 112 (63%) who were initially recommended CT received HT alone and five (3%) who were initially recommended HT alone received CT + HT. After 21-gene testing, 99% of physicians reported strong confidence in their treatment recommendations. CONCLUSION: The change in clinical practice at these public hospitals was greater than expected: 66% of initial treatment recommendations were changed to omit CT with 21-gene test results. Clinicopathologic features did not correlate well with 21-gene test results and did not adequately identify those most likely to benefit from CT.

Indicações da cirurgia conservadora no câncer de mama / Indications for conservative surgery in breast cancer

O rastreamento mamográfico aumentou o número de pacientes em estádios iniciais do câncer de mama, que propiciaram a realização de estudos randomizados sobre cirurgia conservadora. Esses estudos demonstraram que a cirurgia conservadora associada à radioterapia, indicada em tumores com até 3 cm de diâmetro, não modifica a sobrevida após 25 anos de seguimento, apesar de acarretar um aumento significativo de recidiva local.

Screening mammography has increased the number of patients in early stages of breast cancer, which led to randomized studies on conservative surgery. These studies demonstrate that conservative surgery combined with radiotherapy, indicated in tumors with up to 3 cm, does not after survival after 25 years of follow-up, despite a significant increase of local recurrence.