Is Neoadjuvant Chemotherapy Justified When Triple-Negative Breast Cancer or HER2-Positive Breast Cancer Presents as...

Neoadjuvant chemotherapy (NAC) is considered for patients with cN0 triple-negative (TN) or HER2-positive breast cancer ≥1 cm. If the mammogram shows primarily calcifications spanning ≥1 cm, the appropriateness of NAC is unclear due to uncertainty regarding invasive tumor size. We hypothesized that these patients largely do not have invasion ≥1 cm and should undergo upfront surgery.

Women with TN/HER2-positive invasive breast cancer undergoing upfront surgery with a mammogram showing calcifications ≥1 cm were identified in our database. Patients with mass ≥1 cm on ultrasound were excluded. Imaging findings were compared with pathologic tumor size.

Of 149 patients, 83% had HER2-positive tumors, 17% had TN tumors. Median invasive tumor size was 0.7 cm; 32% had invasion ≥1 cm. Ultrasound and magnetic resonance imaging (MRI) were performed in 70% and 39%, respectively; 35% of patients who underwent MRI had a mass (median 0.95 cm); 88% had non-mass enhancement (NME) (median 3.5 cm). MRI mass size strongly correlated with invasive tumor size (R = 0.75; p < 0.001). Total extent of MRI findings was inaccurate (overestimate 2.3 cm). Ultrasound was weakly correlated with invasive size (R = 0.42; p = 0.015). Calcifications overestimated invasion by 2.3 cm. Only 65% of patients received chemotherapy.

Most patients in our study had invasive cancers <1 cm in size despite calcifications spanning ≥1 cm. The accuracy of mammogram, ultrasound, and MRI for invasive tumor size varied and was commonly overestimated. A mass on ultrasound and MRI can be useful for decisions regarding NAC, but when no clear mass is identified, surgery should be offered first to determine pathologic invasive cancer size to allow more nuanced decisions regarding chemotherapy.