Tumor Growth Rate of Luminal and Nonluminal Invasive Breast Cancer Calculated on MRI Imaging

Calculation of the size growth of different types of breast carcinoma based on follow-up data in breast MRI.

Patients were included if they had been diagnosed with an invasive breast carcinoma in the current MRI (aMRI), and had also undergone a breast MRI (pMRI) with unsuspicious findings (MR BIRADS 1 or 2) within 5 years prior to diagnosis. If retrospective analysis of pMRI revealed signs of the current carcinoma, a quantitative one-dimensional-analysis of size progression of the carcinoma over time was performed, and growth rates for different tumor types were calculated.

About 204 patients with 208 invasive breast carcinomas (74 luminal A, 105 luminal B, nonluminal 29) were included. In 129 carcinomas, there were signs of the current tumor in the pMRI. Based on the interval between pMRI and aMRI (average 21 months), the average tumor doubling time was 1126 days (3.1 years), 624 days (1.7 years), and 254 days (0.7 years) of luminal A, luminal B, and nonluminal. The average tumor size was 4.3 mm in the pMRI, and 9.5 mm in aMRI. In 79 cases, the pMRI showed no signs of the actual carcinoma. In this group, the average current tumor size was 8.5 mm.

The study provides specific information on the growth rate of luminal and nonluminal breast cancer. According to this, early detection intervals for nonhigh-risk women using MRI of 2 to 3 years, and for high-risk (HR) women of 1 year appear reasonable. Data also provide a well-founded basis for medico-legal judgements.