Micrometastases in axillary lymph nodes associated with poorer overall survival in breast cancer patients
November 17, 2015
Current guidelines for women at high familial risk of breast cancer recommend annual MRI (with or without ultrasound) and annual MRI starting at age 25-30. "These guidelines were set up based on little or no scientific evidence, and mainly reflect expert opinion", summarizes Prof. Christiane Kuhl, radiologist at the University of Bonn and principal investigator of the EVA trial. "In the light of the results of the EVA trial, such recommendations should be revisited". This seems even more important because digital mammography uses x-rays (ionizing radiation) to detect breast cancer. "The radiation dose associated with regular mammographic screening is clearly acceptable and safe", underscores Kuhl. "However, regular mammographic screening usually starts at age 40-50". The situation is different if systematic annual mammographic screening is started at age 25-30. "Not only because these women will undergo more mammograms and therefore will experience a cumulative lifetime radiation dose that will be substantially higher, but also because the breast tissue of young women is more vulnerable to the mutagenic effects of radiation". This appears to be especially true for BRCA mutation carriers. "Accordingly, we impose more radiation on less radiation-tolerant breast tissue - for a very limited, if any, diagnostic benefit". Therefore, Kuhl advocates a revision of existing guidelines: "It is no longer justifiable to insist on annual mammographic screening women in their thirties if they have access to screening MRI".
MRI is a mature technology
In the past, MRI was used strictly in addition to mammography only. The allegedly high rate of "false positive" diagnoses and the allegedly insufficient sensitivity for DCIS were the main reason to discourage its use as a stand-alone method for breast cancer screening. "In this multicenter trial, with basic quality assurance implemented not only for mammography, but also for MRI, we were able to prove that false positive diagnoses are avoidable if MRI studies are interpreted with adequate radiologist expertise". In the EVA cohort, the Positive Predictive Value achieved with MRI was already even higher than that of mammography or breast ultrasound. "Moreover, we found that MRI offered the highest sensitivity especially for DCIS", adds Dr. Kuhl. "It is simply wrong to state that we need a mammogram to detect intraductal cancer".
Source: University of Bonn