New Haven, Conn. – Physicians conducting needle biopsies with a higher gauge needle the size of a drinking straw and equipped with a vacuum suction device underestimated the severity of cancer in a breast on average in less than 10 percent of the cases, a study by Yale researchers shows.
This compares with an 18 percent rate of underestimation using a smaller, 14-gauge needle and automatic gun to extract breast tissue for testing for cancer, said the principal investigator, Liane Philpotts, assistant professor of diagnostic radiology at Yale School of Medicine.
"We looked at how often we did not fully diagnose the cancer," said Philpotts of the study published in the American Journal of Roentgenology. "It’s not that cancers are missed. These are cases where we realized there was something wrong, but underestimated the severity of it."
Stereotactic core needle biopsy is widely used in place of surgical biopsy for the diagnosis of lesions of the breast diagnosed in mammograms. Although the needle biopsy has been shown to be highly accurate in diagnosing benign and malignant breast disease, it can underestimate cancer. This often results in the need for more surgery.
The retrospective study reviewed biopsies performed between October 1996 and March 1999 using an 11-gauge vacuum suction device. The vacuum suction device is an alternative to the automatic gun technique. Using either 14-gauge or 11-gauge probes, it can obtain core samples that are substantially larger than those obtained with the 14-gauge needle and automatic gun.
The study revealed that out of 753 biopsies in 688 patients, 178 were identified as cases of atypical ductal hyperplasia, or abnormal cell growth, ductal carcinoma in situ, or invasive disease.
The cases were then correlated to identify cases in which cancer was underestimated. Underestimated cancer cases were those in which either carcinoma was not diagnosed or invasive disease was not diagnosed. Of the 178 cases, 158 cases of cancer were ultimately diagnosed. Underestimation occurred in 15, or 9.5 percent, of cases.
The underestimation rate for calcification was 18 percent; for atypical, ductal hyperplasia, 26 percent; for masses, 1.6 percent, and for ductal carcinoma in situ, 18 percent.
No underestimations were found among cases in which the entire lesion identified in a mammogram was removed during the vacuum suction biopsy.
Philpotts said that although underestimation still occurs with the vacuum suction device, the data in the study helps to clarify which cases are more likely to result in underestimation. Underestimation is significantly more likely to occur in cases of calcification than in cases of masses. Also, the study showed that the greater the proportion of the lesion is removed, the less the underestimation.
The senior author of the study was Irena Tocino, professor and chief of breast imaging diagnostic radiology. Co-authors were Carol Lee, associate professor, diagnostic radiology; Laura Horvath, assistant professor, diagnostic radiology; Robert Lange, associate professor diagnostic radiology, and Darryl Carter, professor of pathology.
Journal
American Journal of Roentgenology