Generally, nonsurgical biopsies are less stressful, do not disfigure the skin, leave no internal scar to interfere with the accuracy of future mammograms, and minimize the risk of complications.However, nonsurgical biopsies are not always as reliable as surgical biopsies in producing a diagnosis, and the results at times may be inconclusive. For this reason, some patients who undergo a nonsurgical biopsy must also undergo a follow-up surgical biopsy.