The malignancy rate for palpable breast masses in women younger than 40 years is approximately 3 percent (national average). In these women, mammography is less reliable than it is in older women and has a false-negative rate of nearly 80 percent. Biopsy is usually performed to avoid missing the rare but serious malignancy. Because biopsy results in scarring and disfigurement, Morris and colleagues adapted their triple test score (TTS) system to better select younger women with a high probability of malignancy for biopsy.
Previously, the authors had devised and verified the accuracy of the TTS for quickly and accurately evaluating palpable breast masses in women 40 years of age and older. The three components of the TTS are the physical examination, diagnostic mammography, and fine-needle aspiration (FNA) biopsy. For each test, the examiner rates the lesion as benign (1 point), suspicious (2 points), or malignant (3 points). The scores by the three independent raters are added to achieve the final TTS score. The authors initially tested the scoring system on 484 masses and determined that masses with total scores of 4 points or less were probably benign, while those scoring 6 or more points were likely to be malignant.
Because mammography is unreliable in younger women, the authors substituted ultrasonography for mammography in determining TTS scores in a large group of young women with palpable breast masses. During a three-year period, the modified TTS (MTTS) was used in 108 women younger than 40 years with 113 breast masses. The ratings were performed by a team of surgical oncologists (physical examination), radiologists (ultrasonography), and cytopathologists (FNA biopsy). Each examiner scored every lesion independently, and a final MTTS was calculated for each breast mass.
The women in the study had a mean age of 27 years (range: 14 to 39 years). In 100 masses (89 percent), the MTTS was 3 points, indicating a benign lesion. These masses were followed clinically or biopsied, depending on the patient's wishes. For eight masses (7 percent), the MTTS was 4 points. Seven of these lesions were biopsied, and one was followed clinically; all were benign. Of the three masses scoring 5 points, one was found to be malignant on biopsy. The two masses scoring 6 points were both found to be malignant on biopsy.
The authors concluded that the combination of ultrasonography, clinical examination, and FNA biopsy can be used in women younger than 40 years of age to calculate a total breast mass score that accurately predicts malignancy when the score is 6 points or greater. For masses with these high scores, patients may proceed to definitive therapy with confirmatory frozen section. The authors recommended that open biopsy be performed in patients with masses scoring 5 points, but that follow-up without biopsy was safe in patients with masses scoring 4 points or less. They estimated that use of the MTTS system would avoid biopsy in 97 percent of women younger than 40 years who have breast masses but still identify the 3 percent with malignancy.
editor's note: While welcoming the concept of getting better information for patients without the necessity of biopsy, one wonders how reproducible these results are nationally. Each component of the score depends on a subjective professional judgment. No matter how experienced physicians are, we vary in our level of interpretation of clinical data. A second concern is acceptability by patients. Women with breast masses seem to be sharply divided into those who want biopsy “to be certain” and those who find disfigurement by biopsy difficult to accept. Nevertheless, it would be helpful to see a large study done on patients at nonteaching centers to see if the MTTS can help us in practice. Are any interested researchers reading this?—A.D.W.