Joint Program in Nuclear Medicine

Scintimammography

Gabriel Soudry, MD
J. Anthony Parker, MD, PhD

January 31, 1995

Presentation

A 45 year old women with large fibrocystic breasts was found to have a questionable small lump in the left breast. The mammogram was negative.

Imaging Findings

She was refered for a scintimammogram (immediate anterior, one hour anterior, and left anterior oblique, 41k bytes) prior to biopsy. Scintimammogram showed a small focus of abnormal tracer uptake in the outer upper quadrant of the left breast (arrow, 41k bytes). Biopsy of that abnormality following the scan was positive for breast carcinoma.

Discussion

Breast carcinoma is the second most common malignancy in American women with approximately 150,000 new cases every year. Early detection has been shown to reduce mortality by 30%%. Currently, a women undergoing a screening procedure for the detection of breast carcinoma will be evaluated with physical examination and mammography. The detection of an abnormality is often followed with a breast biopsy witch is associated with significant physical discomfort and emotional stress (1). The risk and cost of performing biopsies are also to be taken in consideration (2). A noninvasive technique to select those who would benefit most from breast biopsy and reduce the number of negative biopsies would clearly be of value.

X-ray Mammography:

The most important abnormalities in interpreting mammograms are masses and calcifications. More subtle signs include architectural distortion, parenchymal asymmetry and neodensity in the breast. It should be noted that the breast of young women are composed primarily of dense fibroglandular tissue that significantly limits the accuracy of mammography. When that tissue is replaced by radiolucent fat in older women, abnormal densities can be detected more readily (3,4).

Sensitivity of mammography in symptomatic patients is on average 90%% (2). Of the 10%% false negative mammograms, 50%% prove to be erroneous mammographic diagnoses due to suboptimal technique, lack of experience of the reader, failure to compare with previous studies. The remaining 50%% are mammographically occult cancers that cannot be recognized on the mammogram even in retrospect. Histologic characteristics of those tumors include a diffuse invasive pattern, poor desmoplastic reaction with poorly outlined tumor margins, lack of calcifications (which occur only in 50%% of breast cancers) (5).

Prelocalization mammograms of 200 consecutive patients were reviewed by 4 radiologists experienced in mammography. Each lesion was rated from definitely benign to definitely malignant. Ratings were compared with the pathologic findings (181 benign, 50 malignant). If biopsies had not been performed on those patients who were judged to have most likely benign lesions, one could reduce the number of biopsies by 48 to 69%%; however 18 to 46%% of malignancies would be missed.(3).

A screening program reported by the Illinois Division of the American Cancer Society involving 80 Chicago metropolitan area mammographic facilities revealed that, of the 9307 women undergoing screening mammography, 82%% had results that were negative for malignancy, 16%% had inconclusive results, and only 2%% had suspicious results. There were 206 patients in the suspicious group, of which 147 underwent biopsy, with 39 (27%%) cancers found. The benign-to-malignant biopsy ratio was 3.8 to 1. On the other hand, 1450 patients had inconclusive mammograms, 136 underwent biopsies, and only 8(6%%) cancer were found. This represented a benign-to-malignant biopsy ratio of 17 to 1 which is considered too high by most standards (6).

Scintimammography imaging technique:

Two imaging methods described.

1. Waxman et al (7):

2.Khalkhali et al (8):

Summary of Reported Accuracy:

1. Waxman et al (7):

Of note:

2. Khalkhali et al(8):

Of note:

3. Lee et al(9):

4. Kao et al(10):

These data suggest that mammoscintigraphy can increase or decrease the suspicion of malignancy in patients with breast abnormalities detected by physical exam and/or mammography and may help triage patients who need biopsies from those who could be followed closely.

Conclusions:

References

1. Potchen EJ, Bisesi MA, Sierra AE, Potchen JE. Mammography and malpractice. AJR 1991; 156:475-480.

2. Winchester DP. Evaluation and management of breast abnormalities. Cancer 1990; 66:1345-1347.

3. Monostori Z, Herman PG, Carmody DP et al. Limitations in distinguishing malignant from benign lesions of the breast by systematic review of mammograms. Surg Gynecol Obset 1991; 173:438-42.

4. Bassett LW, Gambhir S. Breast imaging for the 1990s. Semin Oncol 1991; 18:80-86.

5. Holland R, Hendricks JH, Mravunac M. Mammographically occult breast cancer. A pathologic and radiologic study. Cancer 1983; 52:1810-1819.

6. Winchester DP, Lasky HJ, Sylvester TL, Maher ML. A television promoted mammographic screening pilot project. CA 1988; 38:291-309.

7. Waxman AD, Ramanna L, Memsic LD et al. Thallium scintigraphy in the evaluation of abnormalities of the breast. J Nucl Med 1993; 34:18-23.

8. Khalkhali I, Mena I, Jouanne E et al. Prone scintimammography in patients with suspicion of carcinoma of the breast. J Am Coll Surg 1994; 178:491-497.

9. Lee VW, Sax EJ, McAneny et al. A complementary role for thallium-201 scintigraphy with mammography in the diagnosis of breast cancer. J Nucl Med 1993; 34:2095-2100.

10. Kao CH, Wang SJ, Liu TJ. The use of technetium-99m methoxyisobutylisonitrile breast scintigraphy to evaluate palpable breast masses. Eur J Nucl Med 1994; 21:432-436.

Click here to go to Joint Program in Nuclear Medicine home page and Copyright notice.

J. Anthony Parker, MD PhD, Tony_Parker@bidmc.harvard.edu