Technetium-99m tetrofosmin scintigraphy in the diagnosis of breast cancer

[Technetium-99m-tetrofosmin radionuclide mammography in the diagnosis of malignant breast tumors]

BACKGROUND

Technetium-99m (99mTc) tetrofosmin scintigraphy is a new imaging method for the diagnosis of various malignancies, such as lung, thyroid, and most frequently breast neoplasms. The aim of this study was to evaluate the diagnostic reliability of 99mTc-Tetrofosmin breast scintigraphy in the detection of malignant breast disease.

METHODS

99mTc-Tetrofosmin scintimammography (SMM) was performed in 28 patients with 30 breast lesions suspicious for malignancy. Standard mammography (MM) was also done. After surgery, the results of SMM and MM were compared to definitive histopathological findings as the "gold standard". After intravenous injection of radiotracer, SMM was performed in prone and supine views of the thorax, using large field-of-view Gamma camera.

RESULTS

The results of SMM were interpreted visually and semiquantitatively, and evaluated as positive or negative. Sensitivity, specificity and accuracy, positive (PPV) and negative predictive value (NPV) were obtained in relation to histopathology. After comparing the results of SMM and MM, SMM was proved more sensitive (95% for SMM vs. 80% for MM), while the specificity of both methods was similar.

CONCLUSION

The results of this study indicate that the contribution of SMM as a nuclear medicine procedure has its place in the diagnostic protocol for patients suspected of malignant breast cancer.

Nuclear medicine and breast cancer: a review of current strategies and novel therapies

While breast cancer is still increasing in frequency, new diagnostic procedures are now available to challenge existing procedures and to make diagnosis of breast cancer more accurate and reliable. Mammography remains the standard investigation to reveal disease in an asymptomatic population: it can also be used to diagnose breast cancer in symptomatic patients (e.g. those with palpable breast lumps) and for guiding fine needle aspiration (FNA). Because the majority of breast lumps are benign, the challenge is to distinguish benign from malignant lesions without the use of invasive methods and this has attracted nuclear medicine physicians and medical oncologists to investigate the role of scintigraphic procedures to identify which patients require FNA. This review attempts to shed light on the various scintigraphic methods available which are of potential practical use in the assessment of malignant breast disease as well as looking at the possible role of nuclear medicine in the treatment of advanced disease.

99m-Tc-tetrofosmin scintigraphy for the evaluation of suspicious palpable and non-palpable breast lesions

PURPOSE

To assess the value of 99m-Tc-tetrofosmin (tetrofosmin) scintigraphy in patients with palpable and nonpalpable breast lesions.

PATIENTS AND METHODS

Prospective, blinded trial. One hundred and fifty-nine consecutive patients with 163 breast lesions detected by clinical examination and mammography were included. Tetrofosmin scintigraphy of the breast was performed additionally to the regular diagnostic procedure. Using histologic assessment as the golden standard, sensitivity, specificity, positive and negative predictive value for tetrofosmin scintigraphy of the breast were assessed.

RESULTS

Overall sensitivity and specificity were 82% and 84%. The sensitivity for palpable tumors (65%) was 93% compared to 62% for non-palpable breast lesions. Malignant lesions were nearly twice as big as benign lesions (31.5 mm +/- 2.4 vs. 16.9 mm +/- 2.4). Specificity, positive and negative predictive value (84%, 89%, and 66%) did not differ significantly in palpable versus non-palpable tumors. Of malignant tumors 18% were found false negative by tetrofosmin scintigraphy.

CONCLUSION

The results suggest that tetrofosmin scintigraphy is a valuable tool for the evaluation of palpable breast cancer. In patients with non-palpable tumors, tetrofosmin scintigraphy may not add to the work-up of patients with breast cancer due to a low sensitivity rate.

99m-Tc-tetrofosmin scintigraphy and breast cancer

BACKGROUND

99m-Tc-tetrofosmin holds significant interest among medical oncologists because of its high positive predictive value (>90%) in pilot trials, exceeding sensitivity and specificity rates of mammography. Objective. Our objective was to assess the diagnostic accuracy of 99m-Tc-tetrofosmin whole-body scintigraphy in outpatients.

PATIENTS AND METHODS

Thirty-one patients with an abnormal mammograph (n = 22) or follow-up patients (n = 9), 7 of whom were known to have metastatic disease, were included. Tracer (550 MBq) was injected into the cubital vein. Whole-body planar and single photon emission computed tomography images of regions of interest were obtained. Histology, computed tomography (CT), or magnetic resonance imaging (MRI) were performed to confirm scintigraphic results. Correlation between scintigraphy and CT or MRI was assessed by two independent radiologists. Accuracy, sensitivity, and specificity rates for the diagnosis of local and distant breast cancer lesions were given.

RESULTS

Of the 22 first-visit patients, 15 had breast cancer, and 7 had no evidence of any malignant disease. Of all patients examined (n = 31), 21 had distant metastases. Breast tumors were correctly diagnosed in 14/15 patients (93%), with only 1 false-negative result. Extrahepatic metastatic lesions (n = 16) were correctly diagnosed in 14 (88%) patients, whereas the method was not suitable for the diagnosis of liver metastases.

CONCLUSION

Tetrofosmin scintigraphy has shown very high detection rates of breast tumors and of metastatic lesions and is therefore a valuable option in breast cancer diagnosis.

Pulmonary Tc-99m tetrofosmin imaging: clinical experience with detecting malignant lesions and monitoring response to therapy

The authors prospectively investigated the uptake and kinetics of Tc-99m tetrofosmin (Tetro) in benign and malignant lung lesions and the effect of radiotherapy, chemotherapy, or both on Tc-99m Tetro uptake in malignant lung tumors. Dynamic and planar Tetro imaging were performed in 45 patients with pulmonary lesions during a period of 28 months (34 untreated malignant tumors, 11 benign lesions). Tetro uptake was visibly increased in 26 of 34 malignant tumors, with a mean lesion to contralateral normal tissue ratio of 1.44 +/- 0.29 and a tumor washout rate of 28.4 +/- 6.6% 30 minutes after injection. In 3 of 11 benign lesions, Tetro uptake was observed. Of the 26 patients with malignant tumors and positive Tetro uptake, nine had repeated imaging 6 to 8 weeks after therapy. The patients were treated with radiotherapy, chemotherapy, or both. Reduction in radiological tumor size was used as the clinical response parameter. In five of nine patients, the course of Tetro uptake in follow-up imaging was in accordance with that of radiological tumor size. Two of four remaining patients had only slight discordance between the alteration of Tetro uptake and radiological tumor size. The sensitivity of Tetro to detect malignant lung lesions in our patients was 77%. The specificity and accuracy of the method were 73% and 76%, respectively. Tetro has limited diagnostic value in detecting lung cancer. It may be useful to monitor the response to therapy in malignant lung tumors with initial tracer uptake. Broader trials on this matter are needed for further clarification.

Gamma emission imaging in the management of breast disorders

Breast cancer is the commonest malignancy to affect women. The malignant process may present clinicians with problems in establishing the diagnosis expeditiously, accurately staging the disease and assessing tumour response to primary systemic chemotherapy. Considerable recent interest has focused on the application of imaging techniques that utilize tumour-specific gamma-ray-emitting radiopharmaceuticals to resolve these problems. The wide availability of gamma camera systems makes single photon-imaging techniques, using radiopharmaceuticals incorporating conventional isotopes, attractive options. However, results concerning the detection of the primary breast cancer and the staging of axillary lymph nodes suggest that these techniques would appear to offer no significant advantages, when compared with those obtained using standard diagnostic methods. Dual gamma-ray-emission imaging by positron emission tomography (PET) may offer an alternative solution. Studies performed show that PET can accurately detect primary breast cancers, stage locoregional lymph nodes and visualize distant tumour metastases. Furthermore, PET may be able to monitor early tumour response to chemotherapy agents. It would appear, therefore, that dual gamma emission might have an important role to play in the management of patients with breast cancer.