Detection of bilateral multifocal breast cancer using Tc-99m sestamibi imaging. The role of delayed imaging

Synchronous multiple ipsilateral breast cancers: implications for patient management

Interest in the presence and management of synchronous multiple ipsilateral breast cancer has been reported since the early 1920s. The demonstration of multiple foci of breast cancer has been reported in 9-75% of breast cancer related specimens. The large difference in reported incidence is multifactorial and related to the definitions applied, mode of detection and pathological assessment. However, randomised clinical trials comparing total mastectomy and segmental mastectomy with or without radiation over many years have shown no difference in distant disease-free survival or overall survival in patients with synchronous multiple ipsilateral breast cancer compared with unifocal breast cancer. This review examines the current definitions, incidence, pathological assessment, staging and surgical options of synchronous multiple ipsilateral breast cancer.

Radioguided Intraoperative Margins Evaluation (RIME): Preliminary results of a new technique to aid breast cancer resection

AIMS

Women undergoing breast-conserving surgery for cancer can present residual disease. We have developed a technique called Radioguided Intraoperative Margins Evaluation (RIME) that uses a radiopharmaceutical to distinguish normal and cancer tissues. The aim of this study was to assess whether RIME is a feasible technique, and if it could help in breast cancer resection with free margins, minimizing residual disease.

METHODS

Twenty-three breast cancer patients programmed for mastectomy were selected. Before surgery, the patients were submitted to scintimammography with 99mTc-sestamibi to estimate the optimal time to begin radioguided surgery. Twenty patients were submitted to magnetic resonance imaging (MRI), to evaluate skin, deep fascia and to detect other tumor foci. At the beginning of the surgery, the same dose of 99mTc-sestamibi was intravenously injected into patients. Tumor resection was performed under guidance of a gamma-probe, characterizing the RIME technique. Finally, modified radical mastectomy was performed. Tumor and residual breast were histopathologically examined.

RESULTS

The RIME technique was successfully performed in all patients. The principal tumor was removed by this technique and provided 82.6% of histologically free margins (mean margins, 4.8 mm). Additionally, 47.8% of patients were without residual disease. The mean size of residual carcinoma was 3.67 mm and generally located near the tumor bed (<1.5 cm). There was no significant association between presence of residual disease and tumor size or margin status.

CONCLUSION

RIME is a feasible technique that could help tumor resection with free margins; however, it seems to be limited for small carcinoma foci.

Radioguided Surgery Using Intravenous 99mTc Sestamibi Associated with Breast Magnetic Resonance Imaging for Guidance of Breast Cancer Resection

The purpose of this study was to evaluate the feasibility of surgery radioguided with intravenous (99m)Tc sestamibi associated with magnetic resonance imaging (MRI) of the breast to detect tumor extent and guide complete tumor resection. A descriptive experimental study was developed with 10 breast cancer patients (stage IIA-IIB) who underwent mastectomy. From 2 to 10 days before surgery, the patients underwent breast MRI with 0.1 mmol/kg of gadolinium and scintimammography with a 740 MBq of (99m)Tc sestamibi. A region of interest was drawn around the tumor image and an uptake curve as a function of time was plotted to calculate the optimal time to perform radioguided surgery. In the perioperative period, the same dose of (99m)Tc sestamibi was intravenously injected into the patients. Tumor resection was performed under the guidance of a gamma probe. MRI was used to evaluate the skin and deep fascia involvement and to detect occult tumor foci which were also excised. Subsequently a modified radical mastectomy was performed. Tumor and residual breast were histopathologically examined. In a series of 10 women, all demonstrated (99m)Tc sestamibi uptake in tumor cells. Eight patients showed no disease in the residual breast, one presented with one foci of invasive ductal carcinoma measuring 0.5 cm in diameter located 5 cm from the tumor bed, and one presented with one foci of ductal carcinoma in situ measuring 0.8 cm at the resection margin. The mean tumor size in the histopathologic assessment was 3.3 cm and in MRI was 5.0 cm. Radioguided surgery using (99m)Tc sestamibi associated with MRI is a feasible technique that can be employed in tumor resection.

Clinical applications of 99mTc-sestamibi scintimammography

Mammography is the imaging modality of choice in detection of early, nonpalpable breast cancer. However, scintimammography may prove to be a very useful adjunct to a nondiagnostic or difficult mammography. Future prospective studies will have to be designed so that the specific clinical applications of scintimammography will be well defined. To be clinically relevant, each niche where scintimammography is potentially indicated should be clearly evaluated and incorporated into an algorithm of investigation of breast cancer, taking into consideration the relative advantages and limitations of scintimammography. Special care to obtain high-quality scintimammographic studies is mandatory. Because poor quality studies may be the major drawback, the nuclear medicine community should remind the lesson learned from radiologic mammography. Furthermore, it is also hoped that significant improvement in the scintigraphic equipment and data acquisition will be seen in a very near future to have more widespread clinical diagnostic applications of scintimammography.

The Clinical Utility of Tc-99m Sestamibi Scintimammography in Detecting Multicentric Breast Cancer

The ability to recognize multicentric breast cancer preoperatively would assist in identifying appropriate candidates for breast conservation surgery. Tc-99m scintimammography (SMM) is an adjunct to conventional mammography in identifying selected patients with breast cancer. The purpose of this study is to report the utility of SMM in identifying patients with multicentric breast cancer. Breast cancer patients treated by mastectomy who underwent a preoperative SMM between 1992 and 1999 were identified using the institution's Tumor Registry. The pathology report of each patient was reviewed for multicentric disease defined as an additional focus of cancer within a different quadrant of the breast or greater than 2.5 cm from the dominant tumor mass. Each patient's preoperative SMM was reviewed and compared with the pathologic findings to obtain correlative data. Fifty-eight women treated by mastectomy had preoperative SMM (age range 35–78 years; median 52 years). Pathology revealed infiltrating ductal carcinoma in 49 patients (84.5%), infiltrating lobular carcinoma in five patients (8.6%), ductal carcinoma in situ in three patients (5.1%), and colloid carcinoma in one patient (1.7%). Multicentric disease was present in the specimens of eight patients for a prevalence of 10.3 per cent. SMM was positive for uptake in 36 of 58 patients (sensitivity 62.1%). The sensitivity, specificity, positive predictive value, and negative predictive value of SMM in the detection of multicentric disease were 62.5, 96, 71, and 94 per cent, respectively. Although the overall sensitivity of SMM in the detection of breast cancer is superior to that of conventional mammography and physical examination in identifying multicentric breast cancer it is not an accurate modality for detecting multicentric disease in this study group. However, it may have limited applications in specific cases.