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Methodological aspects of 99m Tc-sestamibi guided biopsy in breast cancer

View Article: PubMed Central - PubMed

ABSTRACT

Purpose: This review aims to discuss the methodological aspects of dedicated molecular breast imaging (MBI) using 99mTc-sestamibi as radiotracer to guide biopsy of occult or unclear breast lesions on mammography (MG) and ultrasound (US) that are suspicious on MBI (BI-RADS criteria 4 and 5), including its advantages, limitations and future clinical applications.

Methods: Literature search was performed using the PubMed/MEDLINE database and “99mTc-sestamibi”, “biopsy” and “breast cancer” as keywords. The search was restricted to English language.

Results: There are few studies on 99mTc-sestamibi guided biopsy methods; to our knowledge, no full studies have yet been reported on clinical validation of this new biopsy procedure. This review describes technical aspects of 99mTc-sestamibi guided biopsy and discusses the advantages and limitations of this procedure in comparison with MG, US and MRI-guided biopsy.

Conclusions: MBI-guided biopsy appears to be a complementary modality and is principally indicated in the case of occult or unclear breast lesions on MG/US, that are suspicious on MBI. The future indication is in targeted biopsies in patients with large heterogeneous tumours. Further studies are needed to define the accuracy of this biopsy procedure.

No MeSH data available.


Procedure time of the different steps in 99mTc-sestamibi MBI-guided biopsy
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Fig4: Procedure time of the different steps in 99mTc-sestamibi MBI-guided biopsy

Mentions: In recent years, percutaneous image-guided breast biopsy has gained importance as an alternative to surgical biopsy, mainly using sonographic, stereotactic, or MRI guidance. US-guided biopsy is the first technique of choice for sampling breast lesions. The sampling probe is placed behind the lesion to be biopsied and the verification of the correct needle placement is real-time. The main advantages of US-guided biopsy are its wide availability, lack of ionizing radiation and low costs [25]. Stereotactic biopsy is usually performed for sampling micro-calcifications and distortions not detected on US [26]. The patient is in upright or prone position and in both situations with compression of the breast [27, 28]. The prone position results in higher comfort for the patient, decreased likelihood of patient motion and less vasovagal reactions [29]. MRI-guided biopsy is principally performed when the breast lesion is occult both on US and MG [30]. The patient is in prone position with the breast located in a dedicated biopsy coil with compression in the mediolateral direction. The procedure time for MRI-guided biopsy is approximately 30–70 min [31, 32]. MRI-guided biopsy poses several challenges, such as the necessity to remove the patient from the magnet to perform the biopsy and the transient nature of the contrast enhancement. Furthermore, the access to the medial and posterior breast tissue is limited. An important limitation concerns the inability to verify the successful sampling of the target lesion, since tissue samples do not enhance ex vivo [33, 34]. As mentioned earlier, MBI is increasingly being used as adjunct modality to MG and US for detecting BC. In contrast to MG, MBI is a functional imaging technique that is not influenced by breast density and architectural distortion, regularly leading to the discovery of MG occult breast malignancies [18, 35]. For patients with occult or unclear breast lesions on MG/US but suspicious MBI, the possibility to use MBI-guided biopsy appears to be an excellent alternative to acquire representative tissue samples for histopathological analysis. To date, several MBI-guided biopsy methods have been described in the literature. In 2004, Coover et al. reported on a method to localise the lesion using a dedicated breast camera with an open biopsy paddle. The site of the lesion was identified using 57Co point source on the breast and the camera monitor in the persistent mode. Subsequently, two localization needles were placed into the site of the lesion followed by an open biopsy of the area where the two needles intersected. The authors reported a suspicious finding in 5 of 37 patients (13.7 %) with dense breasts and at high risk of breast cancer; biopsy revealed carcinoma in 3 out of 5 of these patients [36]. In 2006, Welch et al. reported on the development of a compact dedicated breast camera-guided stereotactic breast biopsy system. A fiducial marker containing 0.925 MBq of 57Co was mounted inside the top of the breast compression paddle as spatial reference point. An algorithm for determining the spatial location of the breast lesion was implemented in the software of the dedicated breast camera [37]. More recently, Weinmann et al. developed a conical slant hole (CSH) collimator for MBI-guided biopsy with dual-head CZT, improving the accuracy of lesion depth determination [38]. To our knowledge, no full studies have yet been reported on clinical validation of MBI-guided biopsy procedures. Based on our own clinical experience, the stereotactic biopsy method using the slant-hole collimator localization system as described here shows good patient acceptability. The procedure time is approximately 75 min, which is longer than the MG/US guided methods. The difference is mainly explained by the prolonged image acquisition which is necessary to accurately display lesion uptake of 99mTc-sestamibi for subsequent stereotactic localization and biopsy (Fig. 4). However, procedure time is comparable to MRI guided biopsy. Complications are similar to those in other radiological biopsy methods such as syncope, hematoma formation and marker migration. Table 3 describes the clinical indications for MBI-guided biopsy. This biopsy method using 99mTc-sestamibi is considered a complementary modality to MG/US-guided biopsy and an alternative to MRI-guided biopsy. It is principally indicated in patients with occult lesions on MG/US but suspicious on MBI (BI-RADS criteria 4–5) and occult after second-look US. Other possible indications include: (i) unclear lesions on MG/US but suspicious on MBI (BI-RADS criteria 4–5); (ii) failure of other biopsy methods. A potential future indication concerns optimization of primary tumour tissue sampling in patients with locally advanced breast cancer (LABC) by means of 99mTc-sestamibi-guided targeted biopsy. In the literature non-correspondence between the core biopsy location and the area with highest metabolic activity in the tumour has been described for stage II/III breast cancer patients scheduled for neoadjuvant chemotherapy [39]. Since early and increased concentration of 99mTc-sestamibi in breast carcinomas is associated with high proliferation rate, indicating more aggressive tumour behaviour [40], the sampling of the most proliferative parts of the tumour that correspond with highest uptake of 99mTc-sestamibi in large heterogeneous tumours could result in more optimal therapy planning in patients with LABC. The advantages and disadvantages of the different biopsy methods are summarized in Table 4. The main advantage of MBI-guided biopsy compared to MRI-guided biopsy is the possibility to measure radioactivity of the tissue samples ex vivo, in this way verifying that the target lesion has been sampled successfully. However, biopsy may be difficult in lesions close to the pectoral muscle because they may not be completely visualized due to the vertical position of the patient in relation to the field of view of the camera.Fig. 4


Methodological aspects of 99m Tc-sestamibi guided biopsy in breast cancer
Procedure time of the different steps in 99mTc-sestamibi MBI-guided biopsy
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

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Fig4: Procedure time of the different steps in 99mTc-sestamibi MBI-guided biopsy
Mentions: In recent years, percutaneous image-guided breast biopsy has gained importance as an alternative to surgical biopsy, mainly using sonographic, stereotactic, or MRI guidance. US-guided biopsy is the first technique of choice for sampling breast lesions. The sampling probe is placed behind the lesion to be biopsied and the verification of the correct needle placement is real-time. The main advantages of US-guided biopsy are its wide availability, lack of ionizing radiation and low costs [25]. Stereotactic biopsy is usually performed for sampling micro-calcifications and distortions not detected on US [26]. The patient is in upright or prone position and in both situations with compression of the breast [27, 28]. The prone position results in higher comfort for the patient, decreased likelihood of patient motion and less vasovagal reactions [29]. MRI-guided biopsy is principally performed when the breast lesion is occult both on US and MG [30]. The patient is in prone position with the breast located in a dedicated biopsy coil with compression in the mediolateral direction. The procedure time for MRI-guided biopsy is approximately 30–70 min [31, 32]. MRI-guided biopsy poses several challenges, such as the necessity to remove the patient from the magnet to perform the biopsy and the transient nature of the contrast enhancement. Furthermore, the access to the medial and posterior breast tissue is limited. An important limitation concerns the inability to verify the successful sampling of the target lesion, since tissue samples do not enhance ex vivo [33, 34]. As mentioned earlier, MBI is increasingly being used as adjunct modality to MG and US for detecting BC. In contrast to MG, MBI is a functional imaging technique that is not influenced by breast density and architectural distortion, regularly leading to the discovery of MG occult breast malignancies [18, 35]. For patients with occult or unclear breast lesions on MG/US but suspicious MBI, the possibility to use MBI-guided biopsy appears to be an excellent alternative to acquire representative tissue samples for histopathological analysis. To date, several MBI-guided biopsy methods have been described in the literature. In 2004, Coover et al. reported on a method to localise the lesion using a dedicated breast camera with an open biopsy paddle. The site of the lesion was identified using 57Co point source on the breast and the camera monitor in the persistent mode. Subsequently, two localization needles were placed into the site of the lesion followed by an open biopsy of the area where the two needles intersected. The authors reported a suspicious finding in 5 of 37 patients (13.7 %) with dense breasts and at high risk of breast cancer; biopsy revealed carcinoma in 3 out of 5 of these patients [36]. In 2006, Welch et al. reported on the development of a compact dedicated breast camera-guided stereotactic breast biopsy system. A fiducial marker containing 0.925 MBq of 57Co was mounted inside the top of the breast compression paddle as spatial reference point. An algorithm for determining the spatial location of the breast lesion was implemented in the software of the dedicated breast camera [37]. More recently, Weinmann et al. developed a conical slant hole (CSH) collimator for MBI-guided biopsy with dual-head CZT, improving the accuracy of lesion depth determination [38]. To our knowledge, no full studies have yet been reported on clinical validation of MBI-guided biopsy procedures. Based on our own clinical experience, the stereotactic biopsy method using the slant-hole collimator localization system as described here shows good patient acceptability. The procedure time is approximately 75 min, which is longer than the MG/US guided methods. The difference is mainly explained by the prolonged image acquisition which is necessary to accurately display lesion uptake of 99mTc-sestamibi for subsequent stereotactic localization and biopsy (Fig. 4). However, procedure time is comparable to MRI guided biopsy. Complications are similar to those in other radiological biopsy methods such as syncope, hematoma formation and marker migration. Table 3 describes the clinical indications for MBI-guided biopsy. This biopsy method using 99mTc-sestamibi is considered a complementary modality to MG/US-guided biopsy and an alternative to MRI-guided biopsy. It is principally indicated in patients with occult lesions on MG/US but suspicious on MBI (BI-RADS criteria 4–5) and occult after second-look US. Other possible indications include: (i) unclear lesions on MG/US but suspicious on MBI (BI-RADS criteria 4–5); (ii) failure of other biopsy methods. A potential future indication concerns optimization of primary tumour tissue sampling in patients with locally advanced breast cancer (LABC) by means of 99mTc-sestamibi-guided targeted biopsy. In the literature non-correspondence between the core biopsy location and the area with highest metabolic activity in the tumour has been described for stage II/III breast cancer patients scheduled for neoadjuvant chemotherapy [39]. Since early and increased concentration of 99mTc-sestamibi in breast carcinomas is associated with high proliferation rate, indicating more aggressive tumour behaviour [40], the sampling of the most proliferative parts of the tumour that correspond with highest uptake of 99mTc-sestamibi in large heterogeneous tumours could result in more optimal therapy planning in patients with LABC. The advantages and disadvantages of the different biopsy methods are summarized in Table 4. The main advantage of MBI-guided biopsy compared to MRI-guided biopsy is the possibility to measure radioactivity of the tissue samples ex vivo, in this way verifying that the target lesion has been sampled successfully. However, biopsy may be difficult in lesions close to the pectoral muscle because they may not be completely visualized due to the vertical position of the patient in relation to the field of view of the camera.Fig. 4

View Article: PubMed Central - PubMed

ABSTRACT

Purpose: This review aims to discuss the methodological aspects of dedicated molecular breast imaging (MBI) using 99mTc-sestamibi as radiotracer to guide biopsy of occult or unclear breast lesions on mammography (MG) and ultrasound (US) that are suspicious on MBI (BI-RADS criteria 4 and 5), including its advantages, limitations and future clinical applications.

Methods: Literature search was performed using the PubMed/MEDLINE database and “99mTc-sestamibi”, “biopsy” and “breast cancer” as keywords. The search was restricted to English language.

Results: There are few studies on 99mTc-sestamibi guided biopsy methods; to our knowledge, no full studies have yet been reported on clinical validation of this new biopsy procedure. This review describes technical aspects of 99mTc-sestamibi guided biopsy and discusses the advantages and limitations of this procedure in comparison with MG, US and MRI-guided biopsy.

Conclusions: MBI-guided biopsy appears to be a complementary modality and is principally indicated in the case of occult or unclear breast lesions on MG/US, that are suspicious on MBI. The future indication is in targeted biopsies in patients with large heterogeneous tumours. Further studies are needed to define the accuracy of this biopsy procedure.

No MeSH data available.