Radio-guided localization of clinically occult breast lesions: current modalities and future directions

Abstract

The extensive availability of breast cancer screening programs and improvement in diagnostic imaging have led to more frequent detection of suspicious and clinically occult breast lesions. Early detection of tumor is important for breast-conserving treatment. Incomplete excision is a major risk factor for local recurrence. Following precise localization and removing the entire lesion while achieving adequate clear margins is the key factor for successful management of non-palpable breast lesions. For this purpose, several techniques such as wire-guided localization, intra-operative ultrasound guided resection, radio-guided occult lesion localization and radioactive seed localization have been described and applied. In this article, we overview the two commonly used localization techniques, radio-guided occult lesion localization and wire-guided localization, particularly describing their advantages and drawbacks.

Keywords::

• breast-conserving surgery
• localization
• non-palpable breast lesions
• radio-guided occult lesion localization
• ROLL
• surgical margin
• wire-guided localization

Financial & competing interests disclosure

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

No writing assistance was utilized in the production of this manuscript.

Key issues

• Early detection of breast tumors increases the chance of breast-conserving surgery while decreasing the mortality and the morbidity. Incomplete excision is one of the important risk factor for local recurrence which is associated with higher mortality.

• The key factors for successful management of these occult lesions are: precise localization; avoiding excessive surgical resection of healthy breast tissue; removing the entire lesion while achieving adequate clear margins; decreasing the procedure time; ensuring optimal cosmesis; and minimal morbidity.

• Traditionally, wire-guided localization (WGL) under mammographic or ultrasonographic guidance has been the gold standard diagnostic and therapeutic method to carry out surgical biopsy of non-palpable breast lesions during last decade. However, it has a number of drawbacks which have led to the development and implementation of alternative guidance approaches including radio-guided occult lesion localization(ROLL), intra-operative ultrasound resection and radioactive seed localization.

• Localization method selection should be dependent on ‘the best can be done’ principle regarding to the case’s features.

• ROLL procedure based on an intra-lesional injection of a nonspecific radioisotope (^99mTc-labeled human serum albumin macroaggregate) under stereotactic, ultrasonographic or MRI guidance was introduced at the European Institute of Oncology in Milan in 1996, and has been demonstrated as a feasible, easier and precise localization technique for non-palpable breast lesions compared with the standard of care (WGL) in most countries.

• Unfortunately ROLL requires a multidisciplinary approach regarding General Surgery, Radiology and Nuclear Medicine Department, and seems insufficient for larger breast lesions according to WGL. And for the lesions near the nipple there is a potential risk of ductal migration of isotope, which may cause inappropriate resections.

• Radioactive seed localization is a further advanced radioguided surgical technique reported by Gray et al. in 2001. A titanium seed measuring 4.5 × 8 mm is labeled with ¹²⁵I. Owing to this long half-life time of seed, the radiologist has enough time to perform localization up to 5 days in advance of surgery. Thereby, both the radiologist and the surgeon can schedule their appointments.

• A real-time intra-operative 3D imaging for sentinel lymph node biopsy called Freehand SPECT is emerging by providing improvement about lateral borders and depth information, and reducing surgeon dependency on the procedure.

• Indocyanine green fluorescence-guided occult lesion localization is a promising procedure for removing non-palpable breast lesions in which flourescent marker is used instead of radioactive material.

• ROLL and WGL, both of the procedures should be complementary to each other, sometimes one should promote the other, or one should be used as an alternative when the other fails.