Recent developments in breast-conserving surgery for breast cancer patients

Do we need to routinely perform cavity shaving with breast-conserving surgery for breast cancer? A systematic review and meta-analysis

AIMS

To evaluate comparative outcomes of breast-conserving surgery (BCS) of breast cancer with and without cavity shaving.

METHODS

A systematic search of multiple electronic data sources was conducted, and all randomised controlled trials (RCTs) comparing BCS with or without cavity shaving for breast cancer were included. Positive margin rate, second operation rate, operative time, post-operative haematoma, cosmetic appearance and budget cost were the evaluated outcome parameters for the meta-analysis.

RESULTS

Six RCTs reporting a total number of 971 patients; 495 of these underwent BCS plus shaving (BCS + S), and 473 underwent BCS alone were included. BCS + S showed significantly lower positive margin rate (Risk Ratio [RR] 0.40, P = 0.00001) and second operation rate (RR 0.38, P = 0.00001). BCS + S demonstrated longer operative time than BCS (79 ± 4 min vs 67 ± 3 min, Mean Difference 12.14, P = 0.002), and there was no significant difference in the risk of post-operative haematoma (RR 0.33, P = 0.20).

CONCLUSION

BCS + S is superior to BCS in terms of positive margins rate and second operation rate. Operative time is longer when cavity shaving is performed.

Direct identification of breast cancer pathologies using blind separation of label-free localized reflectance measurements

Breast tumors are blindly identified using Principal (PCA) and Independent Component Analysis (ICA) of localized reflectance measurements. No assumption of a particular theoretical model for the reflectance needs to be made, while the resulting features are proven to have discriminative power of breast pathologies. Normal, benign and malignant breast tissue types in lumpectomy specimens were imaged ex vivo and a surgeon-guided calibration of the system is proposed to overcome the limitations of the blind analysis. A simple, fast and linear classifier has been proposed where no training information is required for the diagnosis. A set of 29 breast tissue specimens have been diagnosed with a sensitivity of 96% and specificity of 95% when discriminating benign from malignant pathologies. The proposed hybrid combination PCA-ICA enhanced diagnostic discrimination, providing tumor probability maps, and intermediate PCA parameters reflected tissue optical properties.

Enriching the interventional vision of cancer with fluorescence and optoacoustic imaging

Among several techniques considered for surgical and endoscopic imaging, novel optical methods are evolving as a promising approach for interventional guidance. Pilot clinical applications of fluorescence molecular imaging have demonstrated the benefits of using targeted fluorescent agents in cancer surgery. This premise can be extended broadly to interventional guidance through an increasing number of targeted agents and detection techniques. Beyond epi-illumination fluorescence imaging, optoacoustic (photoacoustic) methods are emerging to offer high-resolution cross-sectional optical imaging through several millimeters to centimeters of depth. We present an overview of key recent developments in optical interventional imaging and outline the potential for a paradigm shift in surgical and endoscopic visualization.

Automated classification of breast pathology using local measures of broadband reflectance

We demonstrate that morphological features pertinent to a tissue's pathology may be ascertained from localized measures of broadband reflectance, with a mesoscopic resolution (100-μm lateral spot size) that permits scanning of an entire margin for residual disease. The technical aspects and optimization of a k-nearest neighbor classifier for automated diagnosis of pathologies are presented, and its efficacy is validated in 29 breast tissue specimens. When discriminating between benign and malignant pathologies, a sensitivity and specificity of 91 and 77% was achieved. Furthermore, detailed subtissue-type analysis was performed to consider how diverse pathologies influence scattering response and overall classification efficacy. The increased sensitivity of this technique may render it useful to guide the surgeon or pathologist where to sample pathology for microscopic assessment.