Abstract P4-03-05: Wide-field optical coherence tomography (WF-OCT) for near real-time, point-of-care assessment of margin status in breast-conserving surgery specimens: Results of a feasibility study at a high-volume single-centre

Wide-Field Optical Coherence Tomography (WF-OCT) is a non-destructive, non-contact light imaging modality capable of label-free visualization of the internal microscopic architecture of breast tissue specimens. Its unique combination of high-resolution imaging in near real-time with tissue penetration depths approaching 2-mm makes it a promising imaging modality for obtaining detailed surgical margin status in breast-conserving surgery (BCS) specimens. A prototype WF-OCT imaging platform developed by Perimeter Medical Imaging, Inc. (Toronto, Canada) has permitted fully-automated, dynamically-focused visualization of margin widths around the intact surfaces of freshly excised BCS specimens. Herein are reported the results of a feasibility study at a high-volume single-centre evaluating the routine use of WF-OCT for sampling of surgical margin status in BCS specimens at the point-of-care.

Methods: Women with biopsy confirmed breast cancer and scheduled for primary BCS were recruited at Princess Margaret Cancer Centre (Toronto, Canada). Standard medical care was not altered. Freshly excised BCS specimens including all lumpectomy samples were imaged by WF-OCT immediately prior to standard histological processing. The system acquired dynamically-focused, hemispherical coverage over two contra-lateral surfaces of the intact BCS specimen within the time constraints of the cold ischemic time window. High-resolution (10 μm) images of the tissue surface down to a 1 to 2-mm depth were obtained. Blinded assessments were performed on image data sets by two clinical readers (surgeon and radiologist) trained on a validated and unrelated data set correlating OCT images with histology slides. The readers were first asked to independently assess margin status using only blinded pre- and intra-operative knowledge (without OCT). Upon completion, the readers were provided OCT images of all scanned surface and similarly asked to assess the margin status with the additional OCT information. These assessments were subsequently evaluated by a breast pathologist comparing the OCT images and corresponding histopathology sections. The added utility of WF-OCT imaging information for margin prediction was studied.

Results: [Pending study completion in August 2015]. Through accurate correlation with the histopathologic gold standard, OCT demonstrated capability to differentiate tissue microstructures, including: distinctive patterns for adipose tissue, fibrous stroma, breast lobules and ducts, cysts and microcysts, as well as in-situ and invasive carcinomas.

Implications: The fully-automated WF-OCT imaging platform can integrate conveniently into standard pathological processing workflows to provide comprehensive sampling of surgical margin status in BCS specimens at the point-of-care. Clinical readers from surgical and radiological backgrounds can be trained to competently interpret WF-OCT images of BCS specimens for accurate prediction margin status. The implementation of WF-OCT at the point-of-care for routine surgical margin assessments will be further explored in future clinical trials.

Citation Format: Valic MS, Leong WL, Done SJ, Wilson BC, Kulkarni S, McCready DR, Niu CJ, Atachia Y, Munro EA, Rempel D. Wide-field optical coherence tomography (WF-OCT) for near real-time, point-of-care assessment of margin status in breast-conserving surgery specimens: Results of a feasibility study at a high-volume single-centre. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P4-03-05.

Abstract P4-03-04: The potential use of Optical Coherence Tomography for intraoperative breast tumour margin width estimation

Total mastectomy and lumpectomy with radiation have been shown to have equivalent patient outcomes, which has likely contributed to the more widespread adoption of breast conserving surgery (BCS) procedures. Assessment of breast lumpectomy margin widths in both an accurate and timely manner is essential to successful breast conservation procedures. Current BCS methodologies have been reported to result in reoperation rates of up to 20–60%, which represents a significant and unmet need for improved margin assessment. High reoperation rates present both increased treatment risk to patients and increased burden on healthcare systems. In the USA alone, over 150,000 lumpectomies are performed per year at an average cost between $11,000 and $19,000 USD per procedure. Assuming a relatively modest average repeat operation rate of 25%, potentially preventable repeat surgeries represent an approximate cost to the US healthcare system of $500M (USD) annually.

Reducing the prevalence of repeat surgeries may be accomplished by providing faster and more accurate intraoperative tools for assessing margin widths during the time of the first surgery. One such potential technique involves the use of Optical Coherence Tomography (OCT) imaging, which uses light to produce images in much the same way that ultrasound produces images with sound. Compared to ultrasound, OCT provides decreased depth of penetration, but increased resolution capabilities. The increased resolution that OCT provides allows for the visualization of the internal cellular structure within a tissue sample and therefore, provides the potential ability to differentiate cancerous from normal or benign cells. We propose the use of an intraoperative OCT imaging system to provide near real-time imaging information about the internal structure of tissue samples excised during BCS procedures. Our hypothesis is that the overall rate of repeat operations can be reduced by providing a tool to assist surgeons with the task of margin width estimation during the time of surgery.

We have developed an early stage prototype OCT imaging system that has completed laboratory phantom and preclinical studies. This paper will present the capabilities of an OCT imaging system to provide margin assessment information in biological breast tissue mimicking phantoms. The phantoms were designed to encompass imaging characteristics across a wide range of human breast densities. The paper will go on to describe preclinical imaging that was done in tumor specimens excised from human breast cancer rat models. The results obtained in the phantom and preclinical studies suggest the potential for OCT as a near-real time, intraoperative imaging tool to aid surgeons with breast lumpectomy margin width estimation. To help realize this potential, further research is required in to the use of OCT during BCS.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P4-03-04.

Effectiveness of a community-based multifaceted fall-prevention intervention in active and independent older Chinese adults

Objective:

To evaluate the effectiveness of an 18-month multifaceted intervention designed to reduce the incidence of falls in community-living older adults in China.

Methods:

A population-based community trial evaluated by before-and-after cross-sectional surveys. Four residential communities were randomised to either a multifaceted intervention or a control condition. Baseline information was collected from a sample of older adults in each community. A 1-year annual fall rate was calculated after an 18-month comprehensive intervention.

Results:

After intervention, 7.19% of the intervention community sample reported falls, compared with 17.86% of the control community sample (p<0.000). The annual fall rate decreased by 10.52% in the intervention communities, whereas the difference in control communities was not statistically significant.

Conclusions:

Multifaceted interventions in community settings may be useful in preventing falls among older people, and can be applied in similar settings in China.

Heat shock protein (Hsp70) induced by a mild heat shock slightly moderates plasma osmolarity increases upon salinity transfer in rainbow trout (Oncorhynchus mykiss)

We have investigated whether mild heat shock, and resulting Hsp70 expression, can confer cross-protection against the stress associated with transfer from freshwater (FW) to seawater (SW) in juvenile rainbow trout (Oncorhynchus mykiss). In experimental Series I, juvenile trout reared in FW were transferred from 13.5 degrees C to 25.5 degrees C in FW, held for 2 h, returned to 13.5 degrees C for 12 h, and then transferred to 32 ppt SW at 13.5 degrees C. Branchial Hsp70 increased approximately 10-fold in the heat-shocked fish relative to the control by the end of recovery and remained high 2, 8, and 24 h post-salinity transfer. However, no clear differences could be detected in blood parameters (blood hemoglobin, hematocrit, MCHC, plasma Na(+) and plasma osmolarity) or muscle water content between heat-shocked and sham-shocked fish in SW at any sampling interval (0, 2, 8, 24, 48, 120, 240 and 360 h post-SW transfer). In experimental Series II, trout acclimated to 8 degrees C were heat-shocked at 22 degrees C for 2 h, allowed to recover 18 h, and exposed to a more severe salinity transfer (either 36 or 45 ppt) than in Series I. Branchial Hsp70 levels increased approximately 6-fold in heat-shocked fish, but had declined to baseline after 120 h in SW. Plasma osmolarity and chloride increased in both groups upon transfer to 36 ppt; however, the increase was significantly less in heat-shocked fish when compared to the increase observed in sham-shocked fish at 24 h. No significant differences could be detected in branchial Na(+)/K(+)-ATPase activity or Na(+)/K(+)-ATPase alpha1a and alpha1b mRNA expression between the two groups. Our data indicate that a mild temperature shock has only modest effects on the ability of rainbow trout to resist osmotic stress during FW to SW transfer.

Mössbauer effect studies on some bioinorganic complexes of europium

The bioinorganic complexes of europium with N-acetyl-DL-alanine, N-acetyl-DL-valine, and DL-alanyl-DL-alanine have been synthesized and the Mössbauer spectra at room temperature have been measured for these solid state complexes. The Mössbauer parameters indicate that the water molecules in these complexes are not directly linked to the central europium ion and are outside the coordination sphere of europium and biological ligands, and that the chemical bond between the europium ion and the ligands may be predominantly ionic in character, with the possibility of partial covalent contribution.