Intraoperative Evaluation of Margin Status: How Much Is Enough?

Evaluation of Role of Intraoperative Cytology Technique in Diagnosis and Management of Cancer

Context:

Intraoperative pathological assessment provides valuable information in a patient's diagnosis and management. Touch imprint/crush cytology is simple, rapid, and cost-effective. Also, imprint smears give excellent cytomorphology.

Aims:

To assess the utility and feasibility of intraoperative cytology technique as a rapid and reliable method for diagnosis and to compare sensitivity, specificity and diagnostic accuracy with histopathology.

Materials and Methods:

Cytology smears were collected intraoperatively from 52 cases of suspected/proven malignancy. From tumors, surgical margins, lymph nodes; crush, imprint, and scrape smears were prepared. Smears were taken from specimens before formalin fixation and stained with rapid ultrafast Papanicolaou stain. The slides were compared with the histopathology report which is the gold standard.

Statistical Analysis:

Sensitivity, specificity, and diagnostic accuracy were used for statistical analysis.

Results:

Intraoperative cytology report could be given in time for the surgeon to modify margins of resection and the extent of lymph node dissection. It helps the surgeon to modify surgery. The diagnostic test evaluation showed satisfactory results.

Conclusion:

Intraoperative imprint/crush cytology is a simple, inexpensive, rapid, accurate cytodiagnostic technique in the diagnosis of cancer where frozen section facilities are not available. It can also be used to assess the clearance of surgical margins.

Fat/water ratios measured with diffuse reflectance spectroscopy to detect breast tumor boundaries

Recognition of the tumor during breast-conserving surgery (BCS) can be very difficult and currently a robust method of margin assessment for the surgical setting is not available. As a result, tumor-positive margins, which require additional treatment, are not found until histopathologic evaluation. With diffuse reflectance spectroscopy (DRS), tissue can be characterized during surgery based on optical parameters that are related to the tissue morphology and composition. Here we investigate which optical parameters are able to detect tumor in an area with a mixture of benign and tumor tissue and hence which parameters are most suitable for intra-operative margin assessment. DRS spectra (400-1600 nm) were obtained from 16 ex vivo lumpectomy specimens from benign, tumor border, and tumor tissue. One mastectomy specimen was used with a custom-made grid for validation purposes. The optical parameter related to the absorption of fat and water (F/W-ratio) in the extended near-infrared wavelength region (~1000-1600 nm) provided the best discrimination between benign and tumor sites resulting in a sensitivity and specificity of 100 % (excluding the border sites). Per patient, the scaled F/W-ratio gradually decreased from grossly benign tissue towards the tumor in 87.5 % of the specimens. In one test case, based on a predefined F/W-ratio for boundary tissue of 0.58, DRS produced a surgical resection plane that nearly overlapped with a 2-mm rim of benign tissue, 2 mm being the most widely accepted definition of a negative margin. The F/W-ratio provided excellent discrimination between sites clearly inside or outside the tumor and was able to detect the border of the tumor in one test case. This work shows the potential for DRS to guide the surgeon during BCS.