ABSTRACT
A 69-year-old man developed pulmonary metastases following vertebroplasties for pathological fractures of vertebrae T12-L4. The fractures developed due to spinal metastases from castrate-resistant prostate cancer. A CT scan performed 1 month prior indicated no evidence of pulmonary malignancy. However, CT scans performed 2 months after the vertebroplasties demonstrated intravascular pulmonary metastases distributed similarly to embolized polymethylmethacrylate. Vertebroplasty is a well-established procedure for symptomatic management of vertebral compression fractures. However, studies have demonstrated an increase in circulating tumor cells following vertebroplasties, theoretically increasing the risk of distant metastases. In this case, the chronicity and radiological findings suggest that the pulmonary intravascular metastases may have resulted from the vertebroplasties.
ABSTRACT
CONTEXT: External quality assurance and proficiency testing programs for breast cancer predictive biomarkers are based largely on traditional ad hoc design; at present there is no universal consensus on definition of a standard reference value for samples used in external quality assurance programs. OBJECTIVE: To explore reference values for estrogen receptor and progesterone receptor immunohistochemistry in order to develop an evidence-based analytic platform for external quality assurance. DESIGN: There were 31 participating laboratories, 4 of which were previously designated as "expert" laboratories. Each participant tested a tissue microarray slide with 44 breast carcinomas for estrogen receptor and progesterone receptor and submitted it to the Canadian Immunohistochemistry Quality Control Program for analysis. Nuclear staining in 1% or more of the tumor cells was a positive score. Five methods for determining reference values were compared. RESULTS: All reference values showed 100% agreement for estrogen receptor and progesterone receptor scores, when indeterminate results were excluded. Individual laboratory performance (agreement rates, test sensitivity, test specificity, positive predictive value, negative predictive value, and κ value) was very similar for all reference values. Identification of suboptimal performance by all methods was identical for 30 of 31 laboratories. Estrogen receptor assessment of 1 laboratory was discordant: agreement was less than 90% for 3 of 5 reference values and greater than 90% with the use of 2 other reference values. CONCLUSIONS: Various reference values provide equivalent laboratory rating. In addition to descriptive feedback, our approach allows calculation of technical test sensitivity and specificity, positive and negative predictive values, agreement rates, and κ values to guide corrective actions.
