Three-Dimensional Telomeric Analysis of Isolated Circulating Tumor Cells (CTCs) Defines CTC Subpopulations

International audienceCirculating tumor cells (CTCs) have been identified with the potential to serve as suitable biomarkers for tumor stage and progression, but the availability of effective isolation technique(s) coupled with detailed molecular characterization have been the challenges encountered in making CTCs clinically relevant. For the first time, we combined isolation of CTCs using the ScreenCell filtration technique with quantitative analysis of CTC telomeres by TeloView. This resulted in the identification and molecular characterization of different subpopulations of CTCs in the same patient. Three-dimensional (3D) telomeric analysis was carried out on isolated CTCs of 19 patients that consisted of four different tumor types, namely, prostate, colon, breast, melanoma, and one lung cancer cell line. With telomeric analysis of the filter-isolated CTCs, the level of chromosomal instability (CIN) of the CTCs can be determined. Our study shows that subpopulations of CTCs can be identified on the basis of their 3D telomeric properties

Describing perspectives of health care professionals on active surveillance for the management of prostate cancer

Background: Over the last decade, active surveillance has proven to be a safe approach for patients with low-risk prostate cancer. Although active surveillance presents several advantages for both patients and the health care system, all eligible patients do not adopt this approach. Our goal was to evaluate the factors that influence physicians to recommend active surveillance and the barriers that impact adherence to this approach. Methods: Focus groups (n = 5) were held with physicians who provided care for men with low-risk prostate cancer and had engaged in conversations with men and their families about active surveillance. The experience of health care professionals (HCPs) was captured to understand their decisions in proposing active surveillance and to reveal the barriers and facilitators that affect the adherence to this approach. A content analysis was performed on the verbatim transcripts from the sessions. Results: Although physicians agreed that active surveillance is a suitable approach for low-risk prostate cancer patients, they were concerned about the rapidly evolving and non-standardized guidelines for patient follow-up. They pointed out the need for additional tools to appropriately identify proper patients for whom active surveillance is the best option. Urologists and radiation-oncologists were keen to collaborate with each other, but the role of general practitioner remained controversial once patients were referred to a specialist. Conclusions: Integration of more reliable tools and/or markers in addition to more specific guidelines for patient follow-up would increase the confidence of both patients and physicians in the choice of active surveillance.Other UBCNon UBCReviewedFacult

Canadian Men’s perspectives about active surveillance in prostate cancer: need for guidance and resources

Background: In prostate cancer, men diagnosed with low risk disease may be monitored through an active surveillance. This research explored the perspectives of men with prostate cancer regarding their decision-making process for active surveillance to identify factors that influence their decision and assist health professionals in having conversations about this option. Methods: Focus group interviews (n = 7) were held in several Canadian cities with men (N = 52) diagnosed with prostate cancer and eligible for active surveillance. The men’s viewpoints were captured regarding their understanding of active surveillance, the factors that influenced their decision, and their experience with the approach. A content and theme analysis was performed on the verbatim transcripts from the sessions. Results: Patients described their concerns of living with their disease without intervention, but were reassured by the close monitoring under AS while avoiding harmful side effects associated with treatments. Conversations with their doctor and how AS was described were cited as key influences in their decision, in addition to availability of information on treatment options, distrust in the health system, personality, experiences and opinions of others, and personal perspectives on quality of life. Conclusions: Men require a thorough explanation on AS as a safe and valid option, as well as guidance towards supportive resources in their decision-making.Other UBCNon UBCReviewedFacult

The Terry Fox Research Institute Canadian Prostate Cancer Biomarker Network: an analysis of a pan-Canadian multi-center cohort for biomarker validation

Background: Refinement of parameters defining prostate cancer (PC) prognosis are urgently needed to identify patients with indolent versus aggressive disease. The Canadian Prostate Cancer Biomaker Network (CPCBN) consists of researchers from four Canadian provinces to create a validation cohort to address issues dealing with PC diagnosis and management. Methods: A total of 1512 radical prostatectomy (RP) specimens from five different biorepositories affiliated with teaching hospitals were selected to constitute the cohort. Tumoral and adjacent benign tissues were arrayed on tissue microarrays (TMAs). A patient clinical database was developed and includes data on diagnosis, treatment and clinical outcome. Results: Mean age at diagnosis of patients in the cohort was 61 years. Of these patients, 31% had a low grade (≤6) Gleason score (GS), 55% had GS 7 (40% of 3 + 4 and 15% of 4 + 3) and 14% had high GS (≥8) PC. The median follow-up of the cohort was 113 months. A total of 34% had a biochemical relapse, 4% developed bone metastasis and 3% of patients died from PC while 9% died of other causes. Pathological review of the TMAs confirmed the presence of tumor and benign tissue cores for > 94% of patients. Immunohistochemistry and FISH analyses, performed on a small set of specimens, showed high quality results and no biorepository-specific bias. Conclusions: The CPCBN RP cohort is representative of real world PC disease observed in the Canadian population. The frequency of biochemical relapse and bone metastasis as events allows for a precise assessment of the prognostic value of biomarkers. This resource is available, in a step-wise manner, for researchers who intend to validate prognostic biomarkers in PC. Combining multiple biomarkers with clinical and pathologic parameters that are predictive of outcome will aid in clinical decision-making for patients treated for PC.Medicine, Faculty ofNon UBCUrologic Sciences, Department ofReviewedFacult