Utilization of Immunohistochemistry in Prostate Needle Biopsies: Quality Assurance and Cost Implications
Kristalee Watson, Cheng Wang, Asli Yilmaz, Tarek A Bismar, Kiril Trpkov. Calgary Laboratory Services and University of Calgary, Calgary, AB, Canada
Background: The use of immunohistochemistry (IHC) for high molecular weight keratin (HMWK) and AMACR has been studied extensively as an aid in establishing diagnosis on prostate needle biopsy. However, the quality assurance and the cost implications have not been previously addressed in great detail.
Design: We retrieved pathology reports of 748 prostate biopsies signed over a six-month period (12/10 to 05/11) in our academic practice. We identified the biopsies and the blocks in which IHC for HMWK and AMACR was ordered. We evaluated the rates and the turn-around time for IHC cases, the final diagnosis rendered on individual specimens (CANCER, ATYP, ATYPPIN, PIN and BENIGN), the prostate biopsy departmental consultation rate and the consultation rate when IHC was used. We performed cost analysis for the average cost per biopsy and for the annual IHC cost for prostate biopsies in our lab.
Results: Overall, 39.4% (295/748) of prostate biopsies and 12% (539/4488) of biopsy blocks required IHC evaluation (average 1.8 block/IHC case). The biopsies with IHC were signed-out on average 1.7 work days later (8.6 days with IHC vs. 6.9 days without IHC). The diagnostic breakdown for individual blocks evaluated by IHC was: CANCER 47.7%, ATYP 10.8%, ATYPPIN 6.9%, PIN 12.4% and BENIGN 22.2%. In cases with final CANCER diagnosis in individual blocks, 79% were assigned Gleason 6, 14.4% Gleason 7 and 6.6% Gleason 8-10. Regarding the cancer extent on individual cores, IHC aided in establishing minimal cancer diagnosis (≤5% core) in 39.8% and non-minimal cancer (>5% core) in 60.2% positive cores. IHC supported the diagnosis in 74% (55/74) of single-core positive biopsies. Departmental consultation was performed in 18.3% (137/748) of prostate biopsies; IHC was used in 68% (93/137) of these. In 98% (51/52) of all ATYP cases (ATYP+ATYPPIN) both IHC and consultation were performed. Using the estimated cost of $31 per immunostain in our lab, the average IHC cost per biopsy was $22.30. The estimated annual cost for prostate biopsy IHC was $33,450 (1500 prostate biopsies annual lab volume).
Conclusions: Approximately 40% of prostate biopsies in our institution required IHC which did not affect the turn-around time significantly. Diagnosis CANCER or ATYP (ATYP+ATYPPIN) were rendered in 65.4% of individual blocks assessed by IHC. IHC was used to establish a diagnosis of CANCER in large proportion of either minimal or single-core positive cases. IHC was used in 68% of cases requiring departmental consultation. We calculated an average IHC cost per prostate biopsy of $22.30.
Category: Genitourinary (including renal tumors)
Wednesday, March 21, 2012 9:30 AM
Poster Session V # 125, Wednesday Morning