Gleason Inflation in Sweden 1998-2011. A Registry Study of 97168 Men
Daniela Danneman, Linda Drevin, Par Stattin, Lars Egevad. Karolinska Institutet, Stockholm, Sweden; Uppsala University Hospital, Uppsala, Sweden; Memorial Sloan-Kettering Cancer Center, New York, NY
Background: In recent years there has been a shift upwards of how Gleason grading of prostate cancer is applied. At an International Society of Urological Pathology (ISUP) consensus meeting in 2005 recommendations were issued that might contribute to this trend. There has been a concurrent shift towards lower stages at diagnosis, which may mask some of the upgrading. It has clinical relevance to know the scale of these changes in the pathology community.
Design: All newly diagnosed prostate cancers in Sweden are reported to the National Prostate Cancer Registry (NPCR). In 97168 men with a primary diagnosis of prostate cancer on needle biopsy from 1998-2011, Gleason score (GS), clinical T stage (cT) and serum PSA (S-PSA) at diagnosis were analyzed.
Results: A GS, cT and S-PSA was reported to NPCR in 97.0%, 98.9% and 99.4% of cases. Before and after 2005, GS 7-10 was diagnosed in 51.8% and 57.4%, respectively (p <0.001). After standardization for cT and S-PSA with 1998 as baseline these tumors increased from 58.5% to 71.6%. Newly diagnosed cancers were stage T1c in 19.7% in 1998 and 50.8% in 2011, while median S-PSA was 20.5 ng/ml and 8.9 ng/ml, respectively. Among low-risk tumors (stage T1c and S-PSA 4-10 ng/ml) GS 7-10 increased from 16.3% 1998 to 39.9% 2011 with a mean of 19.2% and 32.8% before and after 2005 (p <0.001). Among high-risk tumors (stage T3 and S-PSA 20-50 ng/ml) GS 7-10 increased from 64.8% 1998 to 93.9% 2011 with a mean of 77.9% and 90.4% before and after 2005 (p <0.001). A GS 2-5 was reported in 19.6% 1998 and in 1.0% 2011. Notably, the use of GS 5 decreased sharply after 2005 and GS 2-4 was almost entirely abandoned. There were small variations in grading practice among the 6 healthcare regions of Sweden. In all regions % GS 7-10 increased from 1998-2004 to 2006-2011.
Conclusions: Over the past 14 years there has been a shift towards higher Gleason grading in Sweden. This has been a gradual process that started several years before the ISUP 2005 revision of the Gleason system. The lowest Gleason scores (2-5) are now hardly used at all. Some of the Gleason inflation is masked by a simultaneous shift towards lower stages at diagnosis. When corrected for stage the upgrading is considerable with a more than doubled reporting of high-grade cancer in low-risk tumors. This has clinical consequences for therapy decisions such as eligibility for active surveillance.
Category: Genitourinary (including renal tumors)
Monday, March 4, 2013 1:30 PM
Proffered Papers: Section A, Monday Afternoon