‘Substantial’ discordance between Gleason score at prostate biopsy and surgery
MedWire News: More than a third of men diagnosed with Gleason score (GS) 6 at prostate biopsy will be upgraded to a score of 7 at radical prostatectomy, show US study results.
Furthermore, men whose GS is upgraded from 6 to 7 are more likely to experience biochemical recurrence after treatment, than men with GS 6 concordance at biopsy and surgery.
“This discordance has potential clinical significance in predicting oncologic outcomes,” write Javier Hernandez (Brooke Army Medical Center, Houston, Texas) and colleagues, who speculate that patients who choose less aggressive treatment after a GS 6 biopsy may be undertreated.
To investigate further, the team determined the frequency of GS discordance at biopsy and surgery in a group of 2771 prostatectomy patients, then evaluated associations with clinical parameters and the likelihood of biochemical recurrence after surgery. In all 67% of men had a GS 6 on biopsy, and 33% had GS 7.
Among men with GS 7 at biopsy, 66% had concordance at surgery, while 55% of men with GS 6 had concordance, and 37% were upgraded to GS 7 at surgery.
Patients who upgraded from GS 6 to 7 had statistically higher prostate-specific antigen (PSA) levels at diagnosis than those with concordant GS 6 scores, and, although not clinically relevant, were older. Additionally, more men with a prostate volume of less than 20 cm3 were upgraded from GS 6 to 7 compared with men whose prostates were 60 cm3 or more, at 34% versus 17%.
Hernandez and team also observed an association between the percent of positive biopsy cores and GS upgrade. The risk for upgrading was 1.9 times higher in men with more than 50% positive biopsy cores compared with men with less than 30% positivity.
Furthermore, men who upgraded from GS 6 at biopsy to GS 7 at surgery had a significantly shorter time to biochemical recurrence (defined as a PSA of 0.2 ng/ml or more at 2 months or more after surgery), compared with those whose GS remained 6 at surgery.
“The occurrence of positive surgical margins, capsular invasion, seminal vesicle invasion, and increased pT stage were all significantly increased in patients who were upgraded,” note the researchers in the journal Urologic Oncology.
“Patients who are upgraded are a unique group and have cancers that behave more like those of patients who are initially diagnosed with GS 7,” they conclude.
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By Sarah Guy