Perineural invasion should not rule out active surveillance for prostate cancer
MedWire News: Signs of perineural invasion (PNI) at biopsy do not necessarily indicate adverse radical prostatectomy outcomes, show US study results, and should not exclude patients with this pathology from treatment with active surveillance.
PNI has previously been demonstrated to be one of the major mechanisms of extension of disease, note the researchers, who add that the importance of PNI with regard to active surveillance is unknown.
Their findings show "no significant difference between cases with and those without PNI in surgical margin involvement, pathological stage, and Gleason score at radical prostatectomy."
Jonathan Epstein and colleagues from The Johns Hopkins Hospital in Baltimore, Maryland, investigated the significance of PNI at biopsy in a cohort of 313 men with low-risk prostate cancer who were eligible for active surveillance, but chose to undergo prostatectomy.
"Recognition that a sizeable number of patients with prostate-specific antigen detected prostate cancer are likely being over treated has increased the interest in active surveillance as an alternative to immediate intervention," the team explains.
Criteria for surveillance were; a Gleason score of 6 or less, two or fewer positive cores for cancer at biopsy, and 50% or less involvement of any positive biopsy cores. The men were aged a mean 58 years and the maximum percentage of cancer per core for each man was 40%.
A total of 51 men in the cohort had PNI - defined as cancer tracking along or around a nerve - and 262 cases did not.
Men with PNI had a slightly higher maximum percentage of cancer at biopsy compared with those without PNI, at 18.6% versus 15.0%, and having 2 positive biopsy cores was more common among men with PNI than those without, at 56.9% versus 39.7%.
However, there was no significant difference in surgical margin involvement between the groups, at 6.0% and 7.3% among PNI and no PNI cases, respectively, neither was there any difference in corresponding cancer stages or Gleason scores.
Epstein and co-investigators write in the Journal of Urology that this lack of significant difference means prostate cancer patients with PNI who meet the criteria for active surveillance "should not necessarily be excluded from this treatment option."
Further, they hypothesize that if PNI is found at repeat biopsy while on active surveillance, it should not "by itself trigger curative intervention."
By Sarah Guy