What does it mean if my biopsy mentions that there is perineural invasion?

Perineural invasion means that cancer cells were seen surrounding or tracking along a nerve fiber with the prostate. When this is found on a biopsy, it means there is a higher chance that the cancer has spread outside the prostate. Still, perineural invasion does not mean that the cancer has spread, and other factors, such as the Gleason Score and amount of cancer in the cores are more important. In some cases, findings perineural invasion may affect treatment, so if your report mentions perineural invasion, you should discuss it with your doctor.