Stage C 
These tumors have penetrated the prostate capsule and spread to nearby structures such as the seminal vesicles or fat next to the prostate gland.
    This stage is further divided into: 
• C-1, indicating spread just beyond the prostate;
• C-2, indicating spread still in the local area but
  involving more of the immediately surrounding tissues.
  Stage C-2 will often obstruct the flow of urine,
  producing voiding difficulties.
      About half of Stage C-1 patients and 80 percent of
  Stage C-2 patients have unsuspected lymph node
  metastases when the tumor is detected.

Standard Treatment  The approach to Stage C cancer depends on the extent of the tumor and the patient's medical condition.