Prostate Cancer: Test and Diagnosis

1st order laboratory parameters – obligatory laboratory tests.

  • PSA (prostate-specific antigen).
    • Total serum PSA level around 50 years of age proved to be a reliable predictor of the occurrence of nonlocalized prostate cancer: 66% of tumors occurred in men who had had a serum PSA level in the upper quintile, that is, a level >0.9 ng/dl. The median time to tumor occurrence was 17 years.
  • Alkaline phosphatase – in suspected bone metastases.
  • Blood count – to rule out tumor-related anemia (anemia).

Laboratory parameters 2nd order – depending on the results of the medical history, physical examination, etc.

  • Renal parameters – urea, creatinine, cystatin C or creatinine clearance, if necessary.
  • Molecular genetic testing
    • PCA 3 test – specific molecular genetic test in which prostate cells from a urine sample are analyzed. PCA3 is a gene expressed exclusively in prostate tissue.
    • P16 (regulator gene) – was an independent prognostic marker in prostate cancer in a phase III study.
    • ESRP1 (oncogene) – associated with very rapidly dividing and highly aggressive prostate cancer (detectable even in early tumor stage).
    • RNA assay measuring serum and urine expression of ten different genes associated with progression and metastasis (progression and formation of daughter tumors) of prostate tumors; following are the results:
      • Related to biopsy results, the authors calculated a sensitivity (percentage of diseased patients in whom the disease is detected by using the test, i.e., a positive test result occurs) of 88-95% for the test
      • Related to the prostatectomy findings, the sensitivity was 92-97%.
      • However, the specificity (probability that actually healthy people who do not have the disease in question are also detected as healthy in the test) was only 39-45%; however, the test is helpful to exclude dangerous tumors in men with low Gleason score (3+3) in the biopsy (tissue sampling)
    • Detection of AR-V7 in exosomal RNA from plasma (is present in any tumor cell with resistant receptor) – predictor of resistance to anti-hormonal therapies (e.g., abiraterone, enzalutamide).
    • TMPRSS2-ERG fusion gene – fusion of TMPRSS2 with ERG occurs in 40-70% of all diagnosed prostate cancers.
  • Histological (fine tissue) examination from tissue cylinders (10-12) after prostate biopsy (punch biopsy/obtaining tissue cylinders for the purpose of histological/fine tissue examination) under transrectal sonographic control:
    • Immunohistochemistry is not to be followed for clearly malignant or benign lesions
    • In cases that are unclear with regard to dignity (biological behavior of tumors; i.e., whether they are benign (benign) or malignant (malignant)): immunohistochemical clarification with one or two basal cell markers, possibly supplemented by a positive marker of prostate carcinoma (e.g., AMACR or FASN)

Interpretation of PSA values before therapy

75-90% of all prostate cancers are revealed by a pathological PSA level. The probability of detecting a prostate carcinoma is:

  • PSA < 4 ng/ml: 4-15 %.
  • PSA > 4 ng/ml and < 10 ng/ml: 25%.
  • PSA > 10 ng/ml: 33-50 %

Currently, above a threshold of 4 ng/ml, despite a negative digital rectal examination (DRU; examination of the rectum (rectum) and neighboring organs (e.g., prostate) with a finger), it is recommended to perform a prostate punch biopsy (tissue sampling from the prostate). Nevertheless, these values mean that especially in the gray zone range between 4 ng/ml and 10 ng/ml and negative digital-rectal examination, prostate punch biopsy does not reveal carcinoma in 75% of cases and is performed “for free”, so to speak. Through various methods, therefore, the differentiation between benign (benign) and malignant (malignant) prostate disease is attempted to increase with the PSA.

Interpretation of the PSA value in recurrent or metastatic prostate cancer

  • After radical prostatectomy, a PSA level confirmed in at least two measurements to be >0.2 ng/mL identifies biochemical recurrence.→ Biooptical confirmation of biochemical recurrence is not required.
  • After radiotherapy alone, a PSA increase of > 2 ng/ml confirmed in at least two measurements above the postinterventional PSA nadir denotes biochemical recurrence.→ Bioptic confirmation of biochemical recurrence in patients after radiotherapy with the option of local recurrence therapy should be sought.