Dr. Ajay Anand
Prostate cancer is usually diagnosed on basis of raised serum PSA (Prostate Specific Antigen). Normal values of serum PSA range between 0-4ng/ml. PSA is organ-specific but not disease specific; that means PSA can be raised in conditions of prostate other than prostate cancer which include:-
* Urinary tract infection
* After digital rectal examination
* Post catheterization
* After any lower tract endoscopic procedure etc.
It is duty of treating urologist to exclude all conditions other than prostate cancer which can lead to rise in serum PSA. After excluding above mentioned causes of raised serum PSA, urologist needs to get a repeat serum PSA after three weeks. Still raised PSA warrants further course of action depending on serum PSA values. PSA values in range of 4-10ng/ml fall in grey zone and three parameters of serum PSA need to be evaluated to get a fair idea of benign or malignant cause of PSA rise. These parameters include PSA velocity, PSA density, and percentage of free PSA.
2-10% of patients with normal serum PSA but abnormal findings on digital rectal examination may turn out to be harbouring prostate malignancy. Another rare prostate malignancy which may be having normal serum PSA levels is neuroendocrine tumor, which needs special stains by pathologist for diagnosis.
Tissue diagnosis in form of prostate biopsy is final conclusive investigation to diagnose prostate cancer. The standard recommendation is 12 core prostate biopsy. Pathologist has to comment on number of cores positive for malignancy, percentage of each core having malignant transformation, Gleason score.
Further treatment of patient is guided by biopsy findings coupled with radiological investigations like CT scan/MRI abdomen and pelvis and bone scan to identify as to whether disease is localized to prostate, locally advanced or metastatic. All these three investigations are minimum required to stage patient.
Patients with localized prostate cancer should be offered curative surgical treatment in form of radical prostatectomy with trifecta aim of cancer cure, urinary continence and potency in order of importance. Patients with locally advanced prostate cancer need to be assessed on individual basis – some can be offered surgical treatment followed by radiotherapy and hormonal blockade in form of LHRH analogues and anti-androgens depending on pathological margin positivity.
Patients with metastatic prostate cancer cannot be offered curative cure and need to be treated with aim of slowing cancer progression. Such patients can be treated by surgical castration in form of bilateral orchidectomy; or medical castration in form of complete androgen blockade by LHRH analogues and anti-androgens, with serial monitoring of serum testosterone to keep them below castrate levels.
All patients with prostate cancer after treatment need to be followed at 3 monthly intervals with serial PSA levels. Target PSA is below 0.2 ng/ml. Some patients may show rise in serum PSA on follow-up, which may be because of residual tumor, local or distant recurrence. Such patients need thorough clinical examination coupled with investigations like PET scan. Further treatment is guided by these investigations and it may be in form of radiotherapy, hormonal therapy or chemotherapy in some cases.
Some patients with metastatic prostate cancer may continue to show rise in serum PSA despite being on androgen blockade treatment. This may be because of mutation of androgen receptors. Treatments in such patients include stopping anti-androgens, starting second line hormonal treatment like fosfestrol (Honvan), ketoconazole etc. Other newer but costly drugs available in market and approved by FDA include abiraterone, enzalutamide. Such drugs significantly delay progression of disease and need for chemotherapy. Chemotherapy (commonly docetaxel based) is indicated as a last resort in patients with persistently rising serum PSA.
Prostate cancer commonly metastasizes to bones and patients have severe bony pains, sometimes not responding to usual pain killers. Bisphosphonates (Zoledronic acid) and radioactive strontium are used to treat these patients with bony metastasis and resistant bone pains.
(The author is presently serving as consultant urologist in Superspeciality Hospital, GMC, Jammu.)
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