Advances in Prostate Cancer
Dr. Aditi Dewan Pathologist, CORE Diagnostics
What is Prostate Cancer?
Prostate cancer is a cancer that arises in the prostate gland, a small reproductive organ in men that is responsible for producing the seminal fluid that nourishes and transports the sperm. The exact cause is not known, however it arises when normal prostate cells undergo mutations, proliferate rapidly and accumalate to form a tumor.
Rise of Prostate Cancer
Prostate cancer is rising fast and becoming an epidemic globally as well as in India. The rate of prostate cancer is 10 per one lakh population that is higher than in other parts of Asia and even Africa.
Prostate is the second leading cause of cancer in men in metros like Kolkata, Delhi, Pune and Thiruvananthapuram. One of the reasons that has contributed to this rise is increased screening for PSA levels.
Diagnosis of Prostate Cancer
Before the treatment comes the diagnosis. There are many ways of diagnosis. Even the process of diagnosing whether a person is suffering from this cancer is not has evolved over the years.
The traditional method to diagnose is to check serum PSA levels followed by a Digital rectal examination (DRE). A change from prior values (more than 0.35 ng/mL/year for a PSA of <4.0 or 0.75 ng/mL if the PSA is >4.0) should be considered suspicious. Transrectal ultrasound (TRUS) is used to confirm the abnormalities detected on DRE as well as guide sites for a sextant biopsy. This creates black & white images of prostate gland using sound waves and may show the tumor as a isoechoic to hypoechoic area.
But a newer way is to measure blood flow within prostate gland using Colour Doppler imaging that has made the prostate biopsies more accurate and the results are more dependable by helping to know which part of the prostate gland is to be sampled.
Magnetic resonance imaging (MRI)-targeted prostate biopsy is being evaluated as a method to improve the accuracy of TRUS biopsy. Clinical settings in which this approach may have utility include patients with a rising PSA and a prior negative biopsy, and those men with prostate cancer who will be managed with active surveillance. MRI-guided biopsy may also have a role when patients are being considered for salvage prostatectomy. The 12 core biopsy is now preferred over sextant biopsy technique as the latter misses out upon 30% of prostatic carcinomas.
Treatment of Prostate Cancer
For men with newly diagnosed prostate cancer, the most important factors in selecting the initial treatment include the following:
Anatomic extent of disease (tumor, node, metastasis stage)
Histologic grade (Gleason score/grade group) of the tumor
Serum PSA level
Estimated outcome with different treatment options
Potential complications with each treatment approach
The patient’s general medical condition, age, and comorbidity, as well as individual preferences
Thus, the initial management of men with newly diagnosed prostate cancer needs to incorporate a consideration of the prolonged natural history of the disease and the risk for progression to disseminated, potentially fatal disease
Early Stage Cancer Treatment
Treatment planning needs to incorporate the natural history of the disease and the risk of progression, since many of these cancers are biologically indolent and may never threaten the health or life of the patient.
For patients diagnosed with prostate cancer confined to the prostate, standard management options include radical prostatectomy, radiation therapy (external beam, brachytherapy), and, for carefully selected patients with very low or low-risk disease, active surveillance.
Ablation therapy: Cryotherapy, high-intensity focused ultrasound (HIFU), and photo-dynamic therapy have been used to selectively destroy tissue. These ablation techniques can be applied either to the entire prostate gland or to focally destroy the part of the prostate gland thought to be involved by tumor. This kills cancer cells in the gland by heating them through highly targeted ultrasonic beams. This technique has been used in a number of countries and is being tested for its safety and efficacy in other countries.
Androgen dprivation therapy (ADT) maybe used in cases with advanced prostatic carcinomas that cannot be treated by RT or surgery or before or in adjunct to radiation therapy to shrink the size of the tumor. There are new forms of hormone therapy that have been developed now. These may work even if standard hormone therapies are no longer working. Some of these are Abiraterone (Zytiga) and Enzalutamide (Xtandi).
There is no definite role of chemotherapy(CT) in combination with RT. Recent studies have demonstrated that many chemotherapy drugs combined wIth ADT have shown promising results. These include docetaxel, estramustine and predisone. Recent studies have also found that in males with metastatic prostate cancer, putting chemotherapy to use earlier in the course of the disease might help them live a longer life.
Doctors are also relying on immunotherapy. The aim of immunotherapy is to improve the body’s immune strength to help fight or kill cancer cells. Prostate cancer cells express a number of tumor-associated antigens that can serve as targets for immunotherapy. The limited immune response to prostate cancer in vivo has been attributed to evasion of immune system recognition by decreased immunogenicity of surface antigens or blunted effectiveness of the immune response mounted against them. Several approaches have been studied to circumvent defective presentation of antigen to effector cells and/or enhance the responsiveness of the patient’s own immune system.