The Current State of Prostate Cancer Treatment

Prostate cancer treatment has evolved rapidly. Recent data shows that >95% of patients with stage 1–3 prostate cancer will survive for at least 10 years after diagnosis. While the outcomes are worse for people with advanced prostate cancer, there is still hope.

Key takeaways:
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    Prostate cancer is generally a slow-growing tumor; it is detected in the early stages in the majority of patients.
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    Stages 1 to 4A have a good response to treatment, and the overwhelming majority of patients live at least 10 years after diagnosis.
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    It is possible to cure prostate cancer in Stages 1 to 3, and in most cases for Stage 4A. Initial treatments frequently include radiation therapy and/or androgen deprivation therapy. There is no current cure for Stage 4B, although there are therapies that can slow growth.
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    Hormone therapy can block testosterone production and thereby impair tumor growth. However, most prostate cancer eventually becomes resistant to hormonal therapy. More recently, abiraterone and similar drugs were shown to sustain treatment effectiveness.
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    Recent developments, including methods to precisely deliver radiation therapy to PC cells and the emergence of new drugs, show great promise.
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    Participation in a PC research study is an option for many patients.

Current treatment strategies combine conventional approaches and emerging therapies. Read on to learn common treatment options for prostate cancer, as well as recent new developments.

Frequent treatments for prostate cancer

PC is a particularly slow-growing type of cancer. If it occurs late in life, patients may choose to avoid the risks associated with tumor treatment. Table 1 shows the average survival of patients by stage. Distinguishing between the Stage 4 subgroups is of great importance since the likelihoods of survival are quite different.

Average survival of PC patients by stage

Average survival in treated PC patients according to tumor stage. PC = prostate cancer, PG = prostate gland.

PC Stage*Characteristics% Alive after 5 years
1PC on one side of the PG
98–100%
2PC may be on one or both sides of the PG98–100%
3The PC progresses but remains in the PG 98–100%
4AThe PC has spread beyond the PG and involves local issue 90–95%
4BCancer has spread locally and to other areas of the body (metastasis)30–33%

*Staging also includes the aggressiveness of the tumor (Gleason score) and the blood prostate-specific antigen level.

The types of PC therapies vary considerably, often based on the stage of the PC, the aggressiveness of the tumor, its initial response to treatment, and other factors including age, other serious medical conditions, expected lifespan, and patient preference. Several options are frequently considered for the initial treatments of Stages 1 to 4A. These fall into three general categories: hormonal, radiotherapy, and surgery. Active surveillance and watchful waiting are also considered.

Active surveillance and watchful waiting

Some patients with early-stage PC choose to defer treatment and, rather, undergo close monitoring of PC activity. This is called active surveillance (AS). With AS, regular physical, biochemical, and radiological testing is done and if there is evidence of tumor growth, specific treatment can begin. Watchful waiting may be considered by elderly individuals or those with life-limiting medical conditions. Under these circumstances, specific treatment for PC is withheld and only associated symptoms (such as impaired urine excretion and pain) are treated.

Androgen deprivation (hormone) therapy

Androgen deprivation therapy (ADT) is a well-established treatment for PC. It can be used for initial treatment, patients with high-risk PC, those whose PC has recurred, or as an attempt to shrink the tumor, particularly in preparation for surgery or radiotherapy. Androgens are male sex hormones, principally testosterone, that stimulate PC growth. The treatment goal is to suppress the body’s level of testosterone. When the PC remains responsive to ADT, outcomes are quite favorable. For instance, among 548 ADT-responsive patients, deaths from PC were around 6% over nearly 7 years. Unfortunately, most patients ultimately become unresponsive to ADT, prompting alternative treatments.

Radiotherapy

Radiotherapy (RT) has long been used for the treatment of PCs. Very high energy (ionizing) radiation can kill malignant cells. Other body tissues exposed to the radiation also can be damaged. To minimize this, newer radiotherapy methods have been developed for precise delivery of the radiation with less damage to nearby tissue.

Two types of radiotherapy are used: external beam RT and brachytherapy. External beam RT delivers radiation to the cancerous tissue. With brachytherapy, the radiation source is contained within tiny “packages” that are often called seeds. These are around the size of a grain of rice. They are injected through the skin and into the tumorous tissue, most often using a small catheter or needle. This way cancer receives higher radiation doses while minimizing the side effects of external beam treatment. When hormonal therapy is combined with radiotherapies, patient survival is better than either approach alone.

Surgery

Localized PC may also be treated by radical prostatectomy in which the entire prostate gland and local lymph nodes are removed to cure cancer. Long-term outcomes for this procedure are similar to those treated with radiotherapy. In addition to common postoperative problems, there also is the potential of developing erectile dysfunction and urinary incontinence. These may improve over 6 to 12 months.

Treatment modifications and recent developments

More recent developments are expanding treatment options. These are often combined with more conventional therapies. Several of the recent developments are quite novel. Some are approved for clinical use while other promising treatments are on the horizon for human use.

Sipuleucel-T

Sipuleucel-T is a patient-specific prostate vaccine. To make the vaccine, the patient’s white blood cells are removed and processed in the laboratory to increase their immune reactivity to prostate cancer cells. They are then returned intravenously into the patient’s bloodstream. At present, research is ongoing to establish its role and effectiveness in treating PC. If effective, the vaccine could treat distant metastases in addition to local disease.

PARP inhibitors

PARP inhibitors eliminate the ability of cancer cells to repair their frequent DNA mutations. With the inability to repair these mutations, PC cells die. Thus far, these drugs appear to be most effective in a group of PC patients with certain specific genetic characteristics. In particular, carriers of the BRCA genes (BReast CAncer genes) are particularly susceptible to PARP inhibitors (normal BRCA genes are part of the DNA repair system).

Radiopharmaceuticals

Radiopharmaceuticals are drugs that use an antibody that binds to a protein that is abundant on the surfaces of PC cells (PMSA). The antibody is first bound to a radioisotope, and when administered, results in specific delivery of radiation directly to the cancer cells while sparing nearby tissue from radiation injury. The concept is a particularly intriguing approach for those whose cancer has metastasized to other locations in the body. The drug, Pluvicto, has very recently become FDA approved for PC that does not respond to hormone therapy. Early data have shown improvements in overall survival for patients with metastatic PC.

Abiraterone

Abiraterone is a drug that inhibits an enzyme critical to the synthesis of androgens. Most prostate cancer eventually becomes resistant to conventional hormone therapy. Abiraterone blocks androgen production differently than ADT and has shown added effectiveness when combined with other treatment types. It was initially approved some years ago for the treatment of patients with ADT-resistant PC. However recent findings have shown significantly better survival when ADT was combined with abiraterone.

Chemotherapy

Chemotherapy for PC most often uses docetaxel. Docetaxel suppresses PC growth by interfering with tumor cell division. It is often used in combination with steroid medications and ADT, among others. Studies have tested the effectiveness of docetaxel in patients with advanced, recurrent, or metastatic PC. Long-term treatment of patients with high-risk PC with or without metastasis has shown improved survival. Using a combination of docetaxel + ADT and radiotherapy, the risk of metastases improves as well. When considering docetaxel, its adverse effects need to also be considered.

Robotic-assisted surgery

Robotic-assisted surgery has also been used for a radical prostatectomy. Through several small incisions, the procedure uses miniaturized surgical instruments that are controlled by a surgeon sitting at a console. The use of the robot decreases the amount of bleeding, the duration of hospitalization, and infections, but the PC outcomes as yet show no differences compared to traditional surgery.

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