Breaking Down Prostate Cancer: An Overview

Ranking as one of the top ten causes of death by the World Health Organization (WHO), prostate cancer is a significant concern for men. It’s also the second most common cancer among men worldwide, making up over 14% of cancer cases and 6.8% of deaths in 2020, according to the Global Cancer Observatory.

How does prostate cancer start?

Prostate cancer arises from the uncontrolled division of cells in the prostate — a reproductive gland around the size of a ping-pong ball found in between the bladder and the rectum.

The prostate produces part of the seminal fluid. It also plays a critical role in the mechanical switch between urination and ejaculation by widening and narrowing the urethra.

Prostate cancer survival rate

Experts from the American Cancer Society projected that about 299,010 new cases and 35,250 deaths from prostate cancer would affect the US in 2024. These numbers have continued to rise annually. Globally, the number of prostate cancer cases discovered annually has been predicted to rise from 1.4 million in 2020 to 2.9 million by 2040.

Despite this, the outlook for cases of prostate cancer caught early is positive — in the US, those with minimal or limited spread can look forward to a 5-year relative survival rate of greater than 99%.

Early detection of prostate cancer

Early detection is critical in extending the life expectancy of prostate cancer patients. This is done by a combination of the prostate-specific antigen (PSA) test, and, in some cases, the digital rectal examination. However, making an informed decision regarding the need to test based on your risk of prostate cancer is also important. Your healthcare providers will be able to help guide you on balancing the benefits of early screening with the risks of unnecessary treatment given too early.

Prostate cancer risk factors

While many factors can increase the risk of cancer, the most common for prostate cancer would be family history, particularly where there is a known inherited genetic abnormality, and age, with half of newly diagnosed cases occurring over the age of 67. Notably, men of African ancestry face an increased risk of prostate cancer as well.

Understanding the risk factors for prostate cancer can help guide the decision to test, especially as early-stage prostate cancer may remain asymptomatic and, otherwise, go undetected.

Prostate cancer symptoms

As prostate cancer progresses, the following symptoms may become more prominent:

• Interruptions or difficulty controlling urination
• Frequent urination (e.g. disrupting sleep to the point of reducing quality of life)
• Blood in urine
• Burning sensation during urination
• Erectile dysfunction
• Bone pain or weakness (may signal cancer spread)

If you recognize any of these signs, it may be a signal for clinical attention. Your doctor can then decide if further testing would be helpful for you, or if another medical issue could underlie your symptoms.

Prostate cancer treatment

If early-stage disease is diagnosed, active surveillance may be recommended for less aggressive tumors, to avoid unnecessary treatment. Once markers, such as the PSA test, scans or biopsies, indicate an increased risk of aggression, then interventions may be considered. These treatments may include surgical removal of the tumor, external or internal radiation therapy and hormone therapy.

Unfortunately, once cancer has spread beyond the prostate to the bones or other organs — the 5-year relative survival rate upon first diagnosis drops to 32%. Despite the prognosis, research is actively ongoing to determine the best treatment for metastatic prostate cancer and some men continue to live for many years with effective treatment.

Drug treatments that may be recommended for metastatic prostate cancer include hormone therapy, chemotherapy, radiopharmaceuticals and targeted therapies. Not all of these drugs are suitable for everyone, and in many cases patients will have a choice of treatments, often holding back other options for the future.

One of the conundrums with prostate cancer is that it may lie dormant for many years and, in some people, will never cause death or symptoms during that person’s remaining life, whilst in others, the cancer has the potential to spread, ultimately causing significant symptoms and premature death. Early detection in this second group, may enable curative treatment, whilst in the first, it can lead to harm from unnecessary treatment.

The challenge of early detection, therefore, is not just in finding tests which can enable diagnosis long before the cancer causes symptoms, but also in identifying which cancers require immediate treatment and which are best left alone. Therefore, one focus of research is in trying to find better tests which preferentially detect potentially life-threatening cancers at a stage when they can still be cured without detecting the cancers which are best left alone.

Another important area of development is in trying to better understand which men are at greater risk of being diagnosed with significant prostate cancer, such as by using genetic tests, so that they can be preferentially tested for cancer earlier in life.

For those who already have clinically significant cancer there are ongoing efforts to identify treatments which can keep the cancer under control for longer periods of time without causing too much burden of side effects. One key area is in better understanding how prostate cancers differ one from another, for example by understanding the genetic events which cause cancer in individual patients. By doing this, the expectation is that we will be able to match each patient to the treatment which will be most effective for them.