Types of Prostate Cancer
Medically reviewed by Matthew Wosnitzer, MD
Prostate cancer is the second most common cancer in people assigned male at birth. It occurs when cells of the prostate—a small male reproductive organ sitting beneath the bladder and above the rectum—become abnormal and grow out of control. There are several types of prostate cancer, but the most common are adenocarcinomas, occurring in more than 95% of prostate cancer cases.
However, there are several other rarer and more aggressive types of prostate cancer, which are categorized based on the type of cells affected. Healthcare providers analyze prostate tissue to identify the cancer's type, stage (how much cancer is present and if it has spread), grade (appearance), and the best course of treatment.
This article discusses adenocarcinoma and the other types of prostate cancer and related treatment options.
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The Most Common Type of Prostate Cancer: Adenocarcinoma
Adenocarcinoma is the most common type of prostate cancer, representing more than 95% of all cases. It affects the gland cells that line the walls of the prostate and produces fluids that comprise part of semen. Prostate fluid is essential in nourishing sperm cells and their ability to move (motility).
The two subtypes of prostate adenocarcinoma are:
Acinar adenocarcinoma affects the basal epithelial cells lining the prostate.
Ductal adenocarcinoma occurs when the cancer spreads to the ducts that secrete prostate fluid into the urethra.
Other Rare Forms of Prostate Cancer
Rarer forms of prostate cancer affect different cell groups in the prostate. During the diagnostic process, healthcare providers identify the cancer type, grade, and stage..
Transitional Cell (or Urothelial) Cancer
Transitional cell (urothelial) cancer is a rare and aggressive prostate cancer that arises in the cells lining the bladder, urethra, and ureters (ducts between the kidney and bladder). It makes up between 1% and 5% of all prostate cancer cases. It often recurs and spreads to other parts of the body.
Small-Cell Carcinoma
Small-cell carcinoma accounts for 0.55% to 2% of all prostate cancers and is more severe and fatal than adenocarcinoma. In this type, the tumors develop from small, round neuroendocrine cells. This type frequently causes bladder and bowel symptoms, with up to 60% of cases displaying cancer in other organs at the time of diagnosis.
Soft Tissue Sarcoma
Sarcomas are a type of cancer that affects stromal, or soft tissue, cells, which comprise connective tissues in the body. Often missed in diagnosis, this type spreads quickly and is severe. Soft tissue prostate cancer is rare, arising in less than 1 in 1,000 prostate cancer cases.
Neuroendocrine Tumors
Also known as large-cell neuroendocrine carcinomas, neuroendocrine tumors are poorly differentiated, meaning it’s hard to determine the cancer cell type. Compared to adenocarcinomas, neuroendocrine tumors are less responsive to hormone therapy and spread more rapidly.
Which Types of Prostate Cancer Are Aggressive?
Aggressive cancer grows quickly, spreads rapidly, or is resistant to treatment. Acinar cancer (common adenocarcinoma prostate cancer), which is the most prevalent type, isn’t aggressive and is often confined to cells in the prostate. However, certain types of prostate cancer are aggressive, such as small-cell carcinoma and squamous-cell carcinoma.
Small-Cell Carcinoma
Small-cell carcinomas are aggressive and require intense treatments. About 50% of those who develop small-cell carcinoma of the prostate have a history of lung adenocarcinoma. This type is often detected in a later stage, impacting the overall outcome.
Squamous Cell Carcinoma
Squamous cell carcinoma is another rare, very aggressive type of prostate cancer, arising from squamous cells—flat cells that line organs. It represents less than 1% of all prostate cancer cases and is characterized by advanced local spread (growing quickly in and around the prostate) or metastasis (spreading to other organs).
Types of Prostate Cancer That Haven’t Spread
Healthcare providers can also detect precancerous conditions, such as prostatic intraepithelial neoplasia and proliferative inflammatory atrophy. These may or may not develop into cancer. In addition, healthcare providers can detect cancer that hasn’t spread beyond the prostate, meaning it is localized prostate cancer.
Prostatic Intraepithelial Neoplasia (PIN)
PIN occurs when a biopsy (a clinical analysis of a sample of prostate tissue) reveals abnormal cells that aren’t spreading to other cells. Usually, PIN doesn’t develop into full-blown cancer; however, high-grade forms do increase cancer risk.
Proliferative Inflammatory Atrophy (PIA)
While cancer and other issues typically cause the prostate to grow larger, this organ is smaller with PIA. It is generally a benign condition, though researchers have associated it with PIN and prostate cancer. The exact relationship between the two conditions is unclear.
Localized Prostate Cancer
Localized cancer (early organ-confirmed prostate cancer) is caught during stage 1 or stage 2, meaning the cancer cells are confined to the prostate and aren’t spreading. At this point, the overall risk is low; the cancer may or may not spread beyond the prostate, and there may or may not be symptoms.
How to Know What Type of Prostate Cancer You Have
Pathologists (specialists in detecting diseases) and oncologists (cancer specialists) primarily diagnose and evaluate prostate cancer through biopsy and blood samples. Following testing, your healthcare provider will give you this information, help you interpret your results, and assess your overall risk.
PSA Levels
Elevated blood levels of prostate-specific antigen (PSA), a protein made by prostate cells, may be signs of prostate cancer. The chance you have cancer is very low with 4 or less nanograms per milliliter (ng/ml) of blood. If your reading is 4 to 10 ng/ml, you have about a 25% risk of cancer, and if it's more than 10 ng/ml, your risk is 50%.
The Gleason Score
The Gleason score is a tool for risk assessment. It is calculated by rating the level of abnormality in cells from 1 (healthy-appearing) to 5 (very abnormal). The scores for the two most dominant cellular patterns are added together for an overall score out of 10. For instance, if the two most dominant cells are a 4 and a 2, the Gleason score would be 6.
Scores are broken down by risk level, as follows:
Low-grade: A Gleason score of 6 or less is low grade, which means the cancer isn’t likely to grow or spread.
Intermediate-grade: A score of 7 is moderately differentiated, meaning there’s a greater likelihood of growth and spread.
High-grade: Gleason scores from 8 to 10 indicate poorly differentiated, which are severe cases in which tumors are likely to spread locally, regionally, and move to distant sites.
Gleason Score Inflation
Controversy surrounds the use of the Gleason score. Some providers don’t consider a score of 6—the upper end of the low-grade spectrum—a fully-fledged cancer. They believe this system inflates seriousness, prompting unnecessary treatment. However, many medical agencies disagree.
Cancer Staging
Healthcare providers stage cancer to measure how much cancer is present and if it has spread (metastasized). They often use the American Joint Committee on Cancer (AJCC) TNM system, in which the following three factors determine prostate cancer stages:
Tumor size (T): The size of the primary tumors and how extensive they are within the organ
Number (N): The number of lymph nodes (immune glands throughout the body) in the area that have cancer cells
Metastasis (M): The presence of cancer cells in other parts of the body
Cancer stages range from stage 1, in which the cancerous tumors are small, well-defined, and confined to the prostate, to stage 5, in which cancer has spread locally and to distant parts of the body.
Treatment by Type of Prostate Cancer
Prostate cancer treatment depends on how aggressive and advanced it is as well as personal choice. Less aggressive types like adenocarcinoma may require just watchful waiting (observing tumors over time to ensure they are not spreading). But for more advanced and aggressive prostate cancers, there is a range of treatment options.
Watchful Waiting
Healthcare providers typically recommend watchful waiting for those with a Gleason score of 6 or below—early- or low-risk cancers. It involves monitoring your condition and only trying treatment if it worsens. They may consider a similar approach if the risks of treatment side effects outweigh the potential benefits. Sometimes called “active surveillance,” this involves:
Having your prostate-specific antigen (PSA) levels checked regularly
Annual digital rectal exams (the provider physically assesses the prostate with a gloved hand)
Biopsies at six months to one year and two to five years after starting surveillance
Surgery
Surgeries take on cases in which the tumors are well-differentiated and inside the prostate. These include:
Radical prostatectomy: Surgeons remove the prostate along with tumors and surrounding tissues like the seminal vesicles, sometimes with robotic assistance. They may also take out the pelvic lymph nodes.
Transurethral resection of the prostate (TURP): This procedure involves applying heat or electricity to tissues in the prostate to relieve symptoms, such as difficulty urinating.
Orchiectomy: Male hormones produced in the testicles, known as androgens, can spur tumor growth and progression. Surgery to remove the testicles may be another option.
Radiation Therapy
With radiation therapy, radioactive energy kills cancer cells. This may be an alternative to surgery or used afterward to promote results. With external beam radiation therapy, the radiation is delivered while you’re on an exam table. Surgeons implant a tiny radioactive seed near the prostate in another approach, known as brachytherapy.
Localized Treatments
Cryotherapy is another option for tumors localized in the prostate. The surgeon delivers argon and helium to freeze and remove tumors.
Another option is high-intensity focused ultrasound (HIFU), which uses ultrasound waves to heat and destroy cancerous tissue. It is usually reserved for cancer that’s come back after radiation therapy.
Hormone Therapy
Androgen deprivation therapy (ADT) involves taking certain medications, including Firmagon (degarelix) or Lupron (leuprolide), to reduce testosterone levels that can spur tumor growth. It is an alternative to orchiectomy.
Chemotherapy
Chemotherapy medications, such as Taxotere (docetaxel) or Novantrone (mitoxantrone), target and kill cancer cells. Due to its side effects, healthcare providers reserve chemotherapy for more aggressive, metastasized cancers.
What Is the Life Expectancy for Someone With Prostate Cancer?
Generally, prostate cancers are highly treatable and move slowly. Most cases are detected in people over age 60, and more than 97% of those with prostate cancer are alive at five years. This number climbs to 100% if the cancer stays localized.
That said, rarer and more aggressive types can cause worse outcomes. Only 34% of those diagnosed with stages 4 and 5 cancer, in which the cancer has spread to distant sites, survive five years.
Prostate Cancer in Black Men
The rate of prostate cancer in the United States in Black men is 64% higher than it is in White men. Deaths due to this cancer are also relatively higher—4.4% in Black men vs. 2.4% in White men—and the average age of onset is lower. Given this higher risk, it’s critical to be proactive about screening.
Summary
There are many types of prostate cancer, and 95% of all cases are adenocarcinoma, which is relatively slow-moving and may or may not spread or require treatment. However, other, rarer types of prostate cancer, such as small-cell carcinoma, can be much more aggressive and dangerous.
In diagnosis, healthcare providers work to analyze how abnormal cancer cells are and whether they’re growing or spreading to other parts of the body. With this risk assessment, they can advise on your treatment options, which range from monitoring the condition to surgery.
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