There are different types of prostate cancer. The most common type is called acinar adenocarcinoma. It is necessary for your doctor to understand the type of prostate cancer you may have. It helps in the treatment process.
Prostate cancer is the second most common cause of cancer in American men after skin cancer. It is still a lethal disease considering that it is the second leading cause of death due to cancer among men in the U.S. with about 94 men dying from it every day.
Low-risk prostate cancer grows slowly and is not likely to spread quickly. High-risk prostate cancer is aggressive and likely to spread quickly outside the prostate to the other parts of the body.
Other prostate cancers are rare and include prostate sarcomas, neuroendocrine tumors, small cell carcinomas, transitional cell carcinomas, and squamous cell carcinomas. Because they are so rare, not much research has been done on them.
1. Adenocarcinoma of the prostate
Adenocarcinomas are cancers that develop in the cells that line the prostate gland. Most cells of the prostate are glandular cells and that’s what makes this cancer the most common type of cancer to develop in the prostate gland. Most of the prostate cancers, about 99 percent, are of this type.
Though malignant, adenocarcinoma of the prostate grows extremely slowly, and therefore, is unlikely to be the direct cause of the man’s death. Hematuria and urinary tract obstruction are the main complaints in patients with prostate adenocarcinomas.
The two main subtypes of prostate adenocarcinomas are Acinar adenocarcinoma and Ductal adenocarcinoma. Marked elevation in serum PSA levels (>10ng/ml) is observed in a large number of cases of both subtypes.
- Acinar adenocarcinoma. Acinar adenocarcinoma is the most common type of adenocarcinoma. The major proportions of prostate carcinomas, about 95%, are acinar adenocarcinomas. Acinar tumors arise from the periurethral prostatic ducts. Histologically, they exhibited glands and sac-like cavities lined by a single layer of cuboidal cells
- Ductal adenocarcinoma. Ductal adenocarcinoma is an unusual variant of the adenocarcinoma of the prostate. It accounts for 0.2–7.5% of all prostate carcinomas. It originates in the cells that line the ducts of the prostate gland. It grows and spreads more quickly than acinar adenocarcinoma. Ductal adenocarcinoma of the prostate usually grows close to the urethra and presents symptoms of hematuria and urinary tract at an early stage. It is the most frequent of the rare subtypes of prostate carcinoma, accounting for 5% of total prostate carcinoma cases and found occurring mostly in older men. The majority of ductal adenocarcinomas are found to occur with an acinar component. Tumors with only the ductal components are extremely rare. More than half of patients with ductal cases are more than 65 years old at the time of diagnosis.
2. Transitional cell (or urothelial) cancer
Transitional cell cancer of the prostate originates in the cells that line the urethra, which drains the urine from the bladder. This type of prostate cancer usually starts developing in the bladder and spreads into the prostate.
However, rarely, it can also start in the prostate and spread into the bladder outlet and neighboring tissues.
Since it grows around the urethra, it can narrow it and cause symptoms of difficulty in passing urine and hematuria (blood in urine).
This type of cancer is rare. It is a very aggressive tumor and has a poor prognosis. Therapy is still undefined.
3. Squamous cell cancer
These cancers develop from the areas of low cuboidal or flat cells that cover the prostate. They grow fast and spread more rapidly than adenocarcinoma of the prostate.
They make up 0.5% to 1% of all prostate carcinomas. Presenting symptoms range from obstructive lower urinary tract symptoms to those of bone metastases.
This cancer is typically described as an aggressive cancer, with an average survival of approximately 14 months since the time of diagnosis.
4. Neuroendocrine prostate cancers
Neuroendocrine prostate cancers grow from the neuroendocrine cells in the prostate. They are found to develop in other organs also. About half start in the digestive tract including the stomach, small and large bowel, and the pancreas.
About 20% start to develop in the lungs. Other places in the body where they are found are skin, womb, adrenal, parathyroid, pituitary glands, and of course in the prostate.
They are of several sub-types including small cell prostate cancer and large cell prostate cancer.
- Small cell prostate cancer. Small cell prostate cancer is a subset of neuroendocrine cancer. It is made up of small round cells. It is a high-grade malignant neoplasm, which is rare and affects less than 1% of the population. It is extremely lethal. Of all types of prosttate cancer, it is one of the most aggressive malignancies of the prostate with a survival rate of 1-2 years from the time it is diagnosed.
- Large cell prostate cancer. Large cell prostate cancer is another type of neuroendocrine prostate cancer, which is aggressive and can spread rapidly. Since it is very rare, very little is known about how it develops, or the effective ways to treat it.
Adult prostate sarcomas are extremely rare malignant tumors and account for less than 0.1% of prostatic malignant tumors. The prognosis of sarcoma is poor.
Most common prostate cancers develop from cells that line the prostate (glandular epithelial cells) but prostate sarcomas develop from the smooth muscle cells in the prostate, called mesenchymal cells.
Prostate sarcoma mainly presents with urinary retention due to bladder outlet obstruction. Prostatic Specific Antigen (PSA) level can be normal.
Imaging studies show a prostate mass with or without pelvic organ invasion depending on how aggressive the tumor is. It has a high prevalence of spreading to the seminal vesicles, bladder, and rectum.
A digital rectal examination, an ultrasound, and a needle biopsy form the preliminary tests towards diagnosis. Other more advanced and specific tests are carried out to look for DNA alterations that are driving the growth of cancer.