Adenocarcinoma is a type of cancer that forms in the glands. These are the cells that secrete substances within the body or excrete them from the body.
Outlook, treatment, and survival rates for adenocarcinoma depend on the tumor’s location, size, and stage, as well as individual factors, such as a person’s overall health.
In this article, we look at the types of adenocarcinoma and how to treat them.
Adenocarcinomas begin in glands but can spread to other types of tissue and areas of the body.
- Lung: Lung adenocarcinomas account for about 40% of all lung cancers. They grow in new, undeveloped mucus-secreting cells.
- Breast: Most breast cancers are adenocarcinomas that develop in the milk ducts or the glands that produce milk.
- Prostate: Prostate adenocarcinoma develops in the cells of the prostate gland. Most prostate cancers are adenocarcinomas.
- Pancreas: Pancreatic adenocarcinomas typically develop when exocrine cells in the ducts of the pancreas grow too quickly. About 95% of exocrine cancers are adenocarcinomas.
- Colon: Most colon cancers are adenocarcinomas. A colon adenocarcinoma begins in the glands that create the mucus to line the colon and rectum.
The brain can also develop an adenocarcinoma, often as a result of cancer cells that have metastasized, or spread, from other areas of the body.
As adenocarcinoma can occur in many areas of the body, no single list of symptoms defines it.
Adenocarcinoma in the lungs can lead to:
- bloody mucus
- weight loss
Adenocarcinoma in the breast shows as a lump or unusual growth.
In its early stages, prostate cancer does not cause any symptoms. At a later stage, an adenocarcinoma may lead to:
- pain when urinating
- issues with bladder control
- more frequent urges to urinate at night
- blood in the semen
- painful ejaculation
Adenocarcinoma in the pancreas can cause:
- unintended weight loss
- pain in the back and stomach
- oily, pale stools
- itchy skin
If adenocarcinoma develops in the colon, the following symptoms might occur:
- a sensation that the bowels are full
- bloody stool
- rectal bleeding
- stomach pain
- unexplained weight loss
Brain or skull
The following symptoms may develop if adenocarcinoma develops in the skull:
- blurred vision
- personality changes
- unusual sensations in the legs or arms
- changes in thinking
Adenocarcinomas develop for different reasons. Researchers are yet to find out why adenocarcinomas develop in some people but not others.
However, there are some clear links between several of the risk factors. The following list highlights the risk factors that cause cancers to develop as adenocarcinomas.
Risk factors common to many of these cancers include a family history of the cancer and previous exposure to radiation therapy.
Smoking tobacco products or being around second-hand smoke are the primary risk factors for lung adenocarcinoma.
Other risk factors include:
- exposure to harmful toxins in the work and home environments
- previous radiation therapy, especially in the lungs
- sex, as women are more likely to get breast cancer than men
- age, as the risk is more significant in older adults
- family history and genetics
- taking hormone replacement therapy (HRT)
Here, learn about all of the risk factors for breast cancer.
There are several confirmed risk factors for prostate cancers, including adenocarcinoma, such as:
- age, as the risk increases significantly once a man reaches 50 years of age
- race and ethnicity, as prostate cancer is more common in African American men and Caribbean men with African heritage than in any other race
- geography, as prostate cancer is most common in North America, Australia, northern Europe, and the Caribbean
- having a close relative with prostate cancer, which can double the risk of developing it
Risk factors include:
- overweight and obesity
- exposure to particular chemicals in metalwork and dry cleaning
- age, as the risk increases with advancing years
- gender, as more men than women develop pancreatic cancer
Cancers of the colon and rectum, including adenocarcinoma, have several risk factors that can promote their development. These include:
- overweight or obesity
- a sedentary lifestyle
- a diet high in red or processed meats
- smoking tobacco
- regularly consuming too much alcohol
- a history of irritable bowel disease (IBD)
- having type 2 diabetes
Some factors increase the risk of adenocarcinoma spreading to the brain. These include exposure to radiation, usually during other treatments.
A family history of other cancer-linked diseases, such as Li-Fraumeni Syndrome, can also increase the risk of brain cancer. However, adenocarcinoma most commonly spreads to the brain from another location.
A 2018 study, published in the Chinese Neurosurgical Journal, examined the risk of metastasis for people with lung adenocarcinoma. The study authors concluded that people under 60 years of age with lung cancer that has spread to the lymph nodes have a significantly higher risk of adenocarcinoma reaching the brain.
Diagnosis usually begins with an examination. A doctor will take an individual’s comprehensive medical history.
The doctor will ask questions about symptoms and any possible risk factors, such as smoking and whether other family members have or have had adenocarcinoma.
Several tests can assist a doctor in diagnosing adenocarcinoma. It may be necessary to carry out multiple tests.
Tests may include the following options.
During this procedure, a healthcare professional removes a small sample of tissue. They will then send this to a laboratory for testing.
The location of the adenocarcinoma and the amount of tissue required will shape the biopsy method. Some use a thin or wide needle to obtain a sample. Others, such as colonic adenocarcinomas, require a more invasive technique, such as an endoscopy.
In an endoscopy, a healthcare professional inserts a tube into the area that is showing symptoms. It is flexible, lighted, and has a camera attached. A doctor may collect a tissue sample during this procedure for further analysis.
A biopsy can indicate whether a tissue sample is cancerous and if the cancer originated at the biopsied site or has metastasized from somewhere else in the body.
A doctor may use an X-ray to aid in diagnosis. In breast adenocarcinoma, for example, a doctor may use a mammogram. This is a specialized machine that provides an X-ray image of the breast.
A CT scan is an X-ray that provides 3D images of the body. Doctors sometimes use them to measure the change of a cancer over time and gauge whether treatment is working. They can also provide close detail on cancerous tissue.
MRI is another option. A doctor uses magnets and radio waves to create a detailed, cross-sectional image of various body parts, organs, and blood vessels. In some MRI scans, a doctor may inject a tracer or dye that may help to provide clearer images to aid in diagnosis.
These can measure changes in blood cells that suggest cancer. Some adenocarcinomas and other cancers can circulate specific chemicals in the blood.
For example, changing levels of prostate-specific antigen (PSA) may indicate prostate adenocarcinoma.
Treatment for adenocarcinoma depends on the location of a cancer, how large it has grown, and whether it has spread.
Doctors will also consider how healthy the person with cancer is since treatment can cause serious side effects.
Treatment options may include the following:
Surgical removal of a tumor is common.
Tumor removal is a safer option with some cancers than others.
For example, a lumpectomy is the removal of breast cancer. It is relatively safe. However, surgically removing a tumor from the brain can be life-threatening.
In people with an aggressive adenocarcinoma that has a high risk of spreading, a surgeon might remove a whole organ or gland.
Doctors may also request a radiofrequency ablation. This treatment uses energy waves to destroy or shrink the tumor. A surgeon might also remove surrounding lymph nodes at the same time as the tumor to prevent spread.
Chemotherapy is a type of treatment in which a healthcare professional delivers cancer-killing medication into a vein using a needle or intravenous (IV) drip. Some people may take chemotherapy drugs orally.
This treatment destroys cancer cells but may also kill some healthy cells. Many people going through chemotherapy become sick, lose their hair, feel fatigued, or experience other adverse effects.
As a result, people undergoing chemotherapy may need to take other drugs or stay in the hospital during their treatment.
Some drugs target specific cancer cells, and doctors may offer this as an alternative to chemotherapy or in addition to it.
The availability of these drugs depends on the type of cancer and an individual’s health.
Radiation uses high energy waves to target and kill cancer cells.
External radiation delivers these waves from a machine outside the body. Internal radiation involves implanting a needle, seed, or another device near the tumor to release radiation over time.
Similarly to chemotherapy, radiation may also kill healthy cells and cause severe adverse effects.
Immunotherapy uses medications that support the immune system to kill cancer.
Most immunotherapy drugs only prolong life and do not fully cure cancer. They may have fewer side effects than either chemotherapy or radiation, but some people may experience mild to severe side effects.
The benefits of immunotherapy depend on the cancer, its stage, and the health of the person with cancer.
Cancer staging is one way for doctors to measure the progress of cancers, including adenocarcinoma. Different doctors prefer different staging systems.
Some doctors use a 0–4 stage system. In this understanding of cancer, stage 0 indicates that there are abnormal cells, but they have not spread.
A higher stage indicates a larger tumor or that the cancer has spread into the surrounding tissue or lymph nodes.
Stages 1–3 indicate that the cancer has not yet spread to other parts of the body. Stage 4 cancer has spread to other parts of the body.
The TNM system involves using letters to describe tumor size, the number of lymph nodes affected, and metastasis.
T measures the primary tumor. TX indicates no measurable tumor and T0 means that doctors cannot find a tumor. T1–T4 denote the size of the tumor. Larger numbers refer to bigger tumors.
N measures the cancer’s effect on the lymph nodes near the tumor. NX indicates no measurable cancer in nearby lymph nodes. N0 means there is no cancer in the lymph nodes. N1–N3 indicate the number of affected lymph nodes. Higher numbers mean that the cancer has spread to more lymph nodes.
M measures the cancer’s spread to other regions. MX indicates no measurable metastasis, M0 indicates none at all, and M1 means that the cancer has spread.
Doctors will often use TNM to calculate the numbered stage of a cancer as Stage 0–4.
Adenocarcinomas can have very different outlooks depending on where they have developed.
Some cancers tend to spread more quickly than others. Others, such as prostate cancer, often go undetected in the early stages, and doctors do not diagnose them until later.
These cancers are more likely to be fatal than cancers that grow slowly or cause detectable symptoms.
It is more difficult for doctors to treat advanced cancers, and they typically have a worse outlook. However, this varies according to the type of cancer a person has, the available treatments, and the location to which the cancer has spread.
A 5-year survival rate indicates how likely it is that a person will live for 5 years beyond a cancer diagnosis compared to a person who does not have cancer.
Survival rates vary significantly, depending on the type of adenocarcinoma. Women with breast cancer that has spread locally but not to distant organs may have a 5-year survival rate of around 85%. A person with an equivalent stage adenocarcinoma in the lung would have a survival rate of about 33%.
Treatment quality and other individual factors can affect prognosis.