What Is Adenocarcinoma?

Adenocarcinoma is a type of cancer that affects glands and glandular tissues. These are the organs and tissues, respectively, that produce substances ranging from hormones to digestive juices. Most breast, colon, esophageal, pancreatic, and prostate cancers are adenocarcinomas. The same is true of a large proportion of lung cancers.

This article discusses the types, symptoms, causes, risk factors, diagnosis, and treatment of adenocarcinoma.

Types of Adenocarcinomas

For many people, the term adenocarcinoma brings lung cancer to mind. While this type of cancer can develop there, it can also occur in any part of the body where there are glands. 

The most common types of adenocarcinoma are:

• Breast cancer
• Colorectal cancer (of the colon or rectum)
• Esophageal cancer
• Lung cancer
• Pancreatic cancer
• Prostate cancer
• Gastric (stomach) cancer

Symptoms and Causes

Symptoms and causes can vary by the adenocarcinoma type. Some types may have early symptoms, such as a lump in the breast. Others may remain largely without symptoms until the disease is advanced and has spread (metastasized).

Causes for a specific case of adenocarcinoma are often not exactly clear. However, certain risk factors—such as age, race, and sex—may increase the chances of getting it. It may also include lifestyle factors, like smoking, drinking alcohol, and lack of physical activity.

Smoking is one risk factor that's independently linked to most adenocarcinomas. Inhaled carcinogens can directly interact with DNA, increasing the risk for cancer. Genetics can also increase your risk, with certain mutations linked to certain cancers.

Below are symptoms and causes based on the type of adenocarcinoma.

Breast Cancer

Symptoms of adenocarcinoma of the breast may include:

• Sudden onset of pain
• Nipple discharge/inversion
• New unwavering skin changes
• New notable breast mass

Causes and risk factors for adenocarcinoma of the breast include:

• Being female (although breast cancer does occur in men, too)
• Excess levels of the hormone estrogen
• Starting menstruation at an early age
• Starting menopause at a late age
• Drinking alcohol
• Genetic risk factors, including having BRCA gene mutations

Colorectal Cancer

Symptoms of adenocarcinoma of the colon or rectum may include:

• Involuntary weight loss
• Tiredness
• Generalized frailty
• Hematochezia (blood in the stool)
• Pain in the abdomen
• Obstruction of bowel movements

Causes and risk factors of adenocarcinoma of the colon or rectum include:

• Being over age 45
• Personal history of colon polyps
• Having inflammatory bowel disease (IBD)
• Gene mutations (such as BRCA)
• Diet high in red and processed meats
• Obesity
• Smoking
• Heavy alcohol use
  
• Family history
  

Hereditary colorectal cancer syndromes are linked to an increased risk for colon cancer. This includes familial adenomatous polyposis, a rare condition involving a mutation in the APC gene.

Lynch syndrome is the most common cause of hereditary colon cancer, including for individuals under 50.

Esophageal Cancer

Symptoms of adenocarcinoma of the esophagus include:

• Difficulty swallowing
• Pain in the chest
• Unexplained weight loss
• Loss of voice
• Chronic cough
• Vomiting
• Anemia (an insufficient number of healthy red blood cells)
• Tiredness
• Bone pain

Causes and risk factors for adenocarcinoma of the esophagus include:

• Being male
• Having gastroesophageal reflux disease (GERD)
• Having Barrett's esophagus
• Obesity
• Smoking

Lung Cancer

Symptoms of adenocarcinoma of the lung include:

• Chronic dry cough
• Difficulty breathing
• Coughing up blood
• Chest pain that's worse with deep breathing
• Hoarseness
• Wheezing
• Weight loss

Causes and risk factors for lung adenocarcinoma include:

• Smoking and exposure to secondhand smoke: Over 90% of lung adenocarcinoma cases are associated with smoking.
• Radiation exposure
• Exposure to asbestos
• Exposure to radon
• Exposure to air pollution
• Genetic factors

Pancreatic Cancer

Symptoms of adenocarcinoma of the pancreas include:

• Chronic pain directly below your ribcage in the upper abdomen
• Nausea
• Vomiting
• Jaundice (yellowing of the skin and/or eyes)
• Unexplained weight loss
• Loss of appetite
• Abnormal weakness
• Oily stool
• Swelling of the liver and spleen
• Blood clots

Causes and risk factors for adenocarcinoma of the pancreas include:

• Smoking
• Long-term diabetes
• Chronic pancreatitis, or inflammation of the pancreas
• Genetic factors

As many as 10% of people with pancreatic cancer have a family history of the disease.

Prostate Cancer

Symptoms of adenocarcinoma of the prostate include:

• Trouble urinating
• Frequent urination, especially at night
• Incomplete emptying of the bladder
• Blood in the urine or semen
• Pain in the back, hips, or pelvis
• Painful ejaculation

Causes and risk factors for adenocarcinoma of the prostate include:

• Age (risk increases over 50)
• Race (more common in African-American men and Caribbean men of African ancestry)
• Smoking
• A family history of prostate cancer
• Genetic mutations such as BRCA1 and BRCA2 genes

Age is the biggest risk factor for prostate cancer. Almost all cases of prostate cancer are in males over the age of 40.

Stomach Cancer

Symptoms of adenocarcinoma of the stomach include:

• Poor appetite
• Unintentional weight loss
• Pain and/or swelling in the abdomen
• Fullness in the upper abdomen after only eating a small amount of food
• Heartburn
• Indigestion
• Nausea
• Vomiting (with or without blood)
• Blood in the stool
• Anemia

Causes and risk factors for adenocarcinoma of the stomach include:

• Age (the median age of diagnosis is 70)
• Prolonged (about two to three decades) exposure to carcinogens
• Family history
• Diet (e.g., eating a lot of processed foods)
• Drinking alcohol
• Smoking

In addition, most people who develop stomach cancer are male.

Diagnosis

There are a variety of tests used to screen for adenocarcinoma. These include imaging like mammograms, lab tests such as prostate-specific antigen (PSA) test, and procedures such as colonoscopy.

A screening test does not confirm the presence of cancer, however. An official adenocarcinoma diagnosis is made based on an examination of cells under a microscope. This involves a biopsy to extract a tissue sample.

Biopsy

Having a biopsy done does not necessarily mean you have cancer. It means your healthcare provider wants to assess your cells or tissue for signs of damage or disease. 

The different types of biopsy include:

• Bone marrow biopsy: A sample of bone marrow tissue, the spongy material inside bone, is withdrawn with a needle. This procedure is usually done under local anesthesia.
• Endoscopic biopsy: An endoscope is a flexible tube with a light attached. It is inserted to help reach locations such as the lung or bladder so that a biopsy can be taken.
• Needle biopsy: This can be used when a provider is able to feel a tumor through your skin. There are several different kinds of needle biopsies. One example is fine needle aspiration of a breast lump.
• Skin biopsy: Most often used to diagnose skin conditions, a skin biopsy removes cells from your body’s surface.
• Surgical biopsy: If other biopsy methods are not an option, or if they have produced inconclusive results, a surgical biopsy is often used. An incision is made to remove a portion of the cells in question for further examination.

Examining the Tissue

Pathologists are the professionals who perform and interpret lab tests. They review biopsy samples and can often identify adenocarcinomas based on their physical structure.

Pathologists use staining to show areas of importance as well as to highlight contrast. Positive stains are absorbed by the cancer cells and negative stains outline the cells. Based on how the cells respond, the pathologist determines if adenocarcinoma or another type of cancer is involved.

With that said, there are variations as adenocarcinomas progress. The pathologist will run other tests to reveal other characteristics of the cancer.

Treatment

Adenocarcinoma treatment varies depending on the location and size of the tumor, as well as the stage and grade of the disease.

Treatment usually includes one or more of the following procedures or medications.

Chemotherapy

Chemotherapy is a drug treatment plan to eliminate the fast-growing cancer cells.

This treatment can be neoadjuvant (given prior to surgery to shrink a tumor) or adjuvant (given post-surgery to target any cancer cells that may be left behind).

Radiation Therapy 

Radiation therapy uses high doses of radiation to kill cancer cells.

Like chemotherapy, it can be neoadjuvant or adjuvant. Palliative radiation can be given to relieve symptoms and improve quality of life.

Surgery 

Surgery involves using instruments, including scalpels or lasers, to remove tumors. You'll receive anesthesia to keep you from feeling pain during the surgery.

Surgery may be minimally invasive, which involves a smaller cut and a scope that allows the surgeon to see the tumor so it can be operated on.

In other cases, it may involve open surgery, where the surgeon makes a larger cut so they can see the tumor directly. This may involve the surgeon taking out the tumor along with surrounding tissue or lymph nodes.

Immunotherapy

Immunotherapy uses drugs or other methods to allow your immune system to fight cancer. There are two main types of immunotherapy: passive and active.

Passive Immunotherapy

Passive immunotherapy uses lab-made antibodies (proteins) to help develop an immune response. This includes monoclonal antibodies (MABs), which can target specific cancer cells.

Another approach is to take lymphocytes from the tumor to create tumor-infiltrating lymphocytes (TILs) in the lab. The TILs are then returned to the body to fight cancer cells.

Active Immunotherapy

Active immunotherapy activates your body’s immune system to fight cancer cells. Cancer cells are examined in the lab to find their antigen, a substance that triggers an immune response. Active immunotherapies stimulate your own immune system to target these specific antigens.

Cancer vaccines are an example of active immunotherapy. These boost the immune system's ability to destroy cancer-specific antigens.

Immune checkpoint inhibitors are another example. These drugs work by acting on checkpoint proteins, which are located on immune cells.

Normally, the checkpoint stops the immune cell from attacking other cells when it binds to another specific protein. Checkpoint inhibitors can block the binding process to improve the body’s immune response to cancer cells.

They may be different depending on the type of cancer:

• Breast: There are several FDA-approved immunotherapy treatments for breast cancer. These include targeted immunotherapies and immune checkpoint inhibitors.
• Colorectal: Checkpoint inhibitors can be used when the tumor has certain gene mutations.
• Lung: Checkpoint inhibitors are used in some cases of non-small cell lung cancer (NSCLC).
• Prostate: Immunotherapies for prostate cancer include vaccines and checkpoint inhibitors.

Hormonal Therapy

Both breast and prostate cancer cells use hormones to grow. Hormone therapy can be used to decrease the size of a tumor prior to surgery. It can also improve chances of remission and kill cancer cells that have returned.

There are two main kinds of hormonal therapies. One blocks hormone production and the other modifies hormone behavior.

Hormonal therapy works differently for breast and prostate cancer.

Breast Cancer Hormone Therapy

Both estrogen and progesterone may cause the growth of some breast cancer cells. Breast cancer cells that are sensitive to hormones have proteins called hormone receptors. These receptors become activated when hormones bind to them.

Hormone therapy for breast cancer can only be used in cases of disease involving hormone receptors. Treatments can include blocking estrogen production and/or ovarian function.

Other treatments involve blocking the effects of estrogen, such as anti-estrogen drugs.

Prostate Cancer Hormone Therapy

Hormone therapy for prostate cancer may include lowering androgen levels through androgen-deprivation therapy. The goal is to keep androgen from stimulating prostate cells to grow.

It may also include drugs that lower the testosterone produced by testicles. 

Summary

Adenocarcinoma can affect glands and glandular tissue in many different parts of the body, including the breasts, lungs, colon, pancreas, and prostate. Some symptoms may present early, while other cases may not have symptoms or signs until the cancer is advanced.

It's not usually clear what causes adenocarcinomas, but there are risk factors that can increase the chance of having it. Smoking is a risk factor that's associated with most adenocarcinomas.

Regular tests like mammograms and colonoscopies can help detect adenocarcinomas. A biopsy is needed to confirm it, and treatment depends on the type of cancer.

A Word From Verywell

When you're dealing with adenocarcinoma, it can be hard to absorb information about your diagnosis and treatment.

Ask if a family member or friend can be a second set of ears for you at appointments and have open conversations with your healthcare provider. They can provide the answers you need and give you advice on where to get additional support.