What is carcinoma? Types, causes, symptoms and treatment

If you’ve been diagnosed with cancer, one of the first things you’ll learn is what type of cancer you have. This will help guide your treatment and influence your prognosis.

Carcinoma is the most common type of cancer. It accounts for about 90% of all cancer diagnoses. Most carcinomas are treatable and can potentially be cured when caught early.

Here, I’ll answer common questions about carcinoma, including the different types, symptoms, risk factors and treatment.

What is carcinoma?

Carcinoma is a type of cancer that originates from epithelial cells. These cells are found on your skin and the lining of internal organs, such as your liver, lungs, pancreas and esophagus.

What is the difference between cancer and carcinoma?  

Carcinoma is cancer. It is always malignant. All carcinomas are cancer, but not all cancers are carcinoma.

While carcinoma makes up the bulk of cancer diagnoses, there are three other main types of cancer.

• Sarcoma: This type of cancer develops in your connective or supportive tissue, including muscles, joints, tendons, fat, blood vessels and nerves.
• Leukemia, lymphoma and myeloma: These blood cancers start in blood-forming tissue, such as bone marrow or in the cells of your immune system.
• Melanoma: Melanoma forms in specialized cells called melanocytes, which give your skin its color.

What causes carcinoma?

Epithelial tissue acts as a barrier to help define our organs. Otherwise, everything would just run together. Epithelial cells are constantly dividing, and in order to do so, cells have to replicate themselves. But the quicker that cells divide, the more errors – or mutations – occur.

Think of it this way: If you are trying to copy a 10,000-page book word for word, errors are bound to happen. Our bodies have about 20,000 genes!

Most mutations are silent and don’t cause any harm. But in rare cases, a combination of mutations can occur in vital genes that control cell growth. These mutations can make a gene lose its normal function or gain a new one. Either way, they can cause an epithelial cell to divide uncontrollably, which leads to carcinoma.

What are the types of carcinoma?

There are several different types of carcinoma. They are often classified into three subtypes.

Adenocarcinoma

This type of carcinoma develops in the glandular tissue lining your organs. Glandular epithelial cells secrete or release fluids. The most common types of adenocarcinoma include:

• Breast cancer: Almost all breast cancers are adenocarcinomas. They begin in the terminal ductal lobular units inside the breast lobes, then travel through the milk ducts.
• Prostate cancer: Nearly all prostate cancers are adenocarcinomas that form in the prostate gland.
• Pancreatic cancer: Most pancreatic cancers are adenocarcinomas that start in the lining of the pancreatic ducts.
• Colorectal cancer: Adenocarcinoma is the most common type of colorectal cancer. It develops when precancerous polyps lining the colon or rectum turn into cancer.
• Lung cancer: Non-small cell lung cancer (NSCLC) makes up about 85% of all lung cancer cases. Adenocarcinoma is the most common subtype of NSCLC.
• Stomach cancer: Most stomach cancers are adenocarcinomas. They develop in the stomach’s mucus-producing inner layer.
• Esophageal cancer: Esophageal adenocarcinoma develops from glandular cells in the lower part of the esophagus, often in people with Barrett’s esophagus. 

Squamous cell carcinoma

This type of carcinoma forms in squamous cells. Squamous cells line the surface of your skin, as well as other parts of the body, including the lining of your mouth, throat, esophagus, anus and cervix.

Squamous cell carcinoma is most commonly found on the skin. It is the second most common skin cancer.

Squamous cell carcinoma is also the most common type of anal cancer, cervical cancer and oral cancer.  

Basal cell carcinoma

This type of cancer forms from basal cells, which are found at the base of the epidermis. Basal cell carcinoma is the most common type of skin cancer.

Other types of carcinoma

Other common types of carcinoma include:

• Renal cell carcinoma: This is the most common type of kidney cancer. It starts in the lining of microscopic tubules inside the kidney.
• Hepatocellular carcinoma: This is the most common type of primary liver cancer. It develops in the liver’s hepatocyte cells.

What are the risk factors for carcinoma?

Anyone can develop carcinoma. Having one or more of the risk factors below does not mean you’ll get carcinoma, but you will have a greater chance of developing it.

• Age: As you get older, your risk increases for several cancers, including breast cancer, prostate cancer and skin cancer.
• Family history: Your cancer risk increases if you have several first- or second-degree relatives with cancer.
• Hereditary genetic mutations: Certain genetic mutations can be passed from a parent to a child. One example is the BRCA mutation, which increases the risk of breast cancer and pancreatic cancer in males and females, ovarian cancer in females and prostate cancer in males.
• Ultraviolet (UV) radiation: Extensive sun exposure or occasional intense exposure can put you at greater risk for developing skin cancers like basal cell carcinoma and squamous cell carcinoma of the skin.
• Tobacco use: Smoking is the biggest risk factor for lung cancer. Using tobacco in any form increases your risk for several other cancers, including kidney cancer, oral cancer, esophageal cancer, bladder cancer and pancreatic cancer.
• Alcohol use: Drinking even a small amount of alcohol increases your risk for developing cancer, including breast cancer, colorectal cancer, esophageal cancer, liver cancer, oral cancer and stomach cancer.
• HPV infection: A human papillomavirus (HPV) infection can increase your risk for several cancers, including cervical cancer, anal cancer and throat cancer.
• Processed meat: Eating processed meat, such as deli meats, hot dogs and bacon, has been linked to colorectal cancer.
• H. pylori infection: Helicobacter pylori (H. pylori) infection can cause chronic inflammation in the stomach lining. When left untreated, over time, this can increase your risk of stomach cancer.

How does carcinoma spread?

As cancer cells grow and multiply, they can spread away from the original tumor site. Aggressive cancers tend to grow and spread more quickly than other cancers. For example, triple-negative breast cancer is an aggressive type of carcinoma that grows quickly and has a high rate of recurrence.

Carcinomas can be categorized based on how they spread. How quickly they spread varies, depending on the type of carcinoma and its stage.

Carcinoma in situ

Epithelial cells sit on a thin layer of tissue called the basement membrane. Think of it as a fence that keeps the cells in place. Carcinoma in situ describes abnormal cells that have not grown through the basement membrane. So, it is contained within that fence.

Carcinoma in situ is also called stage 0 cancer. For example, ductal carcinoma in situ (DCIS) is stage 0 breast cancer.  

Invasive (infiltrating) carcinoma

Invasive – also called infiltrating – carcinoma describes cancer that has escaped the fence and spread to nearby or surrounding tissue. This cancer is often staged as 1, 2 or 3. The higher the stage number, the more it has spread.

Metastatic carcinoma

Metastatic carcinoma describes cancer that has spread to distant parts of the body. This is called stage 4 cancer.

What are the symptoms of carcinoma?

The symptoms of carcinoma vary, depending on where the cancer starts. Some people have symptoms, while others may not notice any signs until the cancer is found during screening or testing for another reason.

Here are some common carcinoma symptoms based on where the cancer is in the body.

• Breast: A new lump in your breast or armpit; breast skin changes such as redness or thickening of the skin
• Prostate: Blood in your urine and other urine changes, including difficulty urinating, frequent urination or a weak urine stream
• Pancreas: Abdominal pain, digestive problems, jaundice (yellowing of your skin or eyes) or unintentional weight loss
• Colon/rectum: Blood in your stool, change in bowel habits, such as the size, shape and frequency
• Lung: Persistent cough, shortness of breath, wheezing, coughing up blood or mucus
• Stomach: Persistent indigestion, feeling full after eating a small amount, bloating or swelling in the abdomen
• Esophagus: Pain when swallowing, burning in the chest or throat
• Skin: A new growth on your skin, a sore that doesn’t heal, a shiny or scaly spot on the skin or moles that change in size, shape or color
• Kidney: Blood in your urine, unintentional weight loss
• Liver: Unintentional weight loss, swelling or bloating in the abdomen or jaundice

See your doctor if you notice any of the above symptoms, so they can evaluate you and get you started on treatment if necessary.

How is carcinoma diagnosed?

Your doctor will go over your medical history and conduct a physical exam. Then, you may have one or more of the following tests to help diagnose carcinoma.

Blood tests

Blood tests can check for things like certain proteins or tumor markers that may indicate cancer.

Imaging

Imaging tests like CT scans, MRIs, PET scans and ultrasounds provide doctors with detailed internal pictures of your body and its structures.

Biopsy

During a biopsy, a small tissue sample is removed and examined under a microscope for cancer cells. A biopsy is the only definitive way to confirm a carcinoma diagnosis.

How is carcinoma treated?

Treatment for carcinoma depends on many factors, such as the cancer’s stage, extent of spread and your overall health. Your doctor will develop a treatment plan that is best for you.

Your treatment plan may include one or more of the following:

• Surgery to remove the tumor and cancerous tissue. Many carcinomas that have not spread beyond the original tumor site, like carcinoma in situ, can be cured by surgery alone.
• Radiation therapy, which uses focused, high-energy beams to destroy cancer cells.
• Systemic therapies treat the whole body rather than just focusing on a specific area. Systemic therapies include chemotherapy, immunotherapy, targeted therapy and hormone therapy.
• Supportive care focuses on improving your quality of life by helping you manage physical symptoms, side effects and/or psychological distress from cancer or its treatment.
• Clinical trials test new treatments for cancer. Talk to your doctor to see if you are eligible for any clinical trials.

Is carcinoma a serious cancer?

Carcinoma can be serious, but every diagnosis is different.

In the U.S., aside from skin cancer, the most common carcinomas are prostate cancer in males and breast cancer in females. Lung cancer is the second most common carcinoma in both groups.

Lung cancer causes more cancer-related deaths than any other type of carcinoma. However, outcomes continue to improve, thanks to advances in screening and treatments that are helping many patients live longer. 

Remember: your prognosis depends on many factors, including the cancer’s stage, type, location, your overall health and even where you go first for treatment. Talk to your doctor about what your diagnosis means for you.

Can carcinoma be cured?

Yes, most carcinomas can be cured, especially when they’re found early and treated before they spread. At UT MD Anderson, advances in screening and treatment options continue to improve outcomes for patients each year.

What can I do to prevent carcinoma?

Anyone can get cancer. There’s nothing you can do to truly prevent cancer, but there are things you can do to lower your risk.

• Tobacco control: If you don’t use tobacco, don’t start. If you use any kind of tobacco, talk to your doctor about resources to help you quit.
• Don’t drink alcohol: For cancer prevention, it’s best not to drink alcohol. If you choose to drink, be aware of the risks, aim to drink less often and have fewer drinks. The less you drink, the lower your cancer risk.
• Eat healthy foods: Aim for a balanced diet that includes vegetables, whole grains, beans, fruit, as well as lean protein. Avoid processed meat and limit added sugar.
• Exercise: Aim for at least 150 minutes of moderate exercise or 75 minutes of vigorous exercise each week.
• Maintain a healthy body weight: Obesity puts you at higher risk for more than 10 cancers. Try to maintain a healthy body weight by staying physically active and controlling your portion sizes.
• Practice skin safety: Protect your skin from harmful UV radiation by using sunscreen and lip balm with SPF 30 or higher and wearing a wide-brimmed hat, protective clothing and UV-protective glasses. Limit time outdoors or seek shade between 10 a.m. and 4 p.m., when the sun’s rays are strongest.
• Get vaccinated: Viruses such as hepatitis B, hepatitis C and HPV can increase your risk for cancer. Vaccines for hepatitis B and HPV can help prevent cancers related to these viruses. There is no vaccine for hepatitis C, but it can be detected with a blood test and cured with antiviral medicine.
• Get screened: Regular cancer screenings can help find cancer early when it’s easier to treat. Some screening exams, like colonoscopy, can find precancerous polyps, and your doctor can remove them before they have the chance to turn into cancer.

Jason Mouabbi, M.D., is a breast medical oncologist at UT MD Anderson.

Request an appointment at UT MD Anderson online or call 1-877-632-6789.