Difference Between Malignant Mesothelioma and  Adenocarcinoma

Quick Summary

Adenocarcinoma and mesothelioma often present in the lungs. Mesothelioma is described as a workplace cancer while adenocarcinoma can present throughout the body as well as in the lungs.

Mesothelioma vs. Adenocarcinoma Overview

Mesothelioma is caused by asbestos fibers entering the body by air or orally. After entering the body, these fibers become trapped in organ tissue and are almost impossible to remove naturally. Once inside the body, the fibers cause cellular changes which include genetic damage, scarring and inflammation that can lead to cancer which is often diagnosed 10 to 50 years later.

Adenocarcinoma is a subtype of non-small cell lung cancer (NSCLC). It usually begins to form in the cells in the glands, which are found in the lungs and some other internal organs. Generally located along the outer edges of the lungs, adenocarcinoma also tends to develop in smaller airways like the bronchioles.

Adenocarcinoma commonly forms in areas such as the:

  • Lungs
  • Prostate
  • Pancreas
  • Breast
  • Colon

It is worth noting that only adenocarcinoma which begins in the lungs is considered lung cancer, which makes up about 40% of all lung cancers.   Found more often in women, adenocarcinomas comprise most cases of lung cancer in people that have never smoked. In all cases, smoking is the first thing to quit for every patient if applicable, as studies show that smokers that quit tend to have a better outcome after diagnosis than those that don’t.

Differences Between Mesothelioma and Adenocarcinoma

When looking at the cell formations during tests, scans, and under microscopes, two primary distinctions allow a proper diagnosis. Lung cancer typically grows with defined boundaries in individual masses. Mesothelioma originally starts as small nodule tumors scattered in the mesothelial lining. Eventually, they grow together to form a sheath-like tumor surrounding the lung or other organs.

While lung cancer is only present in the lung area itself, mesothelioma can present itself in the linings of the lungs, heart, abdomen and testes.

Mesothelioma under an MRI scan reveals diseased tissue (tumors) through the rate of energy release. MRI scans align the water molecules in a person’s body with a magnetic field which are disrupted by a second radio frequency electromagnetic field to encourage the protons to release energy that is detected by the scanner. Additional magnetic fields can be utilized in the scan to capture images of the tumor to recognize which form of cancer is present and how far it has spread.

X-rays are also an excellent diagnostic tool for physicians, except for early stages of mesothelioma. By analyzing the soft tissue lining the chest cavity, the distinction can be seen for lung cancer, pneumonia, or mesothelioma (in later stages). CT scans form a three-dimensional image of the lungs to determine bone, fat, tissue and fluid. This process allows a proper diagnosis to differentiate between lung cancer and mesothelioma

Adenocarcinoma also presents itself as nodules in glands throughout the body when not present in the lungs. The tests and method of diagnosis already mentioned are valid forms of diagnosing adenocarcinoma in areas outside of the lungs as well, though being present in the lungs is much more likely.

What is Adenocarcinoma?

Non-small cell lung cancer makes up 80 to 85% of all lung cancer, which is caused by cells becoming abnormal and growing out of control in the lungs to form a tumor that will spread to other areas of the body. Found mainly in the outer parts of the lung, adenocarcinoma starts in early versions of cells that normally secrete substances such as mucus.

Lung adenocarcinoma makes up about 40% of all lung cancer cases and typically grows slower than other kinds of lung cancer.

Mainly occurring in former or current smokers, adenocarcinoma is also the most common type of lung cancer reported in non-smokers. More often found in younger people than other types of cancer, it is also more common in women. Adenocarcinoma grows slower than any other type of lung cancer and is, in turn, more likely to be found before it’s spread.

It is important to start a conversation with your doctor about adenocarcinoma, treatment options, and survival rates since these all vary from patient to patient based on a variety of factors including:

  • Histology (what the cells look like under a microscope)
  • Biomarker profiles (the mutations/characteristics in cancer that allow it to grow)
  • Stage of cancer
  • Location of the tumor(s)
  • Medical history
  • Symptoms
  • Test results

Diagnosing Mesothelioma vs Adenocarcinoma

A mesothelioma diagnosis can be confused with lung cancer, as they have similar sets of symptoms. A history of asbestos exposure is a huge indicator for doctors to look for mesothelioma traits. Most often, doctors identify mesothelioma because of other problems the diseases cause.

Early warning signs include:

  • A cough that doesn’t go away
  • Shortness of breath
  • Blood in mucus that is coughed up from the lungs
  • Swelling of the face or neck veins
  • Tiredness
  • Trouble breathing or swallowing
  • Unexplained loss of appetite or weight loss

During the examination, doctors review medical history and genetics to figure out if more tests should be ordered and deciphered by specialists.

Imaging tests for mesothelioma diagnosis can involve:

  • X-rays
  • Computed tomography (CT/CAT scan)
  • Magnetic resonance imaging (MRI) scan
  • Positron emission tomography (PET) scan
  • Bone scan

Other lab tests, including biopsies and blood tests, take cells from the lung to determine the diagnosis by scrutiny under a microscope. While looking at the images from all scans and tests, mesothelioma specialists will rule out the possibility of lung cancer in cell growth if a history of asbestos exposure is present by the growth pattern of the cells.

Symptoms of adenocarcinoma vary depending on the location of the tumor. Doctors looking for the cause of these symptoms will order imaging tests like CT and MRI scans.

Symptoms of adenocarcinoma may include:

  • Coughing up blood or a cough that won’t go away
  • Wheezing or a hoarse voice
  • Shortness of breath and trouble breathing
  • Frequent respiratory tract infections, including bronchitis or pneumonia
  • A pain or ache in the chest, shoulder, or upper back that won’t go away and may get worse with deep breathing
  • Swelling of the veins in the neck and/or the face
  • Trouble swallowing
  • Unexplained weight loss and loss of appetite
  • Unusual fatigue

Small cell lung cancer patients (including adenocarcinoma patients) may present unique symptoms because of the tumors involved in this diagnosis secrete hormones. For example, inappropriate hormone secretion of anti-diuretics could cause low blood sodium levels.  Symptoms caused by this hormone secretion are called paraneoplastic syndromes.

Treating Mesothelioma vs Adenocarcinoma

Mesothelioma is incurable, and treatments for this disease are based on improving the quality of life for each patient and removing as much of the tumors as possible for longer odds of survival. Most often, more than one form of treatment will be used based on the stage of the cancerous growth, lung function, a person’s overall health, and specific traits of the subtype of cancer. The order of treatments provided is also determined by these factors.

Options for mesothelioma treatment based on specialist recommendations could include:

  • Radiation therapy: External and internal forms of radiation therapy can be used to treat, shrink or relieve symptoms.
  • Chemotherapy: Drugs that are provided by vein or orally to attack the cancerous cells through the bloodstream to reach cancer anywhere in the body.
  • Surgery: Utilizing surgery to remove cancer or as much of the cancerous growth as possible, depending on the stage presenting.
  • Palliative treatments: Methods that can also be used to help improve quality of life and relieve symptoms.

There are two main types of treatment options for adenocarcinoma:

  • FDA approved
  • Clinical trials

Approved treatments by the FDA include:

  • Immunotherapy: Works to strengthen the immune system’s ability to fight cancer by training it to recognize cancer cells selectively and kill them.
  • Targeted therapy: A type of therapy that targets cancer cells directly by focusing on the signals and certain parts of cells that cause cancer cells to thrive and grow.
  • Surgery: Utilizing surgery to remove cancer, or as much of the cancerous growth as possible, depending on the stage presenting.
  • Radiation therapy: High-powered energy beams that kill cancer cells. This can be given as the main treatment during early-stage lung adenocarcinoma.
  • Chemotherapy: Anti-cancer drugs given to patients usually in combination with radiation therapy or other drugs for treatment.
  • Angiogenesis inhibitors: Angiogenesis is the process of making new blood vessels to supply the cells with blood as the body grows and develops. This process feeds cancer cells and helps them to spread and grow. Angiogenesis inhibitors help to slow or stop the growth and spread of tumors by stopping the body from making new blood vessels.

Side effects of treatment are common and can be long-term or temporary. Before starting a new treatment, speak to your doctor about what to expect, how to manage certain side effects, and which side effects should be reported immediately.

Getting a Second Opinion on Mesothelioma vs Adenocarcinoma

Of the several subtypes of mesothelioma, some resemble lung cancer strongly, while others in women look like ovarian cancer. For this reason, a second opinion on a diagnosis is extremely valuable, as general prognosis drops the longer it takes to make an accurate diagnosis. Once a diagnosis is decided on for either mesothelioma or lung cancer, a subtype can be determined to help determine the best route and options for treatment.

Pathology reports and lab results for the diagnosis of lung cancer should be delivered to other pathologists at different labs for a second opinion. Diagnosing mesothelioma, even in a lab looking at samples from fluid tests, is extremely difficult as cells often resemble other forms of cancer.

Before undergoing treatment for mesothelioma, getting a second opinion and advice on treatment options may assist in making sure each treatment recommendation is the best course of action and that any breakthroughs in clinical trials will or will not influence treatment recommendations.

For more information on seeking a second opinion on your diagnosis, contact Mesothelioma Help Now today to speak to our Patient Advocates.

View Author and Sources

  1. Lungevity, “Lung Adenocarcinoma.” Retrieved from: https://www.lungevity.org/for-patients-caregivers/lung-cancer-101/types-of-lung-cancer/lung-adenocarcinoma Accessed February 11, 2018.
  2. UPMC, “Adenocarcinoma.” Retrieved from: http://www.upmc.com/services/neurosurgery/brain/conditions/brain-tumors/pages/adenocarcinoma.aspx Accessed February 11, 2018.
  3. American Cancer Society, “What is Non-Small Cell Lung Cancer?” Retrieved from: https://www.cancer.org/cancer/non-small-cell-lung-cancer/about/what-is-non-small-cell-lung-cancer.html Accessed February 12, 2018.
  4. Lungevity, “Signs & Symptoms.” Retrieved from: https://www.lungevity.org/for-patients-caregivers/lung-cancer-101/signs-symptoms Accessed February 12, 2018.

Last modified: March 2, 2018