45-year-Old Dad, a Passionate Mountain Biker Who Never Smoked, Diagnosed With Lung Cancer. His Only Symptom Was Pain & Swelling In His Calf

“RET-positive cancer is caused by a mutation or abnormal re-arrangement of the RET gene. It occurs most commonly in lung cancer and several types of inherited and sporadic thyroid cancers,” the RETpositive nonprofit explains. “RET alterations also occur in an estimated 1-2% of multiple other cancers, including ovarian, pancreatic, salivary, breast, and colorectal cancers.”

Dunbar admitted in a video interview, shared on YouTube and social media last year, that he had so many “questions” as to why he was diagnosed with lung cancer as he considered himself extremely health.

It’s unfortunate that his cancer ultimately spread to his” brain, liver, bones and lymph nodes near his heart,” however, despite his doctors informing him he had only a 5% chance of living more than five years after his diagnosis, he maintains a positive outlook.

“I thought, ‘Hey, you know what? Freaking five percent, I’ll take those odds,'” he tells RETpositive.

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Looking back on when he was diagnosed, Dunbar recounted thinking, “No way I’ve got lung cancer. I was doing 3,000 miles on my mountain bike every season and my lungs were probably the healthiest piece of me.

“It was surreal, it was denial, it was … p**sed off, I’d get mad. Lot of questions on how, why … why me.”

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He continued, “In between that time of finding out it was cancer, we did a gene-type test and by the time I started chemotherapy and radiation, we’d found out that my gene type was the RET fusion.”

After undergoing targeted therapy for about six weeks, he said his scans showed “big improvement,” until months later when he learned that he had a “passenger mutation growing in his brain and liver.”

However, he decided to stop having a “pity party” and is embracing the challenges he must face and enjoying his time with his two sons and wife.

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“We’re going to recognize the kindness and compassion that people have shown to us. The support is huge, it’s what allows me to endure through this and that support allows me to have the strength to keep going. Every day is a battle,” he continued.

“I just hang on for one more today because there’s new stuff coming all the time .. I hope one day we can see cancer knocked out for good.”

Further expressing his gratitude and hope for the future, he hopes his story will help spread awareness for the disease and lead to more research being done into new treatment methods.

Understanding Genetic Testing

Genetic testing of lung cancer helps to guide treatment decisions. Specifically, there are targeted therapy options available if a patient has certain genetic biomarkers, sometimes called “driver mutations.”

Cancer cells that have genetic mutations continue to multiply, and each copy contains the same genetic mutation. Targeted therapies work using these specific mutations. Performing genetic testing prior to treatment is critical. Common mutations that have approved drugs include:

• EGFR gene mutation
• KRAS gene mutation
• ALK rearrangement
• ROS1 rearrangement
• NTRK gene fusion
• BRAF V600E Mutation
• ERBB2 mutation
• RET rearrangement
• METex14 mutation

According to the American Lung Association (ALA), an error in the RET gene, like Dunbar has (a RET gene fusion), is one type of lung cancer biomarker.

The ALA explains, “There are two main types of errors in the RET gene. One type is called RET point mutations. You can think of that as places where the DNA is misspelled. These mutations are often found in medullary thyroid cancer and not lung cancer.

“The other type is called RET rearrangements, or gene fusions. That is when a piece of DNA joins with another gene and creates a ‘fusion.’ This fusion leads to uncontrolled cell growth and cancer. This is the most common RET gene error in lung cancer.”

As per the ALA, there are a variety of RET rearrangements and “the type depends on which gene is fused together with RET.” The most common fusion partners are genes KIF5b, CCDC6 and NCOA4 .

Cancerous cells can be tested for these genetic mutations using two techniques. The first is a biopsy in which a physical sample of the tumor is removed and tested.

The second method is through a liquid biopsy or blood test. Liquid biopsies are currently only used when tissue can’t be obtained from traditional biopsies.

Next-Generation Sequencing (NGS): A Tool For Oncologists

It is critical that these genetic mutations and biomarkers are evaluated because the use of targeted therapies is possible; these medications have proven to be more effective than traditional chemotherapy and often have fewer or more tolerable side effects. They also have better side effects profiles because the tumor is specifically targeted, and healthy tissue is not damaged.

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Understanding Lung Cancer

Lung cancer forms when cancer cells develop in the tissues of the lung. It is the second most common form of cancer and the leading cause of cancer deaths in both men and women in the U.S., SurvivorNet experts say. It’s “completely asymptomatic,” thoracic surgeon-in-chief at Temple University Health System Dr. Joseph Friedberg, told SurvivorNet in an earlier interview.

“It causes no issues until it has spread somewhere. So, if it spreads to the bones, it may cause pain. If it spreads to the brain, it may cause something not subtle, like a seizure,” Dr. Friedberg adds.

WATCH: Detecting lung cancer in the absence of symptoms.

Scans such as X-rays can help doctors determine if a shadow appears, which can prompt further testing for lung cancer.

Lung cancer often doesn’t cause symptoms until it has already spread outside the lungs, according to SurvivorNet’s experts.

There are two main types of lung cancer, which doctors group together based on how they act and how they’re treated:

• Non-small cell lung cancer (NSCLC) is the most common type and makes up about 85% of cases.
• Small cell lung cancer (SCLC) is less common, but it tends to grow faster than NSCLC and is treated very differently.

Metastatic cancer means that the disease has spread to distant parts of the body. We understand this diagnosis can be really intimidating, but treatment options are ever-evolving.

Some people with lung cancer may experience symptoms such as:

• A cough that doesn’t go away, that gets worse, or that brings up bloody phlegm
• Shortness of breath
• Fatigue
• Chest pain
• Hoarse voice
• Appetite loss
• Weight loss

If you are experiencing these kinds of symptoms consistently, contact your doctor for further tests.

Smoking and Lung Cancer Risk

Lung cancer is the leading cause of cancer deaths for men and women in the United States. Nonsmokers still get lung cancer, but cigarette smoking is the number one risk factor for the disease. Tobacco smoke contains a mixture of more than 7,000 different chemicals, at least 70 of which are known to cause cancer, the Centers for Disease Control and Prevention (CDC) says.

The CDC says cigarette smoking is linked to about 80 to 90 percent of lung cancer deaths, and people who smoke cigarettes are 15 to 30 times more likely to get lung cancer or die from lung cancer than people who don’t smoke. Additionally, second-hand smoke can cause lung cancer.

Former & Current Heavy Smokers Should Get Lung Cancer Screenings Using CT Scan, Says Leading Expert

Smoking is, of course, the primary cause of lung cancer, but nonsmokers, like Chad Dunbar, can and do develop this disease.

Researchers have made progress in understanding the differences between lung cancer in smokers versus nonsmokers, says Dr. Ronald Natale, a medical oncologist at Cedars-Sinai Medical Center, and they’re developing targeted treatments that will be able to address the genetic drivers of lung cancer in nonsmokers.

“Among patients who are nonsmokers, or former very light smokers, we identify a mutation that we can target with pills in about 60% to 70% of them. That leaves 30% or so, 40%, in whom we either have a target for which we do not have successful treatment,” Dr. Ronald Natale, a medical oncologist at Cedars-Sinai Medical Center, tells SurvivorNet.

“Among patients who are smokers, who have more complex cancers that have hundreds, sometimes thousands of mutations, don’t have a driver mutation that we can give a pill for, which is only a tiny percentage of lifelong smokers. Chemotherapy is the primary treatment in most patients,” Dr. Natale explains further.

Understanding the treatment options for lung cancer

Navigating Clinical Trials

Clinical trials can be an option for people with cancer at many points during the treatment process. Your doctor may have spoken with you about possibly enrolling in a trial if you have advanced disease or if there’s a drug that’s currently considered investigational that may work better than the standard for you.

Clinical Trials Give Hope

A lot of patients may feel uncomfortable about the thought of participating in a trial, but the trials can provide amazing opportunities for patients. For one thing, they give patients access to a bevy of new drugs that are currently being developed by pharmaceutical companies.

Things to Consider

In the U.S., all new drugs have to go through clinical trials before the Food and Drug Administration (FDA) will approve them. In addition to being potentially live-saving for patients, these trials are also necessary to advance science and cancer treatments.

However, participating in a trial comes with risks as well, and it’s important to talk to your doctor about this before getting involved in one. Some risks to consider are:

• The risk of harm and/or side effects due to experimental treatments
• Researchers may be unaware of some potential side effects for experimental treatments
• The treatment may not work for you, even if it has worked for others

Still, joining a clinical trial comes with benefits as well. You will be given access to treatments that could be life-saving, but simply haven’t made it through the approval process yet.

If you’re looking for a clinical trial, SurvivorNet can help. Check out SurvivorNet’s Clinical Trial Finder.

Contributing: SurvivorNet Staff

Learn more about SurvivorNet's rigorous medical review process.

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