What causes lung cancer? Scientists are working to connect the dots.
For Sharon Fisher, the lung cancer diagnosis came as a gut punch. Scientists are working to identify the cause of lung cancer, which affects approximately 15% of patients who have never smoked. Sharon Fisher was diagnosed with lung cancer at Stage 2 and required a surgical lobectomy, but there was no further evidence of disease. A study by the National Cancer Institute revealed that there were many more female never-smokers contracting this cancer at an earlier age than smokers. The five-year survival rate for stage 2 lung cancer after treatment is only 35%. Most people are unaware of any screening for lung cancer and are unaware there is any screening at all. The smoking history of patients, which equates to 20 years of smoking a pack a day, should be considered significant. If patients are eligible for one scan a year, patients are entitled to one. However, those with family histories are twice as likely to contract the disease.
Pubblicato : 2 anni fa di LESLIE CARDÉ | Contributing writer in Health
For Sharon Fisher, the lung cancer diagnosis came as a gut punch. A simple cold had turned into a lingering feeling of congestion, with a dry cough. Eventually diagnosed with pneumonia, a closer look revealed a lesion in the left lobe of her lung. But lung cancer was something she couldn’t imagine. After all, she’d never been a smoker, was an avid hiker, was still the same weight she’d been since high school, had no history of illnesses, and was a foodie who ate no processed foods and cooked healthy meals for herself, in spite of her hectic work schedule. What most people do not realize is that in approximately 15% of lung cancer diagnoses, the patient has never smoked. And, they had no exposure to known carcinogens. While this fact has baffled the medical community, further exploration revealed that there were many more female never-smokers (as they are referred to) who were contracting this cancer, and at an earlier age, than smokers.
Analyzing the tumors of these never-smokers, a study by the National Cancer Institute revealed that there was an accumulation of genetic mutations within this group. Scientists are still trying to connect the dots to figure out what exposures may have added to the risk. For patient Fisher, the lung cancer was already Stage 2 at diagnosis, and required a surgical lobectomy, wherein one of the five lobes of her lungs was removed. After chemotherapy there was no further evidence of disease. But, the five-year survival rate for stage 2 lung cancer, after treatment, is only 35%. Over the next few years, Fisher’s tumors would return in other areas of her lungs, and despite being a part of clinical trials for her specific cancer mutations and receiving various forms of immunotherapy and targeted treatments, she died of the disease four years later. She was 70 when she passed away, in 2019.
“This is why it is so important to catch lung cancer in its earliest stages,” said Ramsy Abdelghani, M.D., Tulane’s Director of Interventional Pulmonology. “At stage 1, your 5-year survival rate is 95%. But, in Louisiana, 80% of those diagnosed are either stage 3 or 4. At these advanced stages, survival rates drop precipitously. At stage 4, you’re looking at a five-year survival rate of 5%. We’re not doing well here with lung cancer screening.” Detecting lung cancer early is easier said than done, and in fact, most people are unaware there is any screening at all for lung cancer. To receive the low-dose CT scan (10% of the normal radiation) that can detect the earliest of lung cancers, one must meet certain criteria. Patients must be between the ages of 50 and 80, either be a current smoker, or someone who has quit in the last 15 years.
And, the smoking history must be significant — that equates to 20 years of smoking a pack a day, or 10 years of smoking two packs a day. If these criteria are met, patients are entitled to one scan a year, covered by insurance. But, those who have family histories of lung cancer should certainly be in that mix, as they are twice as likely to contract the disease. Sadly, there are no signs or symptoms in the earliest of stages, so screening is vital. Finding these cancers at stage 2 means there can still be microscopic areas of disease that are present even after surgery, but are not always detectable. The key is to know your family history, honestly discuss your smoking history with your primary care physician, and take advantage of the ability to screen for this deadly disease. Abdelghany is meeting with primary care physicians to ensure that patients’ histories are triggering notifications that will lead to early screening.
Even if you’re not a smoker, exposure to radon is the second leading cause of lung cancer. It is a colorless, odorless, radioactive gas that is often found in soil and water. Although radon decays quickly, it gives off tiny radioactive particles which can leach into buildings and homes and be inhaled. When that happens, it damages the cells that line the lungs. Long-term exposure can lead to lung cancer. According to the National Cancer Institute, it is the only cancer proven to be associated with inhaling radon. Diagnosis for lung cancer has become far more sophisticated of late. Biopsies are less invasive and pinpointing the exact location of a tumor has become far more accurate. “I do robotic bronchoscopies by navigating an endoscope through the intricate branches of the bronchi, then do intraoperative imaging to confirm my location,” Abdelghany said. “This is a quick, minimally invasive technique to isolate the lesion, and get it analyzed, so treatment can begin.”
Major strides are being made in treating all types of lung cancer Although not technically lung cancer, mesothelioma is a type of cancer that starts in the membranes that cover the lungs. If you didn’t know much about this disease prior to the barrage of television ads now asking those with the disease to join class-action lawsuits, you have now probably learned that 80% of these cases are caused by exposure to asbestos — much of it from factories. Tiny bundles of asbestos fibers which fly through the air can be inhaled. This causes cell turnover, which leads to cancer. There is a high mortality rate associated with this cancer, as there are no early signs or symptoms that would lead someone to treatment. It is critical that anyone working with asbestos wear a proper mask that filters out all particulate matter.
Major strides have been made over the last decade, relative to all types of lung cancer. Before these new treatments, the only recourse for treating lung cancer was surgery, chemotherapy or radiation. Now, by knowing the exact type of cancer you have and determining what stage it is, along with knowing what factors within the tumor can be targeted, precision medicine can go after specific markers within the tumor. As researchers like to say — it is important to know the enemy, so you can find the right tools to fight it.