Lung cancer screening key to early detection, curative treatment needed
When lung cancer is found early, the odds of successful treatment and survival are higher. However, in the early stages of lung cancer, symptoms are not always apparent, making diagnosis difficult and often delayed.
Healio spoke with Douglas Arenberg, MD, professor of internal medicine at Michigan Medicine, about lung cancer identification methods and how to overcome the difficulties of early detection.
Why is early detection of lung cancer so important?
Arenberg: The term early detection is so widely used and is greatly misunderstood. In the context of screening, it means detecting cancer at a point in time when treatment is more likely to result in a long-term cure. This usually means when it is surgically resectable lung cancer. “Early detection,” by itself, is meaningless unless it is also accompanied by a curative treatment. It also means that the disease itself must have been potentially fatal to begin with. There are many instances of “early detection” of disease that would never have been symptomatic or cause harm. This is referred to as “overdiagnosis” and though the precise rate of overdiagnosis in cancer is unknown, it is not zero. But to answer your question, most cancers are easier to cure before they have spread to lymph nodes, or to other parts of the body. Screening is a way of achieving this goal.
What approaches can physicians use to detect lung cancer?
Arenberg: Right now, for people who are asymptomatic, lung cancer screening is the best way to detect cancer when it is most likely to be curable. For people who are symptomatic, or for people who have symptoms suspicious of lung cancer, a simple chest X-ray may be sufficient, but for lung cancer screening, which is for people who have no symptoms, and who are at high risk, a CT scan of the chest is the appropriate test.
What does current research suggest about machine learning to identify lung cancer early?
Arenberg: Machine learning is best thought of as a way of complementing, not replacing the work of a trained thoracic radiologist in interpreting a chest CT scan. Machine learning can “suggest” abnormalities that a radiologist may overlook, but many of these will simply be “false positives” that the radiologist can cross off their list. Sometimes, however, machine learning tools can offer the radiologist a “safety net.”
What may prohibit early detection of lung cancer? How can these obstacles be addressed?
Arenberg: Lung cancer, probably more so than any other cancer, typically causes no symptoms until it has progressed. The biggest hindrance to early detection of lung cancer is the fact that the lungs are an organ with an enormous amount of built in reserve, such that symptoms rarely offer an opportunity for early diagnosis. The best way to overcome this is to find people who are at the highest risk and offer them lung cancer screening when they are asymptomatic. It must be said that no screening test – and this includes lung cancer screening – is capable of or intended to detect all cases of cancer. Screening is simply a way of reducing, not eliminating, the number of people who die of cancer.
Are there any new or promising identification methods on the horizon?
Arenberg: One of the biggest advances we are working on is the ability to use biomarkers, typically blood tests, but it could be a breath test, or brushing of the nasal lining, or airway lining, as a tool to “rule out” lung cancer. Numerous clinical trials are ongoing in search of the ideal biomarker for this purpose.
What are the goals for the future of lung cancer detection and treatment?
Arenberg: While many people bristle at the mention of tobacco because most lung cancer advocates are people who got lung cancer in spite of never smoking, the best way to reduce overall mortality from lung cancer is to completely eliminate combustible tobacco smoking. This is, and always has been the truth. It will not completely eliminate lung cancer, but will greatly reduce it, to a degree that we cannot currently achieve through any other means. This is a long-term goal, but it should be our goal, nonetheless. In the short-term, developing better treatments, and identifying potential blood biomarkers will also go a long way toward achieving this goal.
References:
- American Cancer Society. Can Lung Cancer Be Found Early? Available at: https://www.cancer.org/cancer/lung-cancer/detection-diagnosis-staging/detection.html. Accessed May 18, 2020.
- Lung Cancer Foundation of America. How to detect lung cancer: Early detection and beyond. Available at: https://lcfamerica.org/lung-cancer-info/detect-lung-cancer/. Accessed May 18, 2020.
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