Primary and secondary prevention of lung cancer
HMP Education
Thank you Georgia and thank you Lewis. It's a pleasure to have you both here. Good morning. I am glad that you have joined the primary prevention with early detection. Today, early detection and screening for lung cancer are very popular. However, we must consider the frequency of each option and their possible combinations. In the United States and Europe, there has been a decline in lung cancer mortality since the 70s and 80s. This decline has been parallel to a decrease in tobacco consumption. There is no reason why this decline should not continue until lung cancer mortality reaches zero. Unfortunately, in most countries, preventive measures have stopped once a certain level of current smokers is reached (around twenty percent). I disagree with this approach. We need to continue fighting against tobacco use and reduce the proportion of smokers. It is not acceptable that the number of female smokers is increasing. We should not consider this as something inevitable, but rather as a problem that needs to be addressed.
The cure rate for lung cancer has improved over the years. The proportion of survivors at five years has increased from eight to thirteen percent on average in Europe. However, thirteen percent is still a low number. Screening for lung cancer using low-dose CT scans has shown that it can detect lung cancer in about one percent of individuals who undergo screening. The problem is that only a small percentage of positive CT scans (about one in 20-25) actually indicate cancer. This leads to a high number of false positives. The NELSON trial has shown that three rounds of low-dose CT scans can reduce specific and overall mortality. However, the actual benefit is small (about one percent reduction per year) and does not reach statistical significance in some analyses. Nevertheless, further studies are expected to show similar benefits.
To improve the performance of low-dose CT scans, increasing the cutoff size (e.g. using a 6mm diameter instead of 5mm) and using volume measurements instead of diameter can be helpful. Volume measurements are better at assessing growth and suspicious lesions. Additionally, computer-automated reading of CT scans can make the process easier and cheaper. Ultralow CT scans are also showing promising results with better imaging quality and lower radiation doses. However, the proportion of individuals having surgical biopsies for benign diseases is higher when using volume measurements alone, compared to using PET and volume measurements together.
A randomized study has shown that doing low-dose CT scans every other year can yield similar results to yearly scans. This suggests that doing it for a longer period of time is more important than doing it frequently. Minimal invasive approaches are the consequence of early detection. The earlier the cancer is detected, the more options there are for non-invasive surgeries. The use of robots in surgeries is still debatable, as there are advantages to using them but also simpler and cheaper alternatives like the new 3D vas.
The presence of sub-solid lesions in the lungs is an important problem to address to avoid unnecessary surgeries and over-treatment. Active surveillance of these lesions has been implemented and shown to be feasible. The majority of these lesions do not evolve into invasive cancer, but even if they do, they often appear in different positions. Rejecting these non-evolving lesions may compromise the chances of proper surgery for the invasive disease when it occurs. Active surveillance is safe and effective in managing these lesions.
Screening for lung cancer offers a great opportunity for studying its biology and conducting translational research. There are different approaches to biomarker assessment, such as studying cancer antibodies in the blood, proteomics, and microRNA. MicroRNAs are of interest because they are generated by every cell in the body and can provide information about the microenvironment, not just the presence of cancer.
The micro environment can be used to achieve early detection by combining a microarray in the blood with biomarkers. The question of the future is if the diagnosis or high-risk individuals can be anticipated, thereby improving the chances of managing the disease. There is a good prospect for screening as long as a better target in the virus individual is identified and the diagnostic algorithm is improved. Combining early detection with primary prevention is the most important approach, as it can significantly reduce mortality in high-risk individuals.
Quitting smoking after the age of 50 has been shown to significantly reduce mortality, even after 30-40 years of smoking. Adding smoking cessation to screening is not very expensive and can greatly improve quality of life. Inflammation, as measured by C-reactive protein (CRP), is related to mortality in lung cancer and COPD. Combining a high CRP level with poor lung function can define a subset of heavy smokers with a higher risk of dying. CRP levels and inflammation can be modified by drugs such as metformin and statins, which may reduce mortality.
Other modifiable risk factors include diet and physical exercise. Combining early detection with active intervention using drugs, diet, and physical exercise in high-risk individuals with elevated CRP levels is a promising option. Preventive strategies are necessary for sustainable healthcare in an aging population. Stopping smoking is not only feasible with new drugs, but also very useful for individuals after the age of 50. Modifying the inflammatory, metabolic, and immune profile can be a new approach to chemoprevention and can be related to immunotherapy.
In conclusion, if we want to achieve a significant reduction in lung cancer mortality, prevention measures such as stopping smoking and modifying risk factors are crucial. Immune prevention and immunotherapy hold promise for the future of chemoprevention.
