Many obstacles stand in the way of current lung cancer detection methods, making it one of the deadliest cancers.
A cancer diagnosis is some of the worst news a patient can receive, but when it’s lung cancer, it becomes downright terrifying. Because it generally fails to exhibit symptoms until late stage, in 75 percent of all lung cancer cases, early detection is rare. Of the 228,000 cases detected annually, only 15 percent will survive five years following a late-stage diagnosis.
The key, then, is reliable methods for early identification. When lung cancer is caught early enough to be localized, survival rates improve dramatically, all the way to a 56 percent survival rate, according to the American Lung Association. Screening of the at-risk population is key to achieving these numbers, but there are obstacles that often prevent that from being the case.
In some ways, this proves ironic, as lung cancer stands ahead of many others in having a well-defined high-risk population. Smoking remains the main cause of both small cell and non-small cell lung cancer, contributing to 80 percent and 90 percent of lung cancer deaths in women and men, respectively. The American Lung Association documented an annual average of more than 130,000 deaths tied to smoking-caused lung cancer between the years of 2005 and 2010.
Screening designed for early detection of a defined high-risk population remains the best method for decreasing this high death rate. In March of 2021, the U.S. Preventive Services Task Force (USPSTF) updated its recommendations on who falls into this population. The new parameters are adults aged 50 to 80 who have a 20-pack year smoking history, and currently smoke, or have quit within the past 15 years. This is a change from the previous (2011) recommendations, which considered the at-risk population to be over the age of 55 with a 30-pack year smoking habit. The change roughly doubles the number of people eligible for screening, which is a positive for catching more cases early on.
The current standard of screening for this high-risk population is an annual scan from a low dose computed tomography (CT) machine. While effective at identifying suspicious nodules within the lung, the screening comes with a fair share of downsides.
The trouble with LDCT
One of the biggest problems with the current screening method is that only about 10 percent of those eligible actually get the screening. Access to low-dose CT is a big issue in rural populations, where smoking rates are disproportionately higher than suburban and urban populations. Lacking proximity to large medical facilities, rural residents—who make up 15 percent U.S. residents–are less likely to make a long drive for preventative screening.
Facing similar issues, the United Kingdom has developed a program to help overcome this barrier, setting up scanning trucks in retail parking lots in 10 rural areas across the country. Those identified as high risk will have the opportunity to receive a conveniently located scan. But such a plan has yet to emerge in the States.
Another factor that plays into the low screening adoption rate in the United States is that of those receiving the low-dose CT scan, around 20 percent of the high-risk population will reveal a nodule, which may or may not be relevant. The only way to determine what the nodule is, exactly, is to move the patient on to tissues biopsy, which comes with its own set of drawbacks.
One issue is cost. Non-small-cell lung cancer (NSCLC) makes up 85 percent to 90 percent of all lung cancers. Data from a study in the JCO Oncology Practice journal reveals that the mean cost of a diagnostic tissue biopsy for NSCLC runs nearly $10,000. For the smaller percentage of this group that moves on to a post-progression biopsy, the cost goes up to more than $16,000.
Additionally, patients are often reluctant to undergo invasive biopsy, for a host of reasons. In the end, only about 20 percent of those recommended for biopsy follow through with the test.
Even with tissue biopsy, only about 5-40 percent of tested patients prove positive for lung cancer. This number varies widely depending on a variety of factors. For instance, a patient under the age of 35 who receives a biopsy after identification of a nodule will rarely have a malignancy. In the over-50 population, however, the numbers go up.
Tissue biopsies come with potential for complications, as well. Pneumonia is a risk for all types of lung tissue biopsies, whether needle, thoracoscopic, or open. Other potential complications include severe bleeding, infection and blood clots.
When tissue biopsies result in these complications, the costs go up exponentially—emergency teams must be brought into the picture, hospital admissions increase, and longer term, more sophisticated care is needed.
A new alternative
Given the many barriers and complications associated with early detection of lung cancer, the promise of detection through a simple blood draw (a liquid biopsy) offers many advantages.
Access to labs that can take a blood sample is much more widespread than low-dose CT equipment. This helps bring early detection to even the most rural and remote spots in the country, targeting high-risk patients.
Alternately, liquid biopsy could become the go-to second step after a positive CT scan. Micronoma’s Oncobiota™ platform has the ability to detect cancer in its earliest stages at a high rate of accuracy. Oncobiota™ accomplishes this by focusing on the circulating microbial nucleic acid signatures from a tumor and the body’s response to a tumor. When coupled with a CT scan, patients could avoid riskier, more invasive tissue biopsies.
This offers the potential for lower costs and less stress on the patients and the clinicians. If put into practice successfully, the day may come when high-risk lung cancer patients routinely receive a liquid biopsy, much as females over 40 receive annual mammograms to screen for breast cancer, and males receive prostate cancer screening.
In the end, detecting lung cancer at an earlier, more survivable stage will save substantial costs, for both the patient and the healthcare system—potentially to a tune well into the tens of millions each year. More importantly, however, the promise of highly accurate blood testing offers the opportunity to save hundreds of thousands, if not millions of lives.