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Low-Dose CT Scanning for Earlier Diagnosis of Lung Cancer

Franklin R. Quijano, MD, Pulmonologist

Lung cancer is the leading cause of cancer death in the United States. The five-year survival rate is just 15.6 percent. Yet a recent large-scale study indicates that low-dose CT scanning of the highest-risk population can decrease mortality by 20 percent.

Before now, clinical trials on various lung cancer screening approaches – from X-ray to sputum cytology – had not found a strong correlation between screening and survival. Prompted by observational insight regarding screening with CT, the National Cancer Institute recently embarked on the National Lung Screening Trial – a randomized study, screening more than 53,000 at-risk smokers with either low-dose CT or chest X-ray. Over a six-year period, the study found a 20 percent mortality reduction in the CT-screened population.

Recommended guidelines

Based on the study results, released in 2011, the National Comprehensive Cancer Network formed a working group representing medical oncology, radiation oncology, pulmonary medicine, surgical oncology, epidemiology, diagnostic radiology, hematology/oncology, internal medicine, patient advocacy and pathology. They developed specific guidelines for risk assessment, screening modality and evaluation of findings.

Risk assessment

It's critical to carefully assess potential candidates for this screening to ensure proper selection. The study does not support screening for people who don’t fit the risk criteria. And those who already have symptoms or signs of lung cancer require a much more aggressive approach. The initial assessment should include:

  • Smoking history, present or past
  • Radon exposure
  • Occupational exposure
  • Cancer history
  • Family history of lung cancer
  • Disease history – COPD or pulmonary fibrosis
  • Smoking exposure – second-hand smoke
  • Absence of symptoms or signs of lung cancer

Appropriate candidates

From this assessment, the clinician can determine whether the person is at high, medium or low risk for lung cancer. High-risk candidates fall into two categories:

Category 1

  • 55-74 yearsofage
  • ≥ 30 pack year history of smoking
  • < 15 years smoking cessation
Category 2B
  • 50 years of age or older
  • ≥ 20 pack year history of smoking
  • One additional risk factor

Low-dose CT screening is recommended only for those at high risk.

If the screening detects lung nodules, these candidates should be further evaluated according to the NCCN guidelines. If no nodules are found, the NCCN recommendations suggest annual low-dose CT scanning for two years and until the patient is no longer a candidate for definitive treatment.

For further information, including the evaluation of screening findings LCS-3 and LCS-4, reference the entire guideline available online at nccn.org.

Cautions about new guidelines 

Whenever new guidelines such as these are discussed publicly, physicians are likely to receive patient requests for screening. Among the concerns we need to be prepared to address are:

  • The efficacy of the screening in the ongoing clinical setting vs. the study.
  • Creating a false sense of security in patients who are not appropriate candidates and receive negative results.
  • Causing an emotional and financial burden for those who are at high risk but are found to have no malignancy, yet now will need annual screening.
  • The lack of evidence to support the value of screening for those who don’t fit the criteria.
  • Whether the risks of radiation exposure (though just 10 to 30 percent of what a typical CT scan delivers) outpace the potential detection and early treatment.
  • Concerns about the level of false positive. About 96 percent of the nodules found are benign. This is especially true in the Midwest, where the incidence of benign disease processes such as granulomas, infection and histoplasmosis is quite high.
  • Evaluating the cost-effectiveness of this endeavor from a healthcare system standpoint.

Insurance issues

The national average cost for a low-dose screening CT is approximately $200 to $300.This cost – for an asymptomatic patient – is not likely to be covered by conventional insurance. Physicians will need to prepare their patients for the out-of-pocket expense. With positive findings, however, subsequent scans and evaluations normally are covered. We expect carriers to slowly begin paying for the initial screening as formal programs are developed and they begin to realize the long-term value of earlier diagnosis and treatment.

Program on the way

The risk of screening patients who don’t meet the criteria, along with the high rate of false positive results, underscores the importance of having a deliberate system for screening and follow up that includes a multidisciplinary team of physicians. The University of Kansas Cancer Center has created such a program, which will give community physicians a streamlined way to give their patients access to screening scans and evaluation, but more important, to follow-up care and education.

With this approach, we can take a more robust view of the screening, addressing the whole patient with an academic approach and a strong clinical arm to follow the guidelines, while mitigating unnecessary fear and concern. The committee that developed and oversees the radiology program includes oncology, pulmonary medicine, preventive medicine and our researchers.

In addition to coordinating screening and follow up, the program includes a clinical registry. Because the screening is so new, we plan to track each patient in detail so we can continue to learn more about the efficacy and risks of screening.

To ensure a smooth process for the referring physician and patient, an advanced practice nurse navigator will:

  • Coordinate communication with primary care physicians and patients
  • Ensure patients receive subsequent screenings
  • Assist patients in pursuing tobacco cessation programs and other lifestyle changes

The program is designed to mimic other successful screening programs, such as those for breast cancer. It will begin with consistency in interpretation and proceed with a clear algorithm for guiding follow up and further testing. The protocol will obviously be complex, given that the appropriate diagnosis of lung nodules can vary greatly, depending on many factors. It starts with the least invasive – watchful waiting – and progresses through more invasive procedures, such as bronchoscopy, fine needle aspiration, biopsy, bronchial ultrasound and wedge resection with cardiothoracic surgery.

Read about our lung cancer screening program.

Avoidance remains best strategy

While we're encouraged by the opportunity to effect a significant reduction in lung cancer mortality, we must remain vigilant in the effort to lower the incidence of lung cancer overall. With tobacco use estimated to cause 80 to 90 percent of all lung cancers, cessation is our best defense.

To find smoking cessation programs for your patients, check out these resources:

  • National Cancer Institute's Cancer Information Service: smokefree.gov
  • American Cancer Society QuitforLife program: quitnow.net
  • American Lung Association: lung.org/stop-smoking
  • Missouri and Kansas Quit Line: 800.QUIT.NOW or 800.784.8669

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