Of all causes of death, lung cancer ranks second behind heart disease. According to the American Cancer Society, it is estimated that in 2012 there will be 160,000 deaths from lung cancer. More people die from lung cancer than from breast, colon, and prostate cancer combined. Smoking is by far the most significant risk factor for lung cancer. It has been generally believed that early detection and treatment improve survival. A recent landmark study performed by the National Cancer Institute demonstrated a 20% decrease in deaths from lung cancer in high risk patients who were screened by CT versus those screened by chest x-ray. These results were published in the New England Journal of Medicine in August 2011.
Chest CT can detect lung cancers at a significantly smaller size than can traditional methods such a chest x-ray, increasing the chances of successful treatment and survival. Earlier detection and resectability of lung cancer by CT screening have been proven in screening trials and now a significant mortality benefit has also been shown.
Eligibility criteria for Chest CT Screening:
High risk for lung cancer as defined by the National Lung Cancer Screening Trial and the National Comprehensive Cancer Network (NCCN):
• 55 years or older
• Smoking history of 30 or more pack years (pack years = number of packs/day x years)
• No history of prior cancer
• No signs or symptoms that necessitate diagnostic rather that screening CT (see below)
A patient’s decision to pursue CT lung cancer screening should include a discussion with their health care provider that includes the potential benefits, risks, and costs of screening.
Chest CT for lung cancer screening:
Chest CT protocols for lung cancer screening have evolved rapidly since their introduction in the 1990s. State-of-the-art multidetector CT scanners allow for thin-section, rapid scanning of the entire chest in a single breath hold. These studies are performed with a reduced radiation dose and do not require administration of IV contrast.
The studies are reviewed at a computer work station by a radiologist specializing in body imaging and the results of the CT scan examination, and any recommendations related to the CT findings, are sent to the ordering physician who can direct any further care.
Are there any risks?:
The only direct physical risk from a screening CT is from the radiation from the x-rays. Using a reduced dose protocol, the radiation dose is relatively small ranging from that of a standard chest x-ray to about three chest x-rays. There is a very small risk that this limited radiation exposure might promote cancer development. The risk has been estimated to be equivalent to smoking one pack of cigarettes in a life time.
Small, usually benign, lung nodules are not an uncommon finding (approximately 40% of cases). If a nodule is found it, may require further diagnostic work up, most commonly a follow up CT scan at 12, 6 or 3 months, or for some cases PET scanning. Using these noninvasive methods the biopsy rate is relatively low, with the positive (malignant) biopsy rate greater than 50%
Screening versus diagnostic chest CT:
The lung cancer screening CT is appropriate only for patients without signs or symptoms such as weight loss, chest pain, and/or coughing up blood. Following clinical assessment, symptomatic smokers may benefit from a diagnostic chest CT. Diagnostic chest CT studies are tailored to the patient’s symptoms; they may be performed without IV contrast (using a protocol similar to the screening protocol) or depending on clinical findings or the results of a CT without contrast, may require addition of IV contrast or high-resolution sections.
How do patients get their results?:
We will send a report to the ordering physician detailing our findings and any recommendations.
How often should lung cancer screening be repeated?:
Very small cancers may not be identified by CT, and a negative chest CT screen now does not mean that cancer will not develop in the future. Therefore periodic screening should likely be performed. The NLST trial recommended yearly screens for high risk patients. Most, but not all, cancers that have been detected following this interval are found at an early, more treatable, stage.
How to order a low dose screening chest CT:
• Review the eligibility requirements
• If the patient and his/her doctor agree that screening is appropriate, a CT screening study can be scheduled at the patient’s convenience
• Mt. Baker Imaging requires a physician order for all CT studies
• On the day of the examination, the patient will need to bring their referral slip (doctors order) and should be prepared to pay for the examination at the time of service.
For PeaceHealth providers:
When looking in EPIC, please search for RIS 3755, or in your MBI preference list look for MBI: CT Chest Screening WO contrast (LOW-DOSE SCREENING FOR LUNG CANCER).
For non-electronic orders:
On our CT referral sheet, under “Screening Exams” please check the box marked, “Lung Cancer Screening Chest CT for high-risk patients”.
The most common criteria for insurance coverage is:
- 55 years of age or older
- Current or previous smoker, with a smoking history of at least 30 pack years*
- no history of lung cancer or chest-related conditions. Not currently experiencing any symptoms
*one pack-year=smoking one pack per day for one year
When speaking with insurance companies, the exam code is S8032 or G0297.
We do not accept patient self-referral at this time. Referrals must be made through the physician’s office. We feel that this approach is necessary to facilitate any necessary follow up care or patient counseling by the referring physician.
U.S.Preventative Services Task Force Recommendation for Lung Cancer Screening
NLST Research Team, Reduced Lung-Cancer Mortality with Low-Dose Computed Tomographic Screening. N Engl J Med 2011; 365:395-409.
Henschke CI, Early Lung Cancer Action Project: overall design and findings from baseline screening. Lancet 1999;354:99-105.
Sone S,Mass screening for lung cancer with mobile spiral computed tomography scanner. Lancet 1998;351:1242-1245.
Kaneko M. Peripheral lung cancer: screening and detection with low-dose spiral CT versus radiography. Radiology 1996;201:798-802.
Yankelevitz DF, Small pulmonary nodules: volumetrically determined growth rates based on CT evaluation. Radiology 1999;217:251-256.
Yankelevitz DF, Small pulmonary nodules: evaluation with repeat CT–preliminary experience. Radiology 1999;212:561-566.
Diederich S, Screening for early lung cancer with low-dose spiral CT: Prevalence in 817 asymptomatic smokers. Radiology 2002;222;773-781.
Patz, EF Screening for lung cancer. NEJM 2000;343;1627-1633