Lung Cancer Screening

Background:

According to the American Cancer Society, in 2002 there will be approximately 170,000 new cases of lung cancer diagnosed, and approximately 155,000 people will die from lung cancer. Smoking is by far the most significant risk factor. It is generally believed that early detection and treatment improve survival. Chest CT can detect lung cancers at a significantly smaller size than can traditional methods such a chest x-ray, possibly increasing the chances of successful treatment and survival. Earlier detection and resectability of lung cancer by CT screening have been proven in screening trials. The true impact of resection on long term survival, however, remains unproven. 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.

Low-dose 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 low 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, for some cases PET scanning. Using these noninvasive methods the biopsy rate is relatively low, with the positive (malignant) biopsy rate greater than 50%

Eligibility criteria for Chest CT Screening:

• 45 years or older

• Current or former smoker

• No history of prior cancer

• No signs or symptoms that necessitate diagnostic rather that screening CT (see below)

Screening versus diagnostic chest CT:

The low-dose 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. Unlike screening studies, diagnostic examinations are typically covered by insurance.

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 be considered. The optimal screening interval has not been established; however studies to date would suggest one year is a reasonable target. 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

• NWR 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.

Cost of Low Dose Lung Cancer Screening CT:

For smokers without symptoms, CT scans for lung cancer screening are not currently covered by most health insurance plans. These patients can contact their insurance carriers for confirmation, but should anticipate that they will need to pay for the examination at the time of service.

Referrals:

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.

References:

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