Solitary Pulmonary Nodule

Symptoms

Most persons with SPN do not experience symptoms. Generally, SPN is detected as an incidental finding.

Approximately 20-30% of all cases of  lung cancer   appear as SPNs on chest x-ray films. Therefore, the goal of investigating an SPN is to differentiate a benign growth from a malignant growth as soon and as accurately as possible.

SPNs should be considered potentially cancerous until proven otherwise.

People should always communicate openly and honestly with their health care provider about their history and risk factors.

The following features are important when assessing whether the SPN is benign or malignant.

• Age:Risk of malignancy increases with age.
  • Risk of 3% at age 35-39 years
  • Risk of 15% at age 40-49 years
  • Risk of 43% at age 50-59 years
  • Risk of greater than 50% in persons older than 60 years

• Smoking history: A history of smoking increases the chances of the SPN being malignant.
• Prior history of cancer: People with a history of cancer   in other areas of the body have a greater chance that the SPN is malignant.
• Occupational risk factors for lung cancer: Exposure to asbestos, radon, nickel, chromium, vinyl chloride, and polycyclic hydrocarbons increases the chance that the SPN is malignant.
• Travel history: People who have traveled to areas with endemic mycosis (eg, histoplasmosis, coccidioidomycosis, blastomycosis) or a high prevalence of  tuberculosis   have a higher chance of the SPN being benign.
• People who have a history of  tuberculosis or pulmonary mycosis have a greater chance of the SPN being benign.

Solitary Pulmonary Nodule Treatment

Based on the results of exams and tests, persons with SPN can be divided into the following 3 groups:

• Persons with benign SPN: Persons who have been diagnosed with benign SPN should undergo chest x-ray films or CT scans every 3-4 months in the first year, every 6 months in the second year, and once every year for up to 5 years. Determining that the SPN is benign is based on the following:
  • Persons younger than 35 years without other risk factors
  • Benign appearance on chest x-ray film
  • Stability of the SPN over a period of 2 years on chest x-ray film

• Persons with a malignant SPN: Persons who have been diagnosed with a malignant SPN based on the results of the exams and tests should have the nodule surgically removed.
• Persons with SPN that cannot be classified as either benign or malignant: Most persons fall into this category. However, as many as 75% of these patients have malignant nodules on further evaluation. Therefore, such persons are also advised surgical removal.

Follow-up

Persons who have been diagnosed with a benign SPN should schedule the recommended follow-up, as follows:

• Chest x-ray films should be taken every 3 months for the first 12 months and then every 6 months for the following 12 months.
• After this 2-year period, SPNs may be observed yearly for up to 5 years.

Prevention

Avoiding the possible causes may help prevent SPN formation. Possible avoidable causes include the following:

• Smoking: For information about how to quit smoking, visit the following links:
  • National Cancer Institute, Clearing the Air, Quit Smoking Today
  • American Lung Association, Quit Smoking
  • Smokefree.gov
  • Quitnet
• Traveling to areas endemic for mycosis (eg, histoplasmosis, coccidioidomycosis, blastomycosis) or to areas with a high prevalence of tuberculosis
• Occupational exposure to risk factors for lung cancer (eg, asbestos, radon, nickel, chromium, vinyl chloride, polycyclic hydrocarbons)

Outlook

Most SPNs are benign, but they may represent an early stage of lung cancer.

lung cancer survival rates remain dismally low at 14% at 5 years. However, early lung cancer (ie, lung cancer that is diagnosed when the primary tumor is smaller than 3 cm in diameter [stage 1A]), can be associated with a 5-year survival rate of 70-80%.

Accordingly, the only chance for cure of early lung cancerthat presents as SPN is prompt diagnosis and treatment.