What benefit can I expect from CT scan lung cancer screening?
If you have read the prior sections and reviewed the information on your individual risk of lung cancer and would consider participating in a CT screening program, the first thing that you might wish to know is what the benefits might be for you.
A person who is fortunate and does not get lung cancer, will get no direct benefit from screening. He or she might derive indirect benefit. (This will be discussed in a future segment.)
A person who is unfortunate and does get lung cancer over the next ten years will have direct benefits.
– The Lung cancer will typically be detected at an earlier point in time, before the cancer would otherwise have been diagnosed at the onset of the first symptoms. The is called a “lead=time effect”.
The large majority of lung cancers found in patients who have no symptoms but are at increased risk, are found at a smaller size than those diagnosed after symptom onset.
Caption: 9 mm lung cancer in the right lung detected by CT screening.
Often they are 1 centimeter in diameter (the size of a pea), or smaller, compared to a 3 centimeter, (grape size) or often much larger Lung cancer in unscreened individuals.
Caption: Large lung cancer in the left lung in an unscreened patient.
The large majority of lung cancers found in CT screening are in early stage.
More than 80% of CT screen-detected lung cancers are diagnosed in stage 1 (IELCAP).
In lung cancers that are very small, e.g. one centimeter, approximately 90% are in stage 1.
When a lung cancer is found at a small size and early stage, the cancer, in most cases, has not yet spread to lymph nodes or distant organs.
Treatment is, accordingly, more simple and easily-tolerated.
Increasingly, surgeons remove small lung cancers using “minimally invasive” techniques, including video assisted thoracic surgery (VATS) and robotic surgical methods. Minimally invasive surgery results in shorter hospitalization, low rates of complication and death, and faster recovery.
In many instances, smaller amounts of lung tissue (limited resection) rather than removal of a lobe of the lung (lobectomy) can be performed without compromising the chance of cure.
Chemotherapy is seldom required.
Of greatest importance, the chance of cure in patients with lung cancer detected by CT screening (IELCAP) exceeds 80% – more than 4 times higher – than in unscreened patients.
This result was initially doubted and called an “outlier”, but has now been repeated and confirmed by many other research groups in Holland, Italy, England and the U.S. (NLST).
The benefits discussed here are conditional. They apply to an individual who agrees to
-participate in a lung cancer screening program that meets quality standards and uses a diagnostic algorithm (like IELCAP) or a clinical practice guideline ( like NCCN),
-agrees to have a low-dose, non=contrast, spiral CT scan at yearly intervals for at least a ten year period
-follows program recommendations for further testing or biopsy and treatment.
It is probable that a person who stops being screened or does not follow recommendations based on CT findings will experience lower benefit and / or higher risk.