Dear Dr. Roach: Im a 74-year-old female who smoked a pack a day for 40-plus years, having quit smoking about 18 years ago. As a precaution, I asked my primary doctor to order a screening CT scan, knowing that Im a candidate for lung cancer. The results showed a 3-mm nodule in one lung, and I was advised not to worry and that my doctor would order another CT scan in six months. I cant help but wonder if this is cancer and if an oncologist, after six months, will ask me why I waited so long to see him. T.W.
Answer: Medical professionals have been attempting to screen for lung cancer for decades. Chest X-rays proved insensitive: By the time cancer could be seen on X-ray, it was usually too late to do anything about it. CT scans are much more sensitive (maybe too sensitive; see below), and studies have shown that some lives will be saved with a screening program. However, the number of people who would benefit is relatively small; 256 moderate-to-heavy smokers would need yearly screening for three years in order to prevent one lung cancer death.
There are two other significant concerns about lung cancer screening. The first is the issue you have now: an abnormal result and what to do about it. Its extremely common. Almost 25% of scans will be abnormal, and 96% of the abnormal results will be false positives. But it will require multiple scans and sometimes an invasive procedure to prove it. This means a great deal of anxiety among people who get the type of result you did.