Saturday, May 25, 2013
Questioning when to have the next CT
I had an abdominal CT that accidently found a 5mm noncalcified nodule within the posterior right lung base, that was performed because of lower ab pain. A second CT within a week revealed another 6mm noncalcified within the right middle lobe, along with 3 calcified granulomas. I had a cancerous tumor in my head (petris ridge) that was operated on and I then received 40 treatments of proton beam radiation in 1987. I have had no recurrence. However, I had many CT scans then (over 12). They are recommending CT scan in 3 months. Is this too soon to show any growth? What are the chances of the 6mm being cancerous? I have never smoked but grew up with both parents smoking. Dad died of lung cancer in `85. I am 57 yrs. I am very concerned.
A non-calcified nodule is worrisome for lung cancer. However, they may represent infection as well. If you live in the midwest, a fungal infection known as histoplasmosis is very common, which is totally benign. In some cases they can be just an old scar. Being a non-smoker your risk for lung cancer is low but you are at a slightly higher risk for lung cancer than normal because of passive exposure and family history of lung cancer.
The best way to prove whether this is cancer or infection would be to do a biopsy and examine the tissue from the nodule. However, it is hard to biopsy these nodules when the size is less than 10mm. In these cases we opt to do serial CT scans every 3-6 months upto a period of 2 years to determine if it is increasing in size (usually cancerous nodules will continue to grow), so we can biopsy successfully as soon as they reach the cutoff size. On a follow up CT scan, an infection may disappear, an old infection or scar usually remain unchanged.
In your case if you have three calcified granulomas, then it is likely that the other nodules are benign as well. But, just to be sure your physician has recommended a follow up CT scan. I would not worry too much at this point.
Shaheen Islam, MD, MPH
Clinical Associate Professor
Pulmonary, Allergy, Critical Care & Sleep
College of Medicine
The Ohio State University