5mm nodular density in the lung

[igorvl]

My dad had a CT Scan of abdomen and pelvic area, which included a lower portion of his lung. They found a 5mm nodular density in the lung, and recommended a 3 to 6 months follow up because of that. There is no further characterization of the nodule in the report. I am wondering if this is too long to wait, and may be he should ask for a biopsy.

[Fernando Roque, MD]

Hi.  Various formulas have been devised to estimate the probability of malignancy in a solitary pulmonary nodule. One such formula which I found to be useful was the one proposed by Gould, et al (CHEST 2007; 131:383–388).  Variables such as the person's age, smoking history, nodule diameter, and time since quitting smoking have been factored in to arrive at the estimate.  I can calculate your father's probability of developing lung cancer if you can give me his age and the year he quit smoking (if ever).  You can also look up the journal article and do the calculations yourself.  Here's the link: http://www.chestjournal.org/cgi/reprint/131/2/383.

[igorvl]

My dad does not have family history of cancer, but he is a light smoker (about 3 cigarretes a day).

[igorvl]

Thanks for your reply. What, very roughly, are the chances of this nodule to be malignant ?

[Fernando Roque, MD]

Hi.  The nodule is rather small to warrant immediate investigation.  If the nodule were 1 cm or larger, then it is reasonable to have a biopsy done promptly.  If your father is a heavy smoker, or if he has a strong family history of cancer, I might also consider having the biopsy done now instead of observing for a few months.