Hi COPD is the damage in your lung from long term smoking. This can cause breathing difficulties leading to poor exercise capacity. You will require inhalers and possible tablets depending upon the severity of your COPD plus other factors like how many time you get admitted to the hospital with an exacerbation and quality of life etc. Breast cancer: what was the staging of the disease. Did the lymp nodes taken out during the operation were positive of cancer cells and when did you have the cancer (which year). Coming to the main point which you are worried about the lung nodules, 3 mm is a very small nodule and quite rightly the pulmonologist says he will do a interval scan after 3 months. If you have a single nodule which is more than 1 cm, it may be worth while to do a PET scan if available (not always available most places). nodules cannot be biopsied. It has to be taken out surgically which is a major operation and carries it s own risk. I understand your concern fully and anyone in your shoes will feel the same. However, it doesn t necessary mean that the nodule is malignant. many times it turn out to be benign. Having said that you have important risk factors like father had lung cancer, long term smoker and also hx of breast cancer. So you have to play safe, which you doing anyway. The CT finding are very non specific like clusters of very small nodules. Did you have any CT scan during the time of your breast cancer diagnosis which could be compared with the latest one ? What is important while you wait for the next CT scan is keep any open mind and watch out for any red flag like change in breathing pattern, blood in the sputum or just coughing up blood, weight loss etc. In such case you need to notify your doctor immediately. ideally for the next 2 yrs you need to have interval CT scans at 3 months first 2 and then every 6 months. You have to keep in mind the radiation exposure from the CT scans so try to speak to a radiologist who can do the scan with minimum radiation exposure (spiral CT)