1st stage breast cancer was removed in march, had radiation therapy (30day), now taking tamoxifen, but coughing phlegm now, can it be a transfer to lungs?

Not likely. It is more likely to have bronchitis or pneumonia in the lungs especially following treatment (radiation) for early breast cancer if you develop a cough with phlegm. Check with your doctor who might have you get a chest x-ray.
Unusual. More likely is mild radiation pneumonitis - which can be detected on x ray. You might have a simple upper respiratory infection or bronchitis (especially if you smoke). It is unusual for an er+ tumor, stage i to metastasize that rapidly.
Unlikely. Most likely, simple respiratory track infection- bronchitis, see your doctor for examination, may give antibiotics along with cough medicine, and possible chest x-ray., metastasis is unlikely diagnosis in stage i .

Related Questions

How effective has intraoperative radiation therapy been for u.S. Breast-cancer patients so far?

Early results good. Published results of intraoperative radiation therapy, iort, (targit-a trial) have found no difference as compared to traditional whole-breast radiation therapy in a subset of people at low risk for recurrence. While promising, we await long-term data before expanding this option to more people. To-date, my experience has been very favorable. Read more...
Effective. According to some studies, the results are as effective as traditional radiation. Read more...
Promising. The initial reports are promising. I think i will wait for more long term data to be available before i offer this to my patients. Read more...