I would have to think that there is not a relationship between a flu shot of only months ago and the recent diagnosis of lung cancer. Lung cancers typically take years to grow to a detectable size. Which is not to say that a flu or other vaccine from years past might have been a contributor.
As you may have noted from posts I have made in the past, my own uncle was diagnosed with lung cancer some years ago when he was 80 plus years old. Mainstream medicine all but promised a cure but failed to deliver. Rather than eliminating the cancer with mainstream treatment his tumors continued to grow, new tumors formed and his cancer began to spread to other parts of his body. Instead of following their advice for even stronger treatments and chemo (they initially tried targeted radiation pellets), he listened to me and, after having his brother-in-law check out oleander at MD Anderson and receiving glowing reports, opted to take oleander and follow a natural protocol similar to the one I just posted here (http://www.curezone.com/forums/fm.asp?i=1606070#i). Today, he is in his mid-80's, quite healthy and cancer free.
All the best,
DQ