But for the past several months, the 65-year-old Coburn has privately been undergoing intensive treatment for a recurrence of prostate cancer, a battle that could end up cutting short his second Senate term, which is scheduled to expire in January 2017…

Coburn is currently undergoing chemotherapy, and he may soon have major surgery that could temporarily — or permanently — sideline him from the Senate. When the results of medical tests return in February, Coburn will have a clearer indication of the additional treatment he needs and whether it will interfere with his Senate work.

Coburn said he believes he’s “plenty healthy enough to serve out my term.” But when asked if anything could change that calculation, the no-nonsense Coburn said wryly: “I can have a heart attack and drop over, but my heart is pretty good.”