Nichols, associate director of clinical research for the OHSU Cancer Institute, this month was put on paid administrative leave starting at the end of May and won't have his contract renewed by OHSU when it comes up July 1.
Nichols, who's been at OHSU nearly nine years, wouldn't comment Tuesday on the reasons for OHSU's decision beyond saying he's "disappointed." Asked whether he is considering a lawsuit, the 54-year-old oncologist declined comment.
A source other than Nichols traced the firing to Nichols raising questions about a brain-tumor treatment championed by OHSU neurosurgeon Dr. Edward Neuwelt.
OHSU won't detail why Nichols is leaving, but says it doesn't "take employment action in retaliation for any employee's professional or personal points of view."
OHSU's website says Neuwelt pioneered the treatment known as blood-brain barrier disruption, or BBBD, in the early 1980s. BBBD is described as using a concentrated sugar solution to temporarily break the blood-brain barrier, letting chemotherapy drugs pass into the brain and reach the tumor.
Nichols, who serves on the board for the Lance Armstrong Foundation, met Armstrong at the Indiana University Cancer Center in 1996. After Nichols treated Armstrong, the cyclist went on to win the prestigious Tour de France a record seven times.