Father of three was days from aggressive chemo for ‘terminal lung cancer’ — until an offhand suggestion caught a mistake and stopped the treatment
Sometimes, an accident reveals a truth that is far more life-changing than the injury itself. Similarly, for Andy Provencher, his biggest concern after crashing his mountain bike and flipping over the handlebars was how to explain this accident to his wife. In June 2020, when the accident happened, it led doctors to uncover a medical mystery that upended his life completely. During the peak of the COVID-19 pandemic, with several broken bones and a punctured lung, Provencher, a father to three children, was taken to the emergency room, a place he knew his wife dreaded most at the time. However, when doctors were treating his injuries, they noticed something far more concerning in his scans. “We've done some scans, we've seen in your lungs, and your lungs are littered with masses. This looks like a very aggressive form of lung cancer,” the emergency room doctor said, as reported by CBS News on January 10, 2026.
That changed everything for the family, as they began a year-long medical limbo, with diagnoses being changed repeatedly. While some doctors believed he had terminal cancer, others denied it. All the tests, scans, and biopsies failed to provide a clear picture. “We went to every doctor there was. I went to my PCP, I went to a hematologist, a pulmonologist, and a rheumatologist. And we never really had like a solid answer, a solid diagnosis,” Provencher explained. As uncertainty grew, his condition worsened. He started losing his stamina and struggled with even simple movements. Despite an uncertain diagnosis, doctors suggested chemotherapy.
Weeks before chemotherapy, a physician assistant shared a different possibility: a rare immune disease called IgG4-RD. Hearing this, Provencher went to Dr. John Stone, a leading specialist and a professor of medicine at Harvard Medical School and the Edward A. Fox Chair in Medicine at Massachusetts General Hospital. Provencher shared, “Ever since I went over the handlebars, our world really started spinning. Once I heard that from Dr. Stone, our world stopped spinning.” Dr. Stone shared that IgG4-RD is often difficult to identify and is mistaken for other illnesses. “Unfortunately, Andy's story of delayed diagnosis is the rule rather than the exception,” he said, pointing out that delays are common. “He had multiple large nodules in both lungs. While this was bad enough, his mental status was even worse,” Stone explained.
According to the American College of Rheumatology, IgG4-RD is an immune-mediated condition, involving a disorder where the immune system malfunctions, causing disease to develop in various organs. The study also suggests that it is more likely to be found in middle-aged to elderly males than females. In rare cases, it also affects children.
Then came a groundbreaking clinical trial testing inebilizumab, a medication targeting immune B cells, which changed everything for Provencher. He joined the program, and the treatment helped stabilize his condition. In April 2025, inebilizumab became the first FDA-approved drug for IgG4-RD. “Certainly, I have my struggles from day to day, with a little exhaustion and whatnot, and some other symptoms, but the medicine has put me in a decent place right now,” Provencher, who is continuing the treatment, expressed. “The most important thing is just keep going,” he shared, hoping others facing a similar situation don’t give up.
In the years that followed, the focus shifted beyond treatment to awareness. In 2023, Stone launched IgG4ward! Foundation to help patients understand the disease and access support. He later invited Provencher’s wife, Katharine, to take on the role of director of advocacy and community engagement, a position she accepted. Provencher believes stronger education and outreach could spare others the long uncertainty he endured. “I think about the what-ifs all the time, and I think that my symptoms would have gotten more and more extreme, to the point where I would have hopefully come to the same place, but with more damage,” he said.