Characterizing Immune-Related Side Effects in Breast Cancer Treatment

Peter Schmid, FRCP, MD, PhD: Immune-related side effects are well-characterized for breast cancer as well as other diseases. They are hugely variable in terms of which system is affected and at what time point they may occur, although we’ve learned over the years that there’s a few symptoms we see relatively commonly. And about 5 of those side effects account for, I would say, 90% of the immune-related adverse events. This of course refers to endocrine side effects, to rash, to colitis, pneumonitis, and elevation of liver enzymes. Now these are relatively rare, the last 4. And rash, and more commonly endocrine side effects are seen a bit more commonly. All of these share the fact that they’re well-manageable generally. In the endocrine side effects, some of them are irreversible but can be managed by replacing the hormone that may not be adequately produced. Most of the other side effects are treatable with steroids and generally reversible.