Purpose of review
Diarrhea and colitis are among the most commonly encountered immune-mediated adverse events among patients receiving antiprogrammed cell death protein/ligand-1 (PD-1/L1) as well as anticytotoxic T-lymphocyte-associated protein 4 (CTLA-4) antibodies. With growing indications and widespread use of immune checkpoint inhibitors
, it is imperative to summarize the current body of evidence concerning the incidence, pathogenesis, risk factors, diagnostic challenges, and treatment options currently available for the management of immune-mediated diarrhea and colitis. Additionally, with emerging evidence analyzing the resumption of immune checkpoint inhibitors
, it is pivotal to summarize our current understanding and future challenges.
Immune-mediated diarrhea and colitis can potentially be a viable surrogate marker for improved survival as it is validated further in large-scale studies. Early endoscopic evaluation can aid in the identification of patients at risk of developing steroid refractory immune-mediated colitis
, and hence can be chosen to receive early add-on therapy with infliximab
or fecal microbiota transplantation
, an emerging treatment option for immune-mediated diarrhea and colitis. Resuming immune checkpoint inhibitors
carries a manageable risk of recurrent diarrhea and colitis, with most cases being mild and effectively managed with immunosuppressive therapy.
As our understanding of immune-mediated diarrhea and colitis grows, it is likely that this clinicopathologic entity will represent more than just an adverse event. With a growing number of treatment options, the management algorithms for immune-mediated diarrhea/colitis are likely to evolve in the future.