Using next generation sequencing rather than an immunohistochemistry test can help patients get the best treatment for their mismatch repair deficiency positive cancers, suggests research from Yale Cancer Center.
Colorectal and endometrial cancers are diagnosed in around 150,000 and 65,000 people, respectively, every year in the U.S. These cancers often have a high rate of mismatch repair deficiency, which means errors in the DNA are not corrected as they would normally be. Immunotherapy using immune checkpoint inhibitors has revolutionized treatment for these types of cancers. However, not everyone responds to this treatment.
Writing in the journal Cancer Cell, Amin Nassar, an oncology and hematology clinician and researcher at Yale, and colleagues propose that this is at least partly due to misdiagnosis of mismatch repair status in patients with colorectal and endometrial cancers with mismatch repair deficiency.
“In colorectal cancer and endometrial cancer, which are the two types of cancer where mismatch repair deficiency is most commonly seen, immunotherapy is not the standard treatment,” said first author Elias Bou Farhat, a postdoctoral research fellow in the division of Pulmonary and Clinical Care Medicine at Brigham and Women’s Hospital, in a press statement.
“But in patients with this condition [mismatch repair deficiency], even in late-stage cancer, those who receive immunotherapy can live for years and in some cases be potentially cured.”
For this reason, it is important to correctly diagnose as many patients with this type of cancer as possible.
In this study, Nassar and colleagues show that next generation sequencing testing in 1655 patients with colorectal or endometrial cancer, instead of the more standard immunohistochemistry test, results in an additional 1% and 5.9% of patients being correctly diagnosed with mismatch repair deficiency.
“Including next-generation sequencing as a complimentary testing practice could benefit patients in all phases of cancer, from pre-treatment to advanced stages,” said Farhat.
“We don’t want to miss these patients, or we could be depriving them of a treatment that can have long-term benefits,” added Nassar, who did much of the work while he was a resident at Brigham and Women’s Hospital.
“We also want to avoid giving patients treatments that could be more toxic and/or less effective—we want to treat patients with the appropriate therapy.”
