Memorial Sloan Kettering Cancer Center
The purpose of the study is to learn more about how the body responds to standard treatment (chemoradiation and chemotherapy). The study will use the results of testing down on participants' blook, tissue, and scans to learn more about how people with rectal cancer respond to chemoradiation and chemotherapy treatment and if it is useful for predicting whether a person's cancer get better, gets worse, or stats the same after treatment.
Inclusion Criteria: * 18 years of age or older on day of signing informed consent. * Have a histologically confirmed diagnosis of invasive adenocarcinoma of the rectum with no known mismatch repair deficiency or Her2 amplification. * Eligible for and plan to initiate standard-of-care therapy with any of the following regimens: * Induction fluoropyrimidine (capecitabine \[preferred\] or 5-FU) based chemoradiation * With plan for consolidative CAPEOX, FOLFOX, or FOLIRINOX * Woman with childbearing potential who are negative for pregnancy test (urine or blood) and who agree to use an effect…
Standard of care endoscopy