The purpose of this study is to study the way radioembolization works by collecting biopsy samples of participants' tumors after the procedure. This research may improve the way that radioembolization is performed, which could help people whose cancer has spread to the liver. The research may also provide information about how tumors respond to radioembolization.

Inclusion Criteria:

• age ≥ 18 years
• Eastern Cooperative Oncology Group (ECOG) performance status 0-2
• histologically confirmed primary adenocarcinoma of the colon or rectum
• CLM considered unresectable or not amenable to percutaneous ablation
• existent tissue samples from a standard of care biopsy of the target tumor within 42 days prior to treatment OR clinical indication for biopsy at the time of the treatment under the institutional guidelines for progression of disease.
• adequate blood cell counts (WBC > 1.5 x 109/L, platelet count > 50 x 109/L)
• adequate renal function (creatinine < 1.5 mg/dL)
• total bilirubin level ≤ 1.5 mg/dL

Additional inclusion criteria for patients, undergoing 90Y radiation segmentectomy:

A. patients not amenable to surgery or thermal ablation

Exclusion Criteria:

Study exclusion criteria will be similar to general TARE exclusion criteria, which are as follows:

• prior hepatic radiotherapy (The lesion / lobe being treated cannot have had prior treatment with radiotherapy - untreated lesions / lobes in the liver may be evaluated under the protocol)
• severe cirrhosis
• severe portal hypertension
• uncorrectable flow to the gastrointestinal tract and/or >30 Gy (or >50 Gy in multiple sessions) radiation absorbed dose to the lungs

All patients with liver-dominant disease will be considered candidates for TARE even in the face of oligometastatic (up to 5 sites) extrahepatic disease, that is stable or controlled by chemotherapy.

The patients will be identified and recruited from the existing patient population in the Interventional Oncology/Radiology Service of the Department of Radiology at Memorial Sloan-Kettering Cancer Center (MSKCC). The patients will be presented with a study consent form and an explanation of any concerns they may have by the Principal Investigator or research team (i.e. Co-Investigators and consenting professionals).

Memorial Sloan Kettering Cancer Center supports the international committee of medical journal editors (ICMJE) and the ethical obligation of responsible sharing of data from clinical trials. The protocol summary, a statistical summary, and informed consent form will be made available on clinicaltrials.gov when required as a condition of Federal awards, other agreements supporting the research and/or as otherwise required. Requests for deidentified individual participant data can be made beginning 12 months after publication and for up to 36 months post publication. Deidentified individual participant data reported in the manuscript will be shared under the terms of a Data Use Agreement and may only be used for approved proposals. Requests may be made to: crdatashare@mskcc.org.