Narrative review of the role of yttrium-90 selective internal radiation therapy in the surgical management of colorectal liver metastases

The management of colorectal liver metastasis (CRLM) is complicated and benefits from a multidisciplinary team approach. Liver-directed therapy has been emerging as a modality for better progression-free control. In its early years, selective internal radiation therapy (SIRT) with yttrium-90 (Y-90) was confined as an end-of-line therapy. However, literature has supported other roles including: a first-line treatment for CRLM alone or in combination with systemic chemotherapy; an adjunct to second or third-line chemotherapy; and a salvage treatment for chemo-refractory disease. Although future liver remnant (FLR) hypertrophy may take 3-12 months, the SIRT effect on loco-regional disease control has rendered it to be a useful tool in some pathologies with certain strategic goals. This paper reviews the use of SIRT with Y-90 in a surgical treatment pathway. This includes: (I) an element of multidisciplinary treatment of low-volume CRLMs, (II) convert an R1 to R0 resection by sterilizing the margins of tumor near critical structures, and (III) radiation lobectomy to induce contralateral hypertrophy in order to aid in a safer resection. There are many opportunities to validate the role of SIRT as a first-line therapy along with surgical resection including an umbrella clinical trial design.