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Mahmood et al. | Journal of Clinical and Translational Research 2023; 9(5): 322-326 323
of this work was to describe the survival of consecutive patients For glass microspheres, the medical internal radiation dose
with CRLM treated with radioembolization (Y90 SIRspheres and (MIRD) model was used:
Theraspheres) at a single academic institution. Prescribed activity (GBq) = (Target dose [Gy] × Liver
mass [kg])/(50 × [1–Lung shunting fraction] × ├ [1–Percent
2. Materials and Methods residual after infusion])
The institutional review board approved a retrospective single- The liver volume was determined by computed tomography
institution study. Consecutive patients with CRLM treated at least (CT), magnetic resonance imaging, or cone-beam CT. No
once with TARE between 01/2016 – 07/2020 were included in adjustments were made for prior cytotoxic chemotherapy. For
the analysis. The sample size was based on all available patients segmental treatments, the activity was derived from calculating
seen at the institution within the time frame. The start date for the dose for the entire lobe even though given to selectively to a
data collection was determined as the time when all involved single segment [9-11].
investigators became part of the multidisciplinary tumor board at Routine imaging after completion of TARE was performed at
the institution. The end date for data collection was determined 8 weeks. A positron emission tomography scan was performed
as 24 months before the data analysis, hence allowing for at post-Y90 treatment to evaluate treatment.
least 24-month follow-up for patient survival. This retrospective
chart review study was conducted at a tertiary referral center, 3. Results
and patients’ records were reviewed using institutional electronic A total of n = 55 patients were included in the study. Follow-up
medical records. Clinically relevant variables including dates of time for survival in the entire cohort was at least 24 months. Patient
diagnosis and death, demographics, genomic analysis, primary demographics and tumor characteristics are shown in Table 1.
tumor location, chemotherapy regimen, laboratory values, and Baseline and post-TARE liver function tests are shown in Table 2.
Eastern Cooperative Oncology Group (ECOG) performance Median time from diagnosis to first TARE was 16.4mo (1.7–95.6)
status were extracted from patient charts. OS was calculated from (Figure 1A). Of note, 36.4% of the patients (n = 20) were treated
the time of Stage 4 CRC diagnosis to death. Liver progression-free within the first 12 months of diagnosis. Eleven patients (20%)
survival (LPFS) was calculated from the date of the first TARE were re-treated with TARE. Median OS from diagnosis and first
procedure until the date of documented disease progression or TARE was 43.2 months (29.5–68.7) and 16.7 months (9.9–35.2),
death. Radiographic response was based on RECIST v1.1. Patients respectively.
still alive at the time of last available follow-up were censored. Median LPFS was not reached (95% CI: 4.8 months to not
We performed descriptive analyses for relevant patient and tumor evaluable) (Figure 1B). In 48 patients with at least one follow-
characteristics, Wilcoxon Signed-Rank Test for comparison of up scan post-TARE, two patients had a complete response and
continuous variables, and Kaplan–Meier estimates for survival. 20 patients had a partial response, that is, overall response rate of
The majority of mCRC patients were treated with resin and 45.8%. The clinical benefit rate (i.e., stable disease or better) was
a few with glass Y90 microspheres according to previously 65.6% (31 of 48 patients).
published methodologies [6-8]. Specifically, all cases were
discussed at a multidisciplinary tumor board consisting of 4. Discussion
hepatobiliary surgeons, medical oncologists, interventional
and diagnostic radiologists, radiation oncologists, and clinical Surgical resection is recommended for patients with CRLM
research personnel. Once deemed appropriate candidate for and associated with long-term survival in a subset of patients [12].
radioembolization (i.e., unresectable disease and liver limited/ However, only 10–15% of patients with CRLM are candidates for
dominant metastases), patients underwent a mapping angiogram curative intent liver resection. While initially effective, resistance
to determine tumor vascular supply, identify extra-hepatic arteries to multi-agent systemic treatment will invariably develop in
that require embolization to avoid iatrogenic gastrointestinal virtually all patients with CRLM. Progression-free survival (PFS)
radiation ulcers, and determine the tumor and treatment volumes decreases with each subsequent line of systemic treatment [1].
as well as the lung shunting fraction with MAA administration. To address the unmet need of control of liver metastases in
The microspheres type (resin vs. glass) and the treatment CRLM, two randomized Phase III trials tried to address the role
type (lobar or segmental) affected the method of Y90 activity of TARE in first-line and second-line treatment of CRLM [3,4].
calculation. Moreover, the method evolved during the study period. Both trials failed to show an actual OS benefit, despite of higher
For resin microspheres, the body surface area (BSA) method was objective response rate and liver PFS in both trials. It is unclear why
almost exclusively utilized. The activity to be administered to the no survival benefit was seen in both trials despite improvement of
target lobe was based upon: other endpoints. While patient selection (e.g., performance status,
Prescribed activity (GBq) = (BSA-0.2) + ([Tumor mass/Total disease volume, and extrahepatic disease) and trial design (timing
liver mass] × 100) of TARE, choice, and dose of systemic treatment) might have
If patients had received several lines of chemotherapy, the contributed to the results, there remains a concern that acute and
BSA prescribed activity was reduced empirically by up to 30% to delayed liver toxicity from TARE might negate any initial positive
reduce the risk of radiation-induced liver disease. effect of tumor control in the liver.

DOI: http://dx.doi.org/10.18053/jctres.09.202305.23-00066