Assessment of Delivery, Dosimetry and Imaging Response with FLEX versus Day of Calibration Resin 90Y microspheres for Hepatocellular Carcinoma

Wednesday, March 8, 2023

3:00 PM – 3:09 PM

Location: Phoenix Convention Center, 224AB

Presenting Author(s)

CW

Cayce S. Workman, MD

Resident Physician
Vanderbilt University Medical Center

Disclosure(s): Sirtex Medical: Research Grant or Support ()

Author/Co-author(s)

Patrick W. Doyle, BS (he/him/his)

Medical Student
Vanderbilt School of Medicine
JG

Jared V. Grice, D.M.P.

Medical Physicist
Vanderbilt University Medical Center
LD

Liping Du, Ph.D.

Biostatistician
Biostatistics, Vanderbilt University Medical Center
AB

Anthony J. Borgmann, M.D.

Attending Physician
Vanderbilt University Medical Center
JB

Jennifer C. Baker, MSN, APRN-BC

Nurse Practitioner
Vanderbilt University Medical Center
David P. Duncan, M.D. (he/him/his)

Attending Physician
Vanderbilt
JT

Jason E. Taylor, CNMT

Nuclear Medicine Technologist
Vanderbilt University Medical Center
Daniel B. Brown, M.D.

Attending Physician
Vanderbilt University Medical Center

Disclosure(s):

Cayce S. Workman, MD: Sirtex Medical: Research Grant or Support ()

Patrick W. Doyle, BS: Sirtex Medical: Research Grant Recipient (Ongoing)

Jennifer C. Baker, MSN, APRN-BC: No financial relationships to disclose

David P. Duncan, M.D.: No financial relationships to disclose

Purpose: To assess outcomes with FLEX compared with day of calibration (DOC) resin 90Y microspheres in patients with HCC

Materials and Methods: We retrospectively reviewed 102 HCC patients with 1-2 index tumors treated with resin 90Y between 2014-2022. Two groups of patients received either DOC spheres (maximum activity: 3.6 GBq) or FLEX spheres with up to 3 days pre-calibration (maximum activity 7.8 GBq). Baseline Child-Pugh, BCLC, tumor volume and tumor number were compared. Administered activity and selection level (lobar or segmental) was compared between groups Tumor to normal ratio (TNR) from planning Tc99m-MAA SPECT imaging was calculated using dedicated software (MIM, Beachwood, Ohio). Tumor absorbed dose (AD) was calculated based on TNR and a 3-compartment model. Response was assessed using mRECIST. Objective response rate (ORR) was the sum of complete (CR) and partial response. Disease control (DC) was the sum of ORR and stable disease (SD). Pearson and Wilcoxon tests were used to assess the statistical significance of observed differences.

Results: Outcomes of the 102 patients are in the Table: 46 patients received DOC and 56 received FLEX. Median age was 67 (Interquartile range [IQR] 63-74). 80 (78%) patients were male and 22 (22%) female. Follow-up was a median of 154 days (IQR: 99-292). 20 patients (20%) had previous TACE: 13% (6/46) DOC and 25% (14/56) FLEX. The groups were similar in Child-Pugh class (p=0.1) and BCLC stage (p=0.3). The index tumor number (p=0.85) and TNR ratio (p=0.1) was similar between groups. Patients in the FLEX group had more segmental infusions (p< 0.001), higher administered activity (p=0.004) and estimated tumor dose (p< 0.001). The FLEX group had smaller tumor volumes (p=0.02). Imaging response was similar between groups (p=0.2). ORR was 73% and 67% for the FLEX and DOC groups (p=0.5). DCR was 96% and 91% for the FLEX and DOC groups (p=0.3).

Conclusion: FLEX dose allowed administration of significantly higher activity with greater estimated tumor dose. Complete vial delivery via segmental arteries is feasible and effective.