To determine the relationship of tumor absorbed dose with microsphere distribution/mL using PET/CT derived tumor to normal ratio (T:N) in HCC patients treated with 90Y radiation segmentectomy.

Monday, March 6, 2023

12:00 PM – 1:00 PM

Location: Phoenix Convention Center, North Ballroom 120 D

Poster Presenter(s)

Muhammad Saad Malik, MD

Post-doctoral Research Fellow
Beth Israel Deaconess Medical Center | Harvard Medical School

Disclosure information not submitted.

Author/Co-author(s)

Nhi H. Vo, MD

Resident
BIDMC
Muhammad Mohid Tahir, MD (he/him/his)

Postdoctoral Research Fellow
Beth Israel Deaconess Medical Center
AP

Anthony J. Parker, MD PhD

Associated Professor Radiology
BIDMC
JW

Jeffrey Weinstein, MD FSIR

Program Director, Interventional Radiology Residency Programs
Beth Israel Deaconess Medical Center/Harvard Medical School
MA

Muneeb Ahmed, MD FSIR

Chief, Division of Interventional Radiology
Beth Israel Deaconess Medical Center/Harvard
Ammar Sarwar, MD FSIR (he/him/his)

Associate Professor of Radiology
Beth Israel Deaconess Medical Center

Disclosure(s):

Nhi H. Vo, MD: No financial relationships to disclose

Muhammad Mohid Tahir, MD: No financial relationships to disclose

Jeffrey Weinstein, MD FSIR: BAIM Institute: Advisory Committee or Review Panel Member (Ongoing); Instylla: Advisory Committee or Review Panel Member (Ongoing)

Muneeb Ahmed, MD FSIR: Agile Devices, Inc.: Advisory Committee or Review Panel Member (Ongoing), Consultant (Ongoing), Ownership Interest (Ongoing); Replimune, Inc.: Consultant (Ongoing); RevOps Health, Inc.: Advisory Committee or Review Panel Member (Ongoing), Consultant (Ongoing), Ownership Interest (Ongoing)

Ammar Sarwar, MD FSIR: Agile Devices, Inc.: Advisory Committee or Review Panel Member (Ongoing)

Purpose:

Determine relationship of tumor absorbed dose with microsphere distribution/mL using PET/CT tumor to normal ratio (T:N) in HCC patients treated with ⁹⁰Y radiation segmentectomy.

Materials and Methods:

Consecutive HCC patients from 1/2018 to 7/2022 having PET/CT after TARE (108) with resin in <2 segments (56) & 3-month treatment response (48) were retrospectively studied at a single, tertiary hospital. Prescribed activity & prescribed tumor absorbed dose (pTAD) was based on the ^99mTc MAA dosimetry (PD). Area segmentation on PET/CT was contoured using MIM SurePlan Liver & dose delivered to 50, 70, & 95% of tumor (D₅₀, D₇₀, D₉₅) was derived from dose volume histograms. Sphere distribution was based on single dose size containing 3.0 GBq.

Sphere_stotal = (𝐴𝑐𝑡𝑖𝑣𝑖𝑡𝑦𝑡𝑜𝑡𝑎𝑙 [𝐺𝐵𝑞])/(3−𝑑𝑎𝑦 𝑃𝑟𝑒−𝑐𝑎𝑙 𝑉𝑖𝑎𝑙 [𝐺𝐵𝑞]) 𝑥 44 𝑚𝑖𝑙𝑙𝑖𝑜𝑛

Spheres_tumor = (𝑆𝑝ℎ𝑒𝑟𝑒𝑠 𝑇𝑜𝑡𝑎𝑙)/(𝑇𝑎𝑟𝑔𝑒𝑡 𝑉𝑜𝑙𝑢𝑚𝑒 [𝑐𝑐]) 𝑥 𝑇𝑢𝑚𝑜𝑟 𝑉𝑜𝑙𝑢𝑚𝑒[𝑐𝑐] 𝑥 𝑃𝐸𝑇−𝐶𝑇 𝑇:𝑁

3-month imaging to assess objective response (OR) using mRECIST. Median reported for continuous variables, & unpaired T-test was done on a per tumor per treatment basis.

Results:

A total of 48 tumors (48 treatments) in 44 patients (71 years) were analyzed. 90% had cirrhosis, with MELD of 9 ± 4, & size of 3.4 cm (1.9-4.7). <90% prescribed activity delivered in 29% (14/48) & ≥90% in 71% (34/38) of tumors. 73% (35/48) had OR. Tumors with OR were smaller on PET/CT (19 vs 76 mL, p< 0.01). Spheres to target & tumor were 7.1 x 10⁶ (20,469 spheres/mL) & 1.3 x 10⁶(54,889 spheres/mL). No difference seen in tumor spheres/mL between ≥90% vs 90% activity group (54,881 vs 56,737, p=0.54). Tumors with OR had more spheres/mL than those without (61,826 vs 31,445, p=0.22). A significantly positive relationship existed between D₅₀ & tumor spheres/mL (r [46] = .898, p < .001). There was significant difference in tumor sphere/mL between specific ranges for D₅₀: 20-100 Gy (17,578 [13,777-28,596]), 100-200 Gy (31,701 [26,766-39,498]), 200-300 Gy (64,745 [54,550-90,529]), & 300-500 Gy (102,997 [72,815-172,456]), p< 0.001). Tumors with ≥100k spheres/mL (vs < 100k) had higher D₅₀ (475 vs 173 Gy, p< 0.001), D₇₀ (344 vs 120 Gy, p< 0.001), D₉₅ (125 vs 55 Gy, p< 0.001). Tumors ≥50k spheres/mL (vs < 50k) had higher D₅₀ (280 vs 136 Gy, P< 0.001), higher chance of >200 Gy D₅₀ (88% vs 5%, p< 0.001) & higher OR (88% vs 55%, p< 0.05). Tumors ≥45k spheres/mL achieved 200 Gy in 88% of cases, & OR in 88% of treatments.

Conclusion:

A positive relationship existed between D₅₀ & tumor spheres/mL. ≥45k spheres/mL had a higher chance of achieving OR.