At the Society of Interventional Radiology (SIR) 2022 Annual Meeting (11-16 June, Boston, USA), four of the abstracts submitted were declared ‘Abstract of the Year’ by the society scientific chairs. The prizes were conferred during the final plenary session of the meeting, and, according to SIR, reward the ‘best scientific work’ in terms of ‘overall quality, timeliness and content’.
Erica Emmons (Vanderbilt University Medical Center, Nashville, USA) was one of the winners, for her paper ‘Survival outcomes and toxicities following yttrium-90 (Y90) radioembolization of colorectal cancer metastatic to the liver: 498-patient analysis from the RESiN registry.’ The purpose of the study was to report on the outcomes of 498 patients from a prospective, multicentre, observational registry of Y90 resin microspheres as treatment for colorectal liver metastases. The outcomes measured were treatment characteristics, survival, and safety.
The patients on whom Emmons et al’s study reports were treated from 2015-2020 and the cohort was 40% female (n=200) and 60% male (n=298). The median age was 60 years old.
Regarding tumour burden, it was <10% in 210 (47%), 11–25% in 115 (26%) and >26% in 125 (28%) patients. Treatment was bilobar in 257 (52%) and unilobar in 241 (48%) patients. At baseline, 180 patients (38%) had extrahepatic disease. Eastern Cooperative Oncology Group (ECOG) status was between zero and one in 441 patients (93%).
There was variation in whether Y90 was used as part of first-line therapy (17%), second line therapy (41%) and third line or beyond in 43% of patients. Fourteen per cent of patients had undergone hepatic resections before treatment with Y90, another 14% had received ablation, 6%, and 2% of patients had undergone portal vein embolization.
The median OS among the patients was 15 months after Y90 (95% confidence interval [CI], 13.2-16.9). One-, two- and three-year OS was 60%, 29%, and 19% respectively. Median OS by line of therapy was 13.9, 17.4 and 12.5 months for first-, second- and third-line. PFS across the whole group was 7.4 months (95% CI 6.4-9.5). Median PFS by line of therapy was 7.9, 10, and 5.9 months for first, second and third.
Six months after treatment, hepatic function toxicities were available in 327 patients. Sixty grade three or four hepatic function toxicities developed with bilirubin (in 29 patients), albumin (13), and aspartate aminotransferase (12) toxicity being the most common. The incidence of hepatic function toxicity at grade three or higher significantly increased with multiple lines of therapy, with bilirubin in 6% of patients after first-line, 7.8% after second-, and 10% after third-; p=0.01). Albumin was 4.2% after first-, 3.1% after second-, and 4.7% after third-line; p=0.008). Five patients (1%) died of liver failure, which was able to be attributed to radiation-induced liver disease.
Emmons’ and her co-authors’ conclusion is that Y90 resin microsphere embolization contributed to 15 months OS after treatment, with patients with the longest OS having received the treatment as part of second-line therapy.
Kieran Murphy (Toronto Western Hospital, Toronto, Canada) also won the award, for his report on a non-inferiority, prospective, randomised controlled trial, which compared intradiscal oxygen-ozone chemonucleolysis to microdiscectomy for lumbar disc herniation radiculopathy.
Murphy’s objective was to compare the non-inferiority treatment status and clinical outcomes of the two aforementioned types of treatment in patients with refractory radicular leg pain due to single-level contained lumbar disc herniations.
The study was multicentre, carried out across three European hospital spine centres. Forty-nine patients with a mean age of 40, of whom 17 were females and 32 males, were studied. All had a single-level contained lumbar disc herniation and had been experiencing radicular leg pain for more than six weeks, as well as being resistant to medical management.
Patients were randomly assigned one of the two treatments, with 25 given intradiscal oxygen-ozone and 24 the microdiscectomy. Eighty-eight per cent (n=43) received their allocated treatment and constituted the as-treated (AT) population.
The primary outcome was overall six-month improvement in leg pain, compared to baseline. Secondary outcomes included back numerical rating pain scores (NRS), Roland Morris Disability Index (RMDI) scores and EuroQol (EQ)-5D, which were collected at baseline, one week, and one, three and six months.
In terms of the study’s results, primary analysis found the overall six-month difference between treatment groups in leg pain improvement using the AT population was -0.31 (standard error [SE]=0.84) points, favouring in microdiscectomy. Using the intention to treat (ITT) population, the difference was 0.32 (SE=0.88) points in favour of oxygen-ozone. The difference between oxygen-ozone and microdiscectomy did not exceed the non-inferiority 95% confidence lower limit of treatment difference in either the AT (95% lower limit, -1.72) or ITT (95% lower limit, -1.13) populations.
Both treatments resulted in rapid and statistically significant improvements over baseline in leg pain, back pain, RMDI, and EQ-5D that persisted in follow-up, and no outcome differences were statistically significant between the two groups.
Murphy’s conclusion is that intradiscal oxygen-ozone chemonucleolysis for single-level lumbar disc herniations that are unresponsive to medical management, met the non-inferiority criteria to microdiscectomy on six-month mean leg pain improvement. Moreover, both treatment groups achieved similarly rapid, significant and persistent clinical improvements. The study also found that 71% of patients who were randomised to the oxygen-ozone group were able to avoid having further surgery.
Bela Kis (Moffitt Cancer Center, Tampa, USA) received the prize for the second time in two years. In 2020, his winning abstract was ‘Transarterial chemoperfusion treatment of unresectable pleural mesothelioma—interim results of a phase two prospective study’. This year, he won with ‘Radioembolization with Y90 glass microspheres as first-line treatment for unresectable intrahepatic cholangiocarcinoma—a prospective phase two clinical trial’.
Kis explained that patients with unresectable intrahepatic cholangiocarcinoma (IHC) have a dismal prognosis; without treatment the expected survival is three to six months. Standard-of-care first-line treatment with gemcitabine and cisplatin demonstrated improved median overall survival (OS) of 11.7 months. However, this therapy was complicated by severe adverse events in 70% of patients. Prior retrospective studies demonstrated survival benefit of Y90 radioembolization as a first-line treatment in IHC with minimal side effects. The recent phase two clinical trial (MISPHEC) of a combination of Y90 radioembolization plus chemotherapy (cisplatin and gemcitabine) as a first line-treatment in ICC showed median OS of 22 months, but 71% of patients had severe, grade three and four, adverse events. In view of these prior reports, Kis’ study aimed to evaluate the safety and efficacy of Y90 glass microsphere radioembolization as first-line treatment without chemotherapy for unresectable IHC.
Twenty-five eligible patients were enrolled in Kis’ institutional review board-approved phase two study. Eligibility criteria were absence of evidence of extrahepatic metastasis, Childs-Pugh A or B, without main portal vein thrombus, bilirubin <2mg/dL, ECOG performance status of zero to two, and not having chemotherapy, liver embolization, or radiation therapy for IHC. The primary endpoint was progression-free survival (PFS) and secondary endpoints, OS and toxicity.
Two patients were excluded from the study on the basis of unrecognised lung metastasis at the time of Y90 treatment, and right hepatectomy four weeks after Y90, respectively. Twelve women and 11 men were included, of whom the median age was 76 years.
The patients received a median dose of 136Gy radiation from the Y90 treatment. Median PFS was 5.5 months (95% CI: 3.9–7.1 months). Median OS was 27.2 months (95% CI: 8.5–4.9 months) from diagnosis and 19.4 months (95% CI: 4.6–34.1 months) from Y90 treatment.
Univariate and multivariate analyses were performed to find prognostic factors associated with PFS and OS, but none were identified. Furthermore, Kis states that, patients tolerated the radioembolization treatment well, with only two incidences of grade-three toxicity (radiation capsulitis and gastric bleed) reported. At three months, there was one grade three biochemical toxicity (elevated bilirubin).
Kis concludes that first-line treatment of IHC with radioembolization is promising from an OS and toxicity standpoint. When compared to published data on IHC, radioembolization appears to be at least as effective as systemic chemotherapy, but with a much better toxicity profile. This prospective trial suggests that radioembolization can be considered a first-line treatment for unresectable IHC, and can be a stepping stone to initiate large, multi-institutional randomised trials to compare radioembolization to chemotherapy as a first-line treatment of unresectable IHC.
Amy Deipolyi (Charleston Area Medical Center, Charleston, USA) was another presenter whose abstract ‘Immune activation markers and response to radioembolization of breast cancer liver metastasis: Pilot study’ won the prize. Her purpose in carrying out the study was to ascertain whether radioembolization (RE) of breast cancer liver metastasis (BCLM) activates immune function, as well as to identify the markers of immune function that are associated with RE response. RE was found to be associated with immune activation, as seen within the tumour microenvironment and peripherally. The results also suggest that peripheral markers of inflammation, including monocytes, MDSCs, and ILs may indicate a poor response to RE.
