Radiation segmentectomy, a minimally invasive procedure that can be done on an outpatient, same-day basis, is potentially as curative as other curative strategies for early-stage hepatocellular carcinoma (HCC) and should be considered as an alternative for patients who cannot undergo liver resection, a retrospective analysis suggests.
Potentially curative strategies for early-stage HCC include resection, transplantation, and radiofrequency ablation.
“Radiation segmentectomy (RS) is a targeted form of radioembolization with yttrium 90 (90Y), usually delivered to no more than two hepatic segments [where] the high tumor dose maximizes cytotoxic radiation delivery, whereas the focused delivery minimizes risk of collateral parenchymal damage,” Robert Lewandowski, MD, Northwestern University Feinberg School of Medicine, Chicago, Illinois, and colleagues explain.
“Our outcomes suggest that RS may be considered curative in patients with unablatable BCLC (Barcelona Clinic Liver Cancer) stage 0 or A lesions less than or equal to 5 cm,” they conclude.
The study was published online April 24 in Radiology.
The analysis included 70 patients, median age 71 years, with a solitary HCC 5 cm or less that was not amenable to treatment with percutaneous ablation.
These 70 patients underwent RS treatment over a period of 14 years, the investigators note; 66% had RS to one segment containing the tumor, while the remaining 34% of patients required RS to two segments.
Most (71%) patients had tumors 3 cm or less, while the remaining 29% had tumors between 3 and 5 cm in size.
“RS was performed with glass microspheres (BTG International, Ottawa, Canada) impregnated with 90Y [yttrium 90],” the investigators write.
Cone-beam computed tomography (CT) was also done to ensure the tumor was completely targeted, they add and to guarantee focused delivery of the 90Y to the relevant segment of the liver involved.
As senior author, Riad Salem, MD, chief of vascular interventional radiology, Northwestern University Feinberg School of Medicine in Chicago, Illinois, explained in a statement, cone-beam CT allows radiologists to perform segmental injections isolated to very small tumors, sparing most normal tissue with a high level of accuracy.
Responses to RS
Responses to the procedure were assessed by both the European Association for the Study of the Liver (EASL) criteria, as well as the necrosis criteria of the World Health Organization (WHO).
At a mean follow-up of 29 months, 90% of the group responded to treatment according to EASL criteria, 59% of them being complete responses.
On the basis of WHO criteria, response rates were lower at 71%, some 16% of them being complete responses according to WHO response criteria.
Across 1 year of follow-up, radiographic responses did fluctuate regardless of which response criteria were used.
Table. Radiographic Response
| Variable | EASL: 1 Month | WHO: 1 Month | EASL: 6 Months | WHO: 6 Months | EASL: 12 Months | WHO: 12 Months |
|---|---|---|---|---|---|---|
| Partial response (%) | 46 | 21 | 42 | 44 | 20 | 60 |
| Complete response (%) | 13 | 4 | 44 | 5 | 63 | 11 |
| Stable disease (%) | 37 | 71 | 6 | 43 | 3 | 20 |
| Progressive disease (%) | 4 | 3 | 8 | 8 | 14 | 9 |
“Median time to progression was 2.4 years,” researchers add.
This outcome did not change when tumors were stratified by size (≤3 cm and >3 cm), they note.
Similarly, median time to target lesion progression was not reached regardless of tumor size and the probability of remaining free of disease progression at both 5 and 7 years was 72%.
“Median overall survival for the entire 70-patient cohort was 6.7 years,” Lewandowski and colleagues observe, “with a 1-, 3-, and 5-year survival probability of 98%, 66%, and 57%, respectively,” investigators observe.
Confining their analysis to patients with tumors of 3 cm or less, survival odds were even better with 100% of patients predicted to be alive at 1 year, 82% at 3 years, and 75% at 5 years, the researchers point out.
The toxicity profile of RS was also extremely favorable, with very few patients developing any notable adverse events.
“The favorable adverse event profile in a treatment that can be performed on an outpatient same-day basis should be considered competitive to more invasive traditional curative treatments,” researchers suggest.
“[And] with the advent of the cone-beam CT, [RS] should be considered in patients with unablatable or unresectable HCC,” they add.
“Impressive Results”
Asked by Medscape Medical News to comment on the study, Mohamed Bouattour, MD, Beaujon University Hospital, Clichy, France, suggested that the use of “selective” radioembolization as was deployed in the current study showed “impressive” results in terms of tumor control and survival benefit for this population.
“Unlike advanced stage HCC, when compared or added to systemic therapies, radioembolization with yttrium 90 seems to have a promising effect on early HCC,” Bouattour said in an email.
Bouattour cautioned that study results need to be considered in light of the study’s retrospective design and the limited size of the patient sample.
He also pointed out that the center where these procedures were performed is one with great expertise in this arena, and he cautioned that less experienced centers may not be able to achieve similarly good results.
Nevertheless, “this approach with radiation segmentectomy using radioembolization with yttrium 90 seems to be promising for early HCC in patients not eligible for surgery or liver transplantation, although prospective studies are warranted to confirm such results,” Bouattour concluded.
Lewandowski reports serving as a consultant for BTG. Salem reports serving a consultant for Boston Scientific, BTG, and Terumo and receives travel/accommodation and meeting expenses from BTG as well. Bouattour has received speaker fees from Bayer and Sirtex Medical and is a member of the advisory boards for Bayer, Bristol-Myers Squibb, and SIRTEX Medical.
Radiology. Published online April 24, 2018. Abstract
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