From the Journals

Pretreatment CT data may help predict immunotherapy benefit in ovarian cancer



Pretreatment CT data may help identify responders to immunotherapy in ovarian cancer, according to a new study.

Specifically, fewer sites of disease and lower intratumor heterogeneity on contrast-enhanced CT may indicate a higher likelihood of durable response to immune checkpoint inhibitors, according to results of the retrospective study, recently published in JCO Precision Oncology.

“Our results suggest that quantitative analysis of baseline contrast-enhanced CT may facilitate the delivery of precision medicine to patients with ovarian cancer by identifying patients who may benefit from immunotherapy,” wrote Yuki Himoto, MD, PhD, of Memorial Sloan Kettering Cancer Center in New York, and colleagues.

The study leverages findings from the emerging field of radiomics, which the investigators note allows for “virtual sampling” of tumor heterogeneity within a single lesion and between lesions.

“This information may complement molecular profiling in personalizing medical decisions,” Dr. Himoto and coauthors explained.

The study cohort included 75 patients with recurrent ovarian cancer who were enrolled in ongoing, prospective trials of immunotherapy, according to the researchers. Of that group, just under one in five derived a durable clinical benefit, defined as progression-free survival lasting at least 24 weeks.

In univariable analysis, they found a number of contrast-enhanced CT variables were linked to durable clinical benefit, including fewer disease sites, lower cluster-site entropy and dissimilarity, which they wrote were an indicator of lower intertumor heterogeneity, and higher energy in the largest-volume lesion, which they described as an indicator of lower intratumor heterogeneity.

However, in multivariable analysis, the only variables that were still associated with durable clinical benefit were fewer disease sites (odds ratio, 1.64; 95% confidence interval, 1.19-2.27; P = .012) and higher energy in the largest lesion (odds ratio, 1.41; 95% CI, 1.11-1.81; P = .006), according to the report.

Those two factors combined were a composite indicator of durable clinical benefit (C-index, 0.821).

These findings could represent a step forward in the provision of immunotherapy in ovarian cancer, which exhibits poor response to immune checkpoint inhibitors, compared with some other cancer types, the investigators wrote.

More insights are needed, however, to help personalize the selection of immunotherapy in ovarian cancer, including a better understanding of cancer immune reactions and retooling of immune response criteria, they added.

“Composite multimodal multifaceted biomarkers that noninvasively capture spatiotemporal tumor heterogeneity will likely be necessary to comprehensively assess immune the tumor microenvironment and serve as clinical decision support for prognosis inference and prediction of response,” Dr. Himoto and associates wrote.

The study was supported by the National Cancer Institute, among other sources. Study authors reported disclosures related to Merck, Bristol-Myers Squibb, Genentech, Celgene, AstraZeneca, Y-mAbs Therapeutics, and others.

SOURCE: Himoto Y et al. JCO Precis Oncol. 2019 Aug 13. doi: 10.1200/PO.19.00038.

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