It is now possible to detect residual tumor cells during surgery within minutes, a groundbreaking advancement in the surgical treatment of tumors.
In a recently published study, the UC San Francisco Brain Tumor Center team validated a novel optical imaging technique called stimulated Raman histology (SRH) for rapid, intraoperative detection of glioma infiltration at the tumor margin. This method yields images within minutes for microscopic detection of residual tumor cells—information that can help guide decisions on the extent of resection and improve patient survival rates.
Gliomas typically exist within complex neural networks essential to neurological functions. Differentiating tumor cells from normal brain tissue is challenging, particularly at the infiltrative tumor margin. Because the most common site of glioma recurrence is near the resection cavity, it is critical to identify and remove residual tumor cells to the greatest extent possible.
“It’s shocking that close to 50 percent of radiographically clean glioma margins contain residual tumor cells,” said lead author of the study, Shawn Hervey-Jumper, MD, neurosurgeon and associate professor in residence of neurological surgery at UCSF. “We need better tools to treat patients with low- and high-grade gliomas. SRH has the potential to greatly improve patient outcomes,” he added.
SRH identified residual glioma at the margin
Identification of tumor cells on a microscopic level is normally a time- and labor-intensive process, not feasible for intraoperative rapid detection. SRH is a nondestructive, rapid, label-free technique that provides imaging of unprocessed surgical tissues at microscopic resolutions.
In the recent study, the UCSF Brain Tumor Center team found that SRH imaging of the glioma margins detected microscopic residual glioma cells that were not found by standard intraoperative imaging methods, including white-light microscopy and neuronavigation.
For the study, the team used 179 margin samples procured from 31 patients, ages 22 to 83, during brain tumor resection. The samples were evaluated intraoperatively with the NIO Laser Imaging System developed by Invenio Imaging. This portable, clinical tool images unprocessed tissue without sectioning or staining, enabling rapid histologic evaluation during surgery.
Researchers found agreement when comparing SRH images with IHC and H&E stains
When comparing the SRH images of the 179 margin samples to images of the same samples produced using standard microscopic detection methods, the UCSF researchers found excellent agreement with immunohistochemistry (IHC) and hematoxylin and eosin (H&E) stains. SRH imaging can generate pseudo-H&E images within minutes, allowing for microscopic-level identification of residual tumor cells during surgery. Not previously validated in the intraoperative setting, this innovative technique has the potential to significantly increase the amount of tumor that can be removed and therefore improve survival rates for patients with brain tumors.
The UCSF Brain Tumor Center is one of the largest and most comprehensive programs for brain tumor treatment in the United States. The team’s mission is to provide patients with the best possible outcomes and quality of life, using the latest treatments and technology. UCSF is ranked as the nation’s #1 hospital for neurology and neurosurgery according to the 2020-2021 Best Hospitals survey by U.S. News & World Report.
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