New X-ray Scanner Could Reduce Repeat Breast-Conserving Operations

A new X-ray imaging scanner could make it easier for breast surgeons to determine if they have removed all cancerous tissue during a breast-conserving surgery.

While conserving surgeries – those that remove only the tumor from breast cancer patients rather than removing the entire breast – account for most breast cancer operations, they are not always completely effective. In many instances, a second surgery is needed because it is difficult for surgeons to know for certain if they have removed all malignant tissue at the time of surgery.

However, a group of researchers from University College London, Queen Mary University of London, Barts Health NHS Trust, and Nikon have developed a new new X-ray imaging approach that lets surgeons determine – during initial surgery – if they have cleared the breast of cancer. This method, they said, improves detection of diseased tissue at the margins 2.5-times over standard imaging.

Examples of the imaging performance of XPCI-CT (b,e) compared to conventional specimen radiography (a,d) and benchmarked against histopathology (c,f). he top row focuses on the similarity between the XPCI-CT slice in (b) and the histological slice in (c). Arrow 1 indicates margin involvement, arrow 2 a variation in density in the internal structure of the tumor mass, arrow 3 tumor-induced inflammation. All this is confirmed by the histological slice in (c), and hardly visible in the conventional image in (a). The bottom row focuses on the detection of small calcifications, a key feature in DCIS. These are undetectable in (d), detected in (e), enhanced in the maximum intensity projection (MIP) image at the bottom of (f), and confirmed by histopathology in the top part of (f). The scale bar [shown in (b) and (e)] is the same for all images apart from (f), which has its own scale. Red arrows in (e) and (f) indicate the microcalcifications.

CREDIT

Professor Alessandro Olivo

They published their findings on Feb. 11 in Scientific Reports. In the paper, they discussed how using X-ray phase contrast imaging (XPCI) for phase-based CT can give surgeons a full 3D image of an extracted tissue lump, also known as a wide local excision (WLE). Beyond assisting the surgeon, the researchers said, if implemented, the technology also offers benefits to the patient.

“This technology has the potential to significantly improve radiological intraoperative assessment of tumor margins,” said co-author Louise Jones, Ph.D., professor and director of the Breast Cancer Now Tissue Bank, “potentially reducing the need for repeat operations that many patients require, which can cause significant distress to the patient.”

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According to the team, XPCI offers better soft tissue sensitivity than a conventional X-ray. Rather than detecting a change in an X-ray beams intensity as it moves through tissue, XPCI measures speed changes. In that way, it augments the contrast of soft tissues, including breast tumors.

Currently, WLE histopathological results are only available after a few days, so surgeons – and patients – must wait to find out if a procedure was successful in removing all cancerous tissue. If any affected margins remain, patients must undergo a second surgery.

Knowing whether the entire tumor has been excised before concluding the initial surgery is preferable, the team said, but, to-date, all attempts at intraoperative assessment have failed. Either these strategies have been unable to detect all diseased tissue, they could not penetrate deeply enough into the specimen to provide an accurate assessment, or they could do neither.

To determine the capabilities and efficacy of XPCI, the team tested the scanner with 101 WLEs and compared the outcomes to those from standard imaging, based on conventional X-rays, that was used intraoperatively. Half of the examined specimens contained a neoplastic lesions. Based on their evaluation, the team found XPCI had much higher sensitivity than conventional imaging – 83 percent and 32 percent, respectively. Specificity rates were comparable – 83 percent to 86 percent, respectively.

Overall, they said, the 2.5-times improvement they saw in detection could also translate into a similar drop in the re-operation rate.

“Although we have focused on the impact of XPCI in breast surgery,” said Tamara Suaris, consultant breast radiologist at Barts NHS Health Trust, “there is a much wider clinical potential of this technology, including other intraoperative areas, such as intestinal, esophageal, and prostatic surgery, and in the longer term, diagnostic imaging, notably mammography.”

This development opens the door for the first potential clinical use for XPCI, said lead author Alessandro Olivo, Ph.D., professor from UCL medical physics and biomedical engineering.

“The technology has tremendous potential,” he said, “and I am sure once people see what it can do many other clinical areas will follow suit.”

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