CHARLOTTE, N.C. — Circulating tumor DNA (ctDNA) from patients with gastrointestinal (GI) cancers tin bespeak attraction response, spare immoderate further treatment, oregon awesome imaginable remission successful those with metastatic cancer, a caller survey reveals.
The blood-based trial for ctDNA "can observe tumor DNA successful circulation and frankincense place adjacent a microscopic crab that would not beryllium recovered by different accepted modalities similar endoscopy oregon radiographic imaging," Apaar Dadlani, MBBS, who was an interior medicine nonmigratory successful the Division of Transplant Hepatology astatine the University of Louisville successful Kentucky astatine the clip of the study, told Medscape Medical News. Dadlani is presently a chap successful transplant hepatology astatine Baylor College of Medicine successful Houston, Texas.
On the different hand, helium said, undetectable ctDNA levels rise the likelihood a idiosyncratic does not person malignant crab cells. In this case, a doc mightiness determine to hold oregon forgo further treatment.
The survey results suggest that the Signatera ctDNA trial (Natera) is delicate capable to measure tumor load and tin assistance usher attraction plans for radical with locally precocious oregon metastatic colorectal cancer, helium said.
Dadlani volition contiguous the findings astatine the American College of Gastroenterology (ACG) 2022 yearly gathering being held successful Charlotte, North Carolina, and virtually.
Study Details
Dadlani and colleagues identified 62 patients with GI cancers for whom ctDNA was ordered. Of those, ctDNA results were disposable for 56 patients; six patients were not included owed to insufficient tumor tissue.
The median property astatine clip of diagnosis was 60 years; 53% were women; and 82% were Caucasian, 16% were Black, and 2% were Asian.
Of the patients who could beryllium evaluated, astir cancers (82%) detected by ctDNA were colorectal adenocarcinoma. The remainder had different GI malignancies. More than 1 3rd (37%) had metastatic cancer.
The biomarker findings corresponded to CT imaging findings successful galore cases. For example, ctDNA reflected tumor load successful 30 patients (54%).
What happened erstwhile ctDNA was undetectable is besides noteworthy. In 23% of patients, undetectable levels influenced decisions connected systemic therapy and acted arsenic a surrogate measurement for gauging attraction response.
"ctDNA was adjuvant successful patients with metastatic colon cancer who had nary detectable illness connected CT scans aft respective rounds of treatment," Dadlani said. These were radical "who wanted to halt attraction but were anxious that accepted scans whitethorn not beryllium picking up residual microscopic disease."
Maintenance therapy was discontinued successful 5 patients with metastatic colorectal crab due to the fact that of antagonistic ctDNA and imaging results.
"While the determination to taper oregon halt attraction is typically made connected the ground of antagonistic imaging, a antagonistic ctDNA worth reinforced our determination by providing an further furniture of reassurance," Dadlani said. "The information that each of these patients person not recurred for implicit a twelvemonth is successful keeping with emerging information connected the beardown predictive oregon prognostic quality of this test."
The survey included six patients with signifier III colorectal crab with antagonistic ctDNA and imaging results who had important postoperative complications oregon were different considered precocious hazard for terrible attraction toxicity. In these cases, "ctDNA investigating was adjuvant successful selecting retired definite frail oregon sick patients from having to instrumentality adjuvant chemotherapy aft surgery," Dadlani said.
In different diligent with colorectal cancer, ctDNA was undetectable aft neoadjuvant therapy, a uncovering that aligned with pathological implicit effect connected the surgical pathology report.
The ctDNA trial was not foolproof, however. Five patients had false-negative ctDNA findings, and 1 diligent had falsely elevated levels.
"In our tiny study, the false-negative complaint was astir 9%," Dadlani said. This means if 100 radical were tested, 9 would person crab that the trial fails to detect.
In six different patients, the researchers could not gully important conclusions.
"While the ctDNA trial appears to beryllium powerfully predictive of crab status, it is not perfect," Dadlani said. "Larger studies volition beryllium needed to spot however delicate it truly is successful predicting beingness oregon lack of cancer."
'An Important Study'
"A blood-based trial connected circulating tumor DNA is promising arsenic a biomarker for crab risk, prognosis, oregon recurrence," Aasma Shaukat, MD, MPH, told Medscape Medical News erstwhile asked to comment.
"The survey is important, arsenic it aims to correlate the level of circulating tumor DNA successful patients with known GI malignancies with tumor load and determination astir utilizing chemotherapy," added Shaukat, manager of outcomes probe successful the Division of Gastroenterology and Hepatology astatine NYU Langone Health successful New York City.
The survey is constricted by its tiny illustration size "and should beryllium considered proposal generating," she said. "But it's a measurement successful the close direction, 1 of precision oncology and medicine wherever we tin usage noninvasive biomarkers to tailor attraction decisions."
For this benignant of biomarker investigating to go mainstream, the biomarker assay needs to beryllium developed and validated successful larger divers cohorts, Shaukat said.
"We besides request longitudinal information connected relation with prognosis, recurrence, and disease-free and wide survival," she said.
The assay is already approved successful colon crab and muscle-invasive bladder cancer, and besides to measure effect to immunotherapy crossed each tumor types, Dadlani said.
"The results of ongoing randomized trials volition assistance to amended specify its relation successful making attraction decisions successful patients with GI cancers," helium added.
Dadlani and Shaukat person disclosed nary applicable fiscal relationships.
American College of Gastroenterology (ACG) 2022 Annual Scientific Meeting: ACG Newsworthy Abstract 55. Presented October 26, 2022.
Damian McNamara is simply a unit writer based successful Miami. He covers a wide scope of aesculapian specialties, including infectious diseases, gastroenterology, and captious care. Follow Damian connected Twitter: @MedReporter.
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