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A team at Washington University School of Medicine in St. Louis has developed a novel test for two blood cancers. It marks the first time the Centres for Medicare & Medicaid Services have approved reimbursement for a whole-genome sequencing cancer test. Known as ChromoSeq, this test advances precision medicine approaches in treating blood cancers by identifying the complete range of genetic alterations in a patient’s cancer cells. This information is crucial for physicians in determining the most suitable treatment plan for individual patients.
Since 2021, Washington University oncologists have regularly used ChromoSeq to guide treatment for AML and MDS patients at the Siteman Cancer Centre. Now, Medicare’s approval means healthcare providers serving Medicare patients with AML or MDS can request the test through Washington University Pathology Services, with Medicare covering the costs.
The treatment approach for AML and MDS depends on the patient’s cancer aggressiveness, involving chemotherapy drugs and, sometimes, a stem cell transplant to induce remission. In contrast, less aggressive blood cancers can often be effectively managed with less intense drug regimens.
Treatment choice typically revolves around the genetic alterations in a patient’s cancer. Current diagnostic practices rely on three tests:
- Cytogenetics, which reveals chromosomal rearrangements and abnormalities.
- Fluorescence in-situ hybridisation, which also identifies chromosomal abnormalities and other mutations.
- Targeted sequencing of specific genes previously associated with AML and MDS.
However, these tests have limitations and provide only a partial understanding of the genetic errors potentially driving cancer development.
In the present standard medical practice, genetic alterations are evaluated through a trio of tests: cytogenetics, which detects chromosomal rearrangements and irregularities; fluorescence in-situ hybridisation, which not only identifies chromosomal abnormalities but also other mutations; and targeted sequencing of specific genes known to be associated with AML and MDS.
“We can obtain all the information currently derived from three separate tests, which are standard in medical practice, using just one ChromoSeq test,” explained Meagan Jacoby, MD, PhD, an associate professor of medicine.
It is crucial because the reliability of results from other tests can sometimes be uncertain, impacting our ability to assess a patient’s risk of aggressive disease. Determining a patient’s risk level is vital for tailoring the most appropriate treatment.
“Since ChromoSeq examines the entire genome, it can detect rare mutations not included in targeted genetic sequencing tests,” Jacoby explained.
ChromoSeq is part of WashU Medicine’s ongoing legacy of genomic advancements. Preliminary data from these trials suggests that ChromoSeq can provide additional information that may alter individual patient treatment plans. However, the full extent of ChromoSeq’s impact will only be understood once the trials are concluded.
Furthermore, ChromoSeq can be continually updated as more information emerges about the role of specific genetic changes in blood cancers.
Currently, the researchers are focused on expanding whole-genome sequencing methods to address different cancer types, beginning with additional blood-related cancers like acute lymphocytic leukaemia and multiple myeloma.
They have selected these specific cancers because they share similar patient samples – blood and bone marrow. It allows the researchers to apply the same laboratory techniques developed for AML and MDS.
“With minor adjustments to this approach, whole-genome sequencing has substantial potential to revolutionise the diagnosis and treatment of various other cancer types,” asserted Jacoby.