Genetic testing cost effective for newly diagnosed GIST

Date:
September 28, 2020
Source:
University of California - San Diego
Summary:
Researchers reported that genetic testing is cost-effective
and beneficial for newly diagnosed patients with metastatic
gastrointestinal stromal tumors (GIST), a rare type of cancer.



FULL STORY ========================================================================== Because gastrointestinal stromal tumors (GIST) are sensitive to the
targeted small molecule therapy imatinib, oncologists tend to treat all patients with metastatic GIST with this drug. However, because this rare
type of cancer is caused by different genetic mutations, imatinib does
not help all patients equally.


==========================================================================
To determine whose cancer may be most responsive, the National
Comprehensive Cancer Network suggests that patients undergo genetic
testing to identify each individuals' tumor mutations. And yet, only
30 percent of patients have genetic testing at the time of diagnosis,
likely due to concerns over cost and utility of testing, said Jason
Sicklick, MD, professor of surgery in the Division of Surgical Oncology
at University of California San Diego School of Medicine.

"We recommend that all patients with a new diagnosis of metastatic
GIST undergo genetic testing prior to the initiation of first-line chemotherapy," said Sicklick, surgical oncologist and co-leader of the
Sarcoma Disease Team at Moores Cancer Center at UC San Diego Health. "In
doing so, those who are unlikely to benefit from imatinib can be given
a treatment better suited for their individual tumor." In a paper
published online on September 29, 2020 in the journal JAMA Network Open, Sicklick and colleagues reported that genetic testing is cost-effective
and beneficial for newly diagnosed patients with metastatic GIST, a type
of soft tissue sarcoma that develops in specialized nerve cells in the
wall of the digestive system, most often occurring in the stomach or
small intestine.

The team developed a model to compare the cost effectiveness of targeted
gene testing and personalized therapy to patients with metastatic GIST
who were prescribed imatinib (marketed as Gleevec). Data analyses were conducted October 2019 to January 2020.

"Genetic testing is cost-effective as it allows clinicians to prescribe chemotherapy in a tumor-specific manner. Patients who would not benefit
from imatinib, because of primary tumor resistance, are given alternative therapy," said first author Sudeep Banerjee, MD, who did the research
while in the Sicklick lab at Moores Cancer Center and who is now chief
resident at David Geffen Medical School at UCLA. "Avoiding ineffective treatment and reduced rates of disease progression are the reasons why
genetic testing is cost- effective." Although the most common sarcoma,
GIST is rare with an estimated annual incidence of 6.8 cases per million
people in the United States. Eventually this cancer becomes highly
resistant to existing drug therapies.

Clinicians fight the growth with progressively aggressive drugs, the
downside being that each line of therapy has diminishing effectiveness and higher toxicity for patients. More than 95 percent of patients eventually succumb to drug-resistant GIST, underscoring the importance of starting patients on the most effective available drug not only because it is most cost-effective, but crucial for maintaining and improving quality of life
in these patients, said Sicklick, co-corresponding author on the paper.

"The treatment of cancer is becoming an increasingly personalized
process," said Banerjee. "There is a rapidly expanding body of research
around gene- specific and even mutation-specific therapies that can be effective independent of the site of origin of a given tumor. Genetic
testing provides the necessary information for patients to potentially
benefit from those novel therapies."

========================================================================== Story Source: Materials provided by
University_of_California_-_San_Diego. Original written by Yadira
Galindo. Note: Content may be edited for style and length.


========================================================================== Journal Reference:
1. Sudeep Banerjee, Abhishek Kumar, Nicole Lopez, Beiqun Zhao, Chih-Min
Tang, Mayra Yebra, Hyunho Yoon, James D. Murphy, Jason
K. Sicklick. Cost- effectiveness Analysis of Genetic Testing
and Tailored First-Line Therapy for Patients With Metastatic
Gastrointestinal Stromal Tumors. JAMA Network Open, 2020; 3 (9):
e2013565 DOI: 10.1001/ jamanetworkopen.2020.13565 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2020/09/200928152845.htm

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