Molecular Testing: A Crucial Step for Gastric Cancer Treatment
- Facing advanced gastric cancer is undeniably challenging, but there are resources and innovative treatments available.
- Make sure to ask your doctor about personalized treatment and molecular testing, which can look for specific characteristics in your cancer cells, like the expression of a protein called claudin 18.2.
- Testing for claudin 18.2 is a crucial step in determining whether a medication called Vyloy will be an effective treatment option. The drug has been approved for certain patients with locally advanced or metastatic gastric cancer.
- This personalized approach to cancer treatment helps ensure that patients receive therapies tailored to the specific characteristics of their cancer, maximizing the likelihood of success.
This targeted therapy option just received approval from the Food and Drug Administration (FDA) and the approval highlights why it’s so important for patients to undergo molecular testing.
Read MoreWhat is Vyloy?
Vyloy is a specialized medication designed for adults with locally advanced or metastatic gastric cancer. Metastatic, or advanced, cancer means that the disease has spread to distant parts of the body and cannot be removed by surgery.This treatment is specifically for patients whose tumors test positive for a protein called claudin 18.2 (CLDN18.2) and are negative for HER2 (human epidermal growth factor receptor 2).
HER2 is a protein that can influence cancer growth. Some cancers, including certain breast and gastric cancers, overproduce HER2, which can make the cancer grow and spread faster. Patients with HER2-positive gastric cancer often benefit from treatments that specifically target HER2, such Enhertu or Herceptin. However, Vyloy is meant for patients with HER2-negative gastric cancer, which means their tumors do not over-express this protein.
For HER2-negative patients, treatment options were historically more limited, but Vyloy provides a new avenue for managing the disease, offering hope for those whose tumors test positive for the claudin 18.2 protein.
The Importance of Claudin 18.2 Testing
Claudin 18.2 is a protein found on the surface of certain cancer cells, including those in the stomach. The presence of this protein is crucial because Vyloy specifically targets cancer cells that express claudin 18.2, helping the immune system recognize and destroy them.
Before starting treatment with Vyloy, your healthcare provider will order a test to determine whether your tumor expresses claudin 18.2 (this is called molecular testing).
Molecular testing should be part of discussions between you and your healthcare team.
“We need molecular testing to inform treatment options and treatment decisions for you,” explains Dr. Valsamo Anagnostou, a medical oncologist and leader of the molecular tumor board at Johns Hopkins Kimmel Cancer Center.
This test is done using a sample of the tumor tissue, which is usually obtained through a biopsy. This test is called immunohistochemistry (IHC) and it just got FDA approval as well. The test involves staining the tumor cells and looking for moderate to strong claudin 18.2 expression in at least 75% of the cells.
By looking at the results of the molecular testing, your doctor will get a better idea of:
- Your treatment options & whether you’re likely to benefit from a targeted therapy
- Whether the targeted therapy is likely to increase survival and improve quality of life
- Whether your cancer will likely become resistant to a targeted therapy
A targeted therapy is a kind of cancer treatment that focuses on specific aspects found on cancer cells only. This often leads to better activity against the tumor and fewer side effects compared with traditional chemotherapy.
“Molecular testing should always be part of discussions between you and your healthcare team,” Dr. Anagnostou emphasizes. “It is important to make decisions on molecular testing together.”
Who is Eligible for Vyloy?
Not every patient with gastric cancer will be a candidate for Vyloy.
To be eligible for this medication a patient must:
- Have tumors that cannot be removed with surgery or have spread
- Be HER2-negative
- Test positive for claudin 18.2
What to Expect During Treatment
Vyloy is administered as an intravenous (IV) infusion. The infusion schedule typically depends on the chemotherapy regimen being used alongside Vyloy — it will be given either every two or three weeks.
Each infusion session will be carefully monitored by healthcare providers, who will watch for any potential side effects and provide medications to prevent nausea and vomiting.
Potential Side Effects
As with any cancer treatment, Vyloy can have side effects.
The most common ones include:
- Nausea
- Vomiting
- Fatigue
- Diarrhea
Some patients may also experience a loss of appetite, abdominal pain, or a decrease in weight. These symptoms may be uncomfortable, but your healthcare team will work closely with you to manage them.
More serious side effects, though less common, include allergic reactions during the infusion, which could cause symptoms such as wheezing, hives, or difficulty breathing. In such cases, medical professionals will be on hand to provide immediate care and adjust the treatment as necessary.
Questions to Ask Your Doctor
- What stage is my gastric cancer? Has it spread to other organs?
- Can we surgically remove it?
- Does my tumor harbor genetic mutations such as claudin 18.2 or HER2?
- Am I eligible to receive Vyloy?
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