During the early 20th century, stomach cancer, also called gastric cancer, was the leading cause of death among cancer patients in the United States. Today, other types of cancer replaced it on the top list while the number of new cases is also continuously decreasing. Reasons for this decline are not totally clear, but experts think that it is due to the decrease in the number of people infected with the Helicobacter pylori bacteria (a known major cause of stomach cancer). Moreover, people nowadays eat less smoked and salted foods (one of the known risk factors for stomach cancer) because of the wide use of refrigeration when storing food.
While stomach cancer isn’t anymore in the spotlight like other types of cancer, it still accounts for about 1.5% of the new cancer cases in the country in 2022, according to the American Cancer Society’s estimates. Globally speaking, it ranks as the third leading cause of cancer deaths and records almost a million new cases annually.
Individuals at a higher risk of this disease also have the tendency to dismiss early symptoms due to a lack of awareness. Therefore, it is important that the general population is still aware of this disease and its treatment options—surgery, chemotherapy, and radiotherapy as conventional treatment options, and targeted therapy as an alternative treatment option.
What is targeted therapy?
As surgery is the only curative treatment for stomach cancer and chemotherapy has low efficacy (or has a median overall survival of 10 months only), alternative treatments such as targeted therapy are needed.
Targeted therapy is another form of cancer treatment that uses medication alongside chemotherapy. Unlike chemotherapy, targeted therapy is rather an alternative treatment method that targets cancer’s specific genes, proteins, or the tissue environment that allows the growth and survival of the cancer. This means that this treatment helps avoid the growth and spreading of cancer cells without damaging healthy cells.
Since there are different types of cancer and there are varying gene changes that may occur in a specific type of cancer, the targeted therapy treatment may change. In developing one, experts identify first the mutated gene and target the proteins that cause the mutation. It may be used alone or in combination with a conventional treatment method.
Types of targeted therapy treatments for stomach cancer
The type of medication administered to stomach cancer patients depends on the stage of the disease and the other form of treatment they have undergone or are currently undergoing.
- HER2-targeted therapy
Some stomach cancer patients may have cancer cells that have too much HER2 (human epidermal growth factor 2) protein on their surface. When the cancer has a high level of this protein, it is called HER2-positive and its cells grow more rapidly. To treat HER2-positive stomach cancer, certain drugs that target the HER2 protein are recommended. These include:
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- Trastuzumab (brand name: Herceptin) – Ideal for those with later-stage HER2-positive stomach cancer, this synthetic version of immune system protein or monoclonal antibody is infused into the vein once every 2 or 3 weeks together with a chemotherapy regimen. Experts found that patients receiving this drug have longer survivorship compared to those who go through chemotherapy alone.
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- Fam-trastuzumab deruxtecan-nxki – When trastuzumab is no longer effective, this antibody-drug conjugate is used. This drug acts as a homing signal, where it attaches to the HER2 protein on cancer cells and brings the chemo drug directly to these cells.
- Anti-angiogenesis targeted therapy
Focused on stopping angiogenesis or the process of producing new blood vessels, this type of targeted therapy starves the tumor by limiting its uptake of nutrients delivered by the blood vessels so it cannot grow and spread. Patients who already developed a tumor while receiving their initial chemotherapy treatment may be given the drug ramucirumab, alone or in combination with paclitaxel.
- TRK-inhibiting targeted therapy
In a few cases, stomach cancers can have changes in one of the NTRK genes, whcih lead to production of abnormal TRK (tropomysin receptor kinase) proteins and abnormal cell growth or cancer. Treating advanced cancers that are still growing due to NTRK genese changes despite other treatments would require TRK-inhibiting drugs like larotrectinib and entrectinib.
How often do stomach patients need targeted therapy treatment?
Although commonly administered orally or via IV once every two or three weeks, the frequency and length of targeted therapy treatment for stomach cancer also depend on how well the body responds to the treatment. Doctors may prescribe it in cycles, where a break is needed following the treatment.
Side effects of targeted therapy in stomach cancer patients
Compared to chemotherapy, side effects of targeted therapy come less severely. They mainly depend on the type of medicine the patient receives. Other factors such as whether the drug is taken alone or in combination with others, dosage, and patient’s general heatlh also determine side effects. Some of the most common side effects of targeted therapy include:
- Fever and chills
- Nausea and vomiting
- Tiredness and weakness
- Headaches
- Diarrhea
- High blood pressure
Rare side effects like the following are also possible:
- Blood clots
- Bleeding
- Heart damage
- Difficulty in healing
- Holes forming in the stomach or intestine, which may lead to infection
These side effects commonly appear during the period of treatment, especially on the first dose. In the next doses, they tend to occur less often, and once treatment ends, they normally go away over time.
It is important for patients to reach out to their healthcare provider to manage the side effects better and increase their quality of daily life.