Gastric cancer care has evolved significantly. The way diagnosis and treatment of gastric cancer are approached has developed, and today there are many more treatment options for individual cases. In addition to the established therapies of surgery, chemotherapy, and radiation therapy, targeted therapies and immunotherapies are now available for certain patients with gastric cancer.
The care for a gastric cancer patient has changed considerably. First there is the diagnosis and assessment of the extent and possible biological characteristics of the disease. After that comes the treatment. There are different types of gastric cancer, and therefore the treatment is different for every patient.
Starting With an Accurate Diagnosis
A first step in the treatment of a patient with gastric cancer is the accurate diagnosis and assessment of the extent of the disease. This also includes an assessment of the disease in relation to the patient’s symptoms. Patients with gastric cancer can present in a variety of ways. Some patients, for example, have a decrease in their appetite for food and drink due to abdominal discomfort, while others experience nausea, unexplained weight loss, or other digestive problems.
To diagnose gastric cancer, a healthcare professional performs an endoscopy and a biopsy. If during the endoscopy the doctor suspects gastric cancer, they will take a tissue sample from the suspected area. The tissue sample is then sent to the pathologist, who examines it under a microscope to confirm cancer cells and to determine the type of cancer cells present.
Imaging studies are an important part of the assessment of gastric cancer. In addition to endoscopy and biopsy, further studies such as CT or PET scans are used to assess the extent of the cancer. Assessment of the primary tumor and assessment of local and distant spread are important for planning the treatment of gastric cancer.
Understanding the Stage of Cancer
When gastric cancer is diagnosed, it is also important to determine the stage of the cancer. This will help determine the appropriate treatment for a patient with a potentially curable disease. The stage of the cancer will also help determine whether a tumor can be removed by surgery.
For some patients with localized disease, treatment may include surgery with curative intent. Before, during, and after the operation, systemic treatment can be given. Locally advanced, unresectable, or metastasized gastric cancers are treated with systemic therapy. In addition, the symptoms are controlled as needed.
Other factors can depend on a number of different variables, including the primary site of the cancer, the biological behavior of the primary tumor, prior therapy, and the patient’s overall medical condition.
Looking Inside the Tumor
Biomarker testing in advanced gastric cancer is increasingly considered a key part of modern treatment, enabling individualized treatment of the tumor. According to research published by the National Institutes of Health, four key biomarkers are essential for targeted therapy in gastric cancer.
Biomarkers for gastric cancer are features measured in order to diagnose and assess the course of the disease. For the most advanced gastric cancers, testing for HER2, PD-L1, mismatch repair or microsatellite instability, and CLDN18.2 is recommended.
Biomarker results from a tumor do not define treatment on their own. However, results from biomarker testing, the stage of the cancer, the overall health of the patient, and treatment goals can all be used to decide on the best course of action and the most appropriate treatment for individual patients with advanced gastric cancer.
Understanding HER2 and Targeted Treatment
There are several subtypes of gastric cancer that express higher levels of the HER2 protein than normal stomach tissue. In certain clinical situations, patients with gastric or gastroesophageal junction cancer may be treated with HER2-directed treatment. Trastuzumab is one such agent that has been approved for the treatment of HER2-positive gastric and gastroesophageal junction cancers.
Trastuzumab is used for the treatment of patients with HER2-positive gastric or gastroesophageal junction adenocarcinoma.
A targeted therapy works differently from a chemotherapy drug. Instead of attacking all fast-dividing cells, a targeted therapy attacks specific features that allow a cancer cell to grow and survive. This means that a targeted therapy only works on a patient with a type of cancer that expresses the feature that the treatment targets.
The Role of Immunotherapy
These include the use of immune checkpoint inhibitors. These are used to release the brakes on the immune system and are designed to enhance immune responses against cancer cells.
Certain immunotherapy treatments may be considered for some patients with advanced gastric cancer depending on approved indications and clinical factors. Information about PD-L1 expression, mismatch repair deficiency, and high microsatellite instability can be important for individual treatment decisions.
Immunotherapy, similar to other therapies, is not for everyone with gastric cancer. It depends on a number of factors, including the patient’s disease, prior treatment, general health, and the potential benefits and risks of the therapy.
CLDN18.2 and New Treatment Approaches
Another important biomarker for gastric cancer is CLDN18.2. This protein is expressed on the surface of cancer cells of gastric origin.
Zolbetuximab (brand name Vyloy) is a humanized monoclonal antibody directed to CLDN18.2 for the treatment of adults with locally advanced, unresectable, or metastatic HER2-negative gastric or gastroesophageal junction adenocarcinoma whose tumors are CLDN18.2-positive, as assessed by an FDA-approved test. It is administered by IV infusion in combination with fluoropyrimidine- and platinum-containing chemotherapy.
This treatment was developed based on research into the biological characteristics of certain gastric cancers.
Combining Different Treatment Approaches
There are several different approaches to treating gastric cancer. Many patients receive more than one treatment approach as part of their care plan.
There is also a third approach: before, during, and after the surgery, the patient can be treated systemically. When the cancer has spread in such a way that it cannot be removed by surgery, systemic treatment can be used to control the cancer and to relieve symptoms.
For those with gastric cancer and their families researching treatment options, this information can provide a framework or point of reference in discussions with a healthcare team about the best course of treatment for a specific individual.
Supporting the Person, Not Just the Tumor
Cancer is not just about the tumor. Many cancers, including gastric cancer, can affect appetite, nutrition, energy, physical activity, emotional wellbeing, and many other aspects of a person’s life and health. Many of these effects are not alleviated by treatment of the tumor itself.
Nutritional assessment of the gastric cancer patient is important to establish the causes of loss of appetite and to meet their nutritional needs. Supportive care can help alleviate the symptoms of the cancer as well as the side effects of treatment.
When weighing up the expected benefits of a treatment against the expected side effects, patients and their families can reach a decision about the individualized treatment approach based on the patient’s current situation and how it will affect their daily life in the short and long term.
How Treatment Decisions Evolve
Although gastric cancer is not an entity that changes in a sudden manner, gastric cancer treatment is not a fixed entity at the time of a patient’s diagnosis. Imaging, pathology, and biomarkers are all tested. As a result of a started treatment, there can even be a negative reaction. The patient may get worse as a result of symptoms caused by the treatment.
Ongoing evaluation of a patient’s cancer is needed to assess whether the current treatment remains the most appropriate or if another option should be considered by the patient and their healthcare team.
The scientific search for a cure for gastric cancer continues. As more is discovered about tumors, treatment approaches may continue to become more individualized as research evolves.
This article offers an understanding of the processes behind different gastric cancer treatments. It helps explain the science behind the treatment and, therefore, the sometimes differing treatment recommendations for individual patients. Ongoing communication with the patient’s medical team is important in the cancer treatment process.
Disclaimer: The information provided in this article is intended for educational purposes only and should not be interpreted as medical advice, a clinical guideline, or a recommendation for any specific treatment.
