Immunotherapy for Cancer Treatment: What is it and How Does it Work for Gastric Cancer Patients?
This type of cancer treatment is not suitable for every single gastric cancer case. This cancer has to be at a certain stage of development and, most importantly, of a certain type. The amount of previous treatment a patient has gone through is also an important factor. His biomarkers have to be tested as well in order to establish whether this type of treatment is suitable for the patient. All in all, this cancer treatment is a very complex issue and has to be considered in great detail in every single case of gastric cancer.
What Is Immunotherapy?
Tumor cells evade the immune system. They are not recognized by the immune system or they are suppressed by it. There are many types of immunotherapy. The main class used for the treatment of cancer is the immune checkpoint inhibitors. These drugs release the brakes on the immune system allowing it to recognize and attack cancer cells.
How Immunotherapy Works for Cancer Patients Compared to Chemo.
Why Immunotherapy May Be Considered
Immunotherapy is not a “cure-all” for every type of Gastric Cancer and must be considered on a case by case basis for the individual with Gastric Cancer. When considering treatment for a patient with advanced gastric cancer, another factor to consider is the expression of PD-L1 in the tumor. The PD-L1 status in the tumor can provide additional information to help decide on an immune checkpoint inhibitor for the treatment of patients with advanced gastric and gastroesophageal junction (GEJ) cancer.
In clinical practice, tumor PD-L1 expression levels are determined using established scoring systems for tumor PD-L1 expression. The results are then considered in light of all relevant clinical patient information and a decision is made regarding the appropriate treatment for that patient’s gastric or gastroesophageal junction cancer.
The Importance of Biomarker Testing
For gastric cancer, a number of biomarkers are currently tested for in order to best manage a patient with this type of cancer. The biomarkers that are tested for include the HER2 protein, PD-L1 protein, the mismatch repair proteins (MMR proteins) to see if a tumor is deficient in mismatch repair, and the high levels of microsatellite instability (MSI-H) in a tumor. Tumors can also express the CLDN18.2 protein.
Additionally, it has been established that gastric cancers with mismatch repair deficiency (dMMR) or high microsatellite instability (MSI-H) can benefit from immune checkpoint inhibitors.
Biomarker testing for a tumor does not predict whether a patient with cancer will respond to a particular cancer treatment. However, it can help a cancer patient, and their family members and physician(s), and decide on the best cancer treatment or options for a particular clinical situation. For patients with gastric cancer, it is very important to ask the healthcare professional whether any relevant biomarker testing has been done to help assess the treatment options.
Immunotherapy and Combination Treatment
Immunotherapy is sometimes used in combination with chemotherapy. The most important factor is the indication for the treatment, the disease and the biomarker status.
Pembrolizumab (anti-PD-1 antibody) has been approved for the treatment of patients with gastric cancer and gastroesophageal junction (GEJ) adenocarcinoma and for specific indications, in different tumor stages, with different biomarker profiles and in different clinical situations. Combining immunotherapy with chemotherapy can have both benefits and risks. Therefore it is necessary to carefully consider the expected benefits compared with the expected risks.
Understanding Possible Side Effects
Since the side effects of immunotherapy can cause severe problems in different organs and tissues, they are different from those of chemotherapy and affect healthy tissues when the activated immune system causes inflammation in these tissues.
There can be many effects on other tissues and organs due to the activated immune system, such as inflammation in the skin, bowel, liver, lungs and thyroid, for example. Side effects can be very different from person to person and even affect different organs. It’s very important that patients report any new or unusual symptoms to their doctor. The doctor can then assess the symptoms to see if they could be caused by the treatment.
Early detection and management of any problems that develop as a result of treatment is very important as some of the side effects can be very severe and need specific treatment.
Treatment Decisions Can Change
Changes to treatment are common and are based on a number of factors. For example, if the patient develops new symptoms or the existing ones worsen, a review of treatment can take place. Additionally, any side effects that are caused by the treatment can mean that a change in treatment is necessary.
Pathology information (e.g. biomarker status) about the tumor and information about previous treatment(s) of the individual’s cancer, as well as information about the individual’s organ function, nutritional status and performance status can also be relevant. Immunotherapy is not given for the rest of a patient’s life and is often given for a time frame. Therefore decisions are made with the individual patient’s best interest in mind based on their current clinical situation.
Maintaining Quality of Life
Supportive care to treat side effects of gastric cancer treatment and to ensure the best possible quality of life for the patient with gastric cancer, and their family and/or carers, is an essential component of their overall cancer care.
Support from the cancer treatment team and from the family and friends can also help with any side effects and with maintaining nutrition and overall wellbeing while on immunotherapy.
Discussion of the goals of treatment for patients with gastric cancer and their families can also help to inform them of the intended effects of their current treatment and how it is likely to affect them in terms of their symptoms and activities of daily living.
The Future of Immunotherapy
Much research into new and existing immunotherapies for gastric cancer is currently underway. In the main, these are being assessed in terms of how to best use them, i.e., which patients are most likely to manage from a particular treatment. Future gastric cancer immunotherapies may consist of new single agents as well as combination regimens with chemotherapy and/or other targeted cancer therapies. These novel agents must first be tested in appropriate clinical trials to establish their benefit to patients as well as potential risks and adverse events.
Future potential therapies for gastric cancer are in the early stages of development and are being tested in clinical trials. Such new therapies will require approval by relevant regulatory authorities before they can be prescribed to patients.
An Individualized Approach to Care
Immunotherapy for gastric cancer is not a ‘one size fits all’ treatment. It is essential that the treatment is given on an individual basis and that consideration is given to the tumor, the resulting biomarker results and the patients’ disease, previous treatment and overall health in addition to their treatment goals.
Patients are best equipped to make a responsible decision regarding their cancer treatment when they are thoroughly and sufficiently informed about the use of immunotherapy for their cancer and are able to have the best possible discussion with their doctor regarding this treatment.
Immunotherapy is not a universal treatment for all patients with gastric cancer. The decision to use immunotherapy for the treatment of gastric cancer requires consideration of a number of factors, including the information regarding the patient’s tumor as well as the patient’s individual circumstances. In these days of individualized treatment of gastric cancer, it is important to note that in addition to immunotherapy, gastric cancer is treated with surgical treatment, chemotherapy, radiation therapy, targeted treatment and more.
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.