How immunotherapy works in eligible lung cancer patients
In battling cancer, there is no “one size fits all” treatment strategy because regimens differ depending on a patient’s cancer type, stage and medical oncologists’ understanding of the patient’s cancer cells based on diagnostic results.
Given the range of cancer treatments available, including new breakthrough treatments like immuno-oncology and targeted therapy, early testing and diagnosis are even more so crucial in determining the best course of medication for each individual patient.
“Because cancer patients respond differently to treatment, we need to know the histology of a patient’s tumor cells to be able to give the right treatments that will best improve prognosis for remission and survival,” explained Dr. Wen-Son Hsieh, specialist in medical oncology at ICON SOC, a leading cancer care center in Singapore.
Dr. Hsieh was one of the doctors who spoke during the 32nd Philippine Society of Medical Oncology (PSMO) Convention held recently at the EDSA Shangri-La Hotel in Ortigas Center.
Dr. Hsieh talked about how screening and diagnosis determine eligibility for cancer treatments with focus on immunotherapy, a new treatment option for advanced non-small cell lung (NSCLC) cancer, the most common type of lung cancer.
“For decades, we’ve been studying how we can stimulate the immune system to fight cancer cells just like how it eliminates infections. Now, we are able to do this with immunotherapy without a lot of harsh side effects compared to conventional treatment like chemotherapy,” said Dr. Hsieh.
Immunotherapy allows the immune system to recognize, attack and stop cancer cells from growing. “Our bodies’ immune system usually kills off tumors. Sometimes, tumors as they develop learn to hide from the immune system. An anti PD-1 (programmed cell death protein 1) agent like the pembrolizumab drug used in immunotherapy uncovers cancer cells so the immune system can fight them.”
However, not all cancer patients are ideal for immunotherapy, which is why medical oncologists rely on testing to comprehend the cancer cells’ underlying biology.
Advanced NSCLC patients who respond best to the treatment are those whose cells have a high level of protein biomarker called PD-L1 or programmed cell death ligand-1.
“If a cancer cell population exhibit high expression of PD-L1, it means it uses PD-L1 to stop the immune system from attacking it. This is actually part of the body’s normal mechanism to prevent the immune system from destroying healthy cells — and cancer cells are using this to evade the immune system. If PDL1 is blocked with an anti PD-1 agent, then the immune system is stimulated to find and attack cancer cells,” Dr. Hsieh explained.
This is why cancer patients with more than 50-percent PD-L1 expression are the best candidates for immunotherapy. For those with lower levels of PD-L1, medical oncologists usually recommend a combination treatment regimen of immunotherapy paired with chemotherapy.
Dr. Hsieh added that the benefits of immunotherapy are usually durable and with a manageable safety profile.
“Once it shrinks the tumor, this shrinkage can last for a very long time. It’s like giving a vaccine for an infection. It can keep protecting you from that tumor while having better quality of life,” he said.
Many doctors consider immunooncology and targeted therapy as the holy grails of cancer treatment, with the latter having the facility to precisely locate and stop the spread of cancer cells. Although the list of cancer treatment options is increasing, Dr. Hsieh warned against alternative treatments and herbal therapies whose efficacies in fighting cancer are not proven through rigorous clinical research and testing.
“A lot of people still seek alternate treatments because they’re cheaper, there are no side effects which is not always true, and they’re touted as effective. But in my experience, these types of treatments don’t work very often. There may be a handful of positive testimonials from patients, but we don’t know how many have actually taken them which can be 1 success story in 10,000,” he said.
Today, ongoing clinical trials further explore how other mechanisms of the immune system can be harnessed to stimulate response against cancer. “There are a number of other pathways that cancer cells use to evade immune response. We are looking at how we can block these other pathways and improve treatment outcomes for more patients.”
In the battle against cancer, Dr. Hsieh is positive that future advances in oncology and cancer treatment will save more lives against the dreaded disease but underscored that increasing access to treatments, including screening and diagnostics facilities, are important factors in fighting for this vision.
In the Philippines, local initiatives such as the Hope From Within multisector advocacy, for instance, continually push for greater and strengthened efforts to fight cancer, stressing that close collaboration with stakeholders in the continuum of care will be the key to ensure that the proper testing methods, treatments, care options, and systems are in place, especially for those who need them the most.
Very recently, the Hope From Within– Cancer Game Plan PH was launched, a campaign that aims to put the patients at the heart of the fight against the dreaded disease. Using powerful voices from leaders, advocates, policymakers, survivors, support groups, and patients, it boosted awareness of proper cancer care, sparking conversations and purposive actions on how to save more patients from cancer-related mortalities and burdens.
For information, visit www. hopefromwithin.org.