Recent news about the growing lung cancer diagnosis rates of young, non-smoking Asian American women in the US at 2% per year has brought the disease into the spotlight. Intriguingly, lung cancer incidence rates have dropped for every demographic except this group. The phenomenon has baffled scientists, who posit that Asian Americans are exposed to toxic fumes more frequently and that air pollution could result in genetic changes in Asian Americans that lead to healthy cells dividing uncontrollably and developing into tumors.
Thankfully, the outlook for lung cancer patients today is more optimistic because of ongoing research and innovation in medical care, research and technology that have paved the way for scientific breakthroughs changing the course of lung cancer treatment.
One of the treatment modalities used by oncologists to treat lung cancer is radiation therapy, also known as radiotherapy, which harnesses the power of high-energy radiation to destroy cancer cells and shrink tumours. What is radiation therapy, and is it effective in treating lung cancer? We delve deeper into the topic with the help of radiation oncologist Dr. Lee Khai Mun.
Let’s start with understanding lung cancer and its risk factors. According to data from Johns Hopkins Medicine, smoking continues to be the leading cause of lung cancer, accounting for an astounding 90% of lung cancer cases. Compared to non-smokers, smokers are 15-30 times more likely to acquire lung cancer or pass away from it. Smoking is not the sole perpetrator, though; in some instances, exposure to industrial chemicals like radon and asbestos, air pollution, and genetic predisposition heightens the risk of contracting lung cancer.
Lung cancer is one of the most challenging cancers to diagnose because of its subtle signs that can easily evade early detection. The most common symptoms, such as chronic cough, dyspnea (shortness of breath), chest pain, or unexplained weight loss, are often overlooked or mistaken for other conditions, which severely impacts the likelihood of successful treatment.
A lung cancer patient’s diagnostic journey often begins with a chest X-ray to check for lung abnormalities. However, since X-rays alone cannot differentiate cancer from other conditions, such as lung abscesses, further testing is often necessary to detect lung cancer. An oncologist may employ more advanced imaging techniques such as CT scans, PET-CT scans, and bronchoscopies to better diagnose and stage patients. These imaging procedures allow radiation oncologists to visualise the lungs and surrounding areas of the body in greater detail.
Low-dose CT (LDCT) screening has emerged as an immensely beneficial and even life-saving tool to detect early-stage lung cancer in high-risk individuals, such as chronic smokers. A study published in the Journal of Thoracic Oncology showed that annual LDCT leads to high cure rates of over 80%. LDCT screening is most beneficial when it detects small, early-stage lung cancers that are still curable. The NELSON study shows that increasing the interval between screenings results in the detection of more extensive, later-stage tumours. Therefore, annual screenings are more effective compared to intervals of two or two-and-a-half years.
How does radiation therapy work to combat lung cancer, then? Well, according to Dr. Lee, “Radiation therapy works at the cellular level, inflicting lethal damage to the DNA of cancer cells, thereby inhibiting their ability to multiply and metastasise. Depending on the type and stage of cancer, radiation therapy can be used alone or combined with other treatment modalities such as surgery, chemotherapy, or immunotherapy.”
The two main types of radiation therapy are External Beam Radiation Therapy (EBRT) and internal radiation therapy, often known as brachytherapy.
External Beam Radiation Therapy (EBRT)
EBRT, the more prevalent method, directs high-energy radiation beams from outside the body towards the tumour site. Advanced techniques like intensity-modulated radiation therapy (IMRT) and image-guided radiation therapy (IGRT) allow oncologists to target tumours precisely while ensuring the least amount of damage to surrounding healthy tissues. Dr. Lee affirms, “We can deliver higher doses of radiation directly to the tumour with fewer side effects thanks to the precision of modern EBRT techniques.”
Internal Radiation Therapy or Brachytherapy
Brachytherapy involves directly implanting radioactive elements into or next to the tumour. This technique is especially effective for malignancies of the prostate, cervix, and breast because it is easier to administer a concentrated radiation dose to a small area. Dr. Lee observes, “Brachytherapy minimises exposure to surrounding tissues by delivering radiation from within the tumour site.”
Radiation therapy is a non-invasive treatment modality that has been proven to be effective in controlling and eliminating cancer. “Safety and accuracy in radiation therapy have advanced significantly,” Dr. Lee emphasises. “We can now target tumours more precisely, which lowers the possibility of adverse effects.”
Among the several therapy approaches are:
Like all treatments, radiation therapy can lead to some side effects, which vary depending on the treatment area. Common side effects include fatigue, skin irritation, and changes in the treated area, including hair loss or difficulty swallowing. Dr. Lee counsels patients to “understand the risks and benefits of their treatment plan” and to “discuss potential side effects with their oncologist.”
The field of radiation oncology is continuously evolving as researchers and medical professionals work tirelessly to find new, innovative treatments that maximise efficacy and minimise side effects. Proton therapy, with its promise for improved precision and decreased collateral damage, and MRI-guided radiation therapy, which enables real-time imaging and adaptive treatment planning that considers tumour movement, are two areas of great interest to Dr. Lee.
“Every patient has a unique experience with cancer. As doctors, we aim to devise personalised treatment plans that effectively treat the cancer while supporting the patient’s quality of life.”
