Lung cancer in Malaysia a rising threat

Lung cancer is among the leading health challenges in Malaysia, accounting for thousands of deaths yearly. In 2016, it was reported as the country’s third most common cancer with almost 10 percent of all cancer cases. [J Thorac Oncol 2020;15(3):317–323]

In spite of progress made in treatment, close to 95 percent of lung cancer cases are diagnosed at an advanced stage when there is a very limited opportunity for intervention. Lung cancer advocates, Professor Dr Anand Sachithanandan and Dr Tho Lye Mun, of Lung Cancer Network Malaysia, highlight the importance of recognizing risk factors and early screening, as well as modern therapies. They also touched upon the possible effects of e-cigarettes on lung health.

The risk of lung cancer increases for both men and women after age 45, making this group an ideal target for cost-effective screening. Individuals aged 45 to 75, especially those who have smoked for at least 20 years, are advised to consider regular screening. Additionally, an increasing number of lung cancer cases are being detected in nonsmokers, particularly women. For these individuals, a family history of lung cancer is the strongest identifiable risk factor and a primary reason for considering screening.

Detecting lung cancer earlier significantly improves outcomes, as patients are more responsive to treatment and often achieve remission. According to the Malaysian Study of Cancer Survival (MySCan), the 5-year survival rate is over 90 percent for Stage I diagnoses, but this declines steeply as the cancer progresses to later stages.

In Malaysia, lung cancer impacts men and women across diverse demographics, with ethnic groups facing different risks. Chinese men have almost double the risk of developing lung cancer compared to their Malay and Indian counterparts. Similarly, Chinese women have a lifetime risk of 1-in-80, significantly higher than Malay (1-in-152) and Indian (1-in-184) women. Genetic predispositions also play a role, with those having a family history of lung cancer at higher risk, especially if a first-degree relative (parent or sibling) was diagnosed. Second-hand smoke is a significant risk factor, noting that women tend to be more sensitive to its effects compared to men.

While smoking is the primary risk factor, non-smokers are also at risk, and this particularly affects women. In non-smokers, the most prominent risk factor is a genetic predisposition to the disease. Additionally, there are also external factors such as air pollution or work hazards.

The gold standard in screening of lung cancer
The gold standard for lung cancer screening is a low-dose computed tomography (LDCT) scan, which is available at many private and government hospitals. LDCT uses very low doses of radiation and is usually completed in several minutes. Small, potentially malignant nodules in its early stages can be detected with LDCT’s superior resolution, which was previously impossible with traditional chest x-rays. Studies have demonstrated that this method is effective in identifying lung cancer in the early stages, thus decreasing mortality attributable to lung cancer.

Recently, the LCNM has spearheaded the incorporation of artificial intelligence (AI) technology to enhance the diagnostic sensitivity of primary care practices. With the use of AI on chest X-rays, abnormal findings can be addressed efficiently ie, with prompt referral to undergo LDCT at a tertiary center.  Such approaches may improve the situation when it comes to early diagnosis, especially in community clinics that are the primary users of chest x-ray.

Treatment options
The state of lung cancer treatment has also progressed tremendously with treatments now incorporating targeted and immunotherapy. These advancements have resulted in better survival outcomes and quality of life for the patients, even those diagnosed at advanced disease.

Targeted therapy targets distinct gene mutations that exist in cancer cells. In Tho’s practice every lung cancer patient goes through a biopsy and genetic test which detect specific mutations that are treatable by targeted therapy. Targeted therapy reduces the number of side effects associated with chemotherapy and radiotherapy. Similarly, targeted therapy preserves and improves the patient’s quality of life by eliminating needless treatments.

Immunotherapy causes the body to heighten its immune response and recognize cancer cells and destroy them. However, cancer cells are adept at “hiding” from the immune system. One way to overcome this is to use drugs (such as anti-Programmed Death-1) that can ‘unmask’ the cancer cells and allow for T-cells to recognize and kill them. Nowadays, immunotherapy is an outpatient treatment, allowing patients to be treated non-invasively while preserving their lifestyle.

Radiosurgery, an improvement from radiotherapy, focuses on delivering high doses of radiation directly to the cancer site. Due to its precise nature, there is minimal damage to the surrounding healthy tissues. Radiosurgery has progressed to the point that its precision is comparable to surgery, which makes it especially beneficial for brain metastases, where invasive surgery can be avoided.

Survival is increasing
The conventional thought is that Stage IV lung cancer patients have a life expectancy of 6 months. With current advancements, a survival of over 4 years is possible. Some patients remain responsive to targeted therapy longer than 4 years. There are currently records of patients surviving up to 10 years or more and living life normally.

If a patient is diagnosed earlier at Stage I or Stage II, surgical and other forms of treatments are possible, and they can be cured of lung cancer which means the individual can expect a normal life expectancy.

Concerns about vape or e-cigarettes
A recent trend, particularly among younger Malaysians, is the rise of vaping or use of e-cigarettes. As it is relatively new, there are concerns about its long-term effects on lung health. While evidence on vaping’s risks remains inconclusive, it is generally regarded as a gateway to smoking. The addictive nature of nicotine and the unregulated chemical content in vape liquids pose unknown risks. As more adolescents take up vaping, often perceived as a safer alternative, healthcare professionals face a growing challenge in educating patients on the potential hazards. There needs to be more investigative research into the composition of vape products to better understand their health impact.

Ed: While the gamut of ingredients used in established brands of vape liquids are known, their concentration and composition for each flavor is not known. Some compounds, while safe ingested or applied on the skin, may become cancerous or destructive when inhaled.