Skip to main content
Dr Tho Lye Mun, Lung Cancer, Cigarettes, Alcohol, Beacon Hospital

This article is translated from 风采 Feminine’s November 2023 Issue, pages 66-69. It features an interview with Dr. Tho Lye Mun and Dr. Low Kai Lee titled ‘No cigarettes, no alcohol, no eating out – be cautious, lung cancer can still come knocking.’

Lung cancer is one of the most common cancers worldwide with the highest incidence and mortality rates, earning it the title of ‘number one cancer killer.’ Due to late-stage diagnoses in many cases, the 5-year survival rate is much lower compared to other common cancers such as breast and prostate cancer.

November is ‘Lung Cancer Awareness Month,’ and the Lung Cancer Network Malaysia (LCNM) is once again collaborating with local healthcare institutions, non-governmental organizations, and media to organize lung cancer awareness activities.

The initiative aims to promote knowledge and information about lung cancer, provide health screenings by professional healthcare personnel, and raise community awareness and attention to lung cancer through a series of events.

The goal is to encourage early diagnosis and treatment, thereby reducing lung cancer mortality, prolonging life, and maintaining quality of life.

Must Knows About Our Lungs

Lungs, Oxygen, CO2

The human lungs can be considered the “headquarters” of the respiratory system, consisting of spongy, air-filled organs and tissues. They serve as the site for the exchange of gases between air and blood—extracting oxygen from the atmosphere and delivering it to the bloodstream, while releasing carbon dioxide from the blood into the atmosphere. This exchange process is vital for life.

When abnormal cells (cancerous or malignant) in the lungs grow and reproduce uncontrollably, cancerous transformation occurs, leading to lung cancer. Tumors may originate in the lungs or airways (trachea and bronchi) and can potentially spread to lymph nodes or other organs. 

This spread of cancer cells from one organ to another is referred to as metastasis, including lung metastases or secondary lung cancer originating from cancers in other organs such as breast, liver, pancreas, colon, or kidney cancers, among others.

Types of Lung Cancer

The common types of lung cancer are mainly divided into Non-Small Cell Lung Cancer (NSCLC) and Small Cell Lung Cancer (SCLC). Approximately 80% to 85% of lung cancers are of the non-small cell type, while 15% to 20% are small cell lung cancers. 

Additionally, there are rare lung carcinomas, accounting for less than 5% of cases, such as adenocarcinoma, lymphoma, and sarcoma, and these types of cancers tend to grow slowly.

The main subtypes of non-small cell lung cancer (NSCLC) are adenocarcinoma (ADC) and squamous cell carcinoma (SQCC). There is also a category known as “large cell carcinoma” (LCC), which includes both typical and atypical carcinomas that are rare and challenging to diagnose.

Adenocarcinoma: The most common form, it originates from cells that produce mucus and is typically found in the outer (peripheral) regions of the lungs.

Squamous Cell Carcinoma: Arises from cells lining the airways (bronchi) and is usually located in the central part of the lungs.

Large Cell Carcinoma: Can appear in any part of the lungs and tends to grow and spread rapidly.

In contrast, small cell lung cancer is a more aggressive form of lung cancer that typically originates in the central part of the chest. This type of lung cancer often spreads easily to other parts of the body, and smoking is a primary risk factor for developing small cell lung cancer.

Lung Cancer Staging

Non-Small Cell Lung Cancer
Stage 1 Stage 2 Stage 3
Small lung tumor ≤4 cm,

no lymph node metastasis,

disease has not spread

beyond the lungs.

Larger tumor (about 3 cm-7 cm) and/or

spread to lymph nodes on the same side of the chest, but not distant metastasis.

Large tumor (3 cm to >7 cm) that has invaded the chest wall, heart, nerves, and/or lymph nodes (present in ≥1 lymph node or adjacent tissues), and has spread to the middle or opposite lung, but not distant metastasis.
Small Cell Lung Cancer
early/localized stage metastatic/advanced stage
The cancer is localized to the lungs and small enough to be cured with radiation therapy. Cancer has spread (metastasized) to other parts of the body, such as the liver, bones, or brain, or is too large/advanced to be cured with radiation therapy.

Symptoms of Lung Cancer

  • A cough that lasts for 2 to 3 weeks and doesn’t seem to improve, or a new and different cough, such as a “smoker’s cough.”
  • Coughing Up Blood or Rust-Colored Sputum
  • Pain in the chest, especially when breathing, coughing, or laughing.
  • Persistent difficulty breathing (wheezing), noisy breathing, or unexplained shortness of breath.
  • Hoarseness
  • Frequent or recurrent respiratory infections, such as bronchitis or pneumonia.
  • Loss of appetite or unexplained weight loss.
  • Persistent drowsiness and fatigue.
  • Pain in the chest, shoulder, or back

Asymptomatic in Early Stages: High-Risk Groups Should Be Alert

smoking, cigarette, lung cancer

High-risk individuals should be vigilant, as early symptoms of lung cancer are often subtle, sometimes imperceptible, and can be mistaken for common ailments. 

Additionally, the symptoms of a COVID-19 infection bear similarities to those of lung cancer. Given the concerns about lingering effects of post-COVID conditions (Long-Covid), there might be a subconscious tendency to overlook or attribute symptoms to non-cancerous causes.

Therefore, early and regular screening is a necessary preventive measure for individuals at risk of lung cancer, including:

    • Current or former smokers aged 45 to 75 years.
    • Individuals with a significant smoking history (at least 20 pack or longer smoking history).
    • Non-smokers with a strong family history of lung cancer.

People with unknown risk factors should also consider regular health checkups starting at the age of 45 to 50.

In a routine health examination, blood tests, lung function tests, and chest X-rays are the initial steps to assess lung health, with particular emphasis on chest X-rays. Chest X-rays can reveal abnormalities such as tumors or nodules in the lungs. Based on the preliminary examination results, doctors will proceed with more specific diagnostic procedures if needed.

Diagnosis Methods

Currently, the primary methods used for diagnosing lung cancer include:

  • Biopsy: Involving the examination of live tissue, often done through bronchoscopy or CT-guided biopsy.
  • Computed Tomography (CT) Scan: Providing detailed images that display the size, shape, and location of any tumors.
  • Positron Emission Tomography (PET): Used to detect areas of increased metabolic activity, helping to identify cancerous cells.
  • Magnetic Resonance Imaging (MRI): Offering detailed images of the internal structures, including the lungs.
  • Immunohistochemistry and Molecular Testing: Utilized to analyze proteins and molecular markers, aiding in the identification and characterization of cancer cells.

Low Dose Computed Tomography (LDCT)

Dr. Tho Lye Mun and Dr. Low Kai Lee have pointed out that the preferred method for early diagnosis today is low-dose computed tomography (LDCT). 

In comparison to traditional computed tomography scans, this new technology offers advantages such as being quick, painless, needle-free, and having low radiation exposure. 

Additionally, it provides high-quality detailed imaging, eliminating the need for fasting and blood tests.

“In Malaysia, some government and private hospitals have already adopted this diagnostic method, particularly suitable for individuals with a family history and other high-risk factors.”

With the advancement of medical technology, artificial intelligence (AI) screening and algorithms have significantly improved early detection rates for lung cancer.


AI software designed for lung cancer detection can identify abnormalities in X-rays, leading to further referral of patients for more detailed LDCT scans.


In the era of precision medicine, cancer treatment has become highly personalized. 

Treatment plans are tailored to each patient based on various considerations, including the type and stage of lung cancer, genetic mutations present in the cancer, the patient’s age and overall health (including physical fitness and the presence of other diseases), as well as the patient’s concerns and treatment goals/vision.

Currently, the main treatment options for lung cancer include surgery, radiation therapy, chemotherapy, targeted therapy, and immunotherapy. 

Different tumor types, grades, stages, and the overall condition of the patient may warrant different treatment approaches.

lung cancer, beacon hospital

Lung Cancer : Global Leading Cancer Killer

On the global list of common cancers, lung cancer ranks second, following only breast cancer. The Global Cancer Report indicates that there are approximately 2.2 million new cases of lung cancer annually, with up to 1.8 million deaths. It stands as the leading cause of cancer-related deaths worldwide.

In terms of ethnicity, the highest incidence of lung cancer is observed among individuals of Chinese descent. Regarding gender, while the overall incidence is higher in males compared to females, non-smoking females have a higher incidence than non-smoking males.

In 2020, the estimated cancer mortality data indicate that 4,509 people died from lung cancer, 3,503 from breast cancer, 2,050 from liver cancer, and 2,035 from colorectal cancer. This implies that the mortality rate for lung cancer is higher than that of other cancers.

In Malaysia, lung cancer is the third most common cancer, ranking first among cancers in males and fourth among cancers in females. 

According to local clinical oncologists Dr. Tho Lye Mun and Dr. Low Kai Lee, this does not necessarily indicate a high fatality rate for lung cancer but rather stems from the challenge of low early diagnosis rates. 

Up to 90% to 95% of lung cancer cases are diagnosed at advanced stages (Stage III and IV) when symptoms become apparent, making treatment more challenging and resulting in a very low cure rate.

Data from January 2007 to December 2011 shows that the 5-year survival rate for lung cancer after diagnosis was only 9%, significantly lower than the 62% for breast cancer and 59% for prostate cancer. This highlights the substantial challenges in treating lung cancer.

Continuous Advancements in Treatment and Early Diagnosis are Crucial

Dr. Tho Lye Mun is also a co-founder and Vice President of the Lung Cancer Network Malaysia. He points out that while cancer treatment technologies are advancing, improving the cure rates for lung cancer, early diagnosis remains a crucial factor in enhancing survival rates.

“Previously, lung cancer treatment options were limited to surgery, radiation therapy, and chemotherapy. Nowadays, with the introduction of targeted drugs and immunotherapy, treatment effectiveness has significantly improved. These advancements address past challenges in eradicating cancer cells, providing alternatives for patients who may not be suitable for traditional treatments or may struggle with side effects.”

Dr. Low Kai Lee mentioned that lung cancer requires long-term treatment. Therefore, even after surgery or completing a course of treatment, patients often need to continue taking medications for control and undergo regular follow-up visits to monitor the possibility of cancer recurrence. 

“The recurrence rate depends on the stage of cancer and the type of treatment used. The later the stage, the higher the recurrence rate (metastasis). Fortunately, targeted drugs, as a form of precision treatment, have extended the survival rates for advanced lung cancer to 3 to 5 years or even longer. Some stage IV patients have survived for 8 years.”

Dr. Tho Lye Mun explained that immunotherapy involves using the patient’s immune system to fight cancer. By enhancing the weakened immune system of the patient, immunotherapy aims to achieve anti-cancer effects. This is different from targeted drugs that focus on the patient’s cancer genes.

If a patient has an autoimmune disease or any ongoing infection, they may not be suitable for immunotherapy. Surgery is often employed in the early stages of treatment.

Risk Factors and High Risk Groups for Developing Lung Cancer:

Although smoking is a well-known primary risk factor for lung cancer, this doesn’t mean that non-smokers are free from the risk of lung cancer. Some risk factors can be addressed through dietary and lifestyle changes, while others are uncontrollable environmental factors.

Controllable Factor

  • Smoking
  • Secondhand and even thirdhand smoke exposure
  • Exposure to carcinogens, such as asbestos, radon, nickel, arsenic, soot, and tar, as well as radioactive materials and chemicals

Uncontrollable Factor

  • Air pollution
  • Personal medical history (e.g., a history of chronic bronchitis, tuberculosis, or pulmonary fibrosis)
  • Family medical history
  • Gender and ethnicity

Therefore, healthcare experts always emphasize starting with controllable risk factors to reduce the chances of developing cancer.  


The primary preventive measure for lung cancer is quitting smoking, along with limiting exposure to secondhand smoke, restricting contact with carcinogenic chemicals or radiation (using low-dose CT scans for screening), consuming a healthy diet, engaging in moderate physical activity, maintaining a regular sleep schedule, and more.

When asked about whether contracting the COVID-19 virus or having post-COVID complications increases the risk of lung cancer, both doctors acknowledge that the latency period for lung cancer can be as long as 20 years. Therefore, the relationship between COVID-19 and lung cancer is still under observation and research.

myths and facts

Debunking Lung Cancer Myths

Dr. Tho Lye Mun stated that there are many myths and misunderstandings about lung cancer among the general public. 

The most common misconception is the belief that only smokers die from lung cancer. 

Another misconception is that older individuals are at an increased risk due to the decline in organ function. In fact, anyone can develop lung cancer.

Myth 1: Lung cancer only affects smokers

In Malaysia, up to one-third of lung cancer patients are non-smokers or individuals who have never smoked. Among female lung cancer patients, 20% have never smoked in their lifetime.

In recent years, there has been an increasing trend in the diagnosis of lung cancer in non-smokers. Among the patients Dr. Tho Lye Mun has encountered, half are non-smokers, and a significant number of them are females. 

Data from the World Health Organization (WHO), the International Agency for Research on Cancer (IARC), and the renowned Francis Crick Institute in the UK indicate that, compared to smoking, air pollution might be another major contributor to the rising incidence of lung cancer in urban areas.

Air pollution can trigger inflammation at the cellular level, activate dormant cancer genes, or drive mutations (such as EGFR and KRAS), making non-smokers, particularly those not exposed to traditional risk factors, susceptible to lung cancer. 

This is especially evident in urban areas where air pollution is worsening, leading to an increased incidence of lung cancer among young people and non-smokers.

Myth 2: Lung cancer only affects the elderly

The global trend of cancer becoming more prevalent in younger individuals is a growing reality, with a noticeable increase in cancer incidence and mortality among those under 50. 

According to the British Medical Journal “The Lancet Oncology,” the number of individuals under 50 diagnosed with cancer has increased by nearly 80% over the past 30 years, including common cancers such as breast, lung, and colorectal cancer, which were traditionally considered diseases of the elderly. 

A comprehensive study covering over 200 countries revealed that early-onset cancer cases increased from 1.82 million in 1990 to 3.26 million in 2019, representing a staggering 79% increase.

Among these, the number of young people aged 30 to 40 dying from cancer increased by 27%.

Dr. Tho Lye Mun pointed out that some young patients are diagnosed with cancer at the age of 20 or 30 and are already in the fourth stage at the time of diagnosis.

Myth 3: Surgery causes the spread of lung cancer/treatments have severe side effects

There is a common belief that lung cancer can spread due to exposure to air during surgery, making the surgical process dangerous. 

In reality, surgery does not cause the spread of lung cancer. With early diagnosis and treatment, the cure rate can be quite high. Additionally, some people believe that advanced therapies such as radiation therapy and chemotherapy may lead to severe side effects, causing hesitation in pursuing treatment. 

Instead, they may opt for various alternative therapies without scientific basis.

cancer treatment, old women, hospital

Myth 4: Lung cancer is inevitably fatal

Dr. Tho Lye Mun and Dr. Low Kai Lee both emphasize, “Lung cancer is not a death sentence.” Many still believe that lung cancer is incurable, especially patients and their families who may assume that there is little time left after a lung cancer diagnosis and may deem treatment unnecessary or choose to forgo it. 

There is also a misconception that treatment will bring severe side effects, leading to suffering, and it’s better to accept the inevitable. 

In reality, with the development and progress of precision and personalized treatments like immunotherapy and targeted therapy, even advanced-stage lung cancer patients have the potential to survive for more than 5 years and maintain a relatively good quality of life.


Myth 5: Specific foods/supplements can reduce the risk of lung cancer

In reality, as long as one meets the Recommended Dietary Intake (RDI) set by the World Health Organization, there is no need to take additional nutritional supplements. Excessive nutrients will eventually be excreted from the body unless there is a specific deficiency.

Factors and risk groups for developing lung cancer: Although smoking is a well-known primary risk factor for lung cancer, this doesn’t mean that non-smokers are free from the risk of lung cancer. 

Some risk factors can be addressed through dietary and lifestyle changes, while others are uncontrollable environmental factors.

The Importance of a Healthy Lifestyle

All doctors and healthcare professionals consistently emphasize the importance of reducing cancer risk through healthy eating habits and lifestyle choices. 

Well-known “health tips” such as consuming more fruits and vegetables, engaging in moderate exercise, and ensuring sufficient rest are ingrained and widely recognized.

Despite leading an extremely health-conscious lifestyle—no smoking, no alcohol, no eating out, and no chronic diseases related to the three highs (hypertension, hyperlipidemia, and diabetes)—some individuals still find themselves diagnosed with late-stage lung cancer. 

Moreover, for many, the time from diagnosis to passing is within a year or even six months. 

Why does this happen?

genetics strain

The Role of Genetics

In response, Dr. Tho Lye Mun acknowledges that if there is a close family history of lung cancer, especially among immediate relatives (parents, siblings), and even if more than one family member has succumbed to lung cancer in such a context, other family members should commence regular lung screening to detect any abnormalities in lung health early on.

While a family history of cancer is indeed one of the risk factors for developing the disease, the association between lung cancer and genetic factors is not as clear or prominent as it is for breast cancer. 

The carcinogenic genes for lung cancer are not as well-defined as those for breast cancer, where early detection of the genes associated with breast cancer can help confirm one’s risk and enable proactive preventive measures.

In fact, only 10% to 20% of cancers are typically associated with genetics, while 80% to 90% are linked to lifestyle factors. 

Regardless, Dr. Tho emphasizes that maintaining a healthy diet and lifestyle remains the best way to promote well-being, reduce health risks, and prevent many acquired chronic diseases. Living a healthy life, both physically and mentally, is always preferable to an unhealthy lifestyle.

A Silent Threat to Women's Health

Especially in terms of diet, it’s advisable to minimize frying and deep-frying, as there is a connection between lung cancer and prolonged exposure to cooking fumes. 


This is also one of the potential factors contributing to lung cancer in non-smoking women who spend extended periods in the kitchen.

Ending Note

November is “Lung Cancer Awareness Month,” and Lung Cancer Network Malaysia (LCNM) once again collaborated with various local medical institutions, non-governmental organizations, and the media to organize lung cancer awareness activities. 

The initiative aims to promote knowledge and information about lung cancer and provide health screenings by professional healthcare personnel. 

Through a series of activities, LCNM seeks to increase community awareness and attention to lung cancer, encourage early diagnosis and treatment, reduce the impact of lung cancer, and enable people to walk further on the road of life to see more of life’s sceneries. 

Featured Doctor :


Dr Tho Lye Mun

Consultant Clinical Oncologist

Close Menu