Bangkok Post – PM2.5, gene changes behind lung cancer spike

PM2.5 air pollution and mutations in the EGFR gene are major drivers behind the increasing incidence of lung cancer among non-smoking women, particularly across Asia, says a leading Thai oncologist.

Col Assoc Prof Dr Naiyarat Prasongsook, a medical oncologist at Phramongkutklao Hospital, said more than 2.48 million people worldwide are living with lung cancer. Of these, Asia accounts for the largest share of 63.1% or about 1.56 million patients, while Europe reports about 484,000 cases, or 19.5% of the global total.

The surge in lung cancer cases has been steep in recent years. Between 2022 and 2025, the number of newly diagnosed cases rose by 269.4% in Asia and 136.9% in Europe. In Thailand alone, about 23,500 new cases are reported each year. It is also one of the leading causes of cancer-related deaths worldwide with 1.8 million deaths reported annually and a five-year survival rate of only 15–20%.

Dr Naiyarat said that while smoking remains the leading cause of lung cancer, responsible for 62% of all cases, other risk factors are becoming more prominent.

Air pollution now accounts for 15% of cases, followed by second-hand smoke at 5.8%, indoor air pollution at 4% and occupational exposure at 4%.

“What’s especially concerning is the growing number of non-smoking women diagnosed with lung cancer, particularly in Asia,” he said. “Emerging evidence indicates that PM2.5 air pollution and EGFR gene mutations are significant contributors to the disease.”

EGFR (Epidermal Growth Factor Receptor) mutations are more prevalent in Asian populations, where up to 60% of lung cancer patients carry such abnormalities, he said.

In Thailand, the figure is even higher –68% — compared to much lower rates in Western populations. Dr Naiyarat warned that if current trends continue, lung cancer cases among Thai women are projected to reach 11,200 by 2030, a 35% increase from 8,300 cases in 2025.

“Sadly, many patients seek medical attention only when symptoms become severe,” he noted. “In its early stages, lung cancer often mimics common illnesses, such as persistent coughing, chest pain, fatigue or weight loss.”