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MAY , 2021 | THE HEALTH
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Lung cancer and non-smokers evaluated
Screening is important for the high-risk non-smoker as there are other causative factors besides smoking that cause lung cancer
LUNG cancer has long been associated almost exclusively with male smokers till recently .
Hence understandably screening for early detection of lung cancer has traditionally focused on people with a significant tobacco history . Whilst smoking remains the most common , most identifiable , and most preventable aetiological risk factor , alarmingly the proportion of non-smokers or never smokers developing lung cancer globally each year continues to rise .
The two widely cited published clinical trials ( USA National Lung Screening Trial , 2011 & Dutch-Belgian NELSON 2020 study ) that provide compelling evidence for the life-saving benefit of low dose computed tomography ( LDCT ) screening for lung cancer in high-risk individuals both target
BREATHING EASY only heavy current or recent former smokers .
A recent landmark Taiwanese trial ( TALENT ) demonstrated the value of LDCT screening of the “ high risk ” non-smoker . The Taiwan national lung cancer screening study involving 12,011 individuals yielded a diagnostic pick-up rate of 2.6 per cent which was superior to the 1.1 per cent and 0.9 per cent lung cancer detection rates documented in NLST and NELSON respectively .
Notably , 73.8 per cent of the study population were women with an average age of 61.2 years , and 50.0 per cent had a family history of lung cancer . Fifty-three per cent of lung cancer deaths in Taiwan occur among never-smokers , suggesting other causative factors besides from smoking .
The high-risk non-smoker Talent lead investigator Dr Yang Pan Chyr
Dr Anand
Dr Hilmi
We know that LDCT screening of heavy smokers can help catch lung cancer early and thus reduce mortality . This landmark study now paves the way for further exploration on the value of screening of the high-risk non-smoker especially those with a strong family history of lung cancer or a high cooking index .”
— Dr Anand Sachithanandan
several high-risk features : a family history of lung cancer amongst first , second , or third-degree relatives ; environmental smoking exposure ; a history of chronic lung disease , such as tuberculosis or chronic obstructive pulmonary disease ; cooking without ventilation ; and a cooking index of 110 or greater ( defined as 2 / 7 x the number of days of frying per week x the number of years cooking ).
Lung Cancer Network Malaysia ( LCNM ) President Dr Anand Sachithanandan explains that lung cancer in the neversmoker is a rising global threat and represents a disease distinct from the type of cancer which smokers develop in terms of genomic profile and tumour biology .
“ It is also worth noting that 96.5 per cent of patients diagnosed in TALENT had early-stage disease amenable to curative resection or surgery ,” adds Dr Anand who is also a Cardiothoracic Surgeon .
“ We know that LDCT screening of heavy smokers can help catch lung cancer early and thus reduce mortality . This landmark study now paves the way for further exploration on the value of screening of the high-risk non-smoker especially those with a strong family history of lung cancer or a high cooking index .
“ Till now there has been a paucity of evidence to support screening for the disease in non-smokers .”
Risk factors to consider
Chest Physician and LCNM Council Member Dr Hilmi Lockman noted the TALENT study identified family history as the most significant risk factor with a lung cancer prevalence of 3.2 per cent in patients with a family history of the disease compared to a prevalence of 2.0 per cent in those without .
He said risk was greatest when a first degree relative had the disease as opposed to more distant relations . Furthermore , the TALENT findings reiterate the importance of having a well-ventilated kitchen or the use of an extractor fan to mitigate the hazards of high temperate indoor wok cooking .
“ LDCT lung cancer screening for the high risk never-smoker may be feasible but longer-term data is required to ascertain if LDCT screening in this population will lower the lung cancer mortality rates as has occurred with smokers .
“ Nevertheless , this study will help redefine lung cancer screening criteria especially in Asia .” — The Health
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