Smoking is the most important trigger for small cell lung cancer: AIIMS study
This one is for heavy smokers and the high lung cancer risk they expose themselves to. A study conducted doctors at the All India Institute of Medical Science (AIIMS) has found that Small Cell Lung Cancer (SCLC) predominantly affects males with a heavy smoking index.
In this variant of cancer, malignant cells form in the tissues of the lung, beginning with the breathing tubes (bronchi). They grow very quickly, creating large tumours and spreading (metastasising) throughout the body. The study, which was conducted on patients from north India, found that close to 80 per cent of them were former or reformed smokers, making it the single most important factor associated with SCLC. About 65 per cent of them were heavy smokers, further reiterating the role of smoking and its intensity in the development of SCLC. “Around 20 per cent of the cases were non-smokers and still developed SCLC. Although it is difficult to ascertain the exact reasons for the same, there is evidence that prolonged exposure to particulate matter 2.5 mm (PM 2.5) in ambient air is associated with an increase in the risk of lung cancer, especially in low and middle-income countries,” said the study published in Lung India, a journal of Indian Chest Society.
The study authors include Dr Anant Mohan, professor and head of the pulmonary department and Dr Randeep Guleria, professor and former director of AIIMS. A total of 361 patients with SCLC were included in the study for over 12 years and were in the 46-70 year age group.
The study indicated that the incidence of SCLC seemed to be declining over the last decade but in spite of several diagnostic advancements, the definitive diagnosis continues to be made late, the survival remains poor and is predominantly affected the performance status.
Almost half of the lung cancer patients in the study were either illiterate or educated up to the primary level, so their smoking habits were possibly influenced lower awareness levels. “It has been shown that the incidence of lung cancer is influenced education, possibly because education influences smoking habits and the ability to quit smoking. Furthermore, lower educational status negatively impacts the likelihood of patients undergoing definite investigations and disease-specific treatment, there translating into delayed diagnosis and higher mortality,” the study said.
A majority of the 26.7 per cent test cases had a limited stage at diagnosis. This may possibly be due to a delay in referral to a special physician and initial wrong treatment with anti-TB drugs. “The high prevalence of tuberculosis in Indian settings leads to a significant delay in the diagnosis of lung cancer due to prescriptions of inappropriate empirical anti-TB therapy,” the study added. It found that 33.6 per cent of patients received empirical treatment with anti-tubercular medicines before definite diagnosis and treatment. Out of the 361 patients, only 50 per cent received cancer-specific treatment.
“Among our 49 patients with the limited-stage disease, 34 patients received only chemotherapy, whereas 12 received combined CT-RT. A possible reason for the lack of receipt of combined chemo-radiotherapy is the long waiting period for radiotherapy in our centre, thus making it logically difficult to adminer CT-RT concurrently. None of our patients with a limited-stage SCLC underwent surgery,” said the report.
