90pc of lung cancer cases caused by smoking, seminar told

November is the lung cancer awareness month, turning the spotlight on to the world’s deadliest cancer and encourage people displaying common symptoms of the disease, such as a persistent cough, laboured breathing, chest or back pains and unexplained weight-loss, to get themselves tested.

Prof Ahmad Nadeem Abbasi, head of radiation oncology at the Aga Khan University Hospital and general secretary of the Radiation Oncology Society of Pakistan, said this at a recently-held public awareness seminar at the Neurospinal & Cancer Care Postgraduate Institute, Karachi (NCCI).

“This month is an opportunity to raise public awareness about treatment options and reduce the stigma associated with the disease. Lung cancer is a rapidly multiplying disease and can be very difficult to manage if it spreads,” he said.

Citing the World Health Organisation, he explained that on average, lung cancer accounted for approximately 2.09 million deaths annually and even though new research and experiments continued to make breakthroughs in the treatment of lung cancer, it had one of the least survival rates among other cancers.

“The treatment of lung cancer is complex often involving multiple treatment modalities, including surgery, radiotherapy, systemic therapies, interventional radiology and palliative care,” Prof Abbasi said.

Speaking on the lung cancer treatment from the perspective of a radiation oncologist, he said that radiotherapy was an important modality used for the treatment of lung cancer, and 77 per cent of all patients with lung cancer had an evidence-based indication for radiotherapy, although it was often underutilised.

Radiotherapy can be used as curative or palliative treatment across all stages of the disease, he maintained, adding that technological advances had allowed better radiotherapy targeting of tumours and reduced incidental irradiation of surrounding normal tissues, which had improved the outcomes both in terms of increasing survivals and reducing toxicity & side-effects.

Consultant clinical oncologist and assistant professor at Ziauddin Medical University Dr Shabbir Hussain discussed various types of lung cancers and the role of novel immunotherapies for their treatment.

He said the two main forms of lung cancer were small cell lung cancer and non-small cell lung cancer (NSCLC), which was the most common type of the disease as 85 per cent of the lung cancer patients had this type.

“Immunotherapy for lung cancer is a type of treatment that aims to enhance the body’s immune response and stop the lung cancer from evading the immune system. The immune system has two responses that work together to detect and destroy cancer cells — innate immune response and adaptive immune response,” explained Dr Hussain.

He said that if bacteria, viruses, or cancer cells evade the innate response, the adaptive immune response becomes active, which recognises specific abnormalities in cancer cells that make them different from the cells that are naturally found in the body.

Though the adaptive immune response was more effective than the innate response, it took longer to become activated, Dr Hussain said, adding that the cells of the adaptive immune response included two types of lymphocytes, which were B cells and T cells.

Explaining the two cell types, he said B cells were like the body's military intelligence system, seeking out their targets and sending defences to lock onto them. He added that B cells reacted to non-self antigens by making proteins called antibodies that could attach to foreign and abnormal cells and let the body know that they were dangerous.

Antibodies can kill cancer cells in several ways, he said. Regarding T cells, he explained that they were major cells the body used to recognise and destroy abnormal cells. Once a foreign antigen or abnormal cancer protein has been recognised by T cells, those cells rapidly increased in number, forming an army specifically designed to attack and kill cells that have foreign antigens.

“Immunotherapies block a protein called PD-1 found on immune cells. PD-1 acts like a brake on the immune system, tamping down immune responses, Dr Hussain said, adding that most widely used immunotherapies released this brake, allowing the immune system to mount a stronger attack against lung cancer.

“Clinical trials are testing immunotherapy drugs in all settings — before and after surgery for early-stage lung cancers, as first-line therapy in patients with advanced lung cancers, and in patients who have previously received chemotherapy. There are trials available for multiple forms of lung cancer, including non-small cell lung cancer and small cell lung cancer,” the expert said.

Guest Speaker Dr Reena Kumari, consultant medical oncologist and assistant professor at the Ziauddin University Hospital Karachi, highlighted the benefits of smoking cessation and early detection of lung cancer.

“Lung cancer starts as a small nodule that grows in size over period of months. At an early stage, cancer can be treated with surgery, which usually results in complete cure from this otherwise fatal disease. However, if left untreated or undiagnosed, the cancer grows bigger and spreads to other parts of the body. At this stage, a complete cure is not possible,” she explained.

She said that nearly 90 per cent of lung cancer cases occurred due to smoking. She added that it was not just cigarettes as other forms of tobacco such as Sheesha could also cause lung cancers.

She also rejected the idea of safe cigarette, saying any such thing did not exist. People who smoked light cigarettes were likely to inhale the same amount of toxic chemicals as those who smoked regular cigarettes, she maintained.

“Other risk factors for lung cancer include being exposed to secondhand smoke, exposure to radon [that is] the second leading cause of lung cancer, having a family history of lung cancer, being treated with radiation therapy to the breast or chest, exposure to asbestos, chromium, nickel, arsenic or tar in the workplace. When smoking is combined with other risk factors, the risk of lung cancer is increased,” Dr Reena asserted.

“Early detection of lung cancer greatly relies on screening and that is when it is more likely to be cured. If the disease is spotted and understood well in advance, the likelihood of the patient to survive five years improves from 11% to 55%. A screening tool namely a low-dose CT scan has been recognised as an effective tool for screening lung cancer and reduces its mortality rate. The screening is painless and quick and if you are or were prone

to smoking before or after 55, you should ask your doctor about the screening,” she said.

She also stressed the importance of smoking cessation counselling as an important measure that smokers should take to understand the risk they faced. NCCI representative Adeel Ahmed concluded the event saying that among young adults in Pakistan, especially the university students, the prevalence of smoking was 15 per cent, and what was more worrying was that approximately 1,200 children started smoking every day. He demanded that the government immediately impose a health levy on cigarettes, Sheesha and e-cigarettes to discourage smoking habit.