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The emergence of new therapies in the management of lung cancer has greatly improved long-term disease control and survival rates for patients with the disease. Dr Chin Tan Min, Senior Consultant, Medical Oncology explains.

Until the recent decade, conventional treatment for lung cancer included surgery, chemotherapy and radiation therapy.

As lung cancer is a disease that may be asymptomatic in early stages, patients often present with advanced disease, where conventional treatment alone may not result in effective eradication of the cancer.

Fortunately, thanks to advances in lung cancer treatment over the last decade, new therapies such as immunotherapy have emerged as a viable treatment option for patients with the disease.

What is immunotherapy?

Our immune system is equipped with a natural ability to recognise and eliminate foreign substances in the body, such as viral infections and diseases.

However, cancer cells have the ability to camouflage themselves and avoid being detected by immune cells, making them difficult to detect and destroy.

Immunotherapy involves using medicines called checkpoint inhibitors to enable the immune system to detect camouflaged cancer cells and attack them. They may be used on their own, or in combination with chemotherapy.

Treating lung cancer with immunotherapy

Immunotherapy is effective in a broad range of cancers, including lung cancer.

There are two main histological types of lung cancer: non-small cell lung cancer (NSCLC) and small-cell lung cancer (SCLC). NSCLC can be further sub-categorised into adenocarcinoma, squamous carcinoma, large cell, and poorly differentiated carcinoma. Both NSCLC and SCLC can be treated with immunotherapy, and have been shown to respond favourably, especially if PDL1 (programmed death-ligand 1) is highly expressed in the tumour.

Immunotherapy can be offered as a treatment option to patients with advanced lung cancer, either upfront, or in cases where previous treatment such as surgery, chemotherapy, and radiation have been used. It may also be offered to patients whose tumour has a higher expression of PDL1, as higher expression levels of PDL1 may predict a better response to immunotherapy.

Side effects of immunotherapy

Immunotherapy may sometimes result in an overstimulated immune response, in which the immune system targets the patient’s organs, such as the lungs, liver and colon, although any organ is potentially susceptible to being affected.

Fortunately, patients can typically tolerate immunotherapy well, and side effects can mostly be effectively managed by a trained clinical care team.

The benefits of immunotherapy generally outweigh the risks. The five-year survival rate for lung cancer patients responding to immunotherapy is in the range of 30%, compared to 5% without immunotherapy, making long-term control possible even in patients with stage 4 cancers. This translates to longer survival and good quality of life.

The future of lung cancer treatment

With improved long-term control and overall survival rates, immunotherapy offers a viable treatment option to patients with lung cancer.

However, chemotherapy remains a key treatment modality in the management of the disease. Combination treatment with chemotherapy and immunotherapy has proven to be more effective compared to immunotherapy alone in most patients, or chemotherapy alone in patients with stage 4 disease. The five-year survival rate for patients treated with chemotherapy alone is less than 5 percent. For patients treated with upfront immunotherapy, it is about 30 percent.

As with many cancers, the best treatment for lung cancer is prevention. Reducing your risk of lung cancer through smoking cessation, avoiding secondhand smoke, partaking in regular exercise, staying active, and keeping a balanced diet, can go a long way in lung cancer prevention.