Lung cancers are one of the commonest tumours in Asia. It is the leading cause of cancer death in men and second leading cause in women worldwide. Most lung cancers are attributable to smoking and environmental factors in men, but in women, only half. In non-smoking Asian females, cancer genes mutated tumours are more prevalent.

Lung tumours may exhibit oncogene addiction (when cancer cells grow due to gene expression), particularly in non-small cell lung cancer (NSCLC). One of the well-known examples of oncogene addiction in NSCLC is the addiction to epidermal growth factor receptor (EGFR) mutations. EGFR is a cell surface receptor that, when mutated, can lead to uncontrolled cell growth and division. These tumours have a high probability of responding to targeted drugs called tyrosine kinase inhibitors.

When tumours (NSCLC) are small, surgery or stereotactic radiotherapy (in patients unfit for operation) have a high chance of cancer control. For tumours with limited nodal spread, surgery of the primary tumour and lymph node dissection, followed by drugs or chemotherapy can be used. When there is more extensive lymph node spread to the mediastinum ( central part of the chest near the heart and windpipe), chemotherapy and radiotherapy can be used at the same time. When cancer has spread distantly, chemotherapy or targeted drugs or immunotherapy will be used to control the disease.

In this article, we will discuss concurrent chemoradiotherapy.

Locally Advanced NSCLC (Stage III): Concurrent chemoradiotherapy is commonly used for patients with locally advanced NSCLC, where the tumor has spread to central lymph nodes but has not metastasized to distant organs.

• Chemotherapy: Patients receive chemotherapy drugs during the same period as radiation therapy. The chemotherapy helps to sensitize the cancer cells to the effects of radiation, making the radiation more effective in killing the cancer cells.
• Radiation Therapy: High-dose radiation is delivered to the primary tumor and surrounding affected lymph nodes. The goal is to provide a more comprehensive and aggressive approach than radiation or chemotherapy alone.

Radiotherapy can be given with X-rays using advanced techniques like volumetric modulated arc therapy (VMAT) or IMRT, or with particles like protons or carbon ion. In most individuals, VMAT provides a very safe and effective strategy. However in patients with poorer lung or cardiac function, proton therapy has the added benefit of lowering radiation doses to normal organs. Although some older trials using an older form of proton therapy did not show an advantage, newer but smaller studies have found proton therapy (especially using pencil-beam or scanning )to be safe. 

Studies from Japan with advanced proton techniques simultaneously with chemotherapy showed promising survival and safety outcomes.  

However, proton therapy is costly and requires very advanced hardware. For most patients, VMAT/IMRT with X-Ray provides a good and safe treatment tool with careful expertise. Speak to your oncologist about treatment options in your center.