Metastatic Non Small cell lung cancer treatment guidelines

Introduction to lung cancer:

• Lung cancer arises from cells in the lung that have grown abnormally and multiplied to form a lump or tumour.
• Non-small-cell lung cancer (NSCLC) is a type of lung cancer, which is differentiated from small-cell lung cancer (SCLC) because of the way the tumour cells look under a microscope. The three main types of NSCLC are adenocarcinoma, squamous cell carcinoma, and large cell (undifferentiated) carcinoma of the lung, all are described below. They are diagnosed in the same way but may be treated differently.
• Lung cancer is the third most common cancer in Europe; NSCLC represents 85–90% of all lung cancers. Smoking is the biggest risk factor for the development of lung cancer.

Diagnosis of NSCLC: 

Lung cancer may be suspected if a person has symptoms such as persistent cough or chest infection, breathlessness, hoarseness, chest pain or coughing up blood. Other symptoms may be fever, appetite loss, unexplained weight loss and fatigue.
Following a clinical examination, your doctor will arrange for an x-ray and/or computed tomography (CT) scan (or might use other technologies, such as positron emission tomography [PET] CT scan or magnetic resonance imaging [MRI]) to evaluate the position and extent of the cancer. Examination and observation of a biopsy will confirm a diagnosis of the NSCLC.

Treatment options for NSCLC: 

Chemotherapy: The utilization of anticancer medications in order to destroy the cancerous cells. Chemotherapy should be taken alone or with the other treatments.

Targeted therapy: newer medications that function by blocking the signals that indicate cancerous cells to develop. Gefitinib and Erlotinib are the most promising drugs for the treatment of NSCLC.

• Gefitinib: The FDA approved Gefitinib 250 mg in May 2003 for non-small cell lung cancer (NSCLC). It was approved as monotherapy for the treatment of patients with locally advanced or metastatic NSCLC after failure of both platinum-based and docetaxel chemotherapies. i.e. as a third-line therapy.
• Erlotinib: The U.S. Food and FDA approved erlotinib 150 mg for the treatment of locally advanced or metastatic non-small cell lung cancer that has failed at least one prior chemotherapy regimen.

Immunotherapy: a sort of treatment basically designed in order to boost the body’s natural defences to fight off cancer.
check- what does immunotherapy do for lung cancer patient

Radiotherapy: the utilization of measured doses of the radiation in order to damage the cancerous cells and prevent them from growing.
Combinations of different treatment types are frequently offered based on the stage and type of NSCLC and on the patient’s condition and comorbidities (additional diseases or disorders experienced at the same time).

Types of Stages: 

Cancer is ‘staged’ according to tumour size, involvement of regional lymph nodes and whether it has spread outside the lung to other parts of the body. This information is used to help decide the best treatment.

Early-stage (stage I-II) NSCLC:

• Surgery is kind of the main treatment for the initial-stage NSCLC.
• Chemotherapy may be given after surgery (adjuvant chemotherapy) in patients with Stage II and Stage III NSCLC and in some patients with Stage IB disease. 
• Radiotherapy (either stereotactic ablative radiotherapy [SABR] or conventional radiotherapy) is an alternative to surgery in patients who are unable or unwilling to have surgery. 
• Radiotherapy may be given after surgery (adjuvant radiotherapy) in patients with Stage II and Stage III NSCLC. 

Locally advanced (Stage III) NSCLC:

Treatment for locally advanced NSCLC is likely to involve different types of therapy (multimodal therapy). If it is possible to remove the tumour (i.e. the tumour is resectable), treatment options can include:

• Induction therapy consisting of chemotherapy with or without radiotherapy, followed by surgery.
• Surgery followed by adjuvant chemotherapy and/or radiotherapy.
• Chemoradiotherapy (i.e. chemotherapy and radiotherapy given at the same time or sequentially).
• The type of treatment and sometimes the sequence of treatments offered to patients with resectable Stage III NSCLC will depend on the general health of the patient and any comorbidities, as well as the extent and complexity of the surgery required to remove the tumour.
• In unresectable Stage III NSCLC, chemoradiotherapy is the preferred treatment. Alternatively, chemotherapy and radiotherapy can be given sequentially (i.e. one after the other) in patients unable to tolerate concurrent treatment.
• Immunotherapy may be offered to some patients with unresectable locally advanced NSCLC following treatment with chemoradiotherapy.

Metastatic (Stage IV) NSCLC: 

NSCLC is referred to as metastatic or Stage IV disease when it has spread beyond the lung which was initially affected.

• It is rarely possible to remove Metastatic Non-Small Cell Lung Cancer with surgery or to treat it radically with radiotherapy.
• Intravenous chemotherapy with a two-drug combination (with or without the addition of the targeted therapy called bevacizumab) is the main treatment for patients with metastatic NSCLC. 
• The choice of drugs used will largely depend on the general health of the patient and the histological subtype of the tumour.
• Patients whose tumours express relatively high levels of programmed death-ligand 1 (PD-L1) protein (determined by molecular testing using a tumour biopsy) may receive first-line immunotherapy with pembrolizumab. 
• Patients whose tumours contain specific mutations (alterations) to the epidermal growth factor receptor (EGFR), BRAF, anaplastic lymphoma kinase (ALK) or ROS1 genes (determined by molecular testing using a tumour biopsy) are best treated with oral targeted therapies given continuously.

Subtypes of the NSCLC: The three main histological subtypes of NSCLC are:

Adenocarcinoma: Approx 40% of all the lung cancers are adenocarcinomas. These tumours start in mucus-producing cells that line the airways.

Squamous cell carcinoma (SCC): Approximately 25–30% of all the lung cancers are SCC. This sort of cancer develops in cells that line the airways and is usually caused by smoking.

Large cell carcinoma: This sort makes up about 10–15% of all the lung cancers. It gets its name from the way that the cancer cells look when they are observed Or examined under the microscope.

Read:- Small cell lung cancer treatment-related guidelines