Lung Cancer - Targeted Therapy Brings New Hope For Its Treatment, Says Expert

The most common cancer worldwide is lung cancer. It is marked by having the highest mortality rate among most of the common cancer. Once lung cancer is diagnosed, it is important to find out how much the cancer has spread. For this, the stage of lung cancer is evaluated, and based on the stage, the treatment is planned. The treatment depends on its type, size of the tumour, the extent to which it has spread and the condition of the patient.

Lung cancer is classified into two major types based upon the microscopic appearance of the tumour cells - Small cell lung cancers and non-small cell lung cancers. These two types of cancers grow, spread in different ways with different treatment methods. Now, modern research has revealed several sub-types, each characterized by mutated genes and abnormal proteins. Each of these sub-types can be treated using the new targeted therapies.

Non-small cell lung cancer has four main stages. In stage 1, the cancer is found in the lung, but it has not spread outside the lung. Whereas when the cancer is found in the lung and also in nearby nodes is stated as stage 2. And when the cancer is in the lung and lymph nodes in the middle of the chest, is termed as stage 3. The last stage is stage 4 when cancer has spread to both lungs, into the area around the lungs, or to distant organs.

Small-cell lung cancer has two main stages. Cancer is found in only one lung or nearby lymph nodes on the same side of the chest in the limited stage, while in the extensive stage, the cancer has spread to complete one lung, to opposite lung, to opposite side lymph nodes, to the pleural fluid and metastasised to distant organs and bone marrow.

The prognosis depends on the stage and is always better in early stage of the cancer when it is localised and not spread to other parts. This is where the role of regular screening comes in particularly in asymptomatic high risk populations.

A low-dose CT scan screening can help show any abnormalities in the lung as small as the size of a grain of rice. This helps to find Stage I curable lung cancer with less likelihood of metastasis to other parts of the body. This gives the doctor more options for the treatment and the patient a higher chance of survival.

In stage 0 and state 1 Non-small cell lung cancer, surgery may be the only treatment needed that removes part of the affected area of lung and lymph nodes. Stage 2 and Stage 3 may need to be treated by a combination of surgery, radiation, chemotherapy and surgery with removal of the cancer affected portion of the lung or even the entire lung along with affected lymph nodes. Immunotherapy and targeted therapy can be of help in treating cancers in Stage 3 and 4, which is otherwise very difficult to treat.

Targeted therapies use drugs or other substances to 'target' the cancer cells more precisely and avoid any damage to surrounding normal cells. Targeted therapy is effective for non-small cell lung cancer. Targeted therapies work by targeting specific areas in the cancer cells. Targeted therapy matches the therapy to a particular type of cancer in an individual patient which makes it more effective in treating certain types of cancer like lung cancer. The other advantages include fewer side-effects as compared to standard methods of treatment.

There are two main types of targeted therapy - Monoclonal antibodies, called as mAbs and Small molecule drugs. mAbs block a specific target on or around the cancer cells and prevent them from growing further. Given with standard treatment like chemotherapy, they help medication reach cancer cells better. mAbs are usually given intravenously, i.e. in the bloodstream. Small molecule drugs are usually taken orally and they work by preventing the growth and spread of cancer cells.

To ensure greater chance of success with targeted therapy, the patient's tumor tissue is tested to determine if an appropriate target is present or not. Targeted therapy is most beneficial for patients whose tumor cells have a specific mutation in the gene that defines the target. Patients without the mutation would not be chosen as in their case, the drug would not have anything to target. If a patient has not responded to other therapies or is inoperable, then targeted therapy may be of help.

Targeted Therapy brings new hope to patients with Lung Cancer.

Immunotherapy in Lung Cancer:

In 2015, the U.S. FDA approved the first immunotherapy to treat a subset of lung cancer patients. Immunotherapy is class of treatments that helps a person's own immune system eliminate or control cancer. Recent clinical studies treating patients with immunotherapy, either alone or in combination with other treatments, have shown significant patient improvement, resulting in FDA approval of several other immunotherapy options for more lung cancer patients, including approvals to treat patients with immunotherapy as a first-line therapy instead of conventional treatments.

(Dr Salil Patkar, Consultant, Medical Oncology, Apollo Cancer Centre, Navi Mumbai)

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