August 27, 2017

Lung Cancer: Staging and Treatment


In the previous article, we noted that if lung cancer is suspected as a result of a screening procedure (CT, MRI or PET scan), then a follow-up biopsy would be required, and also that a bronchoscopy might be needed in some circumstances. Please see symptoms and diagnosis of lung cancer for more. In this article, we will discuss the staging and treatment of lung cancer.

Staging of lung cancer

If lung cancer is diagnosed, other tests are done to find out how far it has spread through the lungs, lymph nodes, and the rest of the body. This process is called staging. The type and stage of lung cancer tells doctors what kind of treatment you need.

There are two major types of lung cancer, non-small cell lung cancer (NSCLC) and small cell lung cancer (SCLC). Staging lung cancer is based on whether the cancer is localized or has spread from the lungs to the lymph nodes or other organs. Because the lungs are large, tumors can grow in them for a long time before they are found. Even when symptoms—such as coughing and fatigue—do occur, people think they are due to other causes. For this reason, early-stage lung cancer (stages I and II) is difficult to detect.

1). Non-Small Cell Lung Cancer (NSCLC)

Non-small cell lung cancer accounts for about 85 percent of lung cancers and includes:
  • Adenocarcinoma, the most common form of lung cancer in the United States among both men and women;
  • Squamous cell carcinoma (also called epidermoid carcinoma), which accounts for 25 percent of all lung cancers;
  • Large cell carcinoma, which accounts for about 10 percent of NSCLC tumors.

Stages of NSCLC

Stage I: The cancer is located only in the lungs and has not spread to any lymph nodes.

Stage II: The cancer is in the lung and nearby lymph nodes.

Stage III: Cancer is found in the lung and in the lymph nodes in the middle of the chest, also described as locally advanced disease. Stage III has two subtypes:
  • If the cancer has spread only to lymph nodes on the same side of the chest where the cancer started, it is called stage IIIA.
  • If the cancer has spread to the lymph nodes on the opposite side of the chest, or above the collar bone, it is called stage IIIB.
Stage IV: This is the most advanced stage of lung cancer, and is also described as advanced disease. This is when the cancer has spread to both lungs, to fluid in the area around the lungs, or to another part of the body, such as the liver or other organs.

2). Small Cell Lung Cancer (SCLC)

Small cell lung cancer accounts for the remaining 15 percent of lung cancers in the United States. They tend to grow more quickly than NSCLC tumors. Usually, SCLC is more responsive to chemotherapy than NSCLC.

There are two main types of SCLC. These two types include many different types of cells. The cancer cells of each type grow and spread in different ways. The types of SCLC are named for the kinds of cells found in the cancer and how the cells look when viewed under a microscope:
  • Small cell carcinoma (oat cell cancer).
  • Combined small cell carcinoma.

Stages of SCLC

Limited stage: In this stage, cancer is found on one side of the chest, involving just one part of the lung and nearby lymph nodes.

Extensive stage: In this stage, cancer has spread to other regions of the chest or other parts of the body.

The American Joint Commission on Cancer implemented a more detailed staging system in which the stages of small cell lung cancer are described using Roman numerals and letters (for example, Stage IIA). This is the same method that is used for NSCLC in describing the growth and spread of the cancer.

For more information, visit the CDC-linked National Cancer Institute's Stages of Non-Small Cell Lung Cancer and Stages of Small Cell Lung Cancer.

Types of Treatment in lung cancer

Lung cancer is treated in several ways, depending on the type of lung cancer and how far it has spread. People with non-small cell lung cancer can be treated with surgery, chemotherapy, radiation therapy (also radiotherapy), targeted therapy and immunotherapy—alone or in combination. Each of these types of treatments may cause different side effects. People with small cell lung cancer are usually treated with radiation therapy and chemotherapy.

1). Surgery

Most stage I and stage II non-small cell lung cancers are treated with surgery to remove the tumor. For this procedure, a surgeon removes the lobe, or section, of the lung containing the tumor. Some surgeons use video-assisted thoracoscopic surgery (VATS).

A very small percentage of people who have limited-stage small cell lung cancer and no lymph node tumors may benefit from surgery, after which adjuvant chemotherapy (see below) is given.

2). Chemotherapy

This is using special medicines to shrink or kill the cancer. The drugs can be pills you swallow or medicines given in your veins, or sometimes both. The chemotherapy treatment plan for lung cancer often consists of a combination of drugs.

For people with non-small cell lung tumors that can be surgically removed, evidence suggests that chemotherapy after surgery, known as “adjuvant chemotherapy,” may help prevent the cancer from returning. This is particularly true for patients with stage II and IIIA disease. Questions remain about whether adjuvant chemotherapy applies to other patients and how much they benefit.

For people with stage III lung cancer that cannot be removed surgically, doctors typically recommend chemotherapy in combination with definitive (high-dose) radiation treatments. In stage IV lung cancer, chemotherapy is typically the main treatment. In stage IV patients, radiation is used only for palliation of symptoms.

If these treatments don't work, or if lung cancer comes back after these drugs have worked for a while; doctors often prescribe a second course of drug treatment referred to as second-line chemotherapy.

Recently, the concept of maintenance chemotherapy has been tested in clinical trials, either as a switch to another drug before the cancer progresses; or to continue one of the drugs used initially for a longer period of time. Both of these strategies have shown advantages in selected patients.

Chemotherapy Before Other Treatments (Neoadjuvant Treatment):
Receiving chemotherapy before radiation or surgery may help people with lung cancer by shrinking the tumor enough to make it easier to remove with surgery, increasing the effectiveness of radiation and destroying hidden cancer cells at the earliest possible time.

ii). SCLC:
For people with small cell lung cancer, regardless of stage, chemotherapy is an essential part of treatment. Radiation treatment may be used as well depending on the stage of cancer.

3). Radiation therapy

This is using high-energy rays (similar to X-rays) to kill the cancer. Its application to both non-small cell and small cell lung cancer have already been referred to (see 'Chemotherapy' above). Of special mention here is prophylactic radiation to brain in small cell lung cancer (see below).

Preventive Radiation Therapy to the Brain:
In more than half of the people with small cell lung cancer, the cancer also spreads to the brain. For people whose lung cancer has responded to chemotherapy, doctors may prescribe radiation therapy to the brain to help prevent the cancer from spreading to the brain. This procedure is known as prophylactic cranial irradiation (PCI). This can benefit patient with both limited-stage and extensive-stage small cell lung cancers.

4). Targeted therapy

This is using drugs to block the growth and spread of cancer cells. The drugs can be pills you take or medicines given in your veins. Unlike chemotherapy drugs, which cannot tell the difference between normal cells and cancer cells, targeted therapies are designed specifically to attack cancer cells by attaching to or blocking targets that appear on the surfaces of cancer cells. People who have advanced lung cancer with certain molecular biomarkers may receive treatment with a targeted drug alone or in combination with chemotherapy.

Examples include Erlotinib (Tarceva and others), Afatinib (Gilotrif), Gefitinib (Iressa), Bevacizumab (Avastin), Bevacizumab, Crizotinib (Xalkori), and Ceritinib (Zykadia). Crizotinib has also shown benefits for people with advanced non–small cell lung cancer who have the ALK gene mutation.

5). Immunotherapy

Recently emerged as a new treatment option for certain lung cancers. While any cancer treatment can cause side effects, immunotherapy is generally well-tolerated; in part due to its mechanism of action. Our immune system is constantly working to keep us healthy. It recognizes and fights against danger, such as infections, viruses, and growing cancer cells. In general terms, immunotherapy uses our own immune system as a treatment against cancer.

Treatments for non-small cell lung cancer have advanced the furthest; however, a number of new immune-based treatments for small cell lung cancer are also in clinical development. These treatments fall into four main categories: Monoclonal antibodies, Checkpoint inhibitors, Therapeutic vaccines, and Adoptive T-cell transfer.

Complementary and Alternative Medicine

Complementary and alternative medicine are medicines and health practices that are not standard cancer treatments. Complementary medicine is used in addition to standard treatments, and alternative medicine is used instead of standard treatments. Meditation, yoga, and supplements like vitamins and herbs are some examples.

Many kinds of complementary and alternative medicine have not been tested scientifically and may not be safe. Talk to your doctor about the risks and benefits before you start any kind of complementary or alternative medicine.

Important fact to note

Doctors from different specialties often work together to treat lung cancer. Pulmonologists are doctors who are experts in diseases of the lungs. Surgeons are doctors who perform operations. Thoracic surgeons specialize in chest, heart, and lung surgery. Medical oncologists are doctors who treat cancer with medicines. Radiation oncologists are doctors who treat cancers with radiation. They all work as one team to give the patient with lung cancer the best possibility of survival.

1). Centers for Disease Control: Lung Cancer - Basic information. Accessed 22.08.2017. Available here: https://www.cdc.gov/cancer/lung/basic_info/
2). Lung Cancer 101: What is lung cancer?. Accessed 22.08.2017. Available here: https://www.lungcancer.org/find_information/publications/163-lung_cancer_101/265-what_is_lung_cancer

No comments:

Post a Comment

Got something to say? We appreciate your comments: