Lung Cancer: Medical Oncology
Chemotherapy destroys cells by stopping them from growing or multiplying. Healthy cells may also be harmed, especially cells that divide rapidly. Most side effects of chemotherapy are the result of harm caused to healthy cells. However, healthy cells usually regrow after chemotherapy treatment. The goals of chemotherapy are cure, control or palliation (control of symptoms) and comfort.
While surgery and radiation therapy destroy cancer cells in a specific area, chemotherapy works systematically (throughout the body) by destroying cancer cells that have metastasized (spread) from the primary (original) site. The body regulates the production of dividing cells by maintaining a balance between birth and death of cells. The body’s maintenance of this balance (homeostasis) is disturbed when cancer occurs, and cells grow out of control.
Today, there are more than 100 chemotherapy drugs used in various combinations. A single drug may be used for treatment, but more likely your treatment will consist of a combination of drugs. When using a combination of drugs, with different mechanisms of action, there is greater percentage of cancer cells destroyed. Combination therapy also reduces the chance of resistance to a particular drug and reduces toxicity to any one organ. Usually chemotherapy is given intravenously (I.V.), but it also may be administered orally or by injection or applied to the skin. In other circumstances drugs are delivered directly to the tumor or tumor site.
Chemotherapy is often given in cycles that include treatment alternating with rest periods. Rest periods give your body time to build healthy cells and for you to regain your strength. Keeping to your treatment schedule is important so you receive the most benefit. With each repeated cycle of chemotherapy, more of the cancer cells are killed, with the goal of eliminating enough of the tumor to allow your immune system to destroy any remaining cancer cells.
Non-Small Cell Lung Cancer (NSCLC)
National Cancer Institute (NCI) recommended standard treatment options for chemotherapy in non-small cell lung cancer include a combination of drugs. Most of the drug combinations contain a platin agent, such as Cisplatin or Carboplatin. These platin drugs are administered intravenously every 3-4 weeks for a total of 4-6 cycles.
Some of the most common side effects include:
- Bleeding or bruising easily
- Increased chance of infection
- Loss of appetite
- Loss of hair
- Mouth sores
- Nausea and vomiting
- Tingling or numbness in the fingers or toes
Some of the less common side effects can include:
- Hypersensitivity reaction
- Renal and cardiac dysfunction
With the platin agent, an additional drug is given intravenously during the same cycle. The most common drug agents are Gemzar (gemcitabine), Taxol (paclitaxel), Navelbine (vinorelbine) and Taxotere (docetaxel). A patient may experience many of the same side effects as with the platin agent. It is wise to ask your doctor or nurse for a list of the most common side effects for each chemotherapy that will be given.
Targeted Therapy (Avastin)
Another drug that is used in combination with a platin drug (chemotherapy) is Avastin (bevacizumab). Avastin is a targeted therapy, also known as a monoclonal antibody, anti-angeogenic or biological therapy. Avastin works by blocking and/or interfering with the growth of new blood vessels, potentially helping to block further growth and spread of cancer. It is important to note that Avastin has its limitations and is not recommended for NSCLC patients who have the squamous cell type, GI bleeding or recent surgery. Avastin is given intravenously for a total of 4-6 cycles. Because Avastin works in a different way than chemotherapy there are different side effects.
Some of these include:
- Hypertension (high blood pressure)
- Proteinuria (too much protein in the urine)
- Neutropenia (reduced white blood cell count which may increase the risk of infection).
Additional side effects may include:
- Difficulty breathing
For advanced metastatic non-squamous NSCLC and malignant pleura mesothelioma Alimta
(premetrexed) can be used with Cisplatin. Premetrexed belongs to the class of chemotherapy drugs called antimetabolites. Antimetabolites are very similar to normal substances within the cell. When the cells incorporate these substances into the cellular metabolism, they are unable to divide. Antimetabolites are cell-cycle specific. They attack cells at very specific phases in the cycle. Premetrexed exerts its chemotherapeutic effect by disrupting folate-dependent metabolic processes essential for cell replication.
This action also effects normal cells which can cause significant side effects in the body, such as:
- Low white, red and platelet blood cell counts
These complications and side effects of premetrexed can be reduced by using folic acid and vitamin B-12 supplementation.
The most common side effects associated with Alimta with a cisplatin drug include:
- Low blood counts
- Stomach upset, including nausea and vomiting and diarrhea
- Mouth throat or lip sores
Alimta is given intravenously every 3-4 weeks for 4-6 cycles.
Tarceva (Erlotinib) is used for treatment of patients with locally advanced or metastatic NSCLC after failure of at least one chemotherapy regimen.
Tarceva is an Epidermal Growth Factor Receptor (targeted therapy) and works by blocking tumor cell growth that is present on the surface of some cancer cells and some normal cells. Tarceva inhibits an enzyme within the cell that is associated with Epidermal Growth Factor Receptor. It should be noted however, that the specifics of how this inhibition functions is not fully understood. Unlike other cancer fighting drugs Tarceva is administered in pill form and taken by mouth every day. Tarceva’s side effects are often predictable in terms of onset and duration. There are many options to minimize Traceva’s
side effects and most will go away after treatment is finished.
The most common side effects include:
- Poor appetite
- Shortness of breath
- Nausea and vomiting
The least common side effects include:
- Mouth sores
- Dry skin
- Eye irritation
- Abdominal pain
Small Cell lung Cancer (SCLC)
For patients with limited stage disease a drug regimen with a platin agent and etoposide (VP-16) is recommended. Side effects for the platin therapy are listed above under NSCLC. Etoposide and Cisplatin are generally given every three weeks for 4 cycles. Etoposide is an anti-cancer (“antineoplastic or “cytotoxic”) chemotherapy drug. It is made from plant alkaloids and interferes with specific enzymes that control or manipulate the structure of the DNA necessary for replication. Etoposide is commonly given intravenously (I.V.).
The following side effects are common for etoposide:
- Low blood cell counts
- Hair loss
- Loss of fertility
- Nausea and vomiting
- High blood pressure
The following side effects are less common:
- Mouth sores
- Poor appetite
- Skin reactions (if given prior radiation therapy)
- Metallic taste
- Numbness in the fingers and toes.
For extensive stage disease the same drugs listed above can be used in different doses or a variety of different chemotherapy drugs may be used including, irinotecan, AUC 5, cyclophosphamide, doxorubicin, vincristine and topotecan. Many of these drugs are used in combination with one another and side effects may vary depending on the regime. It is important to ask your physician or nurse what side effects to expect with each different regimen.
All Cancer Fighting Drugs Therapy
Although the side effects of chemotherapy or other cancer fighting drug therapy may be worrisome it is important to realize that chemotherapy treatment has evolved over the last 10 years. Many drugs have been developed to lessen the side effects of chemotherapy and provide a much better quality of life during treatment. These drugs are used for supportive care and can help increase white and red cell blood counts, decrease nausea and vomiting and increase appetite. Also, many of the chemotherapy drugs are less toxic than the drugs used five years ago. Please let your health care team know all of your side effects during chemotherapy so that they can use supportive care drugs to ease your discomfort.
Several new cancer vaccines are being evaluated for lung cancer treatment. These are used as treatment to help the person’s immune system recognize a tumor as foreign and push the body’s normal defense mechanisms to destroy tumor cells. Vaccines have many theoretical advantages, such as greater specificity in targeting cancer cells with fewer toxic side effects. Some of the new approaches have clear clinical efficacy as well. Vaccines come in a wide variety of types, but can be made from an individual’s tumor cells that have been removed and made into a vaccine, or consist of a synthesized tumor-specific antigen.