Lung Cancer

Lung cancer is among the most commonly occurring malignancies in the world and is one of the few that continues to show an increasing incidence. It is the most common cause of cancer death in the United States. Lung cancer is divided into two types: small cell lung cancer and non-small cell lung cancer. The division reflects differences in cell type, presentation, and behavior. Small cell lung cancer has a propensity to be more widespread at diagnosis, and accounts for 20% to 25% of all lung cancers. Non-small cell lung cancer accounts for 75% to 80% of all lung cancers. They are divided according to the cell of origin: squamous cell carcinoma, adenocarcinoma and large cell carcinoma.

The most common known cause of lung cancer is smoking. Certain chemical exposures (e.g., asbestos) are considered risk factors. Coal miners as well, have been found to have an increased risk of lung cancer.

A few of the most frequent presenting complaints include persistent cough, shortness of breath, hemoptysis (cough productive of blood) and chest pain. The diagnostic work-up includes a history and physical examination by your physician, chest x-ray, and CT scan of the chest. A biopsy is then obtained, either through a bronchoscope or via a CT guided fine needle. Additional tests that may be required include a CT scan of the brain, bone scan, CT scan of the upper abdomen, and pulmonary functions tests. Your physician will determine which tests you should undergo.

The management of lung cancer requires an integrated approach, coordinating the involvement of physicians from multiple specialties including the thoracic surgeon, pathologist, radiologist, radiation oncologist and medical oncologist. We at Valley Radiotherapy Associates Medical Group (VRA) endorse this approach and facilitate this multi-specialty integration. Consultation with one of our physicians precipitates the necessary cascade of multi-specialty physician involvement. Treatment strategies are individualized and formulated to maximize cure rates, preserve as much of the normal tissues as possible, and to preserve overall quality of life.

Treatment options for patients with non-small cell lung cancer will depend on a number of factors including the stage of the disease, the individual's overall functional and medical status, and patient preferences. If the cancer has been removed surgically, post-operative radiation therapy may be recommended in order to decrease the chance of the tumor recurring. Positive lymph nodes and positive margins of resections are common indications for treatment. VRA physicians have many years of experience in the treatment of lung cancer, and with the collaboration of the cancer team will help decide whether post-operative radiation is indicated.

When patients present with advanced stage disease at diagnosis, or if surgery is not indicated, treatment options will include radiation therapy alone or radiation therapy in combination with chemotherapy. Chemotherapy may be delivered before, or during radiation therapy. This will, in part, depend on the chemotherapeutic agents being contemplated. Some agents may act to "sensitize" the radiation, and are referred to as radiosensitizers. This means that they may serve to enhance the tumoricidal effects of the loco-regional radiation at the same time that they attack microscopic cells that may have gone to other parts of the body. The most effective strategy of combining the chemotherapy and radiation therapy in the management of non-small cell lung cancer has not yet been determined, and is at this time the subject of clinical investigation. VRA physicians participate in a number of national clinical trials addressing this issue. If appropriate, participation in one of these trials may be offered to an individual. Decisions as to which patients qualify for the various forms of treatment are highly focused and require a multi-disciplinary approach by physicians who are experts in assessing these factors.

Escalating the dose of radiation is another method of intensifying the treatment. Following the lead of academic centers around the country, VRA uses 3D conformal radiotherapy when appropriate, as a means of increasing the dose of radiation to the tumor, while decreasing the dose to the surrounding normal tissues.

Small cell lung cancer is very sensitive to both chemotherapy and radiation therapy. Chemotherapy is recommended for almost all patients with small cell lung cancer because the tumor has a propensity to spread to other parts of the body, and is exquisitely sensitivity to many agents. The addition of thoracic radiotherapy has been shown to increase survival when the disease is limited to the chest (i.e., "limited stage" disease). The sequencing of the chemoradiation, that is, when to deliver the radiation in the overall treatment course, will depend on the agents being used and the patient's overall functional status. Delivering the radiation early in the treatment course concurrently with chemotherapy has been shown in some series to improve the chances of local control. The decision of how to sequence the chemoradiation is one that is made together with the patient's medical oncologist. Chest irradiation may sometimes be recommended in the presence of "extensive stage" disease.

For patients with metastatic disease (i.e., disease that has spread to other parts of the body) radiation therapy is often helpful in relieving symptoms that result from spread of tumor. Pain is a consequence of tumor spread and radiation therapy is considered the treatment of choice when pain is isolated to a focal area or region.

Specialized treatment techniques are used in order to deliver the radiation where it is needed while minimizing the amount of normal tissue in the fields. For example, radio-opaque contrast may be used during simulation to help identify the esophagus so that we may avoid as much of it as possible during treatment.

Side effects of thoracic irradiation include tiredness, redness of the skin in the radiation field, and temporary difficulty or pain with swallowing. For this reason, all patients receiving radiation therapy at one of our centers will have regular, intensive monitoring of their nutritional status by a certified dietician experienced in the effects of radiation, as well a nurse and physician who will institute various remedies as needed. The effects are temporary and will subside following the radiation. Serious potential side effects occur approximately 5% of the time and should be discussed with your physician. VRA uses only advanced radiation techniques so that irradiation of normal tissues is minimized.

The oncologic community continues to strive to improve lung cancer treatment and cure rates. However, a number of questions remain unanswered. Valley Radiotherapy Associates invite you and your family to discuss any issues relating to lung cancer or its therapies with us.

References:

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