Non-Small Cell Lung Cancer

Description

Alternative Names

Radiation Treatments

Radiation is the other primary treatment for early-stage lung cancer. It is also being investigated in advanced lung cancers.

Radical Radiation in Early-Stage Cancer. Radical radiation is used as the sole procedure in stage I and some stage II patients who have adequate lung function but, for medical or other reasons, cannot be treated surgically. In these cases, the five-year survival rate is about 20%, and the cancer is likely to recur. Survival rates may be higher or lower depending on the tumor size. In general, with radiation therapy alone, the larger the tumor, the lower a patient's chance of survival. (A 2002 analysis suggested that the use of radiotherapy after surgery in patients whose tumors had been completely removed might be associated with reduced survival rates.)

Combined Treatments for Improving Survival in Advanced Cancer. Radiation is also being investigated in various combinations with chemotherapy, surgery, or both. At this time, concurrent radiation treatment plus platinum-based chemotherapy may extend survival times in advanced lung cancer. Other combinations are showing promise.

Palliative Radiation. Palliative radiation is used to shrink cancers and reduce pain and symptoms in stage III patients with poor lung function and those with metastasized cancer. In up to 85% of patients with advanced disease, palliative radiation therapy helps relieve pain, shortness of breath, the superior vena cava syndrome, coughed-up blood, and symptoms caused by brain metastases. Radiation, in these cases, is not generally used with the intention of reducing mortality rates, although it may increase survival in some patients, such as those with excellent lung function and whose tumors are small enough that thoracoscopy is needed to detect them. Of note: delaying radiation therapy until symptoms develop does not appear to reduce survival times or impair quality of life compared to starting it right away in patients with minimal or no symptoms.

Radiation Therapy in Metastasis to the Brain. Radiation is the primary treatment when cancer has spread to the brain unless the cancer is small enough to be treated surgically. In such cases, a technique called stereotactic radiosurgery may be employed that delivers powerful, highly targeted radiation to specific areas in the brain. Some trials are investigating using radiation to the head in order to prevent metastasis to the brain.

Standard Radiation Procedures

The goal of radiation treatment is to administer doses as high as possible to kill as many cancer cells as possible, without destroying surrounding healthy tissues or causing excessive toxicity. Different procedures may be tried. The exact radiation procedure depends on the site of the cancer or its extent:

• External-Beam Radiation. External-beam radiation therapy focuses a beam of radiation directly on the tumor. It is generally used for metastasized cancer.
• Brachytherapy. Brachytherapy involved the implantation of radioactive seeds through thin tubes directly into the cancer sites. Brachytherapy may be used for lung cancers that have spread to the throat and cause obstruction. High-dose-rate brachytherapy may also have some value for patients who have inoperable tumors in the central region of the lung.

Hyperfractionated Radiotherapy

Hyperfractionated radiotherapy administers smaller than standard doses a number of times a day (usually two or three). This allows a higher cumulative dose over the whole course of treatment. It is not as useful as sole therapy, but needs to be combined with chemotherapy to have any survival benefits.

Hyperfractionated Accelerated Radiotherapy. Continuous hyperfractionated accelerated radiotherapy (CHART) administers multiple doses per day but uses standard doses. This allows the total dose of radiation to be administered over a shorter time period than the standard six weeks. CHART is proving to extend survival rates of patients with localized cancer over that of standard radiotherapy or non-accelerated hyperfractionated radiation. It can cause severe swallowing problems. A modification in which treatment is suspended for two days out of seven may help reduce this effect.

Three-Dimensional Conformal Radiotherapy

Three-dimensional (3-D) conformal radiotherapy involves external-beam radiation that is designed to conform closely to the specific targeted organs or tissues. This allows significantly higher doses to attack the cancer while reducing the risk to healthy cells. In a 2003 report, three-year survival rates in stage IIIA patients were nearly 60%, and nearly half the patients experienced no side effects.

Stereotactic body radiotherapy, an advance on conformal radiation, uses a body frame and an abdominal press to immobilize the patient's body and limit breath movement. This allows a more precise delivery of high-energy photons, which are delivered to the tumor using a linear accelerator. The technique is still investigational.

Side Effects of Radiation Therapy

Radiation can have significant side effects when used as part of intensive treatments, such as hyperfractionated radiotherapy or radiotherapy in combination with chemotherapy. Among the most serious problems is severe inflammation in the esophagus (esophagitis) or the lungs (pneumonitis). Infection is also a danger.

The use of targeted approaches, such as conformal radiotherapy may help reduce these complications. Investigators are also studying drugs, notably amifostine, that appear to help reduce throat and lung inflammation caused by radiation without reducing its cancer-fighting effects.