Lung Cancer Radiation Therapy

Radiation therapy damages cancer cells, preventing them from reproducing and slowing the growth of the tumor. X-rays, gamma rays, and other radioactive materials are used in radiotherapy. While the radiation also damages healthy cells surrounding the tumor, these are capable of recovering from the damage. Cancer cells are not.

Radiation therapy, also called radiotherapy, is most often used when a tumor, either due to size or location, is inoperable. Radiation may also be used before surgery to shrink tumors, or to kill remaining cancer cells after surgery. If the cancer is advanced, radiation therapy may provide symptomatic relief.

External Beam Radiation Therapy

External beam radiation therapy aims high energy x-rays or gamma rays at the tumor. The procedure is non invasive, but does affect surrounding tissues, limiting the amount of radiation that can be used. The area to be treated is marked with a tattoo on the skin so the energy beam can be accurately directed at the tumor.

Brachytherapy

In brachytherapy, radiation is delivered directly to the tumor, minimizing damage to healthy cells. Radioactive material is implanted directly into (or next to) the tumor. The implants emit radiation for up to a year, exposing the cancer cells to higher levels of radiation than would be possible using traditional external beam techniques.

Endobronchial Brachytherapy

During endobronichal brachytherapy a bronchoscope, or hollow tube, is inserted through the mouth or nose, down the throat and into the bronchial passages. High dose radiation is delivered directly to the tumor through the tube. Endobronchial brachytherapy does not leave implants in the body, but is limited to tumors in the bronchial passages. Tumors surrounded by lung tissue cannot be treated in this manner.

Prophylactic Cranial Irradiation

Prophylactic cranial irradiation may be used to prevent the spread of small cell lung cancer to the brain. Although cranial irradiation may prevent metastasis to the brain, researchers have yet to determine if the procedure improves survival rates. Cranial irradiation can cause brain tissue degeneration, which affects intellect, memory and motor functions.

Cisplatin and Radiation Therapy

Radiation therapy is most successful when combined with surgery, or as follow-up treatment after chemotherapy. By itself, radiation therapy has a low five-year survival rate. Clinical trials suggest that combining radiation therapy with the chemotherapy drug cisplatin may improve survival rates.

A study by the Netherlands Cancer Institute compared combined radiation therapy and cisplatin treatment with radiation alone. The results indicate that three-year survival rates for radiation therapy alone were only two percent, while patients who were also treated with cisplatin had survival rates of sixteen percent, although patients receiving cisplatin were also more likely to experience severe side effects.

Radiation Treatment Side Effects

Radiation damages healthy as well as cancerous tissue, and treatment has some side effects. It’s common to feel tired and sick during therapy. These symptoms usually subside when treatment ends. Other symptoms can include:

  • sore throat
  • difficulty swallowing
  • dry, “sticky” cough
  • hair loss (usually temporary)
  • fever
  • sore skin
  • esophagitis
  • pneumonitis
  • pulmonary fibrosis (lung tissue scarring).

Esophagitis

Inflammation of the esophagus (esophagitis) may occur as a result of radiation therapy. Heartburn is the most common symptom, which may worsen after heavy meals or upon lying down. Nighttime heartburn may cause insomnia and sleep deprivation. Esophagitis occasionally causes chest pain that can be mistaken for a heart attack.

Pneumonitis and Pulmonary Fibrosis

Five to fifteen percent of patients treated with radiation develop some degree of pneumonitis, or lung inflammation. Symptoms of pneumonitis may develop up to six months after treatment, and include fevers, coughing and a feeling of “fullness” in the chest. Severe cases can result in respiratory difficulties, chest pain, and death.

Pulmonary fibrosis, or lung scarring, may occur as a result of pneumonitis, as the body attempts to repair inflammation damage. Scarring compromises lung function, causing shortness of breath, and other respiratory problems.

Radiation Therapy in Palliation

Radiation is often used during palliative care of stage 4 cancer patients. Radiation helps to shrink the tumors which

  • provides pain relief
  • eases symptoms of superior vena cava syndrome
  • improves breathing
  • lessens coughing up of blood.

Out-of-Body Radiation

Conventional radiation therapy cannot deliver large doses of radiation to malignant cells without damaging the healthy tissue around the tumor. Current research is evaluating the effectiveness of “out-of-body” radiation therapy. The entire organ is surgically removed, treated with high levels of radiation to kill cancer cells, and then surgically reattached.

Resources

American Cancer Society. (nd). What’s new in lung cancer research and treatment?

Bergman, B. (2001). Lungcancer. Lkemedelsboken. Apoteket AB, Farmaci/Marknad (ed.). BTJ Tryck AB, Lund, pp. 596-602.

Cancer Research UK. (updated 2002). Radiotherapy: Side effects.

Cancer Treatment Centers of America at Tulsa. (nd). Lung brachytherapy.

Chisam, M.