3D-CRT brings hope for inoperable lung cancers
By American Society for Therapeutic Radiology and Oncology
Sep 1, 2006, 17:34
Modern three-dimensional radiation therapy has been proven to be more successful at curing lung cancer than older two-dimensional radiation therapy for some patients with early stage lung cancer, according to a new study in the September 1, 2006 edition of the International Journal of Radiation Oncology * Biology * Physics, the official journal of the American Society for Therapeutic Radiology and Oncology (ASTRO).
Non-small cell lung cancer (NSCLC) accounts for 87 percent of all lung cancers diagnosed. Currently, the best treatment for stage I NSCLC is surgery or stereotactic radiation therapy (SRT), often followed by chemotherapy if the lesion was larger than 3 cm or radiotherapy and chemotherapy if the surgical margin or hilar or mediastinal nodes were positive at the time of operation. The five-year survival outcomes are very high, with 50 to 67 percent of these patients living at least five years after diagnosis if patients had a well staged stage I NSCLC. When surgery is not an option because the patient has heart problems or other complications, treatment options include varying types of radiation therapy and chemotherapy, alone or in combination.
In this study, doctors at M.D. Anderson Cancer Center in Houston wanted to see if conventional radiation therapy worked as well as the newer three-dimensional conformal radiation therapy (also called 3D-CRT) at curing patients with early stage non-small cell lung cancer. 3D-CRT was created to improve upon older types of radiation therapy by allowing doctors to aim several radiation beams at the tumor to shape or "conform" the radiation to the lung. The idea is that tailoring each beam allows doctors to give more radiation to the tumor while keeping it away from nearby healthy tissues.
Between 1978 and 2003, 200 patients with medically inoperable stage I NSCLC were treated with radiation therapy alone. Eighty-five received 3D-CRT while 115 received conventional therapy. Thirty-six percent of patients who received 3D-CRT lived five years after diagnosis compared to 10 percent who received the conventional therapy. Their causes of deaths were more related to intercurrent disease rather than cancer. Local failure was significantly reduced by 3D-CRT compared to conventional RT.
"This study proves that three-dimensional conformal radiation therapy improves outcomes for patients with medically inoperable stage I non-small cell lung cancer," said Ritsuko Komaki, M.D. "Patients with this type of lung cancer should ask their radiation oncologist about 3D-CRT." Dr. Komaki is a radiation oncologist and professor at M.D. Anderson Cancer Center in Houston.
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