IMRT vs. CRT: For Lung Cancer Patients, IMRT Is Coming Out on Top, Says Study

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Yaneff_191015Primary lung cancer is a type of malignant tumor that begins in the lung cells. Malignant cancers are among the more dangerous cancer types that can spread to other areas of the body. Primary lung cancer will begin in the lungs, while secondary lung cancer may start somewhere else and later reach the lungs.

In the U.S., there will be an estimated 221,200 new cases of lung cancer and 158,040 lung cancer–related deaths for 2015, according to the American Cancer Society.

Locally advanced lung cancer accounts for a third of all lung cancers. Concurrent radiation and chemotherapy is the standard treatment for locally advanced lung cancer. Most patients typically receive three-dimensional conformal radiation therapy (3DCRT) or intensity modulated radiation therapy (IMRT). IMRT is considered the newer and more-advanced technique. It uses more complex radiation beam arrangements than 3DCRT, which has been the standard lung cancer treatment for decades.

Researchers from Radiation Oncology at The University of Texas MD Anderson Cancer Center conducted a secondary analysis of an international, cooperative-led randomized trial of locally advanced non-small cell lung cancer (NSCLC) patients. The researchers found there was less severe lung toxicity and greater tolerability of chemotherapy in patients given IMRT when compared to those receiving 3DCRT. Research results were presented at the American Society for Radiation Oncology’s 57th Annual Meeting.

The study enrolled patients from 2007 to 2011; all had undergone concurrent chemotherapy and either IMRT or 3DCRT. The standard dose of 60 Gy was compared with a higher 74 Gy dose. The study included 482 patients treated with radiation, 47% treated with 3DCRT, and 53% with IMRT.

The team found 44% fewer cases of the life-threatening lung inflammation called pneumonitis in 3.5% of those receiving IMRT compared with 7.9% of patients receiving 3DCRT. It was also found that 37% of IMRT patients completed chemotherapy when compared with 29% of those receiving 3DCRT.

The study’s lead author Stephen Chun commented on the study findings: “This is (the) first analysis of a prospective clinical trial to show a reduction of toxicity associated with IMRT in locally advanced lung cancer and could lead to a major change in the way radiation therapy is delivered for the disease. The data from our study makes a strong argument that we should routinely consider use of IMRT in locally advanced lung cancer.”

The complex and high dose of beams associated with IMRT will target and lead to a low-dose bath. In other words, the lung volume only received 5 Gy of radiation.

“It’s been unclear what the consequences of that low dose bath are. What we’ve seen in this study is that indicators of the low dose bath that’s increased by IMRT had no association with any severe toxicity outcome. This finding suggests that we should be optimizing radiation treatment by the high and intermediate dose region, and not the low dose region,” added Chun.

Researchers believe these findings have the potential to improve the quality of life and reduce the number of hospital admissions for patients with locally advanced NSCLC. The National Cancer Institute (NCI), Eli Lilly and Company, and Bristol-Myers Squibb supported the study with grants U10CA180822, U10CA21661, and U10CA180868.

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Sources for Today’s Article:
“Cancer Facts & Figures 2015,” American Cancer Society web site;, last accessed October 19, 2015.
“What is lung cancer?” Canadian Cancer Society web site;, last accessed October 19, 2015.