Two thirds of cancer patients undergo radiation therapy as part of their treatment regimen. While most patients tolerate it well, some cases can lead to damage in healthy tissues that are also irradiated or a side effect called radiation-induced fibrosis.

"We know that a whole number of growth factors and inflammation-promoting chemical messengers play a role in the development of fibrosis," said Peter Huber of the German Cancer Research Center in a statement. "But until now, agents targeting these molecules have not been effective enough to prevent pulmonary fibrosis or to improve its symptoms significantly. Much less was it possible to reverse fibrosis once it had developed. Therefore, we are urgently searching for targets that we can use to interrupt, slow down or even reverse this dreadful process."

Huber and colleagues published their findings in the Journal of the National Cancer Institute, in which they ran an experiment on mice, testing an antibody that blocks the connective tissue growth factor (CTGF). For eight weeks, mice were treated with the antibody, starting at different time points before and after radiation treatment.

The various therapy regimens protected up to 80 percent of the mice from fibrosis. For mice who were treated 16 weeks after radiotherapy, the antibody reversed the fibrotic transformation, decreased the density of the pulmonary tissue by more than 50 percent and improved pulmonary function and oxygen supply. Following treatment, the mice sustained a leveled health status and survived longer than the untreated animals.

"We therefore think that it is promising to test the antibody also in humans who have to undergo radiotherapy,” said Huber. “Additionally, patients with other types of fibrotic disease that are not related to radiation might also benefit from a blockade of CTGF. And maybe even the chances of curing the cancer will improve: If we reduce radiation-induced side effects, we can increase the radiation dose in the tumor."