Researchers use nano ‘SWAT team’ to bolster radiotherapy

Preliminary results of a pair of studies involving nanoparticles in cancer treatment have shown promising results for boosting the power of radiation therapy while preserving healthy tissue near tumors, according to research presented at the 55^th Annual Meeting of the American Association of Physicists in Medicine (AAPM) in Indianapolis.

The two trials—one using a platinum-based nanoparticle and the other using hollow gold nanoparticles—both leverage the photoelectric effect that was discovered by Albert Einstein. Because of the photoelectric effect, the nanoparticles, when activated by radiation, will emit electrons that damage cells within a short range.

This effect acts as a multiplier during radiotherapy, doubling the radiation dose received by tumor blood vessels and cancer cells, explained Wilfred F. Ngwa, PhD, of Brigham and Women’s Hospital, Dana Farber Cancer Institute and Harvard Medical School, Boston. He likened the nanoparticles to a miniature SWAT team that is deployed within a tumor to selectively increase damage to cancer cells during radiotherapy, while reducing adverse side effects.

“We anticipate that this new strategy would provide major benefits, including helping prevent metastases or cancer recurrence, and hence significantly increasing survival and quality of life for cancer patients,” said Ngwa.

Ngwa and colleagues are currently studying the FDA-approved, platinum-based chemotherapy drug cisplatin for the purpose of boosting radiotherapy effectiveness. While radiotherapy routinely makes use of rice-sized implants embedded within tumors to guide radiation therapy targeting, the current study coats the implants with cisplatin nanoparticles to further disrupt tumor blood vessels. If results of the preclinical trial continue to be successful, Ngwa said the next step is to move on to human trials.

A similar study being presented at the AAPM meeting comes from researchers at UT Southwestern Medical Center, Dallas, who are using hollow gold nanoparticles to enhance the effects of radiation treatment. The hollow nanoparticles are about 10 times the size of standard solid nanoparticles, which increases their surface area and, thus, their radiation boosting abilities, according to Weihua Mao, PhD, of UT Southwestern Medical Center.

“Using this type of gold nanoparticle, we can enhance the radiation so we can use a [lower dose] to have the same treatment effects,” he said.

Both methods of using nanoparticles could be used to treat lung, prostate and other cancers, and result in virtually no additional inconvenience to patients, according to the researchers.