ScienceDaily (Nov. 20, 2009) — High irradiances of low-level laser therapy (LLLT) should not be used over melanomas. Researchers writing in the open access journal BMC Cancer studied the pain relieving, anti-inflammatory 'cold laser', finding that it caused increased tumour growth in a mouse model of skin cancer.

Jan M. Bjordal from Bergen University College, Norway worked with a team of Brazilian researchers to carry out the in vitro and in vivo experiments. He said, "LLLT has gained increasing popularity as a treatment for soft tissue injuries and joint conditions. However, there is a shortage of evidence, especially in vivo evidence, about the effects of LLLT in malignant conditions such as melanoma."

Bjordal and his colleagues applied LLLT to cancer cultures and to mice injected with melanoma cells. Although the treatment did not cause any significant changes in the cell cultures, direct irradiation of the tumor with high-dose LLLT caused a significant increase in tumor mass volume and considerable histological alterations, indicating a worsening of the cancer, in the mice. The researchers write, "A high irradiance (2.5W/cm²) combined with high dose of 1050 J/cm², can stimulate melanoma tumor growth with distinct histological features in vivo."

"It is important that this contraindication is implemented into clinical practice so that LLLT can remain a safe treatment," says Bjordal.

LLLT was pioneered in the 1970s, when it was discovered that light from low-intensity lasers causes cells to proliferate more rapidly. It is marketed as a treatment for hair-loss, pain management, sports medicine and skin care -- among many other things. Home-treatment sets are available online for unsupervised use.

Story Source:

Adapted from materials provided by BioMed Central, via EurekAlert!, a service of AAAS.

Journal Reference:

1. Lucio Frigo, Juliana SS Luppi, Giovani M Favero, Durvanei A Maria, Socrates C Penna, Jan M Bjordal, Rene J Bensadoun and Rodrigo Alvaro Lopes Martins. The effect of low-level laser irradiation (Ga-Al-AsP - 660nm) on in vitro and in vivo melanoma. BMC Cancer, 2009; (in press) [link]

Related Stories

Gold Nanorods May Make Safer Cancer Treatment (Mar. 15, 2006) — Researchers at the Georgia Institute of Technology and the University of California, San Francisco, have found that by using gold nanorods, rather than nanospheres, they can detect malignant tumors ...  > read more

Laser Therapies For Hair Removal Appear To Be More Effective Than Combination Treatments, Study Suggests (Oct. 25, 2008) — Laser therapies commonly used for removal of unwanted hair appear to be safer and remove leg hair more effectively when used separately than when used as a combination treatment, according to a new ...  > read more

Sun-Damaged Skin Responds Well To Laser Treatment (Oct. 24, 2008) — Researchers have found scientific evidence that the appearance of sun-damaged skin may be improved by treatment with a topical product that increases the skin's sensitivity to light, followed by ...  > read more

Skin Cooling Associated With Increased Risk Of Discoloration After Laser Treatment (Sep. 18, 2007) — A cooling technique intended to protect the skin may actually increase the risk of discoloration in dark-skinned patients undergoing laser treatments for mole-like skin lesions, according to a new ...  > read more

Search ScienceDaily

Fiber Optic Laser