A new three-step treatment uses nuclear medicine to target and completely eliminate colorectal cancer, at least in mice. The new technique achieved a 100 percent cure rate without any toxic side effects.

Until now, radioimmunotherapy (targeted therapy) of solid tumors using antibody-targeted radionuclides has had limited therapeutic success. The new treatment's success is due to a combination of steps, including unique reagents — compounds or mixtures used in lab tests to identify, measure, or make other substances — and a specific combination of therapies that can be easily transferred to humans.  

"The success," explains researchers Steven M. Larson, M.D., and Sarah Cheal, Ph.D., "comes from the unique quality of the reagents developed by our group, and the reduction to practice methodology, including a theranostic approach that can be readily transferred, we believe, to patients."

Theranostics is the use of a single agent to both diagnose and treat disease. The theranostic agent first finds the cancer cells, then destroys them, leaving healthy cells unharmed, minimizing side effects and improving quality of life for patients.

In the study, an antigen found on more than 95 percent of primary and metastatic human colorectal cancers called glycoprotein A33 (GPA33), was targeted with two specific antibodies.

Serial SPECT/CT imaging was used to monitor treatment response in mice and to calculate how much radiation the tumors absorbed. All the animals tolerated the treatment well, and microscopic examination of tissue showed no trace of cancer.

There was also no detectable radiation damage to critical organs, including bone marrow and kidneys.

The study was reported in The Journal of Nuclear Medicine.

A Harvard study published earlier this year found that the same low-dose aspirin that doctors advise for heart health may also lower the risk of dying from several cancers, including colon.  The study of more than 130,000 adults found aspirin lowered the risk of colon cancer 31 percent for women and 30 percent for men for those who took aspirin regularly on a long-term basis.

Colorectal cancer is the third most common cancer in America affecting both men and women, according to the Centers for Disease Control and Prevention. Each year, approximately 140,000 new cases are diagnosed and 50,000 people die of the disease.