Vaccine could Fight Colorectal Cancer using Patient's own Tumor
Dartmouth researchers have found they could treat colorectal cancer with a vaccine that uses the patient’s own tumor. This dendritic cell (DC) vaccine is a new way to approach cancer treatment because it personalizes treatment that can be used to destroy microscopic cancer cells after surgery.
The vaccine uses cells from the patient’s own blood, mixed with protein from tumors to destroy colorectal cancer by stimulating T cells that fight disease and are a type of white blood cell.
High Number of Patients Developed Immunity to Colorectal Cancer
According to Richard Barth Jr., MD, Chief of General Surgery at Dartmouth-Hitchcock Medical Center and a member of the Gastrointestinal Clinical Oncology Group at Dartmouth-Hitchcock Norris Cotton Cancer Center, "We showed that a tumor lysate-pulsed DC vaccine can induce immune responses against the patient's own tumor in a high proportion of patients.” In the current study, Dr. Barth used the vaccine to treat colorectal cancer that had spread to the liver, after surgically removing liver tumors.
Dr. Barth has been investigating dendritic cell vaccines in humans and mice for more than 10 years. The researchers now understand the vaccine can be used to destroy tiny cancer cells that would eventually lead to death rather than destroying large colorectal tumors.
He explains, "It turned out we were asking the T-cells to do too much. The small number of T-cells that are generated by a vaccine can't destroy a large tumor. However, what they may be able to do is search out and destroy tumor cells that exist as only microscopic tumor deposits. Once we brought patients into a measurable tumor-free condition with surgery, the anti-tumor T-cells induced by the DC vaccine may help keep them that way."
The study included 26 patients with colorectal cancer and metastasis. The vaccine was given one month after surgery. At five-year follow-up, 63 percent of the patients developed an immune response to the DC vaccine and showed no signs of tumor. Just 18 percent those who failed to develop an immune response were cancer free.
Barth says he believes the vaccine could have an impact for treating cancer because "It's your own immune system doing the fighting.” The DC vaccine could lead to less toxic colorectal cancer treatment that can also prevent its return; pending further studies.
Clin Cancer Res; 16(22); 5548–56