Targeted therapies improve colon cancer survival rates

People diagnosed with advanced colorectal cancer that has spread to distant organs, such as White House spokesman Tony Snow, are much more likely to survive today than even just a few years ago, due to the recent and continued emergence of improved therapies, say cancer experts.

"Anyone who looks at this as a death sentence is wrong," said Dr. Allyson Ocean, a gastrointestinal oncologist at Weill Cornell Medical College, quoted in a CBS News report, in reference to Snow's diagnosis just a few days ago of Stage IV (advanced) colon cancer.

The reason that statement can be made today -- when it would not have been true even five years ago -- is due mainly to the availability now of newer treatments known as "targeted" therapies that boost main therapies by hitting specific molecular targets driving the origin and growth of tumors, say cancer experts.

Snow has the option of adding the targeted therapy bevacuzimab (trade name Avastin) to one of the chemotherapy regimens most often used in Stage IV colon cancer. Doing so is more effective than using the chemotherapy alone, according to the American Cancer Society (ACS).

Such adjunctive treatments are one reason treatment of advanced colon cancer today can be curative, notes the ACS website.

Not all the new targeted compounds are pharmaceutical products, or even drugs per se.

A naturally-occurring extract of fermented wheat germ (FWGE, trade name Avemar, Ave in the US), has been shown to substantially boost the efficacy of conventional therapies against a wide range of cancers, while lessening side effects of those drugs.

Researchers at UCLA found Avemar targets the transketolase (TK) pathway, a biochemical pathway that cancer cells -- but not normal cells -- preferentially use to rapidly make DNA for the fast cell division that makes cancer such a threat. It leaves normal cells unaffected.

Other studies found eight additional molecular targets the compound addresses, preventing the development of cancerous and precancerous lesions, reducing risk of cancer spread, stimulating cancer cell suicide and improving the anticancer effects of chemotherapy drugs.

In Hungary, where Avemar is approved as a medical nutriment in support of cancer therapy, colorectal cancer patients using Avemar along with conventional therapy had less metastases, fewer recurrences, and lived significantly longer. (A medical nutriment has supportive value in the treatment of colorectal cancer, Br J Cancer 2003 Aug 4;89(3):465-9.) Avemar became available in 2005 in the US as a nutritional supplement, Ave, from American BioSciences, Inc.

In childhood cancer patients, Avemar reduced incidences of febrile neutropenia -- low white blood cell count resulting in infection and high fever that can be life threatening. (Fermented Wheat Germ Extract Reduces Chemotherapy-Induced Febrile Neutropenia in Pediatric Cancer Patients, J Pediatr Hematol Oncol 26 (10), October 2004.) It showed none of the side effects of conventional drugs meant to boost blood cell count, and "has the safety profile of bread" according to expert toxicologists who reviewed toxicology test data on the compound.

Additional studies showed the extract improved physical condition and quality of life of late stage and other cancer patients during and following conventional treatment, partly by preventing immunosuppressive side-effects; making cancer related cachexia ("wasting" and weight loss) less likely to occur; reducing fatigue, and enhancing the ability of the immune system's natural killer (NK) cells to identify and kill cancer cells, among other effects.