New Combination Treatment Induces Regression Of Prostate Cancer

"A new treatment protocol combining radionuclide therapy and chemotherapy may represent a distinct advantage over conventional protocols, especially when patients have metastatic (or spreading) prostate cancer that is not responding to hormonal therapy," said Giuliano Mariani, professor of nuclear medicine and director at the Regional Center of Nuclear Medicine at the University of Pisa Medical School in Italy. "Radionuclide therapy alleviated bone pain, but preliminary observations indicated that--if adequately combined with chemotherapy--it might produce clinical benefit in terms of regression and prolonged survival," added the co-author of "Early Response and Toxicity of 153Sm-EDTMP Combined With Docetaxel in Patients With Hormone-Refractory Metastatic Prostate Cancer."

All men are at risk of developing cancer in the prostate, a gland in the male reproductive system. Prostate cancer occurs when the cells of the prostate begin to grow uncontrollably, and these cells may spread--or metastasize--from the prostate to other parts of the body, especially the bones and lymph nodes, said Mariani. More than 234,000 men in the United States will be diagnosed with prostate cancer this year, and more than 27,000 will die of the disease, which is the second leading cause of cancer death in men.

"We explored combining radionuclide therapy based on the radioisotope Samarium-153 with carrier EDTMP and chemotherapy to achieve actual regression and prolonged survival," said Mariani. "Our research confirms the possibility of achieving tumor targeting of a radiopharmaceutical with such efficiency that it induces a definite therapeutic effect, and this shows the possibility of obtaining a synergistic therapeutic effect in combination with conventional chemotherapy," he explained.

"The blood toxic effects of our combination regimen were mild and comparable to those observed when the two therapies were used separately," said Mariani. In addition, researchers "observed significant reduction of PSA (prostate-specific antigen) levels in serum, a marker of the overall burden or severity of the disease," he added. "The majority of patients treated so far have either stable disease or regression of disease in a six-month follow-up," he noted.

"A major concern when attempting combination regimens of this type is to induce reciprocal augmentation of the possible toxic effects of the two therapies (radionuclide and chemotherapy), thus limiting applicability of the new protocol," said Mariani. "We are now evaluating our patients with an extended follow-up in order to assess the effect of the combined protocol on survival. Future investigations should explore the possibility of employing higher doses of the radiopharmaceutical in order to achieve the highest possible therapeutic effect--with the lowest possible toxic effect, he noted.