Response to surgery and RT in patients with prostate cancer is less favorable, if linked with unstable chromosomes

According to a research presented at the American Society for Radiation Oncology`s (ASTRO`s) 55th annual meeting, detailed evaluation of a prostate cancer tumor biopsy may predict treatment outcomes for image-guided radiation therapy (IGRT) or surgery for prostate cancer. In this study, researchers assessed the outcomes of 280 prostate cancer (Cap) patients and reviewed the DNA “fingerprints” of each patient's tumor (using the patient's initial diagnostic core biopsy) to determine if gene copy number alterations (CNAs) or breaks in CFSs were related to a less positive response to treatment. “We thought that patients who have CFS breaks might be more sensitive to radiation therapy-induced DNA damage”, said the lead author of the study, Robert G. Bristow, MD, PhD, a Professor within the radiation oncology and medical biophysics departments at the University of Toronto; and a Clinician-Scientist at the Princess Margaret Cancer Centre in Toronto. “We now think that the CFS breaks are a signal that the cancer cell has acquired numerous genetic changes that lead to more aggressive cancer cells that can spread early and outside the prostate gland. Our data suggest that the patients failing treatment are due to early metastatic (distant spread) disease. If we validate this study in similar, but larger groups of patients, we can develop a test based for CFS breaks; the results would allow us to place patients in one of two categories: those whose tumors do not have CFS breaks and who would likely do well with local treatment alone (e.g. radiotherapy or surgery); and, those patients whose tumors do have CFS breaks and would need a more complex treatment protocol, in addition to RT or surgery, to combat distant spread”.