External beam radiation therapy, radiation seed implants or brachytherapy and surgery are the standard treatments for early-stage prostate cancer.

Lead author Dr. Matthew Katz of Saints Medical Center in Lowell, Mass., said the Web-based tool allows doctors to enter information about a patient's cancer stage, based on their rectal exam, PSA levels and biopsy information.

With the help of the CaP Calculator, doctors can more accurately evaluate the risk of the cancer spreading beyond the prostate and the effectiveness of surgery and radiation treatment. It also provides an individualized printout to allow doctors to review the results with each prostate cancer patient.

"Men with newly diagnosed prostate cancer often have more than one treatment choice available," Katz told the American Society for Therapeutic Radiology and Oncology's 50th annual meeting in Boston.

"We designed CaP Calculator as a resource to help patients to talk to their doctors and feel more confident in their treatment decisions."