NEW YORK — Tennis great Martina Navratilova says she has been diagnosed with breast cancer and her prognosis is excellent.

Navratilova said in a phone interview Wednesday that a routine mammogram in January found a lump, and a biopsy the following month determined it was a noninvasive cancer called ductal carcinoma in situ, or DCIS.

The nine-time Wimbledon women's singles champion had a lumpectomy in March and will start six weeks of radiation therapy next month.