(Photo by Hector Vivas/Getty Images for WTA)

Tennis great Martina Navratilova has been diagnosed with cancer, she announced Monday.

The 18-time Grand Slam singles champion said in a statement that she has been diagnosed with both throat and breast cancer. She is set to begin treatment this month, and her prognosis is good.

“This double whammy is serious but still fixable, and I’m hoping for a favorable outcome,” she said. “It’s going to stink for a while but I’ll fight with all have I got.”

Navratilova initially noticed an enlarged lymph node in her neck during the WTA Finals in Texas in November. A biopsy revealed that she has early stage throat cancer. Further testing uncovered early stage breast cancer.

She previously had been diagnosed with a noninvasive form of breast cancer in 2010 and underwent a lumpectomy.

In a tweet on Monday, the International Tennis Hall of Fame member expressed gratitude for the outpouring of support in the wake of the news.

“Needless to say my phone and twitter are both blowing up,” she said. “So I will say again – thank you for all your support and I am not done yet.”

Navratilova initially retired in 1994 after amassing a record 167 singles titles and spending 331 weeks atop the WTA rankings. She returned in 2000 to play doubles, and she also was inducted into the ITHF in 2000. More recently, she has served as a tennis analyst on television.