Etheridge, 43, will undergo surgery and her doctor expects a "speedy and complete recovery," publicist Marcel Pariseau said in a statement.
The cancer was detected early and Etheridge has been receiving treatment, Pariseau said Thursday.
"I am fortunate to be under a wonderful doctor's care and thankful that this was caught early," Etheridge said in the statement. "I am looking forward to a quick and full recovery."
Etheridge and actress Tammy Lynn Michaels held a commitment ceremony in September 2003. The musician, who lives in Los Angeles, shares custody of a daughter and son with former partner Julie Cypher, who had the children through artificial insemination using a sperm donation from rocker David Crosby.
Etheridge's latest album, "Lucky," was released in February. Refunds for tickets to her upcoming shows will be available where they were bought; the entertainer's Web site says she had been scheduled to play 11 dates in seven cities this month.