Keisuke Kuwata, singer-songwriter of the popular rock band Southern All Stars, has early stage esophageal cancer and will undergo surgery as early as next month, his management firm, Amuse Inc., said Wednesday.

Kuwata, 54, will cancel a planned concert tour that was to run from Oct. 28 to Dec. 31 and postpone the release of a new solo album that had been set to go on sale Oct. 20, the company said.

"We are causing great anxiety to all parties concerned, but the (cancer) was detected at an initial stage and early treatment will be sufficient" to eradicate the disease, Amuse said in a statement posted on its Web site.

In the statement, the company did not mention whether the operation would affect Kuwata's husky voice.

The Southern All Stars are pioneers in Japanese rock. Kuwata, debuting in 1978 with the single "Katte ni Shindobaddo," was one of only a handful of Japanese singers sing rock songs with Japanese lyrics at that time.

"Tsunami," a single released in 2000, sold more than 2.9 million copies, one of the top-selling singles ever in Japan.

"I'm really sorry for causing worries to you," Kuwata wrote in a message posted on Amuse's Web site.

"First I will recover my health and deliver the album in production as early as possible. . . . Please don't worry about me (is that impossible?!) and wait for a while," he wrote.