Jessie J has cancelled her upcoming US tour dates after revealing she needs to undergo more cancer treatment. The Do It like a Dude singer, who told fans in June that she had undergone surgery to remove one of her breasts, says she needs to "have a second surgery". Speaking on Instagram, she said the procedure would be "nothing too serious" but "has to be done by the end of the year". The operation falls in the middle of her upcoming European tour dates in October, which she says will be rearranged, while her US shows have to be cancelled due to calendar clashes. "I'm so sorry, I feel frustrated and sad," she said in the video. "But I need to be better, I need to be healed and this is the right decision to make." The Price Tag singer, who has more than 14 million followers on Instagram, has been candid about her cancer diagnosis. She shared that she had had a mastectomy after an early cancer diagnosis, with following tests revealing at the time there had been no further spread of the disease. The pop star also said she was due to undergo reconstructive surgery to make her breasts look more similar, adding that there was "lots of healing to go".