This passage is from Gao Wenqian’s Zhou Enlai: The Last Perfect Revolutionary:
Doctors in China could not conduct major medical procedures on top leaders without the approval of the Politburo Standing Committee. Such was the long-standing rule. Thus, in 1975, Deng Ziaoping and Marshal Ye Jianying, leaders among the old CCP cadres who had generally despised the Cultural Revolution and had shown little enthusiasm for the political style of the mercurial Jiang Qing, now had to negotiate emergency surgery for Zhou Enlai with her allies Wang Hongwen and Zhang Chunqiao. For once, these tough political adversaries managed to see eye-to-eye. They all gave their consent to surgery and sent their decision to Mao, who always had the final say.
Zhou Enlai had four operations before dying of cancer. For the last two operations, however, Mao instructed the doctors to tell Zhou that in fact he was being cured and the tumors were removed. He ceased to believe that when the unbearable pain arrived.