Using a sense-making and threat management framework in rumor psychology, the authors used an exploratory web survey (n = 169) to query members of online cancer discussion groups about informal cancer statements heard from nonmedical sources (i.e., cancer rumors). Respondents perceived that rumors helped them cope. Dread rumors exceeded wish rumors; secondary control (control through emotional coping) rumors outnumbered primary control (direct action) rumors. Rumor content focused on cancer lethality, causes, and suffering. Rumors came primarily from family or friends in face-to-face conversations. Respondents discussed rumors with medical personnel primarily for fact-finding purposes, but with nonmedical people for altruistic, emotional coping, or relationship enhancement motives. Transmitters (vs. nontransmitters) considered rumors to be more important, were more anxious, and felt rumors helped them cope better, but did not believe them more strongly or feel that they were less knowledgeable about cancer. Most respondents believed the rumors; confidence was based on trust in family or friends (disregarding source nonexpertise) and concordance with beliefs, attitudes, and experience. Results point toward the fruitfulness of using rumor theory to guide research on cancer rumors and suggest that rumors help people achieve a sense of emotional control for dreaded cancer outcomes, inform the social construction of cancer, and highlight the continuing importance of nonelectronic word of mouth.