[en] Irving Janis (1958) theorized that preparatory information may stimulate the work of worry process thought necessary for optimal adaptation to threatening medical procedures. According to this conceptualization, whether preparation is delivered early or late may differentially affect patients' adaptation. To investigate this possibility, three groups of women undergoing an extremely noxious cancer treatment, intracavitary radiation (ICR), were compared. One group received preoperative information routinely provided by hospital personnel (Control), while the other groups received additional treatment information and coping instructions either one week (Early) or one day (Late) before ICR treatment. Results of planned and post hoc analyses indicated that preparation for ICR, regardless of when it was delivered, benefitted women. Prepared women experienced fewer difficulties during treatment, reported less pain and associated distress, and were less anxious, angry and fatigued posttreatment. One week after ICR ended, prepared women continued to report superior adaptation, and were more willing to undergo ICR in the future