- Completed or independently decided to end all direct cancer treatments, such as chemotherapy and radiation, two weeks prior to the first experimental (MDMA) session. If subjects wish to initiate or resume treatment for cancer at any point prior to the second experimental (MDMA) session, then they will be withdrawn from the study and will be asked to see the co-investigator oncologist for a final physical examination. Participants will not be withdrawn from the study if they initiate or resume treatment after the second experimental (MDMA) session. Those who are receiving cycles of cancer treatments for only palliative purposes (no longer for any curative reasons or to induce complete remission), may also be included in this study provided that they, as well, have completed their last cycle of treatment at least two weeks prior to the first experimental (MDMA) session and provided that they will not resume another cycle of treatment until after completion of the second experimental (MDMA) session. If a subject receiving palliative cancer treatment decides to receive a next cycle of this cancer treatment prior to the second experimental session, then, again, they will be withdrawn from the study. Participants will not be withdrawn from the study if they initiate or resume palliative cancer treatments after the second experimental (MDMA) session.