Unequivocally NO, terminal cancer is not equivalent to a death sentence.
There are many people who have been given a terminal cancer diagnosis who are thriving today, many years later. More people have “beaten the odds” than you think. I have personally met hundreds who were given short “time frames,” such as: 3 weeks, 3 months, 6 months, 9 months and 1 year to live. They have been afflicted with all kinds of cancer including brain cancer, pancreatic cancer, lung cancer, colorectal cancer, breast cancer, prostate cancer, melanoma, ovarian cancer, uterine cancer, non-Hodgkin’s lymphoma, kidney cancer and others. I personally know many cancer doctors, in the integrative and alternative worlds, whose clinical work and recommendations have engendered extraordinary long-term outcomes for patients after receiving veritable “death sentences” from their prior cancer doctors.