Oncologists don't usually outright lie to you about your prognosis.
Although oncologists do often avoid hard truths and use vague or overly optimistic language when telling you about your prognosis.
Oncologists also often fail to share the exact timeframes.
But rather than having malicious deceit, the lying or not fully telling the truth about your prognosis often stems from their desire to preserve your hope as a patient and also a result of discomfort with difficult conversations, or even an inherent difficulty of predicting the exact survival times.
A lot of doctors also worry about giving a bleak statistical timeline and worry that by giving a bleak statistical timeline will crush their patient's emotional well-being or even make the patient feel like the medical team is giving up, when that is not the case.
Also instead of using direct numbers, oncologists will also frequently use soft, ambiguous terms that leave enough room for heavy optimism, which also leads to a gap between what the doctor thinks and what a patient actually understands.
And predicting how long a specific body will respond to cancer is also an imprecise art, and estimates are also wrong pretty frequently.
Studies also show that patients also often will hold much higher hopes for a cure or long term survival than their doctors do, and without realizing that they are on different pages.
When doctors also don't clearly state that an illness is terminal, patients also though can miss the change to prioritize their comfort, say goodbye or even choose palliative care over aggressive, painful treatments.
So while it may seem like oncologists are lying to their patients, it's not really that they are lying or trying to deceive you as a patient, but instead is are just trying preserve your hope as a patient.