The Uncertainty of Prognosis in Cancer: You Don't Have an Expiration Date

My initial visit with patients newly diagnosed with lung cancer usually follows a predictable pattern. We start with introductions, and then I ask about symptoms and establish a timeline of the disease (called a "history of present illness"). Next is the physical exam, after which we review the test results and then discuss the diagnosis and what to expect. Finally, together, we outline a plan for how to treat the cancer.

At some point in this predictable progression from fearful uncertainty to (hopefully) cautious determination, a strange ritual will take place. The patient will often put down their notepad and remove their glasses, lock eyes with their spouse or child and sometimes reach out to hold their hand. I recognize these signs and steel myself for my least favorite part of the visit. The words themselves vary, and the questioner may be the patient or their spouse, but the next question always boils down to a version of "How long do I have to live, doc?"

This is the proverbial million dollar question, and it is crucial that oncologists be prepared to answer it since it is likely the one thing the patient will remember vividly from this initial meeting, even if they forget everything else. There are many different approaches to answering this question, none right or wrong.

Some doctors will equivocate and say no one knows, all patients are different and treatments change all the time, so any numbers from the past may not reflect what is possible today. This may well be true, but I think this non-answer leaves the patient with a large unfilled gap that Dr. Google or Aunt Marge will have to fill, possibly providing answers that we would not necessarily agree with.

Some go the opposite direction and simply lay out stark numbers from clinical trials or population databases without putting them in proper context. If a patient is told that lung cancer patients only live six months or a year from diagnosis, they may fixate on this number and give it much more power that it should have. It is not uncommon for people to go home and circle that date on the calendar as though it came straight from the mouth of God.

The uncomfortable reality is simply this: No one knows how long any one person will live, and patients don't have expiration dates that we can check to answer this question. Studies have shown that doctors are generally terrible at predicting prognosis, although as the end gets closer, it gets easier to predict. We do, however, have lots of information about averages and ranges that we can share with patients to give them some idea of how others in their situation have done. The most commonly quoted number is the median survival, which is primarily used for research. For example, if the median survival for a cancer patient is one year, that doesn't mean patients live exactly a year, but rather, means that at one year, half of patients have died and half are still alive. The median isn't very useful for an individual but is important to understand.

What is more useful is the range of survival times. While some patients only live a short while, half of patients live longer than average and some much longer. A number of advanced lung cancer patients, even with incurable disease, live longer than five years and I see them in my clinic every week. I tell my patients that I don't treat them hoping for them to be average; we treat and hope for the best possible outcome.

Of course, this discussion is also important so patients understand that not all people can do better than average and that for some, time is limited. There are important things to do, relationships to repair or nurture, bucket lists to attend to. At the end of the visit, I want every patient to be hopeful for the best, but prepared for the alternative. Ultimately, I hope my patients learn to live each day to its fullest since we are each only granted today, and no one knows what tomorrow may bring.

I think the immortal Henny Youngman said it best: "A doctor gave a man six months to live. The man couldn't pay his bill, so he gave him another six months!"

Dr. Nathan Pennell is a board-certified medical oncologist who joined the staff of the Taussig Cancer Center in 2008. He specializes in the treatment of thoracic malignancies with a focus on lung cancer, and was appointed director of the TCI lung cancer medical oncology program in 2010. Dr. Pennell's research interests include clinical trials using novel therapies, with a goal of facilitating the movement of new treatments from the laboratory to the clinic. He received his Ph.D. in neuroscience in 1998 and his M.D. in 2002 from the University of Florida College of Medicine in Gainesville, FL. Dr. Pennell completed his internal medicine residency in 2005 at Brigham and Women's Hospital in Boston. His medical oncology fellowship training was completed in 2007 at the Dana Farber Cancer Institute.