Prognosis for Extensive-Stage Small Cell Lung Cancer
My Mom was diagnosed with small cell lung cancer in January. They found some spots around her aorta, in her lymph nodes, and in the spine. She is just completing her 4th cycle of chemotherapy. The doctor said now we stop treatment and watch and wait. My question is, what are the chances of recurrence? We were told that there is a 50% mortality rate in 9 months, and 90% mortality in 2 years. Statistically speaking, does that mean it will take a turn for the worse in the next few months, and most likely she will die in the next 1-2 years?
Barbara Campling, MD, Medical Oncologist, responds:
From what you say, it sounds like your mother has "extensive-stage" small cell lung cancer, which means that the cancer had spread outside of the chest at the time of diagnosis. Chemotherapy is generally quite effective at treating this in the short term. The goals of treatment for extensive-stage small cell lung cancer are to shrink the tumor, relieve symptoms, and improve survival, all of which chemotherapy can do. Unfortunately, once the cancer has spread outside of the chest, the cancer cannot be eliminated or cured. She is now completing her planned chemotherapy, and you are now wondering what the future holds for her, and how long she has to live.
Because the cancer had already spread outside of the chest at diagnosis, it is almost inevitable that it will start to grow again in the future, regardless of how well she responded to chemotherapy. How long will it be before this happens? That depends, to a certain extent, on how well she has responded to the initial chemotherapy treatment. If she has had a "complete response" to chemotherapy, meaning that the tumor can no longer be detected on any of her imaging scans, then it is likely to remain dormant for longer than if the response was more limited.
You have been told that the expected mortality is 50% at 9 months. This means that in a large group of patients with extensive-stage small cell lung cancer, half of the patients will be still be alive 9 months after diagnosis, whereas the other half will have died. However, these statistics do not tell us whether your mother will be alive 9 months after diagnosis- they do not tell us anything about an individual patient. A Canadian study that included patients with small cell lung cancer (WJ Mackillop and CF Quirt. Measuring the accuracy of prognostic judgements in oncology. Journal of Clinical Epidemiology. 1997;50:21-29.) demonstrated that doctors are very good at predicting which patients would or would not be cured, but we are not very accurate when it comes to predicting how long individual patients with incurable disease would survive. I often hear patients make statements like "my doctor gave me 10 months to live," and I try to avoid making these predictions myself as we are often wrong.
If your mother has had a very good response to chemotherapy treatment, it could be many months before the cancer starts to cause problems again. Once she has recovered from the side effects of the chemotherapy, she could get back to feeling well for a period of time. When the cancer does recur, it may respond again to chemotherapy, and this could relieve her symptoms and extend her survival. Unfortunately, this type of cancer nearly always becomes resistant to chemotherapy at some point. Even when this occurs, there is usually something that can be done to alleviate symptoms and relieve pain.