Why cancer screening is not a black or white decision

Last month I saw a 65 year-old woman with a mass in her kidney in clinic for follow up. She had recently transferred her medical care to our clinic after her insurance changed.

She came with a few medical problems including high blood pressure, tobacco use and arthritis — diseases which are the bread and butter of primary care medicine — but she also came with a history of a mass in her right kidney. It is not clear how the mass was first detected — she never had symptoms from it. Our best guess that it was found incidentally on a CT scan done for other reasons. But once found her doctors couldn’t ignore it. At the same time they were at a loss for what to do with it.

As her new doctors we certainly did not know what to do either. So at her first visit two months ago we decided to image the mass again, this time using MRI, and then sent her to a kidney specialist. The MRI confirmed the mass, a 3.5cm by 2 cm solid structure sitting quietly in the upper pole of her right kidney. Despite repeated attempts to contact her previous doctors, we could not obtain her prior records. We had no idea how long the mass had been there or how large it had previously been.

At this visit, we reviewed the consultation letter from the kidney specialist we referred her to. In it, he wrote that there was 30 percent chance that the mass was benign, meaning not cancer or not malignant. That left a 70 percent chance that the mass was cancer. The only way to get a definitive answer would be to examine the mass under the microscope. The problem is that this would require undergoing surgery to remove the mass. However, the specialist also wrote that ”…most likely this mass, if cancerous, would be slow-growing” and that it was unclear that such a cancer would “ever cause significant morbidity.” The specialist’s recommendation was to follow the mass with repeat MRIs every 6 months to follow its size. If the mass grew significantly, a partial or total kidney removal could be performed. However, if the patient elected to have surgery now, this too would be “reasonable.” In short, we would watch and wait.

To people outside of medicine, this proposition may sound absurd. “You mean to tell me that there is a 70 percent this thing is cancer and you’re not going to cut it out!” The popular media has conditioned us to have a visceral and often knee-jerk response to the word “cancer” — all cancer is bad, and all cancer must be aggressively treated. The truth is somewhat grayer than that. Yes, generally speaking, cancer is not good. But at the same time, not all cancer is harmful. There is a spectrum of cancers, which vary in their aggressiveness. Non-melanoma skin cancers (e.g. basal cell carcinomas), for example, while common rarely metastatize. Autopsies of people who die from cardiovascular disease or “old age” frequently show evidence of cancer. In fact, by age 80, 80 percent of men have prostate cancer but most will die of causes other than their prostate cancer.

With these issues in mind, I went to see the patient. In the end, it would be her decision about how to proceed and so I laid out the facts as best I could. She had two options: 1) get the surgery now and risk the chance that she might have part or all of her kidney removed for a mass that would have never caused her any problems, or 2) watch and wait and risk the chance that the mass was cancerous and would continue to grow or worse spread to other parts of the body. With Option 1, she would get a definitive answer and her fears would be laid to rest. At the same time, she risked major surgery, which for someone her age could be significant, not to mention losing part or all of her kidney. With Option 2, she would have to get serial MRIs every 6 months and constantly face uncertainty about the unknown mass occupying her kidney. At the same time, she avoided having surgery for what would likely be something that would never cause her any harm.

Often we think of screening for cancers and other diseases too simply. Our knee-jerk assumption is that if screening leads to diagnosis then the screening test is worthwhile. Thus people readily advocate screening women for breast cancer with monthly self-exams, screening men for prostate cancer with PSA blood tests, and screening people at risk for cardiovascular disease with cardiac stress tests. However, things are not always so straightforward. In deciding whether a screening test is worthwhile we have to think at least one step ahead to what we would do with the results. This allows us to answer the crucial question, would screening this person with this test lead to better health? For the case above, on first glance it would be natural to think, “Thank goodness that mass in her kidney got caught.” Some people may even think to themselves that maybe they too should have a CT scan done of their kidneys, in case they also have a kidney mass. But the truth is that CT scan that found the mass in my patient’s kidney has probably not made her life any better. In fact her life is probably worse off because of the anxiety, medical tests, and health care costs it has brought.

There is little we can do to avoid situations like the one faced by my patient. For other medical reasons, she may have needed the CT scan that found the mass, and once found we cannot ethically ignore it. However, we can avoid similar and more common situations like hers that stem from over-screening. The need to think at least one step ahead, to balance risks and benefits, and to keep improvement of health as the overaching aim is critical when making decisions about screening — what diseases should be screened for, who should get screened, and how often screening should be done. After all, medicine is only useful inasmuch as it improves health.

After our discussion my patient was uncertain about how to move forward. In the end, she choose option 2, the “watch and wait” approach, but it was clear that the decision still weighed on her mind. “It would have been just as well if they never found this thing,” she said.

Shantanu Nundy is an internal medicine physician who blogs at BeyondApples.org.

Submit a guest post and be heard.

View 13 Comments >

Most Popular

Get KevinMD's 5 most popular stories.