For patients with metastatic lung cancer, frequent scans are a stark reality of living with cancer. Although most scans happen every 3 months, some clinical trials require scans more often as part of the trial’s protocol. As patients, we obviously want to know what is happening with our cancer and when to adjust our treatment strategies. Yet, while lying in a CT scanner, a PET scanner, or an MRI machine, we often find ourselves wondering what the long-term effects of these scans will be.
We ask ourselves questions such as: “As my success with my medications continue, are these scans one day going to impact my overall quality of life?” or “What exactly are the radioactive sugars or the contrast agents doing in my body?” or “Wouldn’t it be ironic if I got another cancer while treating my current cancer?” Although it might seem trivial, these thoughts go through patients’ minds more than one might think, especially as patients with metastatic cancer are living longer and having higher quality of life with current treatments. While 10 years ago this might not have been much of an issue given patient mortality rates, the fact that patients are living longer and better makes concerns about developing a second cancer as a result of scan radiation more of a realistic issue. Patients with metastatic disease do not receive the low-dose CT scans commonly used for screening; ours are full dose and cause significantly more radiation exposure.
CT: Anxiety and Health Concerns
Adding to our worries about increased radiation risk, patients also have concerns about the contrast we often receive along with CT scans, either through IV infusions or through drinks containing the contrast material. As one of the authors of this article notes, “The only drawback for me with the CT scan is the contrast dye and the feeling that I get when the contrast injection hits my body. For a moment, I feel like I can’t breathe. I have to meditate and slowly bring myself back to reality by counting to 20, and then the panicked feeling disappears. Five minutes later, my scan is done and I can go about my day.” Of course, we are seriously warned before leaving to make sure to drink lots of water for the rest of the day.
Although most patients do not have side effects from the contrast, some of us end up with allergic reactions to the dye and even kidney issues from clearing the contrast materials from our bodies. These reactions can lead to us taking more medications than we already do, with additional potential side effects. Adding contrast to CT scans increases time and expense and turns a noninvasive process into one that is more invasive for the person ingesting the contrast. We recommend that clinicians always carefully consider on a per-scan basis whether there is a true need for contrast to see more closely, as opposed to ordering contrast every time as a reflex.
PET: Diagnostic Benefit but Financial, Logistical Challenges
Most patients have PET scans in addition to CT scans, but not usually as frequently as CT scans alone. Often, we have PET scans at diagnosis and not again until progression, although others in the lung cancer community have PET scans much more regularly. Although PET scans, in contrast to CT scans, require fasting, take several hours, are significantly more expensive, and are frequently difficult to get approved by insurance, the information we receive from PET scans can be critically important and change the direction of our treatment.
As one of the authors explains, “I take comfort in the fact that the areas of cancer ‘light up’ and provide a heat map for my oncologist of where active cancer is in my body. The inconvenience of a PET scan is worth the knowledge of where potential cancerous activity is lurking in my body.” Sometimes it is difficult to tell if potential growth is cancerous as opposed to the result of infection or scar tissue. Only by using a PET scan can this determination be made with more surety. This can lead to great reassurance for us if questionable areas do not light up on PET scans. On the other hand, it can also lead to increased uncertainty and anxiety if an unexpected area lights up that is stable on a CT scan.
Due to more recent improvements in technology, many of us are given combined PET/CT scans by our healthcare providers when these more detailed scans are deemed necessary. Although increased radiation exposure from the infusion material in PET scans is usually not very significant, these combined PET/CT scans involve high radiation dosages and make us think about the risk versus benefit to our health.
To summarize, we agree that if our oncologists were to ask us, from a pure patient-comfort standpoint, which type of scan we prefer to have on an ongoing basis, we would choose the CT scan. However, if our oncologists were to ask us which scan we prefer from purely a diagnostic approach, we would choose the PET scan. There are advantages and disadvantages of both types of scans and only by recognizing our individual needs as patients can the decision be made to choose one type of scan as opposed to another.
