Nuclear-medicine tests use a radioactive substance or material, called a tracer, that is placed in the body. If an area of the body takes up too much or too little tracer, it may imply there’s a cancer or other problem. Common nuclear-medicine tests include bone scans and PET/CT scans.
The use of PET/CT is common across a variety of cancers. Notice the name PET/CT. When you get a PET scan, you also get a CT scan—two for one!
PET/CT: Teaming Up to Find
High Sugar Consumption
Preparing for PET/CT scans involves injecting a labeled sugar that’s taken up by the body; we can then see that sugar on a scanner. Cancer cells use up lots of sugar quickly and inefficiently (remember the Warburg effect), so we can see cancer cells “light up” on PET/CT scans.
The lighting up of a region in PET is called activity. The activity indicates how much sugar a part of the body has taken up, which gives the region a glow. The greater the glow, the faster the cells are using sugar, and the more of them there are. Sounds like cancer, right?
The PET image we get is grainy. This makes it hard to determine exactly where the activity is. To help pinpoint the area, we get a CT scan the same day. That’s why we get a PET and CT together—to see the activity and help localize it.
So why wouldn’t we just use PET/CT for everything? A PET depends on cells taking up labeled sugar. The cancer cells want to use sugar because they’re trying to overtake the rest of the body, like weeds in a garden. They need the energy to keep things moving. But there are also normal fast-growing cells that take up sugar—say, cells of the immune system. Immune system cells take up a lot of sugar to fight off invaders or even cancer! It’s often hard to tell inflammation from cancer on a scan.
Furthermore, not all cancer cells reliably take up the labeled sugar. A PET/CT scan is good for seeing some cancers but bad for others.
PET/CT scans are also of limited use in parts of the body that use lots of sugar normally, like the brain. The brain is always working hard and taking in lots of sugar. This makes it hard to see any cancer that might have gone to the brain.
Finally, you may remember the magical one-centimeter size in scans. PET/CT scans are no different! These scans have limited resolution; they can’t see a single cancer cell. Masses that aren’t big enough don’t show up in the scans.
Putting Together the Clues
Doctors gather all this information to determine the diagnosis (the type of cancer seen under the microscope) and the stage of the cancer. These two things have the biggest influence on how to move forward with care.
We use the diagnosis, clinical examination, and the scans we obtained to provide a clinical stage.
TNM: A Secret Language for Stages of Cancer
Staging depends on the type of cancer, but we generally define staging in two areas: clinical versus pathological stage. This is often confusing to patients.
Clinical stage is determined using information from a physical exam and scans. A pathological stage is determined after surgery (we’ll talk about pathological stage in chapter 6, where we discuss surgery).
So if you’ve had a biopsy, isn’t your stage a pathological stage? No! The biopsy just helps confirm what type of cancer a person has. The pathological stage is classified after a surgical procedure on the cancer—that is, after removing the mass or lymph nodes.
As part of a first diagnosis, a patient gets a clinical stage. The clinical stage is broken up into three parts: T (tumor), N (lymph nodes), and M (metastasis). This is called the TNM staging system, and it’s used across a range of cancers. The criteria vary depending on the cancer type, but here are the general principles:
T considers the size of the tumor.
N looks at the number of lymph nodes into which the cancer has spread (see chapter 2 for more on lymph nodes).
M considers whether the cancer has spread, or metastasized, to other organs (liver, lungs, and so on).
Each one of these groups gets a number. For example, if a woman has a 2.5-centimeter mass in the breast and one lymph node is involved, her stage is T2N1M0.
Most often, when doctors talk about cancer with patients, we do not discuss the TNM. Doctors often only discuss the final stage or group the patient falls into, which you’ll read about in the next section.
Staging: Grouping Patients
The final steps in staging a cancer use the TNM language to place a patient into a group—also known as the final stage. The woman in our scenario with a T2N1M0 breast cancer would be given a Stage II classification. Stages help us predict how the cancer will behave and what the potential outcome for the patient may be.
Just like TNM varies across different cancers, so do staging groups. Staging often goes from I to IV (or 1 to 4, using Roman numerals). Stage I means the cancer is local (it’s a small cancer with no signs of spread to other parts of the body). On the other hand, Stage IV often implies the cancer has spread to other parts of the body.
This does not mean that Stage IV is always bad or incurable. There are some patients with Stage IV cancers that still may be cured of their cancer (see chapter 9 on the gray zone). Patients need to talk to their doctors to understand what a stage means in the context of a specific cancer.
Bringing It All Together
Patients need to understand the name of their type of cancer so they can communicate with doctors and other clinicians. To keep track of information, write down the name of the cancer (diagnosis) and the stage. This allows patients to speak up for themselves in regard to their health and better understand their cancer. Not knowing the diagnosis or stage is a mistake many patients make.
Mistake #1: Not knowing the name and stage of their cancer
The diagnosis, grade, and stage give doctors a sense of how a cancer may behave. This helps determine how to balance treatments. We can then put together a medical and emotional support team to help the patient decide how to move forward. We’ll talk about putting these teams together in the upcoming chapters.
Chapter 4
The Emotional Toll of Cancer
Receiving a cancer diagnosis is life changing. When people hear the words You have cancer, their minds turn off. Those words may be the only thing they take away from the doctor’s appointment. There’s a whirlwind of emotions, and it can be hard to take everything in. Because processing the information is so hard, patients should write down their questions, concerns, emotions, and everything in between.
Patients, families, and doctors sometimes overlook the emotional difficulties that arise when dealing with a cancer diagnosis. Remember that you’re not alone in your journey: family, friends, doctors, nurses, support groups, and social workers are all there for you. In this chapter, we discuss the emotional aspects of a cancer diagnosis and where you can go for help.
Why You Want an Emotional Support Team
What’s the right emotional response to hearing you have cancer?
There is no “right” response.
Crying is normal.
Anger