Certain cancers can be cured with a definitive procedure (usually surgery). For example an early breast cancer may require removal of the disease part of the breast. Early bowel cancer can be cured with removal of the cancerous part of the bowel. Early lung and pancreatic cancers can also be cured with surgical removal.
In each of the cases outlined above, the surgical procedure is designed to remove the whole cancer with clear margins in the hope of curing the patient.
However, even with the best surgical result, some patients may get a recurrence at some point in the future. This could be some years after the original surgery. Sometimes a recurrence can still be cured with aggressive therapy. However, in many situations it is not curable and further treatment is designed to prolong life (see palliative chemotherapy)
Why does the cancer return? Well, we believe this occurs because in some patients tiny, microscopic cancer cells have escaped into other parts of the body such as the bloodstream and are not removed by the surgical procedure. These cancer cells are so small they’re undetectable even using the latest blood tests and scans. Such tiny cells have the ability to settle in a different part of the body and reveal their presence years later when they grow into appreciable growths.
The thing to remember is that at the time of original surgery, nobody knows if these tiny escapee’s are present or not. The patient does not know. The doctors do not know.
Some decades ago doctors wondered if giving some chemotherapy after surgery might obliterate these ‘invisible’ cancer cells. The only way to work this out was to perform clinical trials where some patients had chemotherapy after their surgery while others didn’t. A series of randomised trials were performed. These trials involved speaking to patients after their curative surgery and discussing whether they would want to consider a trial where they may get no further treatment (at that time this was the accepted practice) or having a course of chemotherapy to see if it resulted in a lower risk of cancer recurrence. The important thing about these trials is that they were RANDOMISED. This means that patients who took part could not choose whether to have chemotherapy or not. Their doctors were also not allowed to choose. Patients were allocated randomly, usually 50:50. Why is this important? Its important because if only really fit patients had chemotherapy and frail patients had no chemotherapy, then the results of these trials will have shown that chemotherapy was better when it may not have been. In order to know if any treatment is better than another it’s important to test them in a randomised trial to remove any imbalance.
As you can imagine, if it takes up to 5 years for a cancer to return then these trials will have to run for some years before the full results are known.
All credit to the patients and oncologists who did these trials decades ago, because now we know 100% that chemotherapy after surgery can improve the chance of cure for patients with many types of cancer. We call such chemotherapy ADJUVANT CHEMOTHERAPY.
Therefore, adjuvant chemotherapy describes a course of treatment given after surgery to try and eradicate undetectable microscopic disease. This is proven for many cancers such as breast, bowel, lung, pancreatic cancer.
The thing to remember about adjuvant chemotherapy is that some patients will have been cured by surgery alone. For such a patient, a course of chemotherapy is unnecessary however because we cannot predict who these patients are, they may very well end up having chemotherapy anyway.
Additionally there will be some patients who will get a recurrence even though they completed a course of adjuvant chemotherapy. One could argue that the adjuvant chemotherapy was unnecessary in such patients.
Despite this, there will be a group of patients who were destined to get a recurrence but because they had chemotherapy, the surviving cancer cells were eradicated and as a result these patients have been cured. This is the group of patients who benefit from adjuvant chemotherapy.
So, it’s important to recognize that when it comes to adjuvant chemotherapy, we are treated many patients to benefit a few.
Discussions around the pros and cons of adjuvant chemotherapy are often very complex and require a lot of careful thought on the part of oncologist and patient. Each case is taken on its own merits. Often, a detailed examination of the surgical specimen can give important clues about the risk of future recurrence and also the potential benefit of chemotherapy.
In my practice I routinely meet patients who have had cancer surgery for lung or bowel cancer. Every patient needs an individualised discussion and it’s fascinating how different people will come to different conclusions about what is right for them.
For example if you had a bowel cancer removal, would you be prepared to undergo 6 months of chemotherapy if your doctor said the chance of cure was 70% and that by having chemotherapy, the chance of cure would improve to 73%. That’s a 3% increase in the cure rate. Does not sound like a lot too many people but I will often meet patients who feel that is worth it.
Conversely in some patients, the chance of cure may only to 20-30% after surgery, but by adding chemotherapy, it may improve to 50%. Now, that is quite a big increase in the cure rate! While many people will see that improvement as worthwhile, there will be some who feel it’s not for them.
We all see the same problem differently. That is the wonder of the human condition. Some of us see the glass half full and others half empty. As an oncologist, my job is to empower patients to make the right decision for them.