Adjuvant chemotherapy
What is adjuvant chemotherapy?
Adjuvant chemotherapy is chemotherapy given after the primary treatment (usually surgery) to increase the chances of a cure from early cancer. Surgery, and sometimes radiation therapy are very good at removing all detectable signs of the tumour. However, we know from long experience that cancer cells, which are so tiny that one million would fit on the head of a pin, may escape into the blood stream prior to surgery. These cells could be carried to distant parts of the body where they may lodge, and remain, often in a sleeping state, for many, many years.
At some future time, these cells may “wake up”, begin to grow and cause significant tumours in tissues like the bone, the liver, the lungs or the brain.
It is clearly preferable to “sterilise” the body of these cells before they have had a chance to grow and cause distant tumours, which may then be difficult to eradicate. To do so we must use chemotherapy drugs or hormones which circulate through the body and kill the rogue cells wherever they might be lodging. We need to do this fairly quickly after the primary treatment before the cells have had a chance to grow. Assuming there have been no wound healing complications, we usually like to start adjuvant treatment within 6 - 8 weeks of surgery.
Why can’t you do a test to see if these cells are present?
I wish we could! This is one of the Holy Grails of cancer research – a test that is sufficiently reliable to pick up just a few cells, but does not give any false signals. We don’t have it. Our current imaging tests like CT scans and PET scans still require there to be about 500 million cells present in one lump before we can detect them. The blood tests, with the possible exception of the PSA test for prostate cancer and the CA125 test for ovarian cancer, are just not accurate enough. They give many false positives and false negatives.
How, then, do you decide if adjuvant therapy is indicated?
The decision is made by making a calculation of the chances of the tumour having spread. To do this we rely heavily on the features of the cancer that has been removed by surgery. These include:
Generally speaking, the larger the cancer at diagnosis, the greater the chance of more cancer cells being left behind. However, this is not always true. Some patients have cancers that do not develop the ability to spread. These can become quite large without involving distant organs. Other patients have cancers that develop the migrating ability early in their growth before they can be found on examination or even screening. So we have to use a combination of all of these factors to predict the chance of spread.
We also look at certain important features of the patient herself, including:
We then make an informed estimate of the degree of benefit that will be gained, say, at ten years, from the use of adjuvant treatment. To do this we use information from a large number of clinical trials, and constant expert reviews of this information like that at the biennial International St Gallen Breast Cancer Conference, where consensus expert views are formed.
Most importantly, each patient is carefully discussed in a multidisciplinary team meeting, with surgeon, radiation therapist, medical oncologist and pathologist to make the very best decision.
Finally, each patient will have her views on what risks and benefits she will accept, and this often determines the final decision.
Interestingly, studies have been made of this “patient preference”, and we know that women who have already had chemotherapy would accept the side-effects a second time around for a benefit of around 3% reduction in risk of recurrence at ten years. The majority of young women receive at least this benefit, and sometimes three times this, from adjuvant chemotherapy.
How can you tell if it’s working?
Unfortunately, you can’t tell for sure, because there are no blood tests or X-rays or other tests sensitive enough to allow us to monitor the treatment. We will certainly do tests to make sure that you are getting enough treatment and that your body is not experiencing serious damage from the drugs. However, we have to base our confidence in the success of treatment of the results that have been achieved over the past 40 years. Many thousands of women have taken part in carefully-conducted clinical trials which have shown clearly that chemotherapy works, that it cures people and that a very large number of women are protected by it from having breast cancer recurrence many, many years down the track.
Can you give me a guarantee that the cancer won’t come back?
Unfortunately, no. Adjuvant chemotherapy is like taking out additional insurance against the cancer coming back. However, just as I can’t be sure if I’m not going to be run over by a bus tomorrow, none of us can get gilt-edged guarantees about the future. All we can say is that your chances are much better with the treatment than without it. There will be some short-term inconvenience for some long-term gain. We want you to see your grandchildren growing up, and chemotherapy is often an additional insurance you can take out to help ensure that goal, even if it is 20 or 30 years away.
Should older women have adjuvant chemotherapy?
Today, a healthy 65 year old women is estimated to live on average another 20 years; for a healthy 85 year old average life-expectancy is about 6 years. There is increasing evidence that age should not be a barrier to the use of adjuvant chemotherapy. Older women who do not have other serious health problems tend to tolerate standard chemotherapy, like AC very well. Oncologists have been encouraged to overcome age bias and offer older patients the same treatment options as younger patients.
Adjuvant chemotherapy is chemotherapy given after the primary treatment (usually surgery) to increase the chances of a cure from early cancer. Surgery, and sometimes radiation therapy are very good at removing all detectable signs of the tumour. However, we know from long experience that cancer cells, which are so tiny that one million would fit on the head of a pin, may escape into the blood stream prior to surgery. These cells could be carried to distant parts of the body where they may lodge, and remain, often in a sleeping state, for many, many years.
At some future time, these cells may “wake up”, begin to grow and cause significant tumours in tissues like the bone, the liver, the lungs or the brain.
It is clearly preferable to “sterilise” the body of these cells before they have had a chance to grow and cause distant tumours, which may then be difficult to eradicate. To do so we must use chemotherapy drugs or hormones which circulate through the body and kill the rogue cells wherever they might be lodging. We need to do this fairly quickly after the primary treatment before the cells have had a chance to grow. Assuming there have been no wound healing complications, we usually like to start adjuvant treatment within 6 - 8 weeks of surgery.
Why can’t you do a test to see if these cells are present?
I wish we could! This is one of the Holy Grails of cancer research – a test that is sufficiently reliable to pick up just a few cells, but does not give any false signals. We don’t have it. Our current imaging tests like CT scans and PET scans still require there to be about 500 million cells present in one lump before we can detect them. The blood tests, with the possible exception of the PSA test for prostate cancer and the CA125 test for ovarian cancer, are just not accurate enough. They give many false positives and false negatives.
How, then, do you decide if adjuvant therapy is indicated?
The decision is made by making a calculation of the chances of the tumour having spread. To do this we rely heavily on the features of the cancer that has been removed by surgery. These include:
- Size
- Grade (how “angry” the cells look under the microscope)
- Lymph node involvement
- Hormone receptor levels
Generally speaking, the larger the cancer at diagnosis, the greater the chance of more cancer cells being left behind. However, this is not always true. Some patients have cancers that do not develop the ability to spread. These can become quite large without involving distant organs. Other patients have cancers that develop the migrating ability early in their growth before they can be found on examination or even screening. So we have to use a combination of all of these factors to predict the chance of spread.
We also look at certain important features of the patient herself, including:
- Age (women under the age of 35 are at higher risk of recurrence)
- Menopausal status
- Presence of other illnesses
We then make an informed estimate of the degree of benefit that will be gained, say, at ten years, from the use of adjuvant treatment. To do this we use information from a large number of clinical trials, and constant expert reviews of this information like that at the biennial International St Gallen Breast Cancer Conference, where consensus expert views are formed.
Most importantly, each patient is carefully discussed in a multidisciplinary team meeting, with surgeon, radiation therapist, medical oncologist and pathologist to make the very best decision.
Finally, each patient will have her views on what risks and benefits she will accept, and this often determines the final decision.
Interestingly, studies have been made of this “patient preference”, and we know that women who have already had chemotherapy would accept the side-effects a second time around for a benefit of around 3% reduction in risk of recurrence at ten years. The majority of young women receive at least this benefit, and sometimes three times this, from adjuvant chemotherapy.
How can you tell if it’s working?
Unfortunately, you can’t tell for sure, because there are no blood tests or X-rays or other tests sensitive enough to allow us to monitor the treatment. We will certainly do tests to make sure that you are getting enough treatment and that your body is not experiencing serious damage from the drugs. However, we have to base our confidence in the success of treatment of the results that have been achieved over the past 40 years. Many thousands of women have taken part in carefully-conducted clinical trials which have shown clearly that chemotherapy works, that it cures people and that a very large number of women are protected by it from having breast cancer recurrence many, many years down the track.
Can you give me a guarantee that the cancer won’t come back?
Unfortunately, no. Adjuvant chemotherapy is like taking out additional insurance against the cancer coming back. However, just as I can’t be sure if I’m not going to be run over by a bus tomorrow, none of us can get gilt-edged guarantees about the future. All we can say is that your chances are much better with the treatment than without it. There will be some short-term inconvenience for some long-term gain. We want you to see your grandchildren growing up, and chemotherapy is often an additional insurance you can take out to help ensure that goal, even if it is 20 or 30 years away.
Should older women have adjuvant chemotherapy?
Today, a healthy 65 year old women is estimated to live on average another 20 years; for a healthy 85 year old average life-expectancy is about 6 years. There is increasing evidence that age should not be a barrier to the use of adjuvant chemotherapy. Older women who do not have other serious health problems tend to tolerate standard chemotherapy, like AC very well. Oncologists have been encouraged to overcome age bias and offer older patients the same treatment options as younger patients.