Historically radiotherapy has played an important role in the treatment of cervical cancer and has led to remarkable improvements in cancer survival.
However, surgical techniques have also played an important role in the early stages of cancer treatment. Lately, as we shall see below, there is a tendency to somehow combine both methods to the benefit of the patient with cervical cancer to achieve longer survival rates. Chemotherapy also has made some differences for advanced disease.
But there are limitations because the dosages that are curative are so toxic that bone marrow suppression from the chemotherapy often becomes the limiting factor.
Here is a typical 5-year survival table, which is based on several large trials and modified from data from Ref. 2.
5-year survival rates with different treatments for cancer of the cervix
The following remarks can be made regarding the various treatment protocols:
- Various centres have protocols that they like to adhere to and these average survival rates may be considerably better or worse in a particular centre. The above quoted figures are the average survival rates of the major Cancer Centers across the U.S. as summarized in Ref. 2.
- Even with this consensus there are obviously gaps due to the fact that conventionally a certain stage of cervical cancer has been treated a certain way.
Radiation therapy for up to stage IIB
- Surprisingly, radiation therapy has excellent results up to stage IIB. As can be seen from the second last table, at this stage there are a total of 35% of patients who have metastases at the time of the diagnosis, namely 19% with paraaortic lymph nodes and 16% with distant metastases that were spread through the blood stream (hematologically). No wonder that these patients are dead after 5 years and this is why a survival of 66% is considered very good at this stage. The question to ask is: why did these women not go for a yearly Pap test and pelvic examination? The same question plagues me when I see the sad story regarding stages IIIA to IV!
Stage III cervical cancer treatment
- With stage IIIA the combination of radiation followed by surgery to remove the remaining viable cancer cells has lead to a survival advantage of 10% versus radiation alone.
- As 50% of stage IIIB patients have metastases at the time of diagnosis and 64% of patients with stage IV cancer of the cervix, it is no wonder that the survival rates despite heroic treatments are not better. Patients die from bone metastases, liver metastases, lung metastases and others. Theoretically the highest achievable survival would be 50% for stage IIB and 36% for stage IV. As you can see from the table above the actual 5-year survival numbers are 40% with radiation for stage IIIB and 38% for a combination of chemotherapy with radiation for stage IV.
Limits of curative medicine
- Curative medicine has enormous limits as no one has at this point figured out a way how to stop cancer from growing and how to specifically activate the immune system to attack the cancer cells throughout the body. Until such time the only other way is to do regular screening to catch the cancer earlier when it is still curable (stage IA or less).
- The reason for the good results with radiation is that any lymph gland that is affected in the pelvic area or alongside the aorta can be included in the treatment field. Relatively speaking cancer of the cervix seems to be more radiation sensitive than chemotherapy sensitive.
- Because of the 18% survival advantage in stage IV between the combination chemo- and radiation therapy, there might be in future more clinical trials in an attempt to improve the survival in stages IIB, IIIA and IIIB as well.
- Brachytherapy is a form of radiotherapy, which originally consisted of a metal device containing radioactive radium (226-Ra), which was inserted high into the vagina and/or into the cervical canal. In the 1980’s this older technique has largely been replaced with radioactive caesium (137-Cs), which has less side-effects than radium. This technique has recently experienced a rejuvenation and is combined with proton beam therapy to cover the pelvic and paraaortic lymph nodes.
According to Ref. 1 recurrences after an initially successful therapy had the following 5-year survival:
5-year survival after recurrence of cervical cancer
|Treatment modality:||survival (%):|
|Surgery combined with external beam radiation||30%|
|External beam radiation||4%|
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