Treatment
Of CancerThe three main cancer treatments have not changed that much over
the decades: surgery, radiotherapy and chemotherapy. A)
Surgery: One of the most obvious things for
the physician to do is to cut out the cancer. This is sometimes easier said than
technically done, particularly when it turns out at surgery that the cancer is
more advanced than originally thought. However, with chemotherapy or radiotherapy
in conjunction with surgery this can be partially overcome. Also, surgery can
have complications such as infection, bleeding or blood clots after surgery. With
a heightened awareness the physician can spot any problems like this early and
deal with them immediately. In combination with more refined early cancer
screening tests and a proliferation of new surgical techniques
there has been a mushrooming of new treatment forms. I already mentioned above
laser surgery for cancer of the cervix as one such treatment modality. Another
newer technique is Mohs' technique of shaving skin cancer down to the normal skin
level underneath while doing frozen sections, with close to 100% cure rates. B)
Radiotherapy treatment is
often applied following surgery, for instance after breast cancer surgery to eradicate
local metastases around the axilla. With head and neck cancer radiotherapy might
be the only therapy being used. Other forms of radiotherapy are linear
accelerator treatments or the "Gamma knife", a special form of stereotactic
radiosurgery used for brain cancers. A number of unique modifications of radiotherapy
are being employed by radiotherapists. For thyroid cancer radioactive iodine is
used. The radiotherapist is exploiting the fact that thyroid cells take up iodine
vividly and a radioactive iodine atom is used to deliver a curative radiotherapy
dosage. Following this treatment the patient is then hypothyroid and has no thyroid
hormones, but this is easily replaced by giving the patient thyroid hormone pills.
Radioactive seeds might be implanted by a specialist to control prostate cancer
that cannot be treated by surgery. C) Chemotherapy
has experienced a transformation following the successes with the treatment of
leukemia, lymphoma and Hodgkin's disease. What chemotherapists learnt was
that lower dosages of several chemotherapeutic agents, combined and given according
to a schedule with intervals where the bone marrow can recover, were more effective
on the long term with higher survival rates. To get away from the toxic
effect of the traditional chemotherapeutic agents new ideas were born. Immunotoxin
therapy is one such new idea: An antibody against a tumor specific antigen is
coupled with a toxic substance, which is released when the tumor binds to the
immunotoxin complex. The toxic substance kills the tumor cell, but not
the healthy tissue or bone marrow cells. This technique is being used in phase
1 and 2 trials for non Hodgkins disease patients as well as various leukemias
and lymphomas of the bone marrow and should be soon available on a larger scale
through Cancer Clinics(Ref.5 and 6).This is not the "all cure", but
it can be used as a tool to remove the remaining tumor cells after heavily treating
the non Hodgkins disease first with chemotherapy. In Ref. 5 there was a response
rate of 80% to 100% when immunotoxin therapy was used as a "mop-up"
step following chemotherapy.
The TIL Story: tumor-infiltrating
lymphocytes and gene therapy Rosenberg
et al. have perfected a carefully orchestrated form of immunotherapy at the National
Cancer Institute/ Bethesda, Maryland (Ref. 7).In the early 1990's a new technique
involving lymphocytes, which were isolated from the patient's cancer, was developed
by this group. Briefly, cancer tissue obtained from the patient through surgery
was digested in the lab until it was broken down into single cells.
Through cell separation techniques the cancer researchers could then isolate the
lymphocytes, called " killer lymphocytes" or cytotoxic lymphocytes.
As these lymphocytes are supposed to infiltrate the tumor, they were termed "tumor-infiltrating
lymphocytes"(or "TIL"). However, in cancer patients these seem
to need a bit of a boost and need to be directed specifically against the patient's
tumor surface antigens. Had they worked optimally, then the patient would not
have developed the cancer on the first place. This is exactly what the Rosenberg
group could show. They found that the patients had some response to their own
tumor, but that it was weak or even absent. They developed
a gene therapy where they used retroviruses in the lab to introduce gene material
that would give the TIL a boost so that they would attack the cancer the way nature
meant it to be. This immune response can be amplified by interleukin-2, a cell
mediator. In Ref. 7 the authors have provided a 7-year follow up study of 409
patients with metastatic melanomas and kidney cancers who were treated with high
dose interleukin-2. Surprisingly there was a complete cure in 8% and a partial
response in 9%. There was a measurable blood response in the group that experienced
a complete cure, which was carefully studied. This will help the researchers to
refine the immune therapy and improve on the outcome. Other authors have found
a 30% survival advantage in ovarian cancer with this therapy( Ref.8) in patients
where in the past there was no hope of survival. |
D) Treatment
of cancer pain: Oncologists (cancer experts) are usually the
ones who know most about cancer pain and how to treat this. It is beyond the scope
of this web-based Net Health Book to get into all of the details of this complex
topic. However, I like to give a brief summary of what the patient with cancer
pain can expect in terms of treatments. Generally speaking in the last
few years physicians have become more patient oriented realizing that there is
a difference between the science and the art of medicine. With cancer we have
a situation where science is still lagging behind with respect to good solutions,
so the challenge to the treating physician is to show compassion to the pain and
suffering of the patient realizing that there is ultimately little that can be
done medically at the end-stage to attack the cancer. The patient often is depressed,
may be in denial and needs counselling, support and reassurance. The patient will
want to have the pain treated as best as possible along with the depression and
likely will want to contact also a minister or priest regarding spiritual questions.
With regard to pain issues gabapentin has become a common pain modifier
as it is very well tolerated by more than 90% of patients and can be combined
with other medicines without worries about drug interaction (Ref.16). This
gabapentin link explains how it is used for the pain associated
with diabetic neuropathy. The pain associated with incurable cancer is treated
in much the same fashion. For more severe pain morphine and morphine-like narcotic
drugs are titrated against the pain. Pain Control: There
is an FDA approved non-drug method available, IceWave
patches from Lifewave, which will control pain, but is non addictiong.
This is mentioned in the book "Breakthrough" by Suzanne Somers (Ref.
17) where newer insights of antiaging medicine are also reviewed. Although the
patches are placed over acupuncture points, there are no needles involved. Nanotechnology,
a newer technology, was used in the manufacturing of these patches and infrared
(heat) waves from body heat are utilized to stimulate an acupuncture point, which
modifies pain perception and reduces pain to half or less. Medically this would
be considered an excellent pain reliever. For more info on the patches see the
IceWave patches from Lifewave link above (click "products"). In the
US a 5 pack of the IceWave spray is available that can be directly sprayed onto
the skin in the area where the pain is located. E) Clinical trials
are a powerful tool that University Hospitals are using when new
more effective therapies are developed. All of the leukemia chemotherapy progress
would be unthinkable without prior clinical trials that have proven that the newer
therapy saved more lives. I like to briefly explain how these trials are conducted.
There are three phases: -
Phase I clinical trial:
The purpose is to determine an appropriate dosage of medication that
is safe to use in the phase II trial. In the case of cancer patients the clinician
works with advanced cases, resistant to the standard therapy, but major organ
function in these patients has to be intact as proven by blood tests. All of the
trials are supervised by an Ethics' Committee to ensure that reasonable precautions
are taken to ensure safety of the patients. -
Phase
II clinical trial: A medication is tested in a patient group most
likely to benefit from it. Debilitated patients or patients who had prior chemotherapy
are excluded from this trial. -
Phase III clinical
trial: This arm of the trial provides reliable information about
the effectiveness of the new treatment. Patients' welfare is measured by exact
end points. In the case of cancer therapies improved survival is measured. There
is a correlation of "better symptom control (response rate)" and "survival".
Care is taken that the findings are applicable to community based situations (outside
of the research setting). This is achieved by a multi-institutional setting with
community physician involvement. Some expressions that are used in the setting
of clinical trials are "randomization", "stratification" and
"sample size". Essentially the researchers have to ensure that no
bias enters into the trial. Randomization ensures that
the groups that are entered into the control group are identical in make-up to
the group that is the trial group. Stratification is
a tool that looks at a number of parameters that define the populations and these
groups that are compared have to have a similar distribution pattern in these
parameters to be acceptable before the trial can begin. In the trial there needs
to be a large enough sample size to ensure statistically
significant differences. If the difference we are looking for is small, it takes
a large sample size to be able to observe a difference, if the difference we are
looking for is large, a smaller sample size will do. These are
just the "nuts and bolts" of clinical trials. In light of "evidence
based medicine" modern clinical trials have improved vastly in respect to
the validity in light of the above mentioned parameters. Usually there are a number
of clinical statisticians who are part of the research team. They ensure that
the trial is set up with large enough groups of patients to look at several parameters
and that the results are valid. Despite the best of all intentions, occasionally
a major toxic side-effect of a new drug is overlooked. This is the basis of the
post drug release surveillance where practicing physicians are asked to report
any side-effect that they notice to a central site. The data is now collected
nation wide and sometimes, if the result is proving to be toxic enough, a medication
might be "withdrawn voluntarily" by the drug company. |
