TU VARI PIEDALĪTIES:
Cancer development stage is determined in the result of clinical and morphological tests. The main goal when determining the cancer stage is to identify local or regional damages which can be treated surgically or with beam radiotherapy as well as to determine chemotherapy regime and prognosis.
1) Surgical treatment
a) Radical surgery when the cancer is completely removed from the body;
b) Palliative surgery – patient condition or life-threatening condition may be relieved.
Surgical treatment – surgery is the oldest (the first data about the surgical treatment were found in the Egyptian papyrus), the fastest and the most effective cancer liquidation or its reducing method. In some cases it could be the only and the best possibility of cancer treatment, but correct cancer stage diagnostics without surgical intervention (biopsy, laparoscopy, etc.) is not imaginable.
Surgery can be considered preventive in all cases when pathological formation can protect patients from possibility of further cancer development. For example, removal of cervical dysplasia and suspicious pigmentations, prophylactic surgery of longstanding ulcerative colitis, leucoplacia, surgical placement of the dropped testicle into the correct position in the scrotum (otherwise there is a certain risk of testicular cancer) etc.
Local recurrence or removal of separate metastases in some cases may prolong patients' lives for several years. Sometimes only surgery (palliative surgery) can reduce painful symptoms or cancer size enlargement and restore vital functions.
The first cancer surgery (in modern sense) was performed in 1809 when the abdominal cavity was opened to patient with ovarian cancer. However, the boom real cancer surgery is related to a number of nineteenth century discoveries – anaesthesia, aseptic and training implementation of surgical manipulations. A large part of cancer surgery has almost a century-long history: 1860 – gastrectomy (surgical removal of the stomach), 1878 – rectal cancer removal surgery, 1890 – radical mastectomy (surgical removal of one or both breasts), 1904 – radical prostatectomy etc. Recent achievements mainly are related to modernization of surgical instruments, introduction of new surgery technique (surgery when video device is used) and with patient pre and post surgical care improvement (blood preparation, transfusion solutions, parenteral nutrition, effective anti-bacterial remedies, equipment of anaesthesiology and patient monitoring).
2. Beam Radiotherapy
This radiotherapy is used approximately in half of all cancer treatment cases.
What is irradiation?
Irradiation (in medicine – radiation) also is called x-ray therapy, cobalt therapy or electron therapy. Radiation is done by specially prepared medical personnel (radiation therapists, “beam sisters”, topometrists and medical physicists) in radiology or “beam” units. The flow of very small particles or destructive effect of wave energy is the base of effective treatment method. In the case of radiation contact with cells` oxygen or water molecules (80% of all cell-forming molecules) starts the process of ionization and the effect is formation of cytotoxic substances, the so-called free radicals. Thereby there is no direct radiation induced cell-killing, but it is mediated through the formation of free radicals.
Radiation is localized cancer treatment method – cancer cells are destroyed or significantly damaged and these cells are located only in the radiation zone. Cells which circulate in the blood stream or are located outside the radiation zone are not affected during the radiation. In comparison with chemotherapy, the radiation impact area is much narrower. Theoretically, systemic radiation influence to cancer cells could be achieved by irradiating the whole body, but it would be too hard for the healthy tissues and also a high risk for patients’ health.
If the cancer is detected early and it is locally delimited, it could be even cured with the help of radiation, for example, bazaliom, squamous cell skin cancer, cervical cancer etc. Sometimes radiation is done before the surgery but in the case when the cancer has developed significantly. The main purpose of this procedure is to reduce cancer size and significantly damage malignant cells so that, during the operation, cells would be less vivid and wherewith they have less energy to grow and multiply.
When radiation is used?
Very often radiation is used after the surgery. In these cases surgery scars and regional lymph node basins (with the biggest possibility of cancer lymphatic metastasis) are radiated. Such radiation is like a preventive measure to protect the body from local recrudescence. In many cases it is combined with systemic chemotherapy. In other cases, radiation can successfully be used to remove very large cancer liquidate the incompletely removed cancer, or at least to limit the progression. Pretty often the radiation, especially with systemic chemotherapy, can be the only treatment method in the case if there is no possibility of surgery.
Radiation is essential part of palliative (symptomatic) therapy. With the help of palliative radiation (usually its doses are smaller and time is shorter) it is possible to reduce complaints which are related to cancer or its metastases (pressure, bleeding, pains, difficulty swallowing) and also significantly improve health.
How radiation-sensitive are cancers?
Cancer can be divided into three groups:
- Very sensitive (lymphoma, Wilms` kidney cancer (Wilms` tumor), seminoma);
- Average sensitive (squamous cell cancer, breast cancer);
- Resistant or insensitive (sarcoma, melanoma, digestive organ adenocarcinoma).
Radiation history is nearly a century old and sensitive or not so sensitive cancer spectrum is well- known.
What affects cancer cell sensitivity against the radiation?
Malignant cell sensitivity against radiation subversive activities (so the therapeutic desired) determines several factors:
- Tissue oxygenation degree. Oxygen is one of the most important sources of free radical formation. It is known that tissues, which are well supplied with oxygen, are three times more sensitive than hypoxic tissues (state of oxygen starvation).
- The rate of cell growth. Actively dividing cells are more vulnerable. Tissues with intensive cell growth are less sensitive against the radiation damaging effect.
- Radiation dose. If the dose is insufficient, the cancer cells will recover and will continue to grow and multiply. Type of radiation (protons, neutrons, x-rays, gamma rays). Thus (using the same total radiation dose) the particle flow of neutron and proton has greater cell killing potential than x-rays and gamma rays, besides these two types of radiation can also be affected by the degree of tissue oxygenation.
How I can increase the cancer tissue sensitivity against radiation?
Currently it is done either selectively increasing cancer cell sensitivity against radiation or with different techniques to protect healthy tissues. In clinical practice a number of chemo preparations or its combinations to increase tissue sensitivity are used. In these cases the patient before or during the radiation also receives chemo preparations. It is difficult time for the whole body, therefore, you should think very carefully about this method: consider all potential “for” and “against”.
Why radiation lasts so long? Radiation length depends on different conditions. Mainly from cancer sensitivity and from outcome, whether cancer will be fully or partially taken out or it will be only correction of some of the symptoms (pain, bleeding).
In order to protect healthy tissues from radiation exposure, this treatment method is used in split mode, it means, radiation session is done every day in small portions but in long period, usually five days a week and for 4 to 8 weeks long. It is necessary so that normal cells can recover between radiation sessions. Normal cell ability to revitalize radiation caused DNA damages is much greater than cancer has. Spilt radiation protects healthy tissues from damages. Besides, during the split-dose radiation, a mass of cancer cells gradually decreases and improves its blood flow, oxygen supply and also radiation sensitivity. However, the process of normal cell recovery may be very long and side effects can cause additional sufferings but usually these feelings are temporary.
Is it true that during the radiation the patient can become dangerous for others?
It depends on the type of exposure.
During external beam radiation, patient does not become radioactive and does not danger anyone. Patients can safely embrace and kiss their loved ones, have close contact with children and other relatives, eat from the same dishes, use common household items and make love.
During the internal radiation, patient becomes radioactive and can affect others. The presence of radioactive substances found in human urine, excrements as well as the inserted radioactive implants can cause a small irradiation dosage. Therefore during this therapy you should follow some safety measures. This therapy is always carried out stationary, in specially equipped units. While having internal radiation therapy, doctor or nurse warns about activities that you can or can not do. Attendance time is limited and also service staff will stay only when it would be necessary. You should warn your relatives about the fact that children younger than 18 and pregnant women can not visit you, during internal radiation therapy. As soon as the implant is removed from the body or internal radioactive medicine usage and specified safety time has passed, the patient is no longer potentially dangerous (radioactive) for the public and no restrictions are needed.
What is the external radiation?
External radiation is radiation supply that is aimed only at specific part of our body and this radiation comes from a machine that does not touch you and is located closer or further from your body. Machine definitely is located outside patients’ body.
Depending on cancer type and its location (especially depth) you can choose different radiation equipment: linear accelerators, x-ray tube and cobalt gun. In linear accelerator, so called Betacorton, the high-energy disincentive radiation is made when electrons strike towards target plates. It is also known as electron therapy. Machines with different x-ray voltage bulbs are used for exposure of skin and for superficial cancer. Distance gamma therapy is used for deep, localized cancer radiation and its radiation source is cobalt.
How is the external radiation planned?
Planning aim is to:
- set optimal radiation fields (zone width, number of positions and angle of radiation)
- determine how to adapt some characteristics of individual patient anatomical characteristics of radiated area and cancer size, configuration and connection with near tissues and area of regional metastases.
For this purpose, firstly, each patient topometrical data is created – it is achieved either by performing two mutually perpendicular x-ray images or by computer tomography. After that the data is transferred to the paper and drawn the cross-section body map which displays both cancer and near organs. Then patient is send to the determination of topometrical radiation field. This complex procedure is called simulation and it is carried out with special x-ray equipment (x-ray topometer) which imitates beam machine location – the distance and angle against patient body. Simulation may take from a half-hour to about two hours. On your skin the doctor draws the radiation field. After the simulation topometrist gives the data to radiation therapist (radiologist), who together with medical physicist develops optimal dose and regime of the radiation and create the topometrical and anatomical dose maps, in other words, what kind of doses should be used to particular areas and angles?
During the therapy, doctor regularly follows to patient overall health, tests, radiation reaction and undesirable side-effects. If necessary, therapy can be reconsidered or even stopped.
In which cases the radiation can be abolished or suspended?
Radiation is a big load to the body so the deviation from norms can be a reason of radiation abolishment, thinking about another date, radiation dosage decreasing or even interruption of the therapy.
Blood count is a very important indicator because the decrease of blood cell number (leucocytes, lymphocytes, thrombocytes and erythrocytes), during the radiation, can seriously endanger patients’ health. If the number is very low, radiation is not allowed. Blood count is regularly controlled throughout the whole therapy and also after it.
3. The purpose of chemotherapy is to achieve complete remission during the cancer development or as long as possible to obtain remission with small chemotherapy dose, or remove remaining cancer cells (prevention of metastasis).
Treatment can be:
a) Radical – with various skin cancer forms when other treatment methods are not necessary;
b) Palliative – when it would have non-radical effect, for example, pain removing effect;
c) Combination with other therapy methods – after surgery or with chemotherapy.
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19.-20. marts, 2015
19th-20th March, 2015