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Hyperthermia (or thermotherapy) is a cancer treatment that involves heating tumor cells within thebody. Elevating the temperature of tumor cells results in cell membrane damage, which, in turn, leadsto the destruction of the cancer cells. Over a hundred years ago, doctors first noticed that high heat,such as that resulting from a fever, killed cancer cells and shrank tumors. Research into hyperthermia

as a cancer treatment began soon after. Today hyperthermia is used as an adjunct to radiationtherapy and chemotherapy.

Hyperthermia treatment of cancer requires directing a carefully controlled dose of heat to thecancerous tumor and surrounding body tissue. Cancerous tissues can be destroyed at exposure to atemperature of about 108 F for an hour. This high heat must be used wiselytoo little heat and thecancer will not be killed. However, if too much heat misses the tumor target, the skin or other healthytissues could be burned.

A clinical adaptive microwave phased array hyperthermia system for treating cancer deep in the body

Microwave energy is very effective in heating cancerous tumors, because tumors typically have high-

water content. Such tissue heats very rapidly when exposed to high-power microwaves. Furthermore,microwaves can be delivered to tissue by special-purpose antennas that are located adjacent to the

patients body. Depending on the tumor size and location in the body, one or more microwaveantennas can be used to treat the tumor. When a microwave thermotherapy antenna is turned on,body tissues with high-water content that are irradiated with significant amounts of microwave energyare heated. The temperature rise in the tissue is due to the transfer of microwave energy into heat.Generating heat from microwaves is very similar to the effect of ordinary mechanical friction such aswarming your hands by rubbing them together. As the microwave energy (oscillating about a billion

times a second) passes through the tissue, water molecules are vibrated. Frictional forces between thewater molecules in the tissue result in the heating of the tissue. By concentrating the microwaveenergy, it is possible to selectively heat tumors and protect healthy tissues. This process ofconcentrating or focusing microwaves at a tumor is somewhat analogous to a group of orchestralinstruments being played in synchronizationwhen played together, a bunch of individual instrumentsmake a big sound. In the same way, synchronized radiating antennas produce concentratedmicrowaves.

In 1990, Dr. Alan J. Fenn, an electrical engineer at the Massachusetts Institute of Technologys LincolnLaboratory developed a concept for heating deep tumors by means of adaptive microwaves. Theseadjust to the properties of a patients tissue to concentrate the microwave energy at the tumorposition. These adaptive microwaves are generated by multiple microwave antennas (an adaptivephased array) that surround the human body.

In addition to treating cancer, microwave heating is an effective treatment of an enlarged prostategland (a common non-cancerous condition in males). A microwave-radiating device heats the prostategland, which shrinks it. Microwaves also show promise as a diagnostic tool, where they will act as asort ofradarfor your body. Research in this use of microwaves in medicine, as well as many others,continues. There is little doubt that the doctors office of tomorrow will make increasing use ofmicrowaves.

Categories:Bioengineering|Medical conditions|Cancer|Medical treatment|Oncology|Fields,waves & electromagnetics|Microwave technology|News

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Log in

What is cancer?

Cancer is the name given to a group of diseases, which have one feature in common: uncontrolled

growth of cells, which is of no use to the body. Normally cell growth is balanced by death of equal

numbers of cells - a process called apoptosis or programmed cell death. When this process is disrupted, a

mass of cells is produced - commonly known as a tumour.Tumour:

Tumours may be benign or malignant:Benign: Here tumour growth is slow and spread does not occur to other parts of the body.Malignant: A malignant tumour on the other hand, can destroy organs locally and spread to other

parts of the body, such as lungs, liver and bones-a unique ability, called metastasis.Cancers are of different types, depending on the tissue from which they arise: Broadly, 4 types are recognized;

Carcinomas - which arise from the layers that cover the body[skin] or line the body-mucosa of nose,

throat, lungs, food pipe, stomach, intestine etc,Sarcomas - which arise from soft tissues such as muscle, fat, blood vessels or from bones,Leukaemias - which arise from the bone marrow and spread into the blood andLymphomas - which originate from the lymphnodes and spleen.

2. Causes of cancer

The cause of cancer is multifactorial - multiple agents may act to produce cancer in a particular person. The

risk of developing cancer increases with age - 80% of all cancers occur in those aged above 55 years. The

final common pathway is damage to the genetic component of the cell (DNA), which leads to uncontrolled

cell growth.The common causative factors may be:

External: such as dietary (high fat diet, alcohol), tobacco, excessive sun exposure, viral infections like

Hepatitis B, industrial chemicals; orInternal: inherited defective genes (which explains how cancer runs in some families), orReproductive history (late age at first child birth for breast cancer)

3. Symptoms of cancer

Cancer being a disease which affects any organ in the body, the symptoms are varied, and there is no

particular symptom which can accurately predict the presence of cancer. The exact symptoms depend on the

location of the cancer, which part of the organ is affected, how fast the cancer is growing and whether it has

spread to other parts. Cancer occurring in outer parts of the body, such as skin, breast, limbs, testicles or

nose and mouth, may present with a visible swelling or ulcer, and may be diagnosed earlier.There are certain warning signs of cancer, which should be further investigated:

Unexplained weight lossLoss of appetiteLump in the breast or bleeding from the nippleRecent change of bowel habitsVaginal bleeding after menopauseChange in shape/size or bleeding from a mole

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Chronic cough

4. Organs affected by cancerCancer can affect every organ and cell type in the body, though some organs such as the eye and heart are

rarely affected. Some of the common cancers are: Mouth and tongue cancersThroat and voice box (larynx) cancersLung cancerEsophageal and stomach cancerLiver cancerPancreatic cancerColon and rectal (Large intestine) cancerKidney and bladder cancerProstate cancerOvarian, uterine and cervix cancersBreast cancerBone cancersBlood cancer (Leukemias)

5. Spread of cancer

The hall mark of cancer and what makes it a deadly disease, is its ability to destroy surrounding organs and

spread [metastasize] to far away organs. Cancer which has spread to a far away organ is called stage IV

cancer, and is generally not curable. It is treated with medicines, called chemotherapy. The common organs

to which spread occurs are those with rich blood flow, like lung, liver and bone. Each cancer has a

preference for certain organs; eg. Stomach cancer spreads to the liver, bone cancer to the lungs. Once cancer spreads, it causes the patients condition to rapidly worsen - weakness sets in, appetite goesdown and respiratory or liver failure sets in. Survival after metastases are found is usually less than a year.6. Treatment of cancer

The aim of cancer treatment is to relieve symptoms, cure the patient and prolong or save life. All these aims

may not be met in every case. When cancer is detected early, treatment is very effective and patients are

usually cured.In patients who present with advanced disease, complete cure may not be possible, and treatment aims to

control the disease, improve quality of life and to keep the patient normal and comfortable as long as

possible. The treatment of each patient is designed to suit an individual and depends on the age of the

patient, general condition, type of cancer and stage of disease. There may be only one treatment or

combination of treatments.There are five main modalities of treatment for cancer: Surgery and radiotherapy eradicate the disease at

the primary site (site of origin) of cancer. Chemotherapy, hormonal therapy andimmunotherapy deal with disease which may havespread outside the site of origin of cancer.

Surgery Chemotherapy

Radiotherapy Hormonetherapy Immunotherapy

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Surgery

Surgery is the most important part of the cancer treatment. Surgery removes cancer cells from the body by

cutting away the tumour and any tissues surrounding it which may contain cancer cells, including the

lymphnodes. It is a simple, safe and effective method when cancer is small and confined to the site of origin.

It is best suited for certain cancers like breast cancer, head and neck cancers, early cancers of the cervix

and lung, many skin cancers, soft tissue cancers and gastrointestinal, liver and pancreatic cancers. Surgery

may also be used in advanced cases to relieve symptoms such as bleeding and blockage of the food pipe,intestine or urinary passage.Radiotherapy

Radiotherapy is a form of treatment which uses radiation, a special kind of energy carried by waves or a

stream of particles originating from radioactive substances and delivered by special machines. These

radioactive x-rays or gamma rays can penetrate the cell wall and damage the nucleus of the cell which

prevents growth and division of cells. This also affects the normal cells but these cells recover more fully

than cancer cells. Radiotherapy is required in 50% to 70% of patients, usually before surgery to shrink large

tumours, or after surgery to destroy cells left behind after surgery at the site of tumour origin. Radiation is

also used in patients with metastases, to relieve pain, bleeding or pressure symptoms; eg to relieve

paralysis caused by a tumour pressing on the spinal cord.Modern radiotherapy is very safe, and is technology driven. Recent advances include Intensity Modulated

Radiation Therapy [IMRT] which is the delivery of radiation with high precision, so as to spare normal

tissues, and reduce side effects. Improvements in radiotherapy equipment, technique and applications, have

led to an increasing role both in local treatment and also in its use as a whole-body treatment, as part of

bone marrow transplantation techniques for leukaemias and lymphomas.Chemotherapy

Chemotherapy uses drugs which interfere with the growth and division of malignant cells. Once the drugs

are administered, they circulate throughout the body. It is advantageous over surgery & radiation for

treating cancer that is systemic (spread throughout the body). Chemotherapy is the main modality for

cancers like leukemia (blood cancer), lymphomas, certain lung cancers and paediatric cancers.

Chemotherapy may be used before surgery to shrink large tumours, and make surgery easier, in breast,

esophageal, rectal and bone cancers. Chemotherapy is also used after surgery to treat cells shed in the

blood, so as to prevent reappearance of tumours.The side-effects of the chemotherapy include nausea, vomiting, hair loss, diarrhoea, weakness etc. which

are temporary and completely reversible. Modern chemotherapy is very safe and well tolerated and is often

given on an outpatient basis.Hormonetherapy

Hormonetherapy has limited use in cancer treatment since only minority of tumours are hormone sensitive

e.g. breast and prostate cancer. This therapy provides systemic means of treatment, i.e. to the whole body,

but without the side effects of chemotherapy.Immunotherapy

Immunotherapy is a form of treatment which stimulates the bodys immune system to destroy cancer cells.

It is expensive, and useful only in a few tumours such as melanomas (type of skin cancer) and renal

cancers.