Cancer Care (Nursing and Health Survival Guides), 1e

Tumours

A tumour can be described as a lump or growth of tissue made up from abnormal cells. Tumours are divided into two types, benign and malignant. Cancer is the name given to a malignant tumour.

Images BENIGN TUMOURS

These can form in many parts of the body, growing at a slow rate, not spreading to or invading other tissues. These tumours are:

• not cancerous

• not typically life-threatening

Left alone they do not usually cause any harm, but some benign tumours can cause problems. If the benign tumour grows and becomes large this can result in local pressure symptoms or the size can look unsightly. Some benign tumours arise in cells in hormone glands, for example, the thyroid gland causing excess production of hormones resulting in unwanted effects. What hormones are produced in the following glands?

GLAND

HORMONE(S) PRODUCED

Pituitary

 

Thyroid

 

Adrenal

 

Ovaries

 

Testes

 

Pancreas

 

Images MALIGNANT TUMOURS

Malignant tumours are called cancers and:

• tend to grow quickly

• enter neighbouring tissues and organs causing damage

• can spread beyond the original area, destroying tissues

A primary tumour refers to the original site where a tumour first develops.

Malignant tumours can spread and break away from the primary site to other parts of the body forming secondary tumours, known as metatastic spread (metastases).

Secondary malignant tumours can grow, break away and damage tissues close by and spread again through the bloodstream or lymphatic system.

Some cancers, for example, leukaemia (cancer of the blood) occur where a number of abnormal blood cells are manufactured in the bone marrow and circulate in the blood stream: not all cancers are solid cancers.

Metastases

Image

Images HOW MALIGNANT TUMOURS GROW AND SPREAD

When cancer has metastasesed and affected other parts of the body, the disease is still referred to the organ of origination; for example, if a cancer of the cervix metastaseses to the lungs then it is still called cervical cancer, not lung cancer. Most cancers develop and spread via an organ, but blood cancer such as leukaemia does not; this affects the blood and the organs that form blood (for example the bone marrow) and then invades nearby tissues.

A developing cancer

Image

Source: Egton Medical Information Services

Images LOCAL GROWTH AND DAMAGE TO NEARBY TISSUES

Malignant cells multiply quickly needing a blood supply to obtain oxygen, nutrients and remove waste for new and separating cells: without a blood supply there will be no growth. The immune system has to fail to recognise or respond to the tumour. Malignant cells have a number of properties, for example:

• the ability to push through or between normal cells, dividing and multiplying

• causing damage to the local surrounding tissue as they invade it

A number of host characteristics will impact on tumour growth:

• age

• sex

• overall health status

• immune system function

Age

Cancer is a disease of older people: incidence rates increase with age.

• Few cancers are found in children.

• Leukaemia is the most common childhood cancer.

• Most common cancer in young men is testicular cancer.

• In young women most common cancers are malignant melanoma and Hodgkin Lymphoma.

• One in ten cancers are diagnosed in 25–49 year olds.

• Common cancers in females aged 25–49 years old are breast cancer, malignant melanoma and cervical cancer.

• In men aged 25–49 years the common cancers are testicular cancer, malignant melanoma and colorectal cancer.

• Those aged between 50 and 74 years are mostly affected by cancer.

• Over half of all cancers are diagnosed in 50–74 year olds.

• In men prostate cancer, lung cancer and colorectal cancers are most common.

• Most common cancers in females are breast, lung and colorectal cancer.

• Over a third of all cancers are diagnosed in the elderly population.

• Common cancers in 75 years plus in men are prostate, lung and colorectal cancers; in females these are breast, colorectal and lung cancers.

Sex

Certain cancers are more prevalent in one sex than in the other. Sex hormones influence tumour growth in:

• breast

• endometrial

• cervical

• prostate cancers

In general, it is acknowledged that men are significantly at greater risk of getting all the common cancers that occur in both sexes and dying from them more than their female counter-parts.

Overall health status

A person’s overall health status can impact on tumour growth. The demand made on the body can lead to cachexia (wasting syndrome). Chronic tissue trauma requires cells to multiply and divide as healing occurs, the more rapidly cells divide the more likely there will be cellular mutation, therefore any form of chronic tissue trauma will have an impact on tumour growth.

Immune system function

Cells and organs of the immune system work together to defend the body against attack by foreign or non-self invaders. The immune system helps prevent diseases including cancer and recognises the difference between cells that are healthy and cancerous working to eradicate cancerous cells. If for any reason the immune system fails to function adequately this makes the host more susceptible to tumour growth.

Images SPREAD TO THE LYMPHATIC SYSTEM AND THE LYMPH NODES

There are some malignant cells that can enter the local lymph; the body has a network of lymph channels draining the lymphatic fluid.

The lymphatic system

Image

Source: from Colbert, B.J., Ankey, J. and Lee, K.T. Anatomy and Physiology for Health Professionals. An Interactive Journey, 1st. Printed and electronically reproduced by permission of Pearson Education, Inc., Upper Saddle River, New Jersey.

A malignant cell can be carried to a lymph node and become trapped, multiply and develop into a tumour. When a lymph node is in close proximity to a tumour the lymph node can enlarge, containing cancerous cells.

Images SPREAD TO OTHER PARTS OF THE BODY

Malignant cells can enter the capillary network (a network of small blood vessels), and can then be transported in the bloodstream to other parts of the body. They may multiply forming secondary tumours in one or more parts of the body; these can then grow, invade and injure adjacent tissues and spread again.

BENIGN TUMOURS

MALIGNANT TUMOURS

Non cancerous

Cancerous

May grow large and compress adjoining tissue/organs

Potential to destroy nearby tissue

Slow spreading

Fast rate of spread

Does not grow abnormally

Grows abnormally

Usually encapsulated

Non encapsulated

Differentiated

Undifferentiated

Usually non life threatening (has the potential to become malignant)

Can be life threatening

Images SECTION SUMMARY

Malignant and benign are two terms associated with cancer that can often be confused with each other; however they are different in meaning. Malignant refers to cancerous cells and can invade the tissues close to the surrounding area and spread. Benign tumours are not cancerous; they can grow in size but, do not spread.

There are many characteristics within the host that can affect tumour growth, for example, age, sex, overall health status and immune function.



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