Oncology

Mark Bower, Jonathan Waxman

• Editorial: Wiley-Blackwell
• Año: 2015
• ISBN:
  9781118842126
• Edición: 3
• Categoría: Medicine
• Categoría: Oncology

Cancer is one of the most exciting specialties in medicine. This book aspires to convey the authors' enthusiasm for oncology and this new edition of Oncology Lecture Notes is a must for students and trainees.

There has been a revolution in the practice of oncology. The changes are due to amazing advances in basic science, and the development of new drugs and successful immunisation programmes that have followed. Cancer death rates have fallen and this is in part due to radical new treatments, effective screening programmes, and also, as a result of popular movements for change in patient care, and decreased exposure to carcinogens.

Completely revised and updated, this new edition of Oncology Lecture Notes describes advances in molecular biology research and highlights the importance of patient perspectives in cancer care.The text includes many new figures and tables, an update of molecular biology and highlights new treatments. With learning objectives and key point summaries in each chapter, Oncology Lecture Notes is an ideal introduction to the biological basis and principles of treatment in oncology. Includes a companion website at www.lecturenoteseries.com/oncology featuring cases and self-assessment MCQs

Part 1
Introduction to oncology

1
What is cancer?

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Learning objectives

• 
  List the histopathological features of cancer
• 
  Classify cancers and recognize their nomenclature
• 
  Explain the epidemiology of cancer

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Cancer is not a single illness but a collection of many diseases that share common features. Cancer is widely viewed as a disease of genetic origin. It is caused by mutations of DNA and epigenetic changes that alter gene expression, which make a cell multiply uncontrollably. However, the description and definitions of cancer vary depending on the perspective as described below.

Epidemiological perspective

Cancer is a major cause of ill health. In 2011, in the United Kingdom, there were:

• 434,115 new cases of cancer
• 159,178 deaths from cancer

There are more than 200 different types of cancer, but four of them (breast, lung, colorectal and prostate) account for over half of all new cases (Table 1.1). Overall, it is estimated that one in three people will develop some form of cancer during their lifetime. In the period 1976–2009, the age-standardized incidence of cancer increased by 22% in men and 42% in women but have remained fairly constant over the last decade (Figures 1.1 and 1.2).

Cancer incidence refers to the number of new cancer cases arising in a specified period of time. Prevalence refers to the number of people who have received a diagnosis of cancer who are alive at any given time, some of whom will be cured and others will not. Therefore, prevalence reflects both the incidence of cancer and its associated survival pattern (Box 1.1). In 2010, approximately 3% of the population of the United Kingdom (around 2 million people) are alive having received a diagnosis of cancer. Over a million Britons are cancer survivors having lived more than 10 years since being diagnosed with cancer.

The epidemiology of cancer is littered with jargon, and some of the key terms are defined in Box 1.1.

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Box 1.1 Understand the Geek-speak of epidemiology

• Cancer incidence is the number of new cancer cases arising in a specified period of time.
• Cancer prevalence is the number of people who have received a diagnosis of cancer who are alive at any given time, some of whom will be cured and others will not.
• Cancer mortality is the number of deaths due to cancer in a specific time period and defined population.
• Age-specific rates. To overcome problems of different population age structures, age-specific rates for an age range (usually 5–10 years) are published. For example, age-specific incidence rates of breast cancer in women aged 50–54 years.
• Standardization is used to remove the effect of a variable that you are not interested in studying (often age or gender).
• Age standardized rates. This corrects the crude rates to a “standardized population”. The same “standard population” is used for all rates to allow comparisons.
• Standardized ratios. Standardized incidence ratio (SIR) and mortality ratio (SMR) compare the age-specific rate in the study population with those of a control population.
• Relative risk (also known as risk ratio) is the ratio of the risk of disease (e.g. lung cancer) amongst people exposed to a risk factor (e.g. smoking) to the risk amongst unexposed people (e.g. non-smokers). Data are calculated from cohort studies from which the incidence can be calculated.
• Odds (as every gambler knows) is the ratio of the occurrence of an event to that of non-occurrence. If 20 out of every 100 smokers develop lung cancer, the odds are 20:80 or 1 in 4 (whilst the probability of developing lung cancer is 20/100 or 0.2).
• Odds ratio compares the odds of an event in two different populations.

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Table 1.1 Most frequent cancers according to age and gender

Age	0–14 yr	15–24 yr	25–49 yr	50–74 yr	>74 yr
Male	Leukaemia	Testis	Testis	Prostate	Prostate
	Brain tumour	Hodgkin lymphoma	Melanoma	Lung	Lung
	Lymphoma	Leukaemia	Bowel	Bowel	Bowel
Female	Leukaemia	Hodgkin lymphoma	Breast	Breast	Breast
	Brain tumour	Melanoma	Melanoma	Lung	Bowel
	Lymphoma	Ovary	Cervix	Bowel	Lung

Sociological pe...