View source for 41. Epidemiology of cancers. Incidence and mortality. Changes in death rates of cancers in the last decades

Analysing cancers on a population level is important. It was epidemiology that made us realize that smoking causes lung cancer. Comparing habits between different populations and the cancer rates of the different populations can tell us a lot about which habits that are risk factors for which cancers. Epidemiologist can evaluate the role of race, culture and environment’s role in developing cancer.

We must differentiate between cancer incidence and cancer mortality. Cancer incidence is the occurrence of the cancer, i.e. how many get this type of cancer. Cancer mortality is the number of people who actually die from the cancer. Because some cancers have good prognosis can these two numbers be very different.

In the USA in 2008 were there about 1.4 million new cancers cases and around 550 000 cancer-related deaths. Death due to cancer represent 23% of all mortality, surpassed only by death due to cardiovascular disease.

In Hungary in 2011 was the mortality rate for cancer around 330 people per 100 000 people, while the mortality rate for cardiovascular disease was even higher, at around 640 people per 100 000 people.

== Most common cancers ==
Cancer incidence and mortality differs between genders. Here are some tables showing the most important cancers, according to 2010 data:

Cancer incidence:
{| class="wikitable"
! colspan="2" |Men
! colspan="2" |Women
|-
!Type of cancer
!Percentage of all cancers
!Type of cancer
!Percentage of all cancers
|-
|Prostate
|28%
|Breast
|28%
|-
|Lung and bronchus
|15%
|Lung and bronchus
|14%
|-
|Colon and rectum
|9%
|Colon and rectum
|10%
|-
|Urinary bladder
|7%
|Uterine corpus
|6%
|-
|Melanoma in skin
|5%
|Thyroid
|5%
|-
|Non-Hodgkin lymphoma
|4%
|Non-Hodgkin lymphoma
|4%
|-
|Kidney
|4%
|Melanoma
|4%
|-
|Oral cavity
|3%
|Kidney
|3%
|-
|Leukaemia
|3%
|Ovary
|3%
|-
|Pancreas
|3%
|Pancreas
|3%
|-
|Others
|19%
|Others
|20%
|-
|Total
|100%
|Total
|100%
|}
Cancer mortality:
{| class="wikitable"
! colspan="2" |Men
! colspan="2" |Women
|-
!Type of cancer
!Percentage of all cancers
!Type of cancer
!Percentage of all cancers
|-
|Lung and bronchus
|29%
|Lung and bronchus
|26%
|-
|Prostate
|11%
|Breast
|15%
|-
|Colon and rectum
|9%
|Colon rectum
|9%
|-
|Pancreas
|6%
|Pancreas
|7%
|-
|Liver
|4%
|Ovary
|5%
|-
|Leukaemia
|4%
|Non-Hodgkin lymphoma
|4%
|-
|Oesophagus
|4%
|Leukaemia
|3%
|-
|Non-Hodgkin lymphoma
|4%
|Uterine corpus
|3%
|-
|Urinary bladder
|3%
|Liver
|2%
|-
|Kidney
|3%
|Brain
|2%
|-
|Others
|20%
|Others
|24%
|-
|Total
|100%
|Total
|100%
|}
We can see some patterns here. The three most common cancers in men are prostate, lung and bronchial and colon and rectal cancers, however prostate cancer has lower mortality than lung and bronchial cancer. The three most common cancers are women are breast, lung and bronchial and colon and rectal cancer, but breast cancer has lower mortality than lung and bronchial cancer here as well. The three most common cancers for each gender make up more than 50% of all cancer cancers for that gender.

== Mortality rate in the last decades ==
The incidence and mortality rates of cancer has had characteristic development in the last decades. The incidence rate increased during the 20th century, but after 1995 has the incidence rate stabilized. The mortality rate however, has decreased 18.4% in men and 10,4% in women. Several factors can account for this:

* Decreased use of tobacco has decreased the mortality rate of lung cancers
* Improved detection and treatment have decreased the mortality rate of colorectal cancer, female breast cancer and prostate cancer
* The application of pap (named after Papanicolaou, a Greek guy) smear has decreased the mortality of cervical cancer
* Better food preservation techniques and changes in dietary habits have decreased the mortality of stomach cancer

The mortality rate of primary liver cancer however has doubled since 1970 due to increased hepatitis C incidence.
[[Category:Pathology 1 - Theoretical exam topics]]