Cancer Case:
All neoplasms with a morphology behaviour code of ‘3’ / ‘6’ as defined by the International Classification of Diseases – Oncology, (Third edition) are considered reportable and therefore registered.
A person having diagnosed with a malignancy is considered as cancer case.
Age-Group:
As per WHO guidelines for estimating population and grouping of cancers using five year age group i.e, 0-4, 5-9, 10-14,…, 75+.
Age has been grouped 5 year wise. A child below one year age is considered as 0.
Incidence Cases:
Cancer incidence refers to new cases diagnosed in a given population in a specified period of time. For example all cancers diagnosed from 1 January 2012 to 31 December 2012 in defined geographic area will be registered for 2012.
Rates:
Rates for cancer are always expressed per 100,000 population.
Crude Incidence Rate (CR):
This rate is expressed per 100,000, obtained by dividing the number of new cases by the corresponding estimated population (mid-year) and multiplying by 100,000.
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CR =
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New cases of cancer of a particular year
------------------------------------------------------- × 100,000
Estimated population of the same year
|
This is the number of new cases per 1,00,000 population in a defined geographic area in a specified time period.
Age Specific Rate (ASpR):
For a specified five-year age group and sex the age specific rates are the annual number of cases per 100,000 people in the population of that age and sex.
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ASpR =
|
New cases of cancer of a particular year in the given age group
----------------------------------------------------------------------------------------- × 100,000
Estimated population of the same year for the given age group
|
This is the number of new cases of a particular age group per 1,00,000 Population of the same age group.
Age Adjusted or Age Standardised Rate (AAR):
The age-adjusted rates are rates that would have existed if the population under study had the same age distribution as the "standard" population. Age adjusting rates is a way to make fairer comparisons between groups with different age distributions. The world standard population approximates the proportional age distribution of the world and is given below:
|
Age Group
|
World Standard Population
|
|
0-4
|
12000
|
|
5-9
|
10000
|
|
10-14
|
9000
|
|
15-19
|
9000
|
|
20-24
|
8000
|
|
25-29
|
8000
|
|
30-34
|
6000
|
|
35-39
|
6000
|
|
40-44
|
6000
|
|
45-49
|
6000
|
|
50-54
|
5000
|
|
55-59
|
4000
|
|
60-64
|
4000
|
|
65-69
|
3000
|
|
70-74
|
2000
|
|
75+
|
2000
|
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All ages
|
100000
|
|
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AAR =
|
A
ΣaiXwi
i=1
--------
A
Σwi
i=1
|
|
where:
ai is the age specific rate (ASpR) in age class i;
wi is the world standard population in age class i;
A represents the number of age intervals.
(or) expressed in more simpler terms thus:
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AAR =
|
Σ (ASpR) × (No. of persons in Std. world population in that 5 yr. age group)
----------------------------------------------------------------------------------------------------
100,000
|
Age standardized rate expresses the number of new case per 100,000 population of world standard population so that the rate can the compared among different population on whose age structure are different such as India and USA.
Truncated Age Adjusted Rate (TR):
Similar to age adjusted rate except that it is calculated for the truncated age group of 35-64 years of age.
The truncated rate is actually express the incidence in the most vulnerable age group (35 - 64) for cancer.
Population Estimation:
The growth rate of the population between the census years 2001 and 2011 has been used (through the Difference Distribution Method of Takiar and Shobana, 2009) to estimate the mid-year populations (five year age group and total) for the years, 2012 to 2014.
The Census Population for the year 2001 and 2011 were obtained from the website http://www.censusindia.gov.in.