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Rural Cancer Registry

The Rural Cancer Registry of Karunagappally was established in 1990 as a special purpose registry by the Regional Cancer Centre of Trivandrum, with funding support from the Department of Atomic Energy, Government of India to study cancer occurrence in relation to the high natural background radiation present in the coastal area of Kerala state, which has monazite-rich sands that emit gamma radiation. The registry covers an area of 212 km2 and caters to a mixed rural (96%) and urban (4%) population of 0.4 million with a sex ratio of 1025 females to 1000 males. It has been contributing data to the quinquennial IARC publication Cancer Incidence in Five Continents since Vol VII^[1]. The method of cancer registration is entirely done by active methods. There are no dedicated cancer hospitals or laboratories for tissue diagnosis within the registry area. Over 50 sources of registration, comprising hospitals in the government and private sectors, nursing homes, pathology laboratories, imaging centres and hospices, are visited for data collection. In addition, the enumerators undertake field visits to trace new cancer cases. The average annual age-standardized incidence rate is 112 per 100 000 among males and 81 per 100 000 among females with a lifetime cumulative risk of one in 8 for males and one in 11 for females of developing cancer in 1991–2001. The top-ranking cancers among males are lung, followed by oral cavity and oesophagus. Among females, the order is breast, cervix and oral cavity ^[2].

Map. Map showing location of Karunagappally, India Click here to open map (PDF format)

The registry has contributed data on survival from 22 cancer sites or types for this second volume of the IARC publication on Cancer Survival in Africa, Asia, the Caribbean and Central America.

Data quality indices

The proportion of cases with a histological confirmation of cancer diagnosis in this series is 71%, varying between 39–100%. The proportion of cases registered as death certificates only (DCOs) is 11%, ranging between 0–25%. The exclusion of cases from the survival analysis was the greatest in cancer of the brain and nervous system (25%); it was none for many cancers. Thus, 75–100% of the total cases registered are included in the estimation of the survival probability.

Table 1. Data quality indices - Proportion (%) of histologically verified and death certificate only cases, number and proportion of included and excluded cases by site, Karunagappally, India, 1991–1997 cases followed-up until 1999 Click here to open table (PDF format) Click here to open comparative statistics by registry

Outcome of follow-up

Follow-up has been carried out predominantly by active methods. These included abstraction of cancer mortality information from the vital statistics division records. The abstracted data are first matched with the incident cancer database. The follow-up information for the unmatched incident cases is then obtained through repeated scrutiny of records in the respective sources of registration, postal/telephone enquiries and house visits. Further, the monthly cancer follow-up clinics held by oncologists from the Regional Cancer Centre in the field office and the pain and palliative care clinics held bi-weekly have helped to obtain maximal follow-up information.

The closing date of follow-up was 31^st December 1999. The median follow-up (in months) ranged between 3 for myeloid leukaemia to 59 for non melanoma skin cancer. Complete follow-up at five years from the incidence date ranged from 91% (prostate cancer) to 100%. The losses to follow-up occurred in the first year of follow-up for a majority of cancers.

Table 2. Number and proportion of cases with complete / incomplete follow-up and median follow-up (in months) by site, Karunagappally, India, 1991–1997 cases followed-up until 1999 Click here to open table (PDF format) Click here to open comparative statistics by registry

Survival statistics

All ages and both sexes together

The 5-year relative survival is the highest for thyroid cancer (88%) and the lowest for cancer of the liver (3%) among the cancers studied. The survival figures for other head and neck cancers are oral cavity (41%), larynx (35%), tongue (32%) and hypopharynx (15%). Survival rates from gastrointestinal cancers were rectum (33%) and oesophagus, stomach and pancreas (3%). The survival figures for Non-Hodgkin lymphoma was 30%, lymphoid leukaemia was 37% and myeloid leukaemia 8%.

The 5-year age-standardized relative survival (ASRS) probability for all ages together is less than or very similar to the corresponding unadjusted one for most cancers. The 5-year ASRS (0–74 years of age) is observed to be higher than the corresponding ASRS (all ages) for the majority.

	Table 3. Comparison of 1-, 3- and 5-year absolute and relative survival and 5-year age-standardized relative survival (ASRS) by site, Karunagappally, India, 1991–1997 cases followed-up until 1999 Click here to open table (PDF format) Click here to open comparative statistics by registry
	Figure 1a. Top ten cancers (ranked by survival), Karunagappally, India, 1991–1997 Click here to open figure (PDF format)

Sex

Table 4a. Site-wise number of cases, 5-year absolute and relative survival by sex, Karunagappally, India, 1991–1997 cases followed-up until 1999 Click here to open table (PDF format) Click here to open comparative statistics by registry

Male

The 5-year relative survival is the highest for non-melanoma skin cancer (83%) followed in order by thyroid (60%) and urinary bladder (49%). Survival from lymphoid and myeloid leukaemias is noticeably higher among males than females.

Figure 1b. Top five cancers (ranked by survival), Male, Karunagappally, India, 1991–1997 Click here to open figure (PDF format)

Female

The top ranking cancers on 5-year relative survival probabilities are thyroid (93%), non-melanoma skin (75%), cervix (56%) and breast (51%). Survival is markedly higher among females than males for cancers of the tongue, hypopharynx and thyroid.

Figure 1c. Top five cancers (ranked by survival), Female, Karunagappally, India, 1991–1997 Click here to open figure (PDF format)

Age group

The 5-year relative survival probabilities by age group do not show any distinct pattern or trend for most cancers.

Table 4b. Site-wise number of cases, 5-year absolute and relative survival by age group, Karunagappally, India, 1991–1997 cases followed-up until 1999 Click here to open table (PDF format) Click here to open comparative statistics by registry

Extent of disease

A majority of cases have been diagnosed with a regional spread of disease among cancers of the tongue (48%), oral cavity (66%), hypopharynx (54%), larynx (46%), cervix (61%) and breast (53%). For ovarian cancer, there are more cases in the distant metastasis category (54%) than others. The extent of disease was unknown in 7–17%. The 5-year absolute survival by extent of disease followed the expected pattern: highest for localized disease followed by regional and distant metastasis among known categories of extent of disease for most cancers.

	Table 5. Proportion (%) of cases and 5-year absolute survival by extent of disease and site, Karunagappally, India, 1991–1997 Click here to open table (PDF format) Click here to open comparative statistics by registry
	Figure 2a-2f. Absolute survival (%) from selected cancers by extent of disease: Karunagappally, India Click here to open table (PDF format)
	Figure 2a. Absolute survival (%) by extent of disease: Karunagappally, India: Cancer of the tongue Click here to open table (PDF format) Click here to open comparative statistics by cancer site
	Figure 2b. Absolute survival (%) by extent of disease: Karunagappally, India: Cancer of the oral cavity Click here to open table (PDF format) Click here to open comparative statistics by cancer site
	Figure 2c. Absolute survival (%) by extent of disease: Karunagappally, India: Cancer of the hypophrarynx Click here to open table (PDF format) Click here to open comparative statistics by cancer site
	Figure 2d. Absolute survival (%) by extent of disease: Karunagappally, India: Cancer of the larynx Click here to open table (PDF format) Click here to open comparative statistics by cancer site
	Figure 2e. Absolute survival (%) by extent of disease: Karunagappally, India: Cancer of the breast Click here to open table (PDF format) Click here to open comparative statistics by cancer site
	Figure 2f. Absolute survival (%) by extent of disease: Karunagappally, India: Cancer of the cervix Click here to open table (PDF format) Click here to open comparative statistics by cancer site

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References

1. Parkin DM, Whelan SL, Ferlay J and Storm H. Cancer Incidence in Five Continents, Vol I to VIII: IARC Cancerbase No. 7. IARCPress, Lyon, 2005.
   (link to CI5)


2. Rural Cancer Registry of Karunagappally. Cancer morbidity and mortality in Karunagappally: 1993–2001. Regional Cancer Centre, Thiruvananthapuram, 2004.