Chapter 14: Cancer survival in Chennai (Madras), India, 1990-1999
Swaminathan R, Rama R, Nalini S and Shanta V
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The registry contributed data on survival from the top ten cancers in the region and cancers associated with tobacco in the first volume of the IARC publication on Cancer Survival in Developing Countries[4]. Data on survival from 20 cancer sites or types registered during 1990–1999 are reported in this second volume.
The closing date of follow-up was 31st December 2001. The median follow-up (in months) ranged between 1.5 for unspecified leukaemia to 27.5 for cancer of the cervix. Complete follow-up at five years from the incidence date ranged from 96.3% (cancer of the pancreas) to 79.2% (ovarian cancer). The losses to follow-up generally occurred in the first year of follow-up for a majority of cancers. However, a substantial proportion of cases have been known to be alive for varying periods of time between 1–5 years and more than 5 years. This minimizes the bias in the estimation of survival probability in the respective years.
The 5-year age-standardized relative survival (ASRS) probability for all ages together is less than or similar to the corresponding unadjusted for a majority of cancers. The 5-year ASRS (0–74 years of age) is observed to be higher than the corresponding ASRS (all ages) with a few exceptions.
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Abstract
The Madras metropolitan tumour registry was established in 1981, and registration of incident cancer cases is entirely done by active method. Data on survival for 20 cancer sites or types registered during 1990–1999 are reported. Follow-up has been carried out predominantly by active methods with a median follow-up time ranging between 2–28 months for different cancers. The proportion of histologically verified diagnosis for various cancers ranged between 45–100%; death certificates only (DCOs) comprised 0–5%; 68–95% of total registered cases were included for survival analysis. Complete follow-up at five years ranged between 83–96%. The 5-year age-standardized relative survival rates for common cancers were cervix (60%), breast (47%), stomach (8%), oesophagus (9%), lung (6%) and mouth (36%). The 5-year relative survival by age group portrayed either an inverse relationship or fluctuated. A majority of cases were diagnosed with regional spread of disease, and survival decreased with increasing extent of disease. The absolute difference in 5-year relative survival of most cancers diagnosed in 1984–1989 and 1990–1999 ranged between 2–3%, with lesser survival in the latest period in most instances.Madras metropolitan tumour registry
The population-based cancer registry in Chennai (Madras), known as the Madras metropolitan tumour registry (MMTR), is one of the oldest in India. It was established in 1981 at the Cancer Institute (WIA), a Regional Cancer Centre, where a hospital cancer registry has been established since 1955. MMTR has been contributing data to the quinquennial IARC publication Cancer Incidence in Five Continents since Vol V[1]. The method of cancer registration is entirely done by active methods[2]. Over 200 sources of registration comprising hospitals in the government and private sectors, nursing homes, pathology laboratories, imaging centres and hospices are visited for data collection. The registry caters to an entirely urban population of about 4.3 million in 2005 with a sex ratio of 940 females to 1000 males. The average annual age-standardized incidence rate is 112 per 100 000 among males and 121 per 100 000 among females, with a lifetime cumulative risk of one in 8 of developing cancer for both sexes in the period 1999–2001[3]. The top-ranking cancers among males are stomach followed by lung and oesophagus. Among females, the order is cervix, breast and ovary.| Map. Map showing location of Chennai, India Click here to open map (PDF format) |
Data quality indices
The proportion of cases with histological confirmation of cancer diagnosis in this series is 79%, varying between 99.6% for lymphoid leukaemia and 45% for cancer of the pancreas. The proportion of cases registered as death certificates only (DCOs) was 2%, ranging between 0% in lip cancer and 23% in unspecified leukaemia. The exclusion of cases from the survival analysis was the greatest among unspecified leukaemia (32%) and the least for cancer of the tonsil (5%). Thus, 68–95% 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, Chennai, India, 1990-1999 cases followed-up to 2001 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 mortality information, irrespective of the stated cause of death in the death certificate, from the hospitals and the vital statistics division of Chennai corporation 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 one or more of the following ways: repeated scrutiny of records in the respective sources of registration, postal/telephone enquiries and house visits.The closing date of follow-up was 31st December 2001. The median follow-up (in months) ranged between 1.5 for unspecified leukaemia to 27.5 for cancer of the cervix. Complete follow-up at five years from the incidence date ranged from 96.3% (cancer of the pancreas) to 79.2% (ovarian cancer). The losses to follow-up generally occurred in the first year of follow-up for a majority of cancers. However, a substantial proportion of cases have been known to be alive for varying periods of time between 1–5 years and more than 5 years. This minimizes the bias in the estimation of survival probability in the respective years.
 | Table 2. Number and proportion of cases with complete / incomplete follow-up and median follow-up (in months) by site, Chennai, India, 1990–1999 cases followed-up to 2001 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 lip cancer (47%) and the lowest for cancer of the hypopharynx (14%) among the cancers of the head and neck. Cancers of the stomach, pancreas and oesophagus had the survival figures of 10%, 9% and 8%, respectively. Hodgkin lymphoma had a better survival rate (41%) than non-Hodgkin lymphoma (24%). The survival figures for leukaemias are lymphoid (24%), myeloid (16%) and unspecified (12%).The 5-year age-standardized relative survival (ASRS) probability for all ages together is less than or similar to the corresponding unadjusted for a majority of cancers. The 5-year ASRS (0–74 years of age) is observed to be higher than the corresponding ASRS (all ages) with a few exceptions.
 | Table 3. Comparison of 1-, 3- and 5-year absolute and relative survival and 5-year age-standardized relative survival (ASRS) by site, Chennai, India, 1990–1999 cases followed-up to 2001 Click here to open table (PDF format) Click here to open comparative statistics by registry |
 | Figure 1a. Top ten cancers (ranked by survival), Chennai, 1990–1999 Click here to open figure (PDF format) Click here to open graph for all the cancer sites |
Sex
 | Table 4a. Site-wise number of cases, 5-year absolute and relative survival by sex, Chennai, India, 1990–1999 cases followed-up to 2001 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 lip cancer (52%) followed in order by Hodgkin lymphoma (38%), larynx and oral cavity (37%). Survival from lip cancer is noticeably higher among males than females (41%). | Figure 1b. Top five cancers (ranked by survival), Male, Chennai, 1990–1999 Click here to open figure (PDF format) Click here to open graph for all the cancer sites |
Female
The top ranking cancers on 5-year relative survival are cervix (59%), breast (49%), Hodgkin lymphoma (47%) and lip (41%). The survival is markedly higher among females (32%) than males (14%) for cancer of the tonsil. | Figure 1c. Top five cancers (ranked by survival), Female, Chennai, 1990–1999 Click here to open figure (PDF format) Click here to open graph for all the cancer sites |
Age group
The 5-year relative survival by age group portrays an inverse relationship: a decreasing survival with increasing age at diagnosis for cancers of the hypopharynx, stomach, lung and ovary. In the majority, it is seen to fluctuate, especially with an increase in the age group of 75+ years compared to that of 65–74 years. | Table 4b. Site-wise number of cases, 5-year absolute and relative survival by age group, Chennai, India, 1990–1999 cases followed-up to 2001 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 all the selected cancers: from 62% (cancer of the ovary) to 89% (oral cavity). Correspondingly, a meagre 1% (ovary) to 7% (larynx) had a localized disease at diagnosis. The highest proportion of cases with distant metastasis at diagnosis is observed for breast cancer (13%). The extent of disease was unknown in 4–18%. The 5-year absolute survival by extent of disease followed the expected pattern: highest for localized cases followed by regional and distant metastasis cases among known categories of extent of disease. | Table 5. Proportion (%) of cases and 5-year absolute survival by extent of disease and site, Chennai, India, 1990–1999 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, Chennai, India Click here to open figure (PDF format) |
 | Figure 2a. Absolute survival (%) by extent of disease, Chennai, India: Cancer of the tongue Click here to open figure (PDF format) Click here to open comparative statistics by cancer site |
 | Figure 2b. Absolute survival (%) by extent of disease, Chennai, India: Cancer of the oral cavity Click here to open figure (PDF format) Click here to open comparative statistics by cancer site |
 | Figure 2c. Absolute survival (%) by extent of disease, Chennai, India: Cancer of the larynx Click here to open figure (PDF format) Click here to open comparative statistics by cancer site |
 | Figure 2d. Absolute survival (%) by extent of disease, Chennai, India: Cancer of the breast Click here to open figure (PDF format) Click here to open comparative statistics by cancer site |
 | Figure 2e. Absolute survival (%) by extent of disease, Chennai, India: Cancer of the cervix Click here to open figure (PDF format) Click here to open comparative statistics by cancer site |
 | Figure 2f. Absolute survival (%) by extent of disease, Chennai, India: Cancer of the ovary Click here to open figure (PDF format) Click here to open comparative statistics by cancer site |
Survival trend
The data on trend in survival are available for 17 cancers spanning 16 years in two time periods between 1984–1989[4] and 1990–1999. The completeness of follow-up at 5 years from incidence date was higher in 1990–1999 than 1984–1989 for a majority of cancers. In the rest, there was not much change. The absolute difference in 5-year relative survival of most cancers diagnosed between 1984–1989 and 1990–1999 ranged 2–3%, with a lesser survival in the latest period in most instances. This may be attributable to the increase in the completeness of follow-up for cases diagnosed in 1990–1999 due to the matching of incident cases with all deaths occurring in the city of Chennai, irrespective of the cause of death, since 1992. A notable increase in survival in 1990–1999 compared to 1984–1989 was observed only for cancer of the urinary bladder. | Table 6. Comparison of 5-year absolute and relative survival of cases diagnosed between 1984–1989 and 1990–1999, Chennai, India Click here to open table (PDF format) Click here to open comparative statistics by registry |
Acknowledgements
The authors express their sincere thanks to the staff of MMTR and the institutions providing data to MMTR, without which this study would not have become a reality.References
- 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) - Shanta V, Gajalakshmi CK, Swaminathan R, Ravichandran K, Vasanthi L. Cancer registration in Madras Metropolitan Tumour Registry, India. Eur J Cancer. 1994; 30: 974-78.
(link to pubmed) - Shanta V, Swaminathan R. Cancer incidence and mortality in Chennai, India: 1999–2001. National Cancer Registry Programme, Cancer Institute (WIA), Chennai, 2004.
- Shanta V, Gajalakshmi CK and Swaminathan R. Cancer survival in Chennai (Madras), India. In: Cancer Survival in Developing Countries (eds) R Sankaranarayanan, RJ Black and DM Parkin. International Agency for Research on Cancer, IARC Scientific Publications No. 145, Lyon, 1998, pp 89–100.
(link to Cancer Survival, volume 1)