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Tianjin cancer registry

The Tianjin cancer registry was established in 1978 at the Tianjin Cancer Institute and Hospital, Tianjin, and is partly funded by the Tianjin Health Bureau. The registry has been contributing data to the quinquennial IARC publication Cancer Incidence in Five continents since Vol V^[1]. Cancer is a notifiable disease, but registration of cases is done by active methods. The principal source of information is the report form filled by all physicians and medical clerks in the registry area for each new case diagnosed as malignant tumour. An active re-checking is done by the registry to review all patient records at every medical unit within the registry area to ensure completeness. The registry covers an area of 12 000 km2 and caters to an entirely urban population of about 4 million with a sex ratio of 1010 females to 1000 males in 2000. The average annual age-standardized incidence rate is 200 per 100 000 among males and 152 per 100 000 among females with a lifetime cumulative risk of one in 5 of developing cancer in the period 1993–1997. The most common cancers among males are lung, stomach, liver and oesophagus. The rank order among females is lung, breast, stomach and liver^[1].

Map: Map showing location of Tianjin, People's Republic of China Click here to open map (PDF format)

The registry contributed data on survival from 51 cancer sites or types registered during 1991–1999 for the first time in this volume of the IARC publication on Cancer survival in Africa, Asia, th Caribbean and Central America. In the present volume, data on survival from 1981–1990 are also utilized to elicit the trend in cancer survival.

Data quality indices

The proportion of cases of histologically verified cancer diagnosis in the series is 55%, varying from 21% (liver cancer) to 95% (myeloid leukaemia). The proportion of cases registered based on a death certificate only and cases excluded from the study without any follow-up information or due to other reasons is negligible. For cancers of the brain and central nervous system and other endocrine glands, the exclusions comprise benign or uncertain malignant cases. Thus, in the rest of cancers, 97–100% 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, Tianjin, China, 1991–1999 cases followed-up until 2000 Click here to open table (PDF format) Click here to open comparative statistics by registry

Outcome of follow-up

Follow-up has been a mixture of both active and passive methods. These included obtaining cancer mortality information from the death certificates registered in local police station. The mortality data are periodically matched with the incident cancer database. The vital status of the unmatched incident cases is then collected by postal/telephone and house visit enquiries.

The closing date of follow-up was 31^st December 2000. The median follow-up ranged from 5 months for cancer of the liver to 77 months for cancer of the placenta. The completeness of follow-up at 5 years from the incidence date is 100%, as there are no losses to follow-up.

Table 2. Number and proportion of cases by vital status and median follow-up (in months) by site, Tianjin, China, 1991–1999 cases followed-up until 2000 Click here to open table (PDF format) Click here to open comparative statistics by registry

Survival statistics

All ages and both sexes together

The top ranking cancers on 5-year relative survival are other endocrine gland (101%), lip (98%), penis (97%), renal pelvis (96%) and placenta (94%). The lowest survival rate is encountered with unspecified leukaemia and uterus (22%) preceded by liver (25%), bone (28%) and pancreas (30%). Salivary gland (89%) and tonsil (87%) among other head and neck cancers and anus (82%) among gastrointestinal cancers, have higher survival than others. Hodgkin lymphoma had a better survival (81%) than non-Hodgkin lymphoma (48%). The survival figures for haematopoietic malignancies are multiple myeloma (46%), lymphoid leukaemia (66%) and myeloid leukaemia (68%).

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

	Table 3. Comparison of 1-, 3- and 5-year absolute and relative survival and 5-year age-standardized relative survival (ASRS) by site, Tianjin, China, 1991–1999 cases followed-up until 2000 Click here to open table (PDF format) Click here to open comparative statistics by registry
	Figure 1a. Top ten cancers (ranked by survival), Tianjin, China, 1991–1999 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, Tianjin, China, 1991–1999 cases followed-up until 2000 Click here to open table (PDF format) Click here to open comparative statistics by registry

Male

The top ranking cancers on 5-year relative survival are renal pelvis (107%), other endocrine gland (100%), lip (99%), penis (97%) and breast (91%). Survival from prostate and testicular cancers are 72% and 69%, respectively. A notably higher survival for cancers of the larynx, kidney, renal pelvis, ureter and bladder is seen among males than females.

Figure 1b. Top five cancers (ranked by survival), Male, Tianjin, China, 1991–1999 Click here to open figure (PDF format) Click here to open graph for all the cancer sites

Female

The highest 5-year relative survival is observed in cancer of the hypopharynx followed by other endocrine gland, anus, placenta, lip and non-melanoma skin cancers. Survival from cancers of the breast, cervix, corpus uteri and ovary are 85%, 62%, 91% and 64%, respectively. Survival is distinctly higher among females than males in cancers of tongue, hypopharynx, anus, mesothelioma and multiple myeloma.

Figure 1c. Top five cancers (ranked by survival), Female, Tianjin, China, 1991–1999 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 reveals an inverse relationship: a decreasing survival with increasing age at diagnosis for many cancers like nasopharynx, lung, bone, breast, uterus (unspecified), thyroid, adrenal gland and non-Hodgkin lymphoma. In the rest, it is observed to fluctuate.

Table 4b. Site-wise number of cases and 5-year relative survival by age group, Tianjin, China, 1991–1999 cases followed-up until 2000 Click here to open table (PDF format) Click here to open comparative statistics by registry

Trend

The data on survival trends is available for all cancer sites or types spanning 19 years in the two time periods 1981–1990 and 1991–1999. An increasing trend in the 5-year relative survival estimates to the tune of an absolute difference of 10% between 1981–1990 and 1991–1999 is observed in cancers of the tongue, salivary gland, tonsil, hypopharynx, colon, rectum, anus, gallbladder, nose/sinuses, non-melanoma skin, mesothelioma, penis, prostate, ureter, urinary bladder, eye, Hodgkin lymphoma, multiple myeloma and myeloid leukaemia. A decreasing survival is noted for cancers of the uterus (unspecified), testis, vulva, lip, oral cavity and non-Hodgkin lymphoma.

Table 5. Comparison of 5-year absolute and relative survival of cases diagnosed between 1981–1990 and 1991–1999, Tianjin, China Click here to open table (PDF format) Click here to open comparative statistics by registry

Trend of survival estimated by period and cohort approaches

The availability of data on registration and follow-up together for both a long and more recent period of calendar time led to the possibility of estimating up-to-date survival and trend by period approach. Survival is also estimated by cohort approach for comparison.

The 5-year relative survival estimates for the calendar period 1991–1995 by period approach seem to be approximately similar to the survival estimates obtained by cohort approach for the period 1996–1999 for most cancers. Thus, period survival closely predicts the survival experience of most cancer cases diagnosed in that period. However, this seems to vary for the earlier calendar periods, indicating some limitation in the ascertainment of follow-up in those periods, especially mortality.

Table 6. Up-to-date 5-year relative survival estimates using cohort and period approaches by site and calendar period, Tianjin, China, 1981–1999 followed-up until 2000 Click here to open table (PDF format) Click here to open comparative statistics by registry

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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)