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Qidong cancer registry

The Qidong cancer registry was established in 1972 at the Qidong Liver Cancer Institute, Qidong. The registry has been contributing data to the quinquennial IARC publication Cancer Incidence in Five Continents since Vol VI^[1]. Cancer registration is done by active and passive methods. The principal source of information on incident cancer cases is the data file received from lower-level registries managed by a physician or a health worker. The registry checks these files with cancer report lists to find missing and/or duplicate cases. The registry caters to a mixed rural and urban population about 1.2 million with a sex ratio of 1016 females to 1000 males in 1999. The average annual age-standardized incidence rate is 242 per 100 000 among males and 111 per 100 000 among females with a lifetime cumulative risk of one in 4 of developing cancer in the period 1993–1997. The common cancers among males are liver, lung and stomach. The rank order among females is liver, stomach, lung and breast^[1].

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

The registry contributed data on survival to the first volume of the IARC publication on Cancer Survival in Developing Countries^[2]. In the present volume, the main tables pertain to the period 1992–2000. The data on survival for the years 1972–1991 are also utilized to elicit the trend in cancer survival.

Data quality indices

The proportion of cases with histologically verified cancer diagnosis in the series is 35%, varying from 9% (liver cancer) to 100% (all leukaemias). The proportion of cases registered based on a death certificate only is negligible. Cases excluded from the study without any follow-up information is the highest for thyroid cancers (13%). Thus, 87–100% 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, Qidong, China, 1992–2000 cases followed-up until 2000 Click here to open table (PDF format) Click here to open comparative statistics by registry

Outcome of follow-up

The methods of follow-up have been a mixture of both active and passive ones. These included receiving mortality information from all causes of death and periodically matching with the incident cancer database. The vital status of the unmatched incident cases is then collected by scrutiny of medical reports and house visits.

The closing date of follow-up is 31^st December 2000. The median follow-up ranged from 2 months for lymphoid and myeloid leukaemias to 25 months for breast cancer. 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, Qidong, China, 1992–2000 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 thyroid (78%), breast and corpus uteri (59%), larynx (53%) and urinary bladder (43%). The lowest survival is encountered with lymphoid leukaemia and oesophagus (5%), preceded by liver and myeloid leukaemia (6%) and lung (7%). Colon (39%) and rectum (31%) cancers have a higher survival among gastrointestinal cancers. The figure for Non-Hodgkin lymphoma is 14%, and that for multiple myeloma is 11%.

The 5-year age-standardized relative survival (ASRS) probability for all ages together is observed to be lesser 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, Qidong, China, 1992–2000 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), Qidong, China, 1992–2000 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, Qidong, China, 1992–2000 cases followed-up until 2000 Click here to open table (PDF format) Click here to open comparative statistics by registry

Male

Cancers of the breast (114%), larynx (59%), urinary bladder (43%), thyroid (42%) and soft tissue (39%) form the order when ranked on 5-year relative survival. Survival from prostate cancer is 32%. Cancers of the larynx, soft tissue and melanoma skin have a notably higher survival among males than females.

Figure 1b. Top five cancers (ranked by survival), Male, Qidong, China, 1992–2000 Click here to open figure (PDF format) Click here to open graph for all the cancer sites

Female

The rank order based on 5-year relative survival is cancer of the thyroid (93%), nose/sinuses (64%), corpus uteri and breast (59%) and non-melanoma skin (44%). Survival from cancers of the cervix and ovary are 39% and 36%, respectively. Survival is markedly higher among females than males in cancers of the nasopharynx, nose/sinuses, non-melanoma skin, kidney and thyroid.

Figure 1c. Top five cancers (ranked by survival), Female, Qidong, China, 1992–2000 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 no distinct pattern or trend and is seen to fluctuate with increasing age groups.

Table 4b: Site-wise number of cases and 5-year relative survival by age group, Qidong, China, 1992–2000 cases followed-up until 2000 Click here to open table (PDF format) Click here to open comparative statistics by registry

Trend

The trend of survival data, estimated by the same method of semi-complete analytic approach, is available for 15 cancer sites or types spanning 19 years in the two time periods 1982–1991 and 1992–2000. An increasing trend in the 5-year relative survival with an absolute difference of 10% and more between 1982–1991 and 1992–2000 is observed only in cancer of the nose/sinuses. A decreasing survival of similar magnitude is forthcoming for cancers of skin melanoma and non-melanoma, soft tissue, prostate and kidney.

Table 5: Comparison of 5-year absolute and relative survival of cases diagnosed between 1982–1991 and 1992–2000, Qidong, China, Click here to open table (PDF format) Click here to open comparative statistics by registry

Trend of survival by period and cohort approaches

The availability of data on registration and follow-up together for both a long (from the calendar year 1972) and a more recent period (year 2000) 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 by cohort and period approaches are estimated for the five calendar periods 1977–1981, 1982–1986, 1987–1991, 1992–1996 and 1997–2000. The period survival estimates in a calendar period are seen to resemble the cohort survival estimates of the succeeding calendar period for most cancers. Thus, period survival closely predicts the survival experience of cancer cases diagnosed in that period. However, this seems ta vary for some calendar periods in a few cancers, indicating some limiting factor either in the ascertainment of follow-up information or some changes in the registration process in those periods.

	Table 6. Number of cases by cancer site and calendar period, Qidong, China, 1977–2000 Click here to open table (PDF format) Click here to open comparative statistics by registry
	Table 7. Up-to-date 5-year relative survival estimates using cohort and period approaches by site and calendar period, Qidong, China, 1977–2000 cases followed-up until 2000 Click here to open table (PDF format) Click here to open comparative statistics by registry
	Figure 2a–2e. Up-to-date 5-year relative survival estimates over the calendar periods by period and cohort approaches for selected cancers, Qidong, China, 1972–2000 cases followed through 2000 Click here to open figure (PDF format)
	Figure 2a. Up-to-date 5-year relative survival estimates over the calendar periods by period and cohort approaches for selected cancers, Qidong, China, 1972–2000 cases followed through 2000: Cancer of the breast Click here to open figure (PDF format) Click here to open comparative statistics by cancer site
	Figure 2b. Up-to-date 5-year relative survival estimates over the calendar periods by period and cohort approaches for selected cancers, Qidong, China, 1972–2000 cases followed through 2000: Cancer of the colon Click here to open figure (PDF format) Click here to open comparative statistics by cancer site
	Figure 2c. Up-to-date 5-year relative survival estimates over the calendar periods by period and cohort approaches for selected cancers, Qidong, China, 1972–2000 cases followed through 2000: Cancer of the non-melanoma skin Click here to open figure (PDF format) Click here to open comparative statistics by cancer site
	Figure 2d. Up-to-date 5-year relative survival estimates over the calendar periods by period and cohort approaches for selected cancers, Qidong, China, 1972–2000 cases followed through 2000: Cancer of the rectum Click here to open figure (PDF format) Click here to open comparative statistics by cancer site
	Figure 2e. Up-to-date 5-year relative survival estimates over the calendar periods by period and cohort approaches for selected cancers, Qidong, China, 1972–2000 cases followed through 2000: Cancer of the non-Hodgkin lymphoma Click here to open figure (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. Swaminathan R, Black RJ and Sankaranarayanan R. Database on Cancer Survival from Developing Countries. In: Cancer Survival in Developing Countries (eds) R Sankaranarayanan, RJ Black and DM Parkin. IARC Scientific Publications No. 145. IARCPress, Lyon, 1998.
   (link to Cancer Survival, volume 1)