Chapter 20: Cancer survival in Busan, Republic of Korea, 1996-2001

Shin HR, Lee DH, Lee SY, Lee JT, Park HK, Rha SH, Whang IK, Jung KW, Won YJ and Kong HJ

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Abstract

The Busan cancer registry was established in 1996; cancer registration is done by passive and active methods. The registry contributed survival data for 48 cancer sites or types registered during 1996–2001. Follow-up information has been gleaned predominantly by passive methods with median follow-up ranging between 1–57 months for various cancers. The proportion with histologically verified diagnosis for different cancers ranged between 20–100%; death certificates only (DCOs) comprised 0–53%; 47–100% of total registered cases were included for survival analysis. The top-ranking cancers on 5-year age-standardized relative survival were penis (94%), thyroid (91%), non-melanoma skin (89%), placenta (86%), breast (76%), Hodgkin lymphoma (75%) and testis (72%). Five-year relative survival by age group showed a decreasing trend with increasing age groups for cancers of the nasopharynx, gallbladder, lung, bone, soft tissue, breast, cervix, corpus uteri, thyroid, multiple myeloma, lymphoid leukaemia and myeloid leukaemia or was fluctuating for other cancers.


Busan cancer registry

The Busan cancer registry was established in 1996 in cooperation with the cancer centres in four university hospitals, supported by the Department of Public Health and Sanitation of Busan City and the medical association of Busan and funded by the Korean national cancer control programme. The registry contributed data to the quinquennial IARC publication Cancer Incidence in Five Continents for the first time in Vol VIII[1]. Cancer registration is done by passive and the active methods. The principal source of information on 72% of cancer cases is the data file from the hospital-based Korean central cancer registry. The rest of the cases are registered by active method of visiting more than 50 hospitals and perusing of records in the departments of anatomical pathology, diagnostic radiology and radiation oncology. The registry covers an area of 531.17 km2 and caters to a population of about 3.9 million with a male female ratio of 1:1 in 1995. The average annual age-standardized incidence rate is 304 per 100 000 among males and 169 per 100 000 among females, with a lifetime cumulative risk of one in 4 of developing cancer in the period 1996–1997. The most common cancers among males are stomach, liver and lung. The rank order among females is stomach, cervix and breast[1].

Map. Map showing location of Busan, Republic of Korea

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The registry is contributing data on survival from 48 cancer sites or types registered during 1996–2001 for the first time in this volume of IARC publication on Cancer Survival in Africa, Asia, the Caribbean and Central America.

Data quality indices

The proportion of cases with histologically verified cancer diagnosis in the series is 69%, varying from 20% in liver cancer to 100% in cancer of the penis. The proportion of cases registered on the basis of death certificates only (DCOs) is 8%, ranging between nil for a few cancers (tonsil, corpus uteri, placenta, penis, testis and ureter) and 53% for unspecified leukemia. Cases excluded without any follow-up are negligible. Thus, 47–100% 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, Busan, Republic of Korea, 1996–2001 cases followed-up until 2003

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Outcome of follow-up

Follow-up information has been obtained predominantly by passive methods. These included obtaining of mortality information from the death certificates in the national statistical office. The mortality data are periodically matched with the incident cancer database. The vital status of the unmatched incident cases is also ascertained by scrutiny of hospital records. However, all incident cases for whom death information is not available were presumed to be alive on the last date of the year for which the mortality data are finaly utilized for matching.

The closing date of follow-up was 31st December 2003. The median follow-up ranged from zero in case of unspecified leukaemia to 57 months for cancer of the placenta.

Table 2. Number and proportion of cases by vital status and median follow-up (in months) by site, Busan, Republic of Korea, 1996–2001 cases followed-up until 2003

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Survival statistics

All ages and both sexes together

The top-ranking cancers in terms of 5-year relative survival are thyroid (93%), penis (89%), non-melanoma skin (88%) placenta (87%) and breast (82%). The lowest survival rate is encountered with pancreatic cancer (6%) preceded by unspecified leukaemia (8%), cancer of the liver (10%) and lung (12%), and multiple myeloma (12%). Salivary gland (71%) among other head and neck sites, colon and rectum (54–55%) among gastrointestinal sites and bladder (69%) among urinary system sites are the ones with higher survival than others. Hodgkin lymphoma had a better survival (65%) than non-Hodgkin (46%). The survival figures for leukaemias are 42% for lymphoid and 28% for myeloid.

The 5-year age-standardized relative survival (ASRS) probability for all ages together is generally less 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, Busan, Republic of Korea, 1996–2001 cases followed-up until 2003

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Figure 1a. Top ten cancers (ranked on survival), Busan, Republic of Korea, 1996–2001

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Sex

Table 4a. Site-wise number of cases, 5-year absolute and relative survival by sex, Busan, Republic of Korea, 1996–2001 cases followed-up until 2003

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Male

The top-ranking site on 5-year relative survival is breast (89%). The survival figures for oropharynx including tonsil, larynx, bone, mesothelioma, ureter and unspecified leukaemia are noticeably higher among males than females.

Figure 1b. Top five cancers (ranked on survival), Male, Busan, Republic of Korea, 1996–2001

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Female

The top-ranking cancer in terms of 5-year relative survival is non-melanoma skin (94%). Survival estimates for cancers of the breast, cervix and ovary are 82%, 76% and 58%, respectively. The survival is distinctly higher among females than males for cancers of tongue, oral cavity, salivary gland, oesophagus, small intestine, non-melanoma skin, eye and adrenal/other endocrine glands.

Figure 1c. Top five cancers (ranked on survival), Female, Busan, Republic of Korea, 1996–2001

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Age group

The 5-year relative survival by age group reveals a decreasing survival with increasing age at diagnosis for cancers of the nasopharynx, gallbladder, lung, bone, soft tissue, breast, cervix, corpus uteri and thyroid, and multiple myeloma, lymphoid leukaemia and myeloid leukaemia. For all other cancers, the survival by age group did not display any pattern.

Table 4b. Site-wise number of cases, 5-year absolute and relative survival by age group, Busan, Republic of Korea, 1996–2001 cases followed-up until 2003

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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)