Chapter 10: Cancer survival in Cuba, 1994-1995

Garrote LF, Alvarez YG, Babie PT, Yi MG, Alvarez MG and Cicili ML

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Abstract

The population-based cancer registry in Cuba is a national cancer registry started in 1964; cancer registration is entirely done by passive methods. Data on survival from 13 cancer sites or types registered during 1994–1995 are reported. Follow-up has been carried out predominantly by passive methods, with median follow-up ranging from 13–54 months. The proportion with histologically verified diagnosis for various cancers ranged between 34–100%; death certificates only (DCOs) comprised 8–50%; 50–89% of total registered cases were included for the survival analysis. The 5-year age-standardized relative survival for selected cancers were breast (69%), colon (41%), cervix (56%), urinary bladder (64%), rectum (48%) and non-Hodgkin lymphoma (49%). The 5-year relative survival by age group showed no distinct pattern or trend, and was fluctuating. A decreasing survival with increasing clinical extent of disease was noted for all cancers studied. The data on survival trend revealed that the 5-year relative survival of most cancers diagnosed in 1994–1995 was greater than that in 1988–1989.


National cancer registry

The population-based cancer registry in Cuba is a national cancer registry started within the framework of the national health system in 1964 to describe the annual cancer burden in the country. Its central office is based at the National Institute of Oncology and Radiobiology, Havana. It has contributed data to the quinquennial IARC publication Cancer Incidence in Five Continents in volumes III, IV and VI[1]. A health ministry resolution of 1986 makes it mandatory for physicians to report cancer cases diagnosed in the country. Cancer registration is entirely done by passive methods. The principal source of data is the cancer report form in the Hospital Statistics Department in addition to the pathology, clinical laboratory and the hospital discharge reports. The registry caters to a population of about 11.2 million in 2002 with a sex ratio of 997 females to 1000 males. The average annual age-standardized incidence rate is 203.6 per 100 000 among males and 179.6 per 100 000 among females in 2002. The top ranking cancers among males are lung, non-melanoma skin, prostate and larynx. Among females, the order is breast, non-melanoma skin, cervix and lung.

Map. Map showing location of Cuba

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The registry contributed data on survival for 16 cancer site or type in the first volume of the IARC publication on ‘Cancer survival in developing countries’[2]. Data on survival from 13 cancer sites or types registered during 1994–1995 are reported in this volume.

Data quality indices

The proportion of cases with histological confirmation of cancer diagnosis in this series is 64%, varying between 100% for lymphomas and 34% for cancer of the colon. The proportion of cases registered based on a death certificate only is 32%, ranging from 8% in cancer of the anus to 50% in colon cancer. Cases excluded due to lack of follow-up information were negligible. The exclusion of cases from the survival analysis is the greatest in colon cancer (50%) and the least for cancer of the anus (11%). Thus, 50–89% of the total cases registered are included in the estimation of 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, Cuba, 1994–1995 cases followed-up until 1999

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Outcome of follow-up

Follow-up has been carried out predominantly by passive methods. A copy of the national death certificate file is obtained every year from the national statistical department of the Ministry of Health and is matched with the cancer registry database using record linkage techniques. The vital status of the unmatched incident cases are then ascertained by matching with the national identity registry, repeated scrutiny of hospital records and some minimal postal enquiries.

The closing date of follow-up was 31st December 1999. The median follow-up varied from 13 months in tongue cancer to 54 months for breast cancer. Complete follow-up at five years from the incidence date ranged between 94–99%. The losses to follow-up generally occurred in the first year of follow-up.

Table 2. Number and proportion of cases with complete / incomplete follow-up and median follow-up (in months) by site, Cuba, 1994–1995 cases followed-up until 1999

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Survival statistics

All ages and both sexes together

The 5-year relative survival was the highest in cancer of the larynx (53%) among head and neck cancers. The corresponding survival estimates for cancers of the colon, rectum and anus were 41%, 49% and 58%, respectively. Hodgkin lymphoma had a better survival (52%) than non-Hodgkin lymphoma (47%).

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

Table 3. Comparison of 1-, 3- and 5-year absolute and relative survival and 5-year age-standardized relative survival (ASRS) by site, Cuba, 1994–1995 cases followed-up until 1999

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Figure 1a. Top five cancers (ranked by survival), Cuba, 1994–1995

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Sex

Table 4a. Site-wise number of cases, 5-year absolute and relative survival by sex, Cuba, 1994–1995 cases followed-up until 1999

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Male

The 5-year relative survival was the highest for cancer of the urinary bladder (63%) followed in order by larynx (53%), anus (51%), Hodgkin and non-Hodgkin lymphomas and rectum (46%).

Figure 1b. Top five cancers (ranked by survival), Male, Cuba, 1994–1995

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Female

The top-ranking cancers in terms of 5-year relative survival were breast (70%), urinary bladder and tonsil (67%) and anus (60%). Survival from cervix cancer was 58%. Survival was markedly higher among females than males for cancers of the tongue, oral cavity, oropharynx including tonsil, and anus, and Hodgkin lymphoma.

Figure 1c. Top five cancers (ranked by survival), Female, Cuba, 1994–1995

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Age group

The 5-year relative survival by age group was seen to fluctuate, with no definite pattern or trend emerging.

Table 4b. Site-wise number of cases, 5-year absolute and relative survival by age group, Cuba, 1994–1995 cases followed-up until 1999

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Extent of disease

Among cancers except tongue cancer, a majority of cases have been diagnosed with a localized disease at diagnosis, from 51% for cancer of the larynx to 28% in cancer of the colon. Regional disease among tongue cancers constituted 40%. The extent of disease was unknown in 18–42%. 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, Cuba, 1994–1995

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Figure 2a-2g. Absolute survival (%) from selected cancers by extent of disease, Cuba, 1994–1995

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Figure 2a. Absolute survival (%) by extent of disease, Cuba, 1994–1995: cancer of the tongue

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Figure 2b. Absolute survival (%) by extent of disease, Cuba, 1994–1995: cancer of the oral cavity

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Figure 2c. Absolute survival (%) by extent of disease, Cuba, 1994–1995: cancer of the colon

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Figure 2d. Absolute survival (%) by extent of disease, Cuba, 1994–1995: cancer of the rectum

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Figure 2e. Absolute survival (%) by extent of disease, Cuba, 1994–1995: cancer of the larynx

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Figure 2f. Absolute survival (%) by extent of disease, Cuba, 1994–1995: cancer of the breast

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Figure 2g. Absolute survival (%) by extent of disease, Cuba, 1994–1995: cancer of the cervix

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Survival trend

The data on trends in cancer survival are available for 9 cancers registered in two time periods between 1988–1989[2] and 1994–1995. The 5-year relative survival of most cancers diagnosed between 1994–1995 is greater than those registered in 1988–1989. The absolute difference exceeded 10% in cancers of tongue, oropharynx (including tonsil) and non-Hodgkin lymphoma. Hodgkin lymphoma and cancer of the oral cavity experienced a decrease in survival in 1994–1995 compared to 1988–1989.

Table 6. Comparison of 5-year absolute and relative survival of cases diagnosed between 1988–1989 and 1994–1995, Cuba

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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. Garrote LF, Boschmonar MG, Alvarez YG, Cicilli ML, Garcia AM and Rodriguez RC. Cancer survival in Cuba. In: Cancer Survival in Developing Countries (eds) R Sankaranarayanan, RJ Black and DM Parkin. IARC Scientific Publications No. 145. IARCPress, Lyon, 1998, pp 51–59.
    (link to Cancer Survival, volume 1)