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Rizal cancer registry

The Department of Health-Rizal Cancer Registry (DOH-RCR) was the first population-based cancer registry in the Philippines to be established in 1974 as one of the activities of the community cancer control programme of the province of Rizal. It is based at the Rizal Medical Centre, and data collection on incident cases has been in place since 1978. DOH-RCR contributed data to the quinquennial IARC publication Cancer Incidence in Five Continents in Vols V, VI and VIII^[1]. Even though cancer is reportable by legislation, active method of cancer registration is being pursued^[2]. The sources of registration include hospitals in the government and private sectors, consultants, pathology laboratories and imaging centres. Data are collected from the records maintained at these places. The registry covers an area of 1387 km² and caters to a mixed urban and rural population of about 5.9 million in 2000 with a sex ratio of 970 males to 1000 females. The average annual age-standardized incidence rate is 178 per 100 000 among males and 167 per 100 000 among females with a lifetime cumulative risk of one in 5 of developing cancer for both sexes in the period 1993–1997. The top-ranking cancers among males are lung followed by liver and prostate. Among females, the order is breast, cervix and lung.

Map: Map showing location of Rizal, Philippines Click here to open map (PDF format)

The registry contributed data on survival from 11 cancer sites or types in the first volume of the IARC publication on Cancer survival in Developing Countries^[3]. Data on survival from cancer of the breast registered in 1996–1997 are presented in the current volume.

Data quality indices

The proportion of cases with histological confirmation of cancer diagnosis in this series is 90%, and death certificates only (DCOs) constituted 6%. Cases without any follow-up information represent 11%. Thus, 1299 (83%) out of 1570 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, Rizal, Philippines, 1996–1997 cases followed-up until 2002 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 passive and active methods. These included collection of cancer mortality information from local civil registry offices in the municipalities and metropolitan Manila and Rizal provinces. The mortality data are first matched with the incident cancer database. The follow-up information for the unmatched incident cases is then obtained through the attending physicians, repeated scrutiny of records in the respective sources of registration, postal/telephone enquiries and house visits.

The closing date of follow-up was 31^st December 2002. The median follow-up was 6 months. Complete follow-up at five years from the incidence date was 30%. The losses to follow-up generally occurred in large numbers in the first year of follow-up and decreased through successive intervals of follow-up time. Though the losses to follow-up have been ascertained to be random, the high magnitude of incomplete follow-up at 5 years from diagnosis may introduce a bias in the estimation of survival probability.

Table 2: Number and proportion of cases with complete / incomplete follow-up and median follow-up (in months) by site, Rizal, Philippines, 1996–1997 cases followed-up until 2002 Click here to open table (PDF format) Click here to open comparative statistics by registry

Survival statistics

All ages and both sexes together

The relative survival probabilities of breast cancer at one-, three- and five-year from the incidence date are 89%, 56% and 37%, respectively. The age-standardized relative survival for all ages together is 35%, while the corresponding figure for 0–74 years of age is 40%.

Table 3: Comparison of 1-, 3- and 5-year absolute and relative survival and 5-year age-standardized relative survival (ASRS) by site, Rizal, Philippines, 1996–1997 cases followed-up until 2002 Click here to open table (PDF format) Click here to open comparative statistics by registry

Age group

The 5-year relative survival of breast cancer by age group did not display any pattern and was observed to be fluctuating with increasing age groups.

Table 4: Site-wise number of cases, 5-year absolute and relative survival by sex and relative survival by age group, Rizal, Philippines, 1996–1997 cases followed-up until 2002 Click here to open table (PDF format) Click here to open comparative statistics by registry

Extent of disease

A majority of breast cancer cases were diagnosed with a regional spread of disease (44%) followed by localized stage (17%). Distant metastasis accounted for 10%, while the extent of disease is unknown in 29%. The 5-year absolute survival rates by extent of disease was localized (65%), regional (35%), distant metastasis (12%) and unknown (35%).

	Table 5: Proportion (%) of cases and 5-year absolute survival by extent of disease and site, Rizal, Philippines, 1996–1997 Click here to open table (PDF format) Click here to open comparative statistics by registry
	Figure 1: Absolute survival (%) by extent of disease, Rizal, Philippines: Cancer of the breast Click here to open figure (PDF format) Click here to open comparative statistics by cancer site

Survival trend

The data on trend in survival from breast cancer is available for two periods of time: 1987[3] and 1996–1997. The 5-year relative survival in 1987 is 46% compared to 37% in 1996–1997.

Table 6: Comparison of 5-year absolute and relative survival of cases diagnosed between 1987 and 1996–1997, Rizal, Philippines 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)


2. Laudico AV, Esteban D and Parkin DM. Cancer in the Philippines. IARC Technical Report No. 5. IARCPress, Lyon, 1989.
   (link to WHO Bookshop)


3. Esteban D, Ngelangel C, Lacaya L, Robles E and Monson M. Cancer survival in Rizal, Philippines. 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)