The impact of follow-up type and missed deaths on population-based cancer survival studies for Hispanics and Asians.

The accurate estimation of cancer survival across racial and ethnic groups is an important aspect of cancer surveillance. It relies on completeness of follow-up to identify cancer deaths. In cancer surveillance, there are two different methods of follow-up. Active follow-up is defined as any type of follow-up that involves contact with the patient, his/her next-of-kin or his/her physician to ascertain vital status. Passive follow-up involves obtaining follow-up data through linkages without contact with the patient or his/her physician. Cancer registration in the United States is administered by one of two programs that use different types of follow-up. The first, the National Cancer Institute Surveillance, Epidemiology and End Results (SEER), covers 28% of the US population and employs resource intensive activities to capture the last date of contact for each cancer case. Cases are matched to national and statewide databases such as the National Death Index, Social Security, Medicare and Medicaid, hospital discharge, as well as records of contact with physicians, pathology labs, and hospital registries. SEER registries also perform data linkages with voter registration and driver license data, and some use information obtained from research studies to supplement registry data. SEER standards require that their registries report vital status and date of last contact that is current within 22 months of the date of their annual data submission for a minimum of 95% of all registered cancer patients, living and deceased (1). The follow-up information can be from either linkages or direct contact with patients, so SEER registries perform a combination of active and passive follow-up. In spite of this, in this paper we refer to the follow-up carried out by SEER as “active” follow-up because a date of last contact is available for all cases. Because of the availability of this last date of contact, the traditional method of survival analysis with SEER data is the “reported or documented alive” method, which relies on the reported date of death and the date of alive last contact if there is no date of death available. This method censors patients at the date of last alive contact. Researchers who perform survival analyses often use SEER data because of its high quality. Moreover, this was the only source of population level survival data available until recently. The second US cancer surveillance program is the National Program for Cancer Registries (NPCR). The NPCR was established by the Centers for Disease Control and Prevention and covers the balance of the US population. NPCR registries conduct passive follow-up by matching cancer cases with in-state death lists and the National Death Index. However, NPCR registries do not systematically collect a date of last contact for living cases. As a result, NPCR survival statistics are calculated using what is known as the “presumed alive” method. This method assumes that if a person is not found to be dead, then he/she is alive on the most recent date covered by the National Death Index. Presumed alive survival statistics appear less commonly in the literature (2–5), partly because NPCR survival data have only recently become available. Both Centers for Disease Control and Prevention and the North American Association of Central Cancer Registries now recognize passive follow-up as a suitable approach for some types of population-based survival calculations (6). In the United States, Hispanics, and Asians and Pacific Islanders (APIs) are the fastest growing racial and ethnic groups, comprising 22% of the US population (7). The effects of active versus passive follow-up and their corresponding methods of estimating cancer survival have not been thoroughly examined among these groups. We hypothesized that active and passive follow-up procedures are not equally effective across the four major US racial-ethnic groups: whites, blacks, Hispanics, and APIs. In this study, five-year survival proportions were obtained and compared for these groups using the two described methods, reported alive and the presumed alive, that is, by considering the date of last contact (active follow-up conducted by SEER) and by assuming the patient was alive if not reported dead within 5 years of diagnosis (passive follow-up conducted in NPCR registries), respectively. In addition, the completeness of SEER “active” follow-up was compared across racial-ethnic groups (whites, blacks, Hispanics, and APIs) by stage at diagnosis and by racial-ethnic subgroups (eg, Mexican, Chinese, and so on) to assess potential biases across racial-ethnic populations.