Historical Background of the CSP

The Los Angeles County Cancer Surveillance Program (CSP) is the population-based cancer registry for Los Angeles County. It identifies and obtains information on all new cancer diagnoses made among residents of Los Angeles County. The CSP was organized in 1970 and operates within the administrative structure of the University of Southern California (USC) Keck School of Medicine. The CSP was initially a component of a laboratory-based viral oncology program and, as such, was part of the Nation al Viral Cancer Program. It was developed with the voluntary cooperation of hospitals and other institutions, clinics, and medical laboratories equipped to diagnose cancer in Los Angeles County. By 1972, the registry became essentially population-based and complete incidence data for Los Angeles County are available from that year onward. To date, the CSP master file contains over one million records and some 41,000 incident cancers are added annually.

Since 1981, the CSP has been the designated legal agent of Los Angeles County for collecting information on all new cancer cases occurring among County residents for the purpose of monitoring cancer incidence patterns and trends. In 1987, it became the regional registry for Los Angeles County for the new California Cancer Registry (CCR). The CSP is one of ten such regional registries providing, as a group, statewide coverage. In September 1992, the CSP became the largest registry of the National Cancer Institute’s Surveillance, Epidemiology, and End Results (SEER) program. The consortium of 18 population-based SEER registries provides the federal government with a “snapshot” of cancer incidence and survival across the United States.

The CSP is one of the most productive cancer registries in the world, in terms of scientific contributions toward understanding the demographic patterns and the etiology of specific cancers. The CSP has a bibliography of more than 774 publications contributed to scientific journals. The registry supports a large ongoing body of research funded mainly by the National Cancer Institute.

How Cancer Is Registered

Under the California State model of reporting, a passive cancer surveillance system has been implemented in which hospitals and other facilities where cancer is diagnosed and treated bear the responsibility, including the fiscal responsibility, for identifying, abstracting and reporting cancer cases to the regional registry within six months after the patient’s admission.

In order to provide complete demographic and treatment information on each new cancer occurring among the residents in Los Angeles County and guarantee compliance with reporting requirements, the CSP combines elements of an active and a passive surveillance system. For active surveillance, each of the medical facilities in which microscopic verification of cancer occurs is visited periodically by a CSP field technician who systematically screens all hematology and pathology reports, and collects a copy of each that describes a previously undiagnosed cancer. The State-mandated passive surveillance system requires each hospital or other reporting facility to complete a full abstract, including stage and treatment information, on every cancer case seen in the facility. All of these completed abstracts are linked by the CSP to the pathology reports obtained under active surveillance to assure that one abstract is completed for each histologically verified case. In addition, any previously unrecognized cancer diagnoses among Los Angeles County residents, identified as a result of searching computerized death records, are followed back to patient records in hospitals or other facilities so that data can be abstracted, when possible, in a similar way to data found using pathology reports.

Use of CSP Data for Research

The CSP data serve as a descriptive epidemiological resource to generate new hypotheses regarding specific cancer sites or histologic subtypes, to monitor descriptive trends and patterns of cancer incidence, and to identify demographic subgroups at high risk of cancer. A high priority is always placed on exploring demographic patterns and trends in cancer incidence among the racially and ethnically diverse population of Los Angeles County.

As a service to the community, the CSP provides community-wide or hospital-specific data on cancer occurrence. The CSP receives occasional requests from community physicians or from the County and State health departments seeking assistance in investigating perceived cancer risks from environmental exposures.

The CSP can generate rosters of cancer patients who are eligible for case-control studies. In such studies, additional information about each of the patients is gathered by personal interview, record abstraction, or by the processing of laboratory specimens. The data are then compared with similar information gathered from healthy persons (controls) who have been chosen to represent the population from which the cases came.

The CSP data can also be used for analytic studies of the cohort design. In such studies, a large roster of Los Angeles County residents who have had in common a particular exposure of public health interest are matched to the CSP registry of cases in order to see whether or not an excess of cancer cases has appeared among them.

Protection of Confidentiality

Confidentiality procedures at the CSP are rigidly formulated and maintained. All employees of the CSP sign a confidentiality pledge after being advised of the necessity for maintaining strict confidentiality of case information and instructed in routines to assure this. Any forms containing identifying information are transported to the CSP in locked carrying cases and are stored in locked filing cabinets at the CSP. Confidentiality of computerized data is assured by highly restricted access. All reports and summaries produced for distribution by the CSP, such as those presented here, are in statistical form without any personal identifiers. All individual studies using confidential information obtained from the registry are individually reviewed by the USC Institutional Review Board as is the registry itself on a regular basis. For studies from outside investigators, review and approval by a federally approved institutional review board is also required.

CSP and Head and Neck Cancer Research

Dr. Lihua Liu, research scientist at the CSP noticed: "The CSP has been such a valuable resource in supporting cancer research. Utilization of the CSP database has resulted in hundreds of publications that have advanced our knowledge and understanding of many cancers.  I want to see our database be used and contribute to fighting head and neck cancers," Indeed, because of the relatively low incidence of head and neck cancers, a centralized, population-based database can really help identify risk patterns and generate hypotheses regarding the causes of these diseases.  Observations obtained at the population level can help guide the focus of basic science research for maximum efficiency. Dr. Liu and her colleagues use the CSP data to examine the head and neck cancer incidence patterns by demographic characteristics, tumor locations, and cell type s. Teaming up with Dr. Uttam K. Sinha of the USC Head and Neck Group, Dr. Liu is currently conducting a survey of tongue cancer patients in Los Angeles County diagnosed in the 12 months after March 2005 to investigate the quality of life after tongue cancer treatments. By studying outcomes, researchers may begin to better understand the effects of various surgical, radiation and chemotherapy treatments. Dr. Liu is also conducting an NCI-supported study to examine how carefully pathologists describe characteristics of tongue cancer tumors in pathology reports, something that can help determine the course of patients' treatments.