Application Series 23

THE FIGHT AGAINST CANCER

Sven-Erik Kofoed, a programmer at the Division of Cancer Epidemiology at the Danish Cancer Society uses caseless SIR-databases as an administrative tool for the Human Papilloma Virus project.

Background

Sven-Erik told SIR about the Human Papilloma Virus project. "It is sponsored by The National Cancer Institute, USA and takes place at the Division for Cancer Epidemiology, conducted by senior researcher Susanne K Kjaer." The purpose of the project is to provide enough data to measure the risk of cervical cancer in relation to the occurrence of HPV-infection. More than 17,000 women were asked to participate in the study "and more than 11,000 accepted the invitation." Sven-Erik told us - a very high response rate to a voluntary project.

The data

A considerable amount and variety of data are collected to conduct this study as Sven-Erik describes. "In addition to a personal interview with the women volunteers, cervical swabs and PAP smears from a gynaecological examination and blood samples were taken from all participants." The biological samples were frozen at -80°C for later examination. "If the woman later in her lifetime develops cervical cancer, it must be possible to find these samples and compare with samples from healthy women in order to find differences which then may be used to detect risk factors of cervical cancer."

The SIR Solution

A SIR database was constructed to administer the flow of visits in the clinic and the placement of samples in the freezers with 10 record types linked together using FORMS and MASTER.

There are two distinct types of data being collected in this project, administrative information (names, addresses, study number, dates of invitation, the volunteer's responses, dates of visits etc) as well as the biological samples and their location in the freezers. The SIR database provides various levels of detail on each of these.

Information, collected from the volunteer through the interview process is recorded in a single background record type, which is indexed using the volunteer's personal identification number. "At their first visit a study number is assigned to each volunteer and, by means of a CALL in FORMS, a secondary index, using this study number, is automatically created. I can later on obtain fast access to the background record via this index."

"With 11,000 volunteers, it is difficult to provide a personal service, but the SIR solution allows us to do this." A calendar record type uses the opening days in the clinic as a key with the possible times of consultation and the personal identification number of the visitors as variables. By telephoning the secretary it is possible for volunteers to get knowledge of free visit times. "This calendar record type is automatically updated via the background record type, passing the chosen time of visit and the personal identification number" Sven-Erik explained.

Recording samples

As each volunteer visits to provide samples for the project, details of their visits and the samples they provide must be recorded. A record in the visit record type with the study number and visit number as keys is created. It also contains information about the sample types and the position of each sample in the freezer.

"With 11,000 women providing a number of different samples at every visit, you can imagine the enormity of the task of keeping track of all of these." Sven-Erik's system does this by use of a freezer record type which records the position of each sample in the freezer along with study number, type of sample and time of placement. When the visit record is created, a CALL is made to the freezer record returning the last used position to temporary variables. "This is the last record because I use freezer number, rack number, box number and the position in the box as keys" Sven-Erik pointed out. "By adding 1 to one or more of these variables I can create a new record in the freezer record type by a CALL only allowing new records." Sven-Erik continued. "The visit record is updated at the same time."

Followup

A further record with the date of visit, status of enrolment and personal identification number as keys is then created. "By use of PQL I can invite the women to their next visit in the correct sequence very easily."

What makes it work

"SIR facilities such as a fully relational database, automatic record creation and updating, indices, automatic FORMS CALL commands, PQL for generating reports and letters are the things that have made this project administratively very easy to handle." Sven-Erik explained "We are quite satisfied with the solution."

The application is installed on a UNIX-computer (HP-9000) using MASTER to obtain access by multiple users to the information. "It runs fine" Sven-Erik said confidently. "The only problem that occurs is if the machine halts in my absence. Since I am the only one with access-rights to start up MASTER, this has occasionally caused the users problems."

For more information on the use of SIR in the fight against cancer contact:

Sven-Erik Kofoed
Programmer,
Division of Cancer Epidemiology
Danish Cancer Society
Copenhagen Denmark

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