Several PUF projects examine one or more laboratory prognostic indicators. These are available as Site Specific Factors (SSF) collected as part of the Collaborative Stage Data Collection System (CS). The term “collaborative” means that the data collection tool was devised to meet the various needs of cancer registry data standard setters such as the Commission on Cancer (CoC), Surveillance Epidemiology and End Results (SEER), and the National Program of Cancer Registries (NPCR).
Up to 25 data fields are used to collect SSFs. Being site specific, they contain different information depending on the type of cancer in the report. For example, for breast cancer reports, SSF1 contains “Estrogen Receptor (ER) Assay” results, but for colon cancer reports, SSF1 contains “Carcinoembryonic Antigen (CEA)” results.
SSFs also may convey non-laboratory site-specific information that is relevant to prognosis for some cases. For example, SSF1 for gastric cancers is “Clinical Assessment of Regional Lymph Nodes”, and for melanoma of skin it is “Measured Thickness (Depth), Breslow Measurement”.
Some detective work is required to identify the data fields of interest, the applicable codes, and the adequacy of the data for the particular study:
I. The codes, and occasionally the fields used, for a particular prognostic factor have changed over time. In the PUF, the SSF data are retained in the form in which they were submitted. That means that it will be necessary to identify the CS Version Numbers that are used in the PUF file, and use those to identify whether the data contents for the desired SSF may have changed or moved. Links to the site-specific codes can be found at http://ncdbpuf.facs.org/?q=node/370. The CS web sites are maintained by Collaborative Stage Work Group of the American Joint Committee on Cancer. Select the applicable CS Version from the link above, and then select the schema name that applies to the cases in the project.
II. The quality of the SSF data items has undergone minimal review by NCDB, and PUF users are advised to examine the data consistency and completeness of these items carefully before proceeding with the study.
a. All SSF data items are edited for validity and internal consistency before the case report is submitted, and the submitter is required to correct any edit errors. However, some coding errors remain.
b. Case coverage of the SSFs is limited for a variety of reasons , potentially seriously affecting their applicability for some studies.
i. The availability of the measures to hospital registrars at the time of data entry is sparse for many prognostic measures. The source of information is usually the laboratory report as it appears in the hospital patient record. The information may not be available in the hospital if it was requested by a physician and the report was sent to the physician’s office. Alternatively, it may be delayed and not picked up later.
ii. The individual tests are not run at all locations or for all patients, even if the test is part of an acknowledged treatment protocol.
iii. Finally, many hospital registries begin abstracting data for the years the measures were introduced prior to the hospital’s upgrade of the software essential to collecting those items, and they did not necessarily return to the cases to abstract the missed data. . Some of the SSFs were first introduced in 2004, and are underrepresented for cases diagnosed that year compared to later years. Most prognostic SSFs were introduced in 2010, and are certainly underrepresented for 2010 diagnoses; those are not available at all for earlier years.
The SSFs, the versions in which they were implemented, and whether the field was required for CoC registries are described in http://seer.cancer.gov/csreqstatus/index.html. To access the list of Site-Specific Factors required by the Commission on Cancer, click the "Get Started" button in the Collaborate Stage Requirements Status box on the right-hand side of the page. Then, press the plus sign in the middle of the page, select "Required Factors" as Report, "CoC" as the Standard Setter, and the applicable version under Version. As noted above, the fields in which these items were stored and the codes used may have changed over time.