s of April 4, 2003, the National Cancer Institute (NCI) has retired its CANCERLIT database and is linking users of NCI's Cancer.gov Web site directly to NLM's PubMed^® database for journal citations. NCI and NLM are working together in several ways to improve access to cancer-related citations in PubMed.

Improvements In Progress
NCI and NLM will develop and maintain a Cancer Subset on PubMed to help searchers who want to limit their results to cancer-related citations. This subset should be available for use by the end of April; in the interim, NCI is advising its users to append the word cancer to searches they wish to restrict in this way, as this will accomplish most of the desired effect. Following initial implementation of the cancer subset, NCI and NLM will review the subset strategy at least annually to ensure that it remains current and comprehensive.

NCI's specialized Cancer Topic Searches have been expanded and redefined to return results directly from PubMed, and efforts are underway to further extend the scope and availability of this service. Users should check this convenient list of searches to see if the specific cancer topic they want to search has already been developed as a strategy, e.g., bone sarcoma. If so, the PubMed results are only a click away and the baseline strategy can be adjusted further, if desired.

At some point in the future, the new NCI Thesaurus will be inserted into the UMLS Metathesaurus. The UMLS is part of PubMed's Automatic Term Mapping, so searches will include the appropriate MeSH concept term for the cancer term. Until that implementation, terms that do not map to MeSH vocabulary can be entered using double quotes, as NCI and NLM have augmented the PubMed index of searchable terms with over 17,000 phrases from the NCI Thesaurus not previously found in the PubMed index, e.g., "surface osteosarcoma". The new NCI Thesaurus currently includes some 5,500 neoplasm concepts with 35,000 synonyms as well as some 20,000 other concepts often related to cancer.

Background
For nearly 30 years, CANCERLIT combined cancer-related MEDLINE citations with a much smaller number of meeting abstracts, monographs, and other materials. Almost all of these materials have become directly accessible via the Web, and NCI stopped adding these extra contents after 1999. As the clinical and research value of CANCERLIT's added content diminished, and PubMed's features improved, NCI decided that the costs and delays of creating a separate database were no longer warranted.

NCI is exploring ways to help provide access to any such materials of continuing value. One of the most-used additions was meeting abstracts from the American Society of Clinical Oncology (ASCO); NCI has provided ASCO with a full set of abstracts from 1995-1999, to fill in its Web-accessible collection of meeting abstracts.

For more information or to ask a specific question about the changes to Cancer.gov's cancer literature search options, please use the Cancer.gov Contact Us form or send an email message to ncicancergovstaff@mail.nih.gov. Special arrangements regarding access to CANCERLIT contents may also be discussed with Dr. Richard Manrow at (301) 496-9096.

By Larry Wright
NCI Office of Communications/Office of Cancer Information Products and Systems

Wright L. CANCERLIT^® Retired, NCI and NLM Collaborate to Improve Access to Cancer-Related PubMed Citations. NLM Tech Bull. 2003 Mar-Apr;(331):e9.