Leslie H. Sobin

World Health Organization classification of tumors.

World Health Organization Collaborating Centerfor International Histological Classification of Tu-mors, Armed Forces Institute of Pathology, Wash-ington, DC.Address for reprints: Leslie H. Sobin, M.D., ArmedForces Institute of Pathology, Alaska Avenue and14th Street, Building 54, Room 3009, Washington,DC 20306-6000.Received March 23, 2000; accepted March 23,2000.

Classification of isolated tumor cells and micrometastasis

Findings of isolated (disseminated or circulating) tumor cells (ITC) by immunocytochemistry and molecular pathology methods have led to varied interpretations and different applications of the TNM system.

TNM Residual Tumor Classification Revisited

For cancer patients, prognosis is strongly influenced by the completeness of tumor removal at the time of cancer‐directed surgery or disease remission after nonsurgical treatment with curative intent. These parameters define the relative success of definitive treatment and can be codified by an additional subclassification within the TNM system, the residual tumor (R) classification. Despite the importance of residual tumor status in designing clinical management after treatment, misinterpretation and inconsistent application of the R classification frequently occur that diminish or abrogate its clinical utility.

Primary malignant neoplasms of the appendix: a population-based study from the surveillance, epidemiology and end-results program, 1973-1998.

Cancer of the appendix is an uncommon disease that is rarely suspected rarely before surgery. Although several case series of these tumors have been published, little research has been anchored in population‐based data on cancer of the appendix.

The world health organization's histological classification of salivary gland tumors. A commentary on the second edition

The second edition of the World Health Organizations Histological Classification of Salivary Gland Tumors is more extensive and detailed than the previous edition published 20 years ago. The new edition is based on data regarding newly described tumor entities and the behavior and prognosis of the previously classified tumors. The distinct morphologic features of monomorphic adenomas justify their separation for purposes of identification. Among the carcinomas, various types were distinguished for purposes of recognition, prognosis, and treatment. The term tumor was replaced by carcinoma in the following two entities: acinic cell carcinoma and mucoe‐pidermoid carcinoma. The tumor‐like lesions were described in more detail. Cancer 1992; 70:379–385.

The process for continuous improvement of the TNM classification

The TNM classification is a worldwide benchmark for reporting the extent of malignant disease and is a major prognostic factor in predicting the outcome of patients with cancer. The objectives for cancer staging were defined by the International Union Against Cancer (UICC) TNM Committee almost 50 years ago and are still broadly applicable today. To keep pace with the modern demands of evidence‐based practice, the UICC introduced a structured process for introducing changes to the TNM classification. The elements of the TNM process were determined to include the development of unambiguous criteria for the information and documentation required to consider changes in the classification, establishment of a well‐defined process for the annual review of relevant literature, formation of site‐specific expert panels, and the participation of experts from all over the world in the TNM review process. Communication between the oncology community and those involved in the TNM classification was established as being essential to the success of the process. The process, which was introduced in 2002, will be tested over the next 3–4 years and evaluated. In addition to the formal process, individual initiative, involvement by the national staging committees, and group consensus are required. Furthermore, increased involvement by the experts should improve the understanding and dissemination of the TNM classification. Cancer 2004;100:1–5. Published 2003 by the American Cancer Society.

Classification of isolated tumor cells: Clarification of the 6th edition of the american joint committee on cancer staging manual

In May 2002, the 6th edition of the American Joint Committee on Cancer (AJCC) Cancer Staging Manual was published, and the new staging system was officially adopted for use in tumor registries in January 2003. The changes adopted for the chapter concerning breast carcinoma were the result of recommendations made by a task force comprising internationally recognized experts in the field of breast carcinoma management. This task force was charged with proposing changes that reflected published clinical data and current clinical consensus. Although the breast carcinoma staging system presented in the 6th edition includes much-needed changes reflecting contemporary standards of care, it is undeniably more complex than the system presented in previous editions of the staging manual. This is especially true of the new material dealing with the distinction between isolated tumor cells and micrometastases. With the increasing use of sentinel lymph node biopsy, immunohistochemical (IHC) staining, and molecular biologic techniques, pathologists can more easily detect microscopic lesions at the level of isolated tumor cells. We do not yet know whether these isolated cells have any clinical significance, and the accrual of relevant data has been hindered by the lack of a clear quantitative distinction between isolated tumor cells and micrometastases. The 6th edition of the AJCC Cancer Staging Manual has made this distinction based on size; isolated tumor cells are defined as metastatic lesions no larger than 0.2 mm in dimension and classified as pN0, whereas micrometastases are defined as metastatic lesions larger than 0.2 mm in dimension but no larger than 2.0 mm in dimension and classified as pN1mi. The AJCC Cancer Staging Manual is an evolving document. Even as one revision is published, new information is coming to light that will ultimately mandate the need for future editions. Since the publication of the 6th edition, task force members have fielded a large 2740

Carcinoids of the jejunum and ileum

Carcinoid tumors of the gastrointestinal tract differ in their clinical and histopathologic features, depending on the site of origin. There are few clinicopathologic studies that specifically describe jejunoileal carcinoid tumors.

The WHO histological classification of tumors of the gallbladder and extrahepatic bile ducts. A commentary on the second edition

The second edition of the WHO Histological Classification of Tumors of the Gallbladder and Extrahepatic Bile Ducts is more comprehensive and detailed than the previous one. Advances in our understanding of dysplasia, carcinoma in situ, various lines of differentiation among the carcinomas, and the recognition of a variety of tumor‐like lesions have resulted in more than three times as many entities in the current classification as in the previous one. The new edition should facilitate pathologic, epidemiologic, and therapeutic comparisons. Cancer 1992; 70:410–414.

Carcinoid tumors of the ampulla of Vater

Although ampullary carcinoid tumors (ACs) are often categorized clinically as duodenal carcinoid tumors (DCs), there are distinct clinical and pathologic differences.