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Second pathology review boosts diagnostic accuracy in lymphoma

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The importance of expert pathology review
Dr. Mitchell Smith is with the Cleveland Clinic.

Given the complexity of lymphoma classification, it is not surprising that expert hematopathologists can refine diagnoses. As we progress in understanding the specific pathogenesis of lymphoma subtypes and utility of targeted therapy, it becomes even more critical to make correct diagnoses. This study reiterates the importance of expert review for many, if not all, lymphoma samples, particularly any T-cell lymphoma and non—follicular small B-cell lymphoma.



In patients with newly diagnosed lymphoma and suspected lymphoma, a second pathological review found inaccuracies in the original diagnosis among 17% of more than 42,000 cases, based on data presented at the International Congress on Malignant Lymphoma in Lugano, Switzerland.

In more than 25% of all discrepancies, tumors were reclassified at the second pathology review as the result of findings from additional immunostaining and molecular studies – polymerase chain reaction and fluorescence in situ hybridization.

In 15% of cases, diagnostic changes were expected to result in a change in patient management.

“Our study highlights the importance of specialized centralized review of lymphoma diagnosis, not only in the setting of clinical trials but also in routine clinical practice, for optimal patient management,” reported Dr. Camille Laurent of the Institut Universitaire du Cancer Oncopole, Toulouse, France.

In 2010, the French National Cancer Agency (INCa) established the Lymphopath Network, comprising 33 reference centers, to provide a review by expert hematopathologists of every newly diagnosed lymphoma or suspected lymphoma prior to treatment. These new diagnoses were entered in a central national database. Between 2010 and 2015, 42,146 samples were reviewed: 35,753 were newly diagnosed as lymphomas, while the remaining 6,393 cases included 4,610 reactive lymphoid conditions and 1,783 nonlymphoid malignancies, including especially myeloma and leukemic disorders.

Discordant diagnoses among extra-cutaneous lymphomas were carefully examined by a hematologist and recorded as major or minor depending on the expected therapeutic impact. Dr. Laurent said.

The discordance rate between the referral diagnosis and the final diagnosis was 17.2%. Small B-cell lymphomas and peripheral T-cell lymphoma subtyping were the most common discrepancies; 6.4% of discordances were due to an unspecified lymphoma diagnosis, Dr. Laurent stated.

Less than 2% of discrepancies were due to misclassifications of benign versus malignant lymphoid conditions and of Hodgkin lymphoma versus non-Hodgkin lymphoma. There were minor discrepancies (2.2%) in follicular lymphoma misgrading and diffuse large B-cell lymphoma subtypes.

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