Composite Nuclear Grading System

The Composite Nuclear Grading System is a pathology scoring method used to predict prognosis in epithelioid mesothelioma. It combines two features seen under the microscope, how abnormal the tumor cell nuclei look (nuclear atypia) and how rapidly the cells are dividing (mitotic count), into a single grade of I, II, or III. Higher grades are associated with shorter survival.

Origin

The system was developed and published by Kadota and colleagues at Memorial Sloan Kettering Cancer Center in 2012 and validated in a larger multi-institutional study led by Rosen and colleagues in 2018. It was created because earlier mesothelioma reports often lacked a reproducible way to predict how aggressively an epithelioid tumor would behave.

Significance in Asbestos Context

For patients diagnosed with epithelioid mesothelioma, the nuclear grade on the pathology report can meaningfully shape prognosis discussions and treatment decisions. Grade I tumors tend to have substantially longer median survival than Grade III. Patients should ask their oncologist or pathologist whether nuclear grading was performed and what grade was assigned, because not every pathology report includes it. The grade can also influence eligibility for surgery, clinical trials, and aggressive multimodal therapy, and it commonly appears in medical records and expert reports used in asbestos claims to describe disease severity and life expectancy.

Example Sentence

Her pathology report showed an epithelioid mesothelioma with a Composite Nuclear Grade of II, which her oncologist explained placed her prognosis between the most and least aggressive ends of the spectrum.

Related Terms

Epithelioid Mesothelioma, Mitotic Count, Nuclear Atypia, Histologic Subtype, Ki-67, Sarcomatoid Mesothelioma

Notes

• Ask your pathologist or oncologist whether nuclear grading was performed on your biopsy; if it was not, request that the slides be re-reviewed with grading specifically applied.
• The system applies only to epithelioid mesothelioma. Sarcomatoid and biphasic subtypes are not graded this way.
• Request a copy of your full surgical pathology report and keep it with your medical records, as the grade and mitotic count are often cited in life-expectancy and damages analyses.
• Consider a second pathology opinion at a mesothelioma specialty center (such as an NCI-designated cancer center), since grading can vary between pathologists and accurate grading affects treatment planning.