Tumour regression

MyPathologyReport
October 17, 2023


tumour regression

In pathology, the term tumour regression is used to describe a tumour becoming smaller, or decreasing in size, over time. This change may be spontaneous or occur as a result of treatment such as chemotherapy.

Spontaneous versus treatment-related regression

Spontaneous regression means the tumour decreased in size without any form of medical treatment. The most common type of tumour to show spontaneous regression is melanoma, a type of skin cancer. Doctors believe that spontaneous regression occurs when cells from the immune system start to attack the tumour. For some patients, the entire tumour may disappear.

More commonly, regression occurs after treatment, such as chemotherapy or radiation therapy. Pathologists determine the amount of regression by comparing the size of the tumour after treatment to the size of the tumour before treatment. Partial regression means that part, or some, of the tumour, has disappeared after treatment. With complete regression, the entire tumour has disappeared after treatment. The term tumour bed is used to describe the area of the body where the tumour was located prior to treatment.

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This article was written by doctors to help you read and understand your pathology report. Contact us if you have questions about this article or your pathology report.

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