Tumor deposits
Tumor deposits (in the context of rectal cancer) are discrete nodules of tumor tissue within the mesorectum, often found along the path of draining vessels, and are distinct from lymph node metastases. They are found in >50% of MRI studies of patients with rectal cancer .
Radiographic features
MRI
Tumor deposits (known on MRI as mrTDs) are discontinuous to the main primary tumor, along the path of draining vessels and found to be interrupting the vessels when assessed on two orthogonal views. These vessels will frequently be found to have signs of extramural venous invasion. In contrast, lymph node metastases do not interrupt the course of vessels. Tumor deposits have an irregular margin, as opposed to lymph node metastases which generally will have a smooth capsule.
Treatment and prognosis
Tumor deposits, alongside the ancillary finding of extramural venous invasion, are increasingly recognized as being the most important predictors of distant metastatic disease, overall survival and disease-free survival for patients with rectal cancer . It has been found that moving from a positive to a negative mrTD status as a result of chemoradiotherapy, had a better outcome than those who remain mrTD positive following such therapy .
See also
