Signatera test for tumor remnants

My wife’s Mc suggested she take the Signatera test prior to chemo and pst treatment to measure whether or not all stray cancer cells have been eliminated.  My concern with this test is that if post chemo there are still stray cells,  she will need to undergo further stronger chemo.  Wondering if anyone has any experience with this test and can enlighten us on what to expect.  

Clinical postoperative tumor residues are divided into tissue residues and cell residues. The so-called tissue residues refer to the reduction of tumor size or other reasons. The purpose is to alleviate the condition, but it cannot be cured. Cell residues refer to the naked eye. Seeing that when the tumor tissues are all removed, there are still a small amount of tumor cells remaining in the patient’s blood or lymphatic system. Generally, these remaining cells will be killed in subsequent adjuvant treatments. Therefore, in theory, most of the tumor cells will be killed after surgery. There are a small amount of residual cells, but these cells will be killed in the follow-up adjuvant treatment. Whether the recurrence is related to the disease, pathological type and stage of the primary lesion is very much related. Please make up the above medical history for analysis.