Novel Testing Modalities Are Poised to Improve Diagnosis and Prognosis

John M. Burke, MD

Last years, a 70-year-old woman presented to her (and my) local hos- pital with a seizure. An MRI of the brain demonstrated a 2.4-cm mass in the left temporal lobe. A lumbar puncture demonstrated lymphocytes and an elevated protein, and flow cytometry on the cerebrospinal fluid detected malignant B cells. A craniotomy was performed, and biopsy of the brain tumor, read by an expert pathologist at an academic institution, indi- cated lymphomatoid granulomatosis, grade 1—not a diagnosis I personally am accustomed to seeing on a brain biopsy, to say the least.

This work-up took quite some time, and then I had to muddle around, trying to figure out how to manage the extremely rare situation of lymphomatoid granulomatosis of the brain.

My patient and I decided to initiate rituximab (Rituxan). However, at the family’s urging, I sought a second opinion on the pathology. Several weeks later, the second expert pathologist, who happened to be at a different aca- demic institution, informed me that this was not lymphomatoid granuloma- tosis but was, instead, a CD5-expressing diffuse large B-cell lymphoma. So after having given this patient 3 doses of weekly rituximab, I changed her treatment to rituximab, methotrexate, vincristine, and procarbazine. One year later, she remains in a complete remission.

Wouldn’t it be great if we could reliably diagnose central nervous system lym- phoma without an invasive brain biopsy? One potential solution to this problem, and perhaps to many others we face in our field, is discussed in the Precision Medicine in Oncology column in this issue: “Exploring Prognostic Testing in Hematologic Malignancies” (page 67).

Novel testing modalities are already changing the practice of hematology and oncology and will likely do so even more in the future. One example that has affected clinical practice is testing for measurable residual disease, or MRD. In acute lymphoblastic leukemia, the results of MRD testing after multiagent chemotherapy are now used to select patients for treatment with the bispecific T-cell engager blinatumomab (Blincyto).

Improving our diagnostic and prognostic testing capabilities is certainly one of the most important and exciting ways to improve how we care for patients with cancer. I would predict that 10 to 20 years from now, how we diagnose cancer, how we choose therapies, how we adjust treatments during therapy, and how we monitor for relapse will be quite different from what we do today...at least I hope so, for the patient’s sake.