Dr Katims on the Utility of the MSK-ACCESS Assay in Node+ MIBC

Andrew Katims, MD, MPH, urologic oncology fellow, Memorial Sloan Kettering Cancer Center, discusses the utility of a circulating tumor (ct)DNA assay (MSK-ACCESS) in patients with node-positive muscle-invasive bladder cancer (MIBC).

ctDNA is associated with disease progression, worse overall survival, and recurrence in patients with bladder cancer. As such, investigators sought to evaluate whether ctDNA sequencing could be used to predict pathologic response to neoadjuvant chemotherapy and metastatic recurrence in patients with node-positive MIBC undergoing radical cystectomy. Patients in the trial provided plasma samples, which were collected before, during, and after neoadjuvant chemotherapy, and 3 months following radical cystectomy. The samples were evaluated using MSK-ACCESS, an ultrasensitive ctDNA assay designed to identify somatic mutations in 129 cancer-associated genes.

The results indicated that the sensitivity of the assay in detecting disease was high, Katims says. Specifically, 80% of patients with node-positive disease had detectable ctDNA, and 90% of patients with metastatic disease had detectable ctDNA. When evaluated as a predictive biomarker, investigators demonstrated that the presence of ctDNA at any point during or after treatment with chemotherapy was a poor prognostic factor and was associated with shorter recurrence-free survival in both the localized and node-positive settings. These data support existing literature on the prognostic effect of ctDNA, Katims says.

Notably, positive ctDNA at the time of diagnosis was associated with pathologic nodal upstaging at the time of cystectomy. Moreover, in addition to seeing whether ctDNA is present or absent from the blood with a positive or negative result, the assay was also able to identify targetable gene mutations like FGFR3 and ERBB2, which distinguishes it from other from commercial assays on the market, Katims concludes.