An unnecessary evil.

Lots of big news is coming out of RSNA 2017 this week. The treatment of locally-advanced (cT3-4 or N+) rectal cancer relies on all three pillars of oncology: pre-operative chemo and radiation followed by surgery (at least for now). But, wait, one discipline is missing from this sequence: radiology! About 4-6 weeks after completion of neoadjuvant chemoradiation, patients routinely receive an MRI of the pelvis to reassess the primary tumor in addition to CT abdomen/pelvis to reassess for metastatic disease prior to surgery. So what does this add besides a big bill? The restaging MRI has long been in question. As reported more recently (as in yesterday at RSNA), the CT AP seems to add about as much harm as it does benefit. Of 231 patients who received a restaging CT AP in a South Korean prospective observational study, hepatic mets were reported in 5 patients who went on to receive curative resection...as well as in 3 patients who went on to receive resections of benign liver segments. Oops. What’s more, when compared to 218 who did not receive a restaging CT AP during the same time period, there were no differences in oncologic outcomes. It’s important to remember upfront staging scans are necessary--and, at least according to this data, are also probably sufficient.