Once again, I have been given the distinct honor of analyzing two of the most provocative studies in colorectal cancer this month for Clinical Edge. The first study I will examine was done by Khamzina and colleagues and attempts to define the optimal time to perform surgery after neoadjuvant chemoradiotherapy in locally advanced rectal cancer. In this retrospective analysis, 770 patients who received long-course chemoradiotherapy for rectal cancer followed by total mesorectal excision (TME) were analyzed by how long the interval was between completion of radiation and surgery. Patients were separated into two groups: 6-8 weeks (n = 502) vs >8 weeks (n = 268). Though the pathologic complete response rates and 5-year disease-free survival rates were not significantly different between the two groups, tumor regression grade was significantly better in the >8 weeks arm (P = .004). This result confirms many previous studies that demonstrate continued tumor shrinkage months after completion of chemoradiotherapy and may provide an explanation of why the OPRA trial demonstrated a higher TME-free rate in the chemoradiotherapy-then-chemotherapy arm than it did in the induction chemotherapy-then-chemoradiotherapy arm (53% vs 41%).
Schaefer and colleagues looked at the potential prognostic markers for efficacy of transarterial radioembolization (TARE) with 90Y resin microspheres in the treatment of liver-dominant metastatic colorectal cancer (mCRC). Their study evaluated 237 patients with liver-dominant mCRC from the prospective observational CIRSE Registry for SIR-Spheres Therapy (CIRT) study who were scheduled to receive TARE with 90Y resin microspheres. For these patients, the aspartate transaminase-to-platelet ratio index (APRI), international normalized ratio (INR), and albumin-bilirubin (ALBI) grade were measured prior to treatment to potentially detect values that might be associated with differential outcomes from TARE. An APRI > 0.40 independently predicted worse overall survival (OS) (hazard ratio [HR] 2.25; P < .0001), progression-free survival (PFS) (HR 1.42; P = .0416), and hepatic PFS (HR 1.50; P = .0207). The other independent predictors for worse OS and hepatic PFS were an INR value of < 1 (HR 1.66; P = .0091) and ALBI grade 3 (HR 5.29; P = .0075), respectively. It is very difficult to make much out of this study save to say that poorer liver function at baseline (at least with respect to APRI and ALBI) predicts worse outcomes after TARE, which is none too controversial an opinion. That said, APRI and ALBI may be able to provide an extra measure of granularity to determine who might be more of a marginal candidate for TARE than would categorization according to Child-Pugh score alone. Saving these patients from a potentially morbid procedure would be a significant benefit.