Delaying surgery after neoadjuvant therapy may improve tumor regression and decrease recurrence in advanced rectal cancer but does not translate to better overall survival.
A total of 1506 patients with locally advanced rectal cancer who underwent neoadjuvant therapy followed by total mesorectal excision were divided into three groups based on the time interval between therapy and surgery: short (8 weeks), intermediate (> 8 to 12 weeks), and long (> 12 weeks).
The primary outcome was pathologic complete response, and secondary outcomes included other histopathologic results, perioperative events, and survival outcomes.
Median follow-up was 33 months.
Overall, a pathologic complete response was observed in 255 patients (17.2%).
Compared with the intermediate interval (reference) group, investigators found no association between time interval and pathologic complete response in the short-interval (odds ratio [OR], 0.74; 95% CI, 0.55 - 1.01) or long-interval groups (OR, 1.07; P = .70).
A long interval was significantly associated with a lower risk of a bad response as measured by tumor regression grade 2-3 compared with the reference category (OR, 0.47), but a higher risk of minor postoperative complications (OR, 1.43), conversion to open surgery (OR, 3.14), and longer operative time.
The long-interval group was associated with a significantly reduced risk of systemic recurrence compared with the reference group (hazard ratio [HR], 0.59; P = .04), but not improved overall survival (HR, 1.38; P = .11) or locoregional recurrence (HR, 0.53; P = .18); no significant findings occurred for the short versus intermediate group.
"Findings suggest that delaying surgery may improve tumor regression and decrease risk of distant metastasis but increase surgical complexity," the authors conclude. "Nonetheless, the reported improvements in tumor regression and systemic recurrence in the long-interval group were unexpectedly not followed by improved [overall survival]."
The study's main limitation was its retrospective design, which could have resulted in missing or inconsistent data, as well as the short follow-up time.
Decisions about time interval were based more on professional preference rather than specific tumor characteristics.
de Lacy has reported no relevant financial relationships. No outside funding source was disclosed.
Lead image: La Fabrika Pixel S.l./Dreamstime
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Cite this: Does Timing of Surgery Affect Rectal Cancer Outcomes? - Medscape - Jul 14, 2023.