Effect of surgery timing after neoadjuvant chemotherapy on pathological complete response (pCR) rate in view of Radiological image evaluation: a systematic review

Background: The interval between completion of neoadjuvant chemotherapy (NACT) and definitive surgery is variably reported to influence pathological complete response (pCR) rates across tumor types. This systematic review synthesizes evidence on how surgery timing after NACT affects pCR rates and examines the role of radiological assessment (MRI, CT, PET/CT, ultrasound) in guiding timing decisions.Methods: We searched PubMed, Embase, Web of Science, and Cochrane CENTRAL from inception to [search date] for studies comparing different time-to-surgery (TTS) intervals after NACT with reported pCR outcomes and reporting radiological response measures. Study selection, data extraction, and risk-of-bias assessment were performed independently by two reviewers. Outcomes were summarized qualitatively and, where feasible, meta-analyzed using random-effects models. Heterogeneity was quantified with I² and explored via subgroup and sensitivity analyses.Results: [Number] studies (n = [total patients]) across breast, rectal, esophageal, gastric, lung, and other cancers met inclusion criteria. Studies used a range of TTS cutpoints (e.g., <۴ vs ≥۴ weeks; <۸ vs ≥۸ weeks; ۶–۱۲ weeks windows). Several retrospective and cohort studies reported higher pCR rates with modestly longer intervals (commonly ۶–۱۲ weeks) after NACT/nCRT in certain tumor types (rectal cancer, esophageal, gastric), while other reports—especially in breast and NSCLC—showed mixed or null effects and potential trade-offs with postoperative complications or oncologic outcomes. Conclusions: Current evidence suggests that modest delays (approximately ۶–۱۲ weeks from NACT completion) may be associated with increased pCR rates in some cancers treated with neoadjuvant chemoradiation or chemotherapy, but benefits are heterogeneous and tumor-specific.

کلیدواژه ها:

Neoadjuvant chemotherapy ، Timing of surgery ، Pathological complete response ، MRI ، PET/CT