Shifting Treatment Strategies to Prevent Early Relapse of Locally Advanced Rectal Cancer After Preoperative Chemoradiotherapy

Nuclear Factor Erythroid 2-Related Factor 2/Kelch-Like ECH-Associated Protein 1 as a Predictor of Prognosis and Radiotherapy Resistance in Patients With Locally Advanced Rectal Cancer: A Prospective Analysis

BACKGROUND

The nuclear factor erythroid 2-related factor 2/Kelch-like ECH-associated protein 1 (Nrf2/Keap1) signaling pathway is involved in the regulation of cellular responses to oxidative stress. Nrf2 acts as a cell protector from inflammation, cellular damage, and tumorigenesis, whereas Keap1 is a negative regulator of Nrf2. Dysregulation of the Nrf2/Keap1 pathway results in tumorigenesis and the active metabolism of tumor cells, leading to high resistance to radiotherapy. This study aimed to evaluate the predictive role of Nrf2 and Keap1 in the radiosensitivity and prognosis of locally advanced rectal cancer (LARC).

METHODS

In total, 90 patients with LARC underwent surgery after preoperative chemoradiotherapy (CRT). Endoscopic biopsies from the tumors were obtained before radiation, and the Nrf2 and Keap1 expressions were assessed by immunohistochemistry. The response to therapy was evaluated after surgery following CRT according to the pathologic tumor regression grade. The disease-free survival (DFS) and overall survival rates were also documented. The association between the Nrf2 and Keap1 immunoreactivity and the clinicopathological parameters was analyzed.

RESULTS

The overexpression of the nuclear Nrf2 before CRT showed a significant correlation with better DFS. The cytoplasmic Nrf2 expression was associated with more residual tumors after radiotherapy and a more unfavorable DFS, indicating lower radiosensitivity.

CONCLUSION

CRT is an important issue in LARC and is a major aspect of treatment. Thus, the Nrf2/Keap1 expression may be a potential predictor of preoperative therapeutic resistance. The Nrf2-Keap1 modulators that interact with each other may also be effectively applicable to CRT effect in LARC.

Surgical safety in the COVID-19 era: present and future considerations

The impacts of coronavirus disease 2019 (COVID-19) have been globally paradigm shifting in all aspects. Surgeons have experienced unprecedented changes regarding operation schedules, preparations before surgery, and the precautions needed both during and after surgery. Many medical centers simultaneously reported a decrease in their numbers of surgeries, whether they were elective or emergent, or for cancerous or benign resections. However, accumulated surgical outcomes from the last 2 years of experience presented postoperative morbidity and mortality data that were comparable to the pre-pandemic era, whether in elective or urgent settings. Although COVID-19 showed a significant association with postoperative morbidity and mortality, the majority of noninfected patients could be treated successfully with stringent mitigation protocols. Initially recommended to be avoided at the start of the pandemic, minimally invasive surgery seems to be safe and feasible according to reported surgical outcomes. Numerous sets of guidelines have now been produced from medical societies and adhering to the basic precautions has been found to be practicable. It is crucial that health care systems and surgical staff remain vigilant and attentive to the ever-changing situation in this pandemic in order to provide optimal medical support to their patients.