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Elevated tumor-infiltrating T-cell density is associated with favorable outcomes in patients with rectal cancer treated with neoadjuvant chemoradiotherapy (CRT). Here, we evaluated the significance of programmed cell death 1 (PD-1)-positive cells, regulatory T cells, and macrophages in response to CRT and prognosis.We assessed CD8+, PD-1+, FOXP3+, CD68+, and CD163+ intratumoral and stromal cell densities by immunohistochemistry using pre-treatment biopsies from 275 patients with rectal cancer treated with neoadjuvant CRT. We determined the impact of these measurements on response to CRT and survival. Response to CRT was determined by tumor regression grade (TRG) of surgical specimens, with good responders defined as TRG3-4.Intratumoral CD8+ and PD-1+ cell densities were significantly higher in good responders than in poor responders, whereas stromal CD68+ cell density was significantly lower in good responders as compared with poor responders. The multivariable analysis revealed high intratumoral CD8+ and PD-1+ cell densities to be independently associated with good responders (CD8: odds ratio [OR], 2.27; 95% confidence interval [CI], 1.21 - 4.34, P = .010; PD-1: OR, 1.97; 95%CI, 1.03 - 3.84, P = .039), and improved recurrence-free survival (CD8: hazard ratio [HR], 0.56; 95%CI, 0.32 - 0.98, P = .044; PD-1: HR, 0.37; 95%CI, 0.19 - 0.71, P = .002). Only high intratumoral CD8+ cell density was associated with improved overall survival (P = .022).Pre-treatment high intratumoral PD-1+ and CD8+ cell densities were independently associated with good response to CRT and improved recurrence-free survival, with high intratumoral CD8+ cell density additionally associated with improved overall survival. These values may serve as predictive and prognostic biomarkers in rectal cancer.

Highlights • Appendiceal mucinous neoplasms account for less than 1% of all cancers. • LAMNs have an aggressive biological potential. • Preoperative diagnosis of appendiceal mucinous neoplasms is difficult. • Here, we used emergency MRI to identify nodules in the appendix before operation., Introduction and importance We report the case of a patient with a low-grade appendiceal mucinous neoplasm (LAMN) who underwent emergency laparoscopic ileocecal resection to avoid the metastatic spread of tumor cells due to an impending rupture. Case presentation A 55-year-old woman presented to our hospital with pain in the right lower quadrant of the abdomen. Computed tomography revealed a markedly tense appendiceal mucinous tumor with surrounding inflammation, and laboratory test results showed elevated serum C-reactive protein (7.47 mg/dL), indicating impending rupture of the appendix. Magnetic resonance imaging revealed nodules inside the appendix, suggesting the possibility of appendiceal cancer. We performed emergency laparoscopic ileocecal resection with regional lymph node dissection. The tumor was pathologically diagnosed as a LAMN without rupture. Clinical discussion LAMN is classified as a clinically malignant tumor because it can cause pseudomyxoma peritonei due to perforation or the presence of residual tissue. Although an appendectomy would be appropriate for LAMN if the tumor margin is secured, ileocecal resection with lymph node dissection is necessary when preoperative discrimination of appendiceal cancer is impossible. Conclusion Further studies of preoperative imaging for appropriate differential diagnosis were necessary.