Efficacy and Safety of Re-Challenging PD-1 Inhibitors in Second-Line Treatment in Metastatic Nasopharyngeal Carcinoma Previously Treated with Chemotherapy and PD-1 Inhibitors.

Background: We aim to evaluate the efficacy and safety of anti-PD1 rechallenge in combination with chemotherapy in patients with metastatic nasopharyngeal carcinoma (mNPC) who have progressed on prior anti-PD1 therapy. Patients and Methods: We enrolled patients with mNPC who received chemotherapy combined with PD-1 immune-checkpoint inhibitors (ICIs) or chemotherapy alone after prior progression of anti-PD1 therapy. The primary endpoint was progress-free survival (PFS), and the secondary endpoints included overall survival (OS), disease control rate (DCR) and objective response rate (ORR). Results: A total of 96 patients were eligible between January 2015 and December 2020. Thirty-seven (38.5%) were in the PD-1 ICIs re-challenge group, while the remaining 59 patients (61.5%) were in the chemotherapy group. The ORR and DCR of PD-1 ICIs group and chemotherapy group were 37.8% vs 23.7% and 86.5% vs.74.5%, respectively. After a median follow-up period of 21.1 months (IQR 16.1-28.7), the log-rank analysis demonstrated a significantly improved PFS in the PD-1 ICIs re-challenge group compared to the chemotherapy group (8.4 months [95% CI 4.3-14.0] vs 5.0 months [95% CI 2.8-7.2], P = 0.03). However, no significant difference in OS was observed between the two groups (28.3 vs 24.1 months, P = 0.09). The two groups had similar adverse reactions, but the incidence of grade 3 or 4 thrombocytopenia was significantly higher in the PD-1 ICIs re-challenge group (18.9% vs 3.4%, P = 0.025). Conclusion: mNPC patients who progressed from prior anti-PD1 therapy could benefit from the anti-PD1 rechallenge in combination with chemotherapy. However, further validation is needed.

Short-term versus long-term metronomic adjuvant chemotherapy in locally advanced nasopharyngeal carcinoma: A propensity score-matched real-world study.

BACKGROUND: This retrospective study aimed to determine the optimal metronomic chemotherapy duration (MTCD) as adjuvant therapy for patients with locally advanced nasopharyngeal carcinoma (LANPC). METHODS: This study involved LANPC patients treated with metronomic chemotherapy (MTC) using a 5-FU prodrug (S1, capecitabine, or tegafur) from May 2013 to September 2020. The optimal MTCD threshold was established using X-tile Bioinformatics software. The overall survival (OS), progression-free survival (PFS), distant metastasis-free survival (DMFS), and locoregional relapse-free survival (LRRFS) were compared between short-term and long-term groups using propensity score matching (PSM). RESULTS: A total of 546 patients were analyzed. MTCD was an independent prognostic factor for OS, PFS, and DMFS (all P < 0.05). Patients were categorized into long-term (>3 months) and short-term (≤3 months) MTCD groups. After a median follow-up of 48 months, significant differences were observed in 4-year OS (97.0 % vs. 87.1 %; P < 0.01), PFS (84.6 % vs. 70.9 %; P < 0.01), DMFS (87.3 % vs. 78.8 %; P < 0.01), and LRRFS (95.3 % vs. 87.4 %; P < 0.01) between the long-term and short-term groups. In the PSM-matched cohort of 196 patients per group, the long-term group demonstrated superior 4-year OS and LRRFS (97.3 % vs. 87.1 %, P < 0.01; 95.2 % vs. 90.0 %, P < 0.05). No significant differences in acute toxicities were observed between the groups (P > 0.05). CONCLUSION: Extended MTC with a 5-FU prodrug (>3 months) may benefit NPC patients. Further prospective studies are needed to validate these findings.

MRI-detected residual retropharyngeal lymph node after intensity-modulated radiotherapy in nasopharyngeal carcinoma: Prognostic value and a nomogram for the pretherapy prediction of it.

BACKGROUND AND PURPOSE: To evaluate the prognostic value of MRI-detected residual retropharyngeal lymph node (RRLN) at three months after intensity-modulated radiotherapy (IMRT) in patients with nasopharyngeal carcinoma (NPC) and second, to establish a nomogram for the pretherapy prediction of RRLN. MATERIALS AND METHODS: We included 1103 patients with NPC from two hospitals (Sun Yat-Sen University Cancer Center [SYSUCC, n = 901] and Dongguan People's Hospital [DGPH, n = 202]). We evaluated the prognostic value of RRLN using Cox regression model in SYSUCC cohort. We developed a nomogram for the pretherapy prediction of RRLN using logistic regression model in SYSUCC training cohort (n = 645). We assessed the performance of this nomogram in an internal validation cohort (SYSUCC validation cohort, n = 256) and an external independent cohort (DGPH validation cohort, n = 202). RESULTS: RRLN was an independent prognostic factor for OS (HR 2.08, 95% CI 1.32-3.29), DFS (HR 2.45, 95% CI 1.75-3.42), DMFS (HR 3.31, 95% CI 2.15-5.09), and LRRFS (HR 3.04, 95% CI 1.70-5.42). We developed a nomogram based on baseline Epstein-Barr virus DNA level and three RLN status-related features (including minimum axial diameter, extracapsular nodal spread, and laterality) that predicted an individual's risk of RRLN. Our nomogram showed good discrimination in the training cohort (C-index = 0.763). The favorable performance of this nomogram was confirmed in the internal and external validation cohorts. CONCLUSION: MRI-detected RRLN at three months after IMRT was an unfavorable prognostic factor for patients with NPC. We developed and validated an easy-to-use nomogram for the pretherapy prediction of RRLN.

[Influence of patient setup error on planning risk volumes for nasopharyngeal carcinoma patients receiving intensity-modulated radiation therapy].

BACKGROUND & OBJECTIVE: Determination of planning risk volumes (PRVs) for an organ at risk greatly affects dose optimization in designing the intensity-modulated radiation therapy (IMRT) regimen. Patient setup errors have been found to closely correlate to the definition of PRVs. This study was to investigate the safety margin for the organ at risk during IMRT planning for nasopharyngeal carcinoma (NPC) patients. METHODS: Nineteen NPC patients (stage T1-2N0M0) who received IMRT for the first time were studied. Repeated computed tomography (CT) scans were performed for the patients once a week during the whole treatment course. A total of 85 CT scan reports were obtained. Differences between patient positioning of each time and first treatment setup were caluculated by comparing the anatomical landmarks (that is, optical nerve, pituitary, spine, and parotid) on each CT scan image using Osiris software. RESULTS: The displacement of optical nerve and pituitary in X, Y, and Z directions were, in absolute values, (0.86+/-0.53) mm, (0.84+/-0.68) mm, and (0.93+/-1.02)mm, respectively. The standard deviations (SDs) of systematic errors for the axial vector displacement were 0.83 mm, 1.08 mm, and 1.21 mm, while the SDs of random errors were 0.85 mm, 0.83 mm and 1.14 mm. The displacement of spine and parotid in X, Y, and Z directions were, in absolute values, (0.98+/-0.74) mm, (1.25+/-0.88) mm, and (1.43+/-1.02) mm, respectively. The SDs of systematic errors for axial vector displacement were 0.98 mm, 1.35 mm, and 1.87 mm, while the SDs of random errors were 1.02 mm, 1.46 mm, and 1.54 mm. CONCLUSION: It is feasible to determine the size of a safety margin of IMRT for organs at risk using repeated CT scans for NPC patients.