Objectives:We sought to construct a nomogram model predicting lymph node metastasis (LNM) in patients with squamous cell carcinoma of the buccal mucosa based on preoperative clinical characteristics. Methods:Patients who underwent radical resection of a primary tumor in the buccal mucosa with neck dissection were enrolled. Clinical characteristics independently associated with LNM in multivariate analyses were adopted to build the model. Patients at low risk of LNM were defined by a predicted probability of LNM of less than 5%. Results: Patients who underwent surgery in an earlier period (January 2015-November 2019) were defined as the model development cohort (n = 325), and those who underwent surgery later (November 2019-March 2021) were defined as the validation cohort (n = 140). Age, tumor differentiation, tumor thickness, and clinical N stage assessed by computed tomography/magnetic resonance imaging (cN) were independent predictors of LNM. The nomogram model based on these four predictors showed good discrimination accuracy in both the model development and validation cohorts, with areas under the receiver-operating characteristic curve (AUC) of 0.814 and 0.828, respectively. LNM prediction by the nomogram model was superior to cN in AUC comparisons (0.815 vs. 0.753) and decision curve analysis of the whole cohort. Seventy-one patients were defined as having a low risk of LNM, among whom the actual metastasis rate was only 1.4%. Conclusions: A robust nomogram model for preoperative LNM prediction is built.

Objectives: To compare tumor volume reduction after induction chemotherapy (IC) with gemcitabine plus cisplatin (GP) and docetaxel plus cisplatin (DP) and to evaluate the influence on subsequent radiotherapy in locoregionally advanced nasopharyngeal carcinoma (NPC).Study Design: Retrospective clinical study. Methods: Patients who received GP or DP IC followed by concurrent chemoradiotherapy (CCRT) were retrospectively enrolled. Propensity score matching (PSM) was adopted to control the balance between the GP and DP groups.Results: A total of 41 patients treated with GP and 53 patients treated with DP were enrolled. After matching, 33 subpairs of 66 patients were generated in the post-PSM cohort. As compared with DP, GP was superior in its gross tumor volume of the nasopharynx (GTVnx) reduction (28.88% vs. 18.73%; P = .014) but equivalent in its gross tumor volume of the lymph nodes (GTVnd) reduction (37.58% vs. 29.79%; P = .229). Univariate and multivariate analyses confirmed that the chemotherapy regimen was an independent factor associated with the reduction in GTVnx (P = .011). The GP group exhibited advantages in the dosimetric parameters of the planning target volume of high-risk volume and low-risk volume (PTV1 and PTV2), lenses, temporal lobes, and parotid glands. Univariate and multivariate analyses confirmed that chemotherapy regimen was an independent factor associated with the dosimetric parameters of PTV1, PTV2, lenses, temporal lobes, and parotid glands.Conclusion: GP regimen achieves a greater GTVnx reduction than DP regimen and has an advantage in the dosimetry of subsequent CCRT.

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