Prognostic value of cervical nodal necrosis on staging imaging of nasopharyngeal carcinoma in era of intensity-modulated radiotherapy: a systematic review and meta-analysis

Pre-treatment and post-treatment nasopharyngeal carcinoma imaging: imaging updates, pearls and pitfalls

PURPOSE

Nasopharyngeal carcinoma (NPC) is endemic in Southeast Asia, requiring precise imaging for personalized treatment. This review highlights key imaging challenges and updates from recent literature, emphasizing findings that impact oncological management.

METHODS

We discuss common and uncommon clinical entities, detailing salient imaging features and diagnostic distinctions to aid accurate interpretation.

RESULTS

In the pre-treatment setting, leveraging the characteristic MR signals and spread patterns of NPC aids in defining the tumor volume for accurate staging and radiotherapy contouring. Key diagnostic challenges include differentiating tumor from benign hyperplasia, skull base osteomyelitis, and other skull base tumors. Perineural tumor spread, radiological extranodal extension and nodal necrosis further refine primary tumor and nodal assessment. In the post-treatment setting, the key question is whether tumor recurrence exists. Diagnostic challenges involve distinguishing tumor recurrence from scar tissue, post-radiation nasopharyngeal necrosis, or hypertrophied cervical ganglia. For recurrences, endoscopic nasopharyngectomy has emerged as the preferred approach over open surgery or re-irradiation. The text highlights characteristic post-treatment appearances and emphasizes recognizing these patterns to avoid misinterpretation and guide appropriate management.

CONCLUSION

Imaging plays a pivotal role in NPC precision oncology. Mastering imaging pearls and pitfalls empowers radiologists to provide clinicians with reliable, actionable guidance.

Advances in Nasopharyngeal Carcinoma Staging: from the 7th to the 9th Edition of the TNM System and Future Outlook

PURPOSE OF REVIEW

Nasopharyngeal carcinoma (NPC), characterized by its aggressive nature and sensitivity to radiation, demands accurate staging for optimal clinical outcomes. The purpose of this review was to provides a comprehensive overview of the evolution of the TNM staging system for NPC based on recent and previously published studies, with particular emphasis on the transition from the 7th to the 9th edition.

RECENT FINDINGS

The 9th edition introduces critical changes, particularly in the N and M classifications, to enhance prognostic accuracy. Our analysis also incorporates the burgeoning roles of biomarkers, especially Epstein-Barr virus (EBV)-DNA, and the potential of Artificial Intelligence (AI) in refining NPC staging. Each iteration of the TNM staging system for NPC has successfully enhanced the prognostic precision of NPC, with notable advancements from the 7th to the 9th edition. We also delves into the incorporation of biomarkers, such as EBV-DNA, and the potential of AI in refining staging accuracy. These innovations are anticipated to offer personalized prognoses and inform tailored treatment strategies for NPC patients in the future.

Machine learning-derived prognostic signature for progression-free survival in non-metastatic nasopharyngeal carcinoma

BACKGROUND

Early detection of high-risk nasopharyngeal carcinoma (NPC) recurrence is essential. We created a machine learning-derived prognostic signature (MLDPS) by combining three machine learning (ML) models to predict progression-free survival (PFS) in patients with non-metastatic NPC.

METHODS

A cohort of 653 patients with non-metastatic NPC was divided into a training (n = 457) and validation (n = 196) dataset (7:3 ratio). The study included clinicopathological characteristics, hematologic markers, and MRI findings in three machine learning models-random forest (RF), extreme gradient boosting (XGBoost), and least absolute shrinkage and selection operator (LASSO)-to predict progression-free survival (PFS). A Venn diagram identified the overlapping signatures from the three ML algorithms. Cox proportional hazard analysis determined the MLDPS for PFS.

RESULTS

The RF, XGBoost, and LASSO algorithms identified six consensus factors from the 33 signatures. Cox proportional hazards analysis showed that the MLDPS includes age, lymphocyte count, number of positive lymph nodes, and regional lymph node density. Additionally, MLDPS effectively stratified prognosis, with low-risk individuals showing better PFS than high-risk individuals (p < 0.001).

CONCLUSION

MLDPS, based on clinicopathological characteristics, hematologic markers, and MRI findings, is crucial for guiding clinical management and personalizing treatments for patients with non-metastatic NPC.

Evaluating the Efficacy of Different Treatment Intensities in Nasopharyngeal Carcinoma Patients: A Nationwide Cancer Registry-Based Study

OBJECTIVE

The aim of this study was to evaluate the efficacy of different treatment intensities (TIs) in patients with nasopharyngeal carcinoma (NPC).

METHODS

The study assessed newly diagnosed, non-metastatic NPC patients from the Taiwan Cancer Registry between 2010 and 2017. TIs were divided into four groups: TI1 [radiotherapy (RT) alone or induction chemotherapy (IC) followed by RT); TI2 (concurrent chemoradiotherapy (CRT) alone); TI3 (IC followed by CRT or CRT followed by adjuvant chemotherapy (AC)]; and TI4 (IC followed by CRT followed by AC). The primary outcome was cancer-specific survival (CSS).

RESULTS

The study included 9863 patients. For stage I-II NPC patients, there was no significant difference in CSS among the different TI groups. For stage III patients, those receiving TI3 had better CSS (hazard ratio [HR] 0.69) compared with those receiving TI1. No significant differences in CSS were noted among those receiving TI2, TI3, and TI4. For stage IVA-B patients, those receiving TI2 (HR 0.70), TI3 (HR 0.49), and TI4 (HR 0.43) had better CSS compared with those receiving TI1. Compared with stage IVA-B patients receiving TI2, those receiving TI3 (HR 0.70) and TI4 (HR 0.61) had significantly better CSS. No differences in CSS were noted between those receiving TI3 and TI4.

CONCLUSIONS

For stage I-II NPC patients, RT alone is appropriate. For stage III and IVA-B patients, IC + CRT or CRT + AC may be needed to achieve optimal outcomes. No advantage of IC + CRT + AC over IC + CRT or CRT + AC was observed.

Radiologic extranodal extension for nodal staging in nasopharyngeal carcinoma

PURPOSE

Extranodal extension (ENE) has the potential to add value to the current nodal staging system (N8th) for predicting outcome in nasopharyngeal carcinoma (NPC). This study aimed to incorporate ENE, as well as cervical nodal necrosis (CNN) to the current stage N3 and evaluated their impact on outcome prediction. The findings were validated on an external cohort.

METHODS & MATERIALS

Pre-treatment MRI of 750 patients from the internal cohort were retrospectively reviewed. Predictive values of six modified nodal staging systems that incorporated four patterns of ENE and two patterns of CNN to the current stage N3 for disease-free survival (DFS) were compared with that of N8th using multivariate cox-regression and concordance statistics in the internal cohort. Performance of stage N3 for predicting disease recurrence was calculated. An external cohort of 179 patients was used to validate the findings.

RESULTS

Incorporation of advanced ENE, which infiltrates into adjacent muscle/skin/salivary glands outperformed the other five modifications for predicting outcomes (p < 0.01) and achieved a significantly higher c-index for 5-year DFS (0.69 vs 0.72) (p < 0.01) when compared with that of N8th staging system. By adding advanced ENE to the current N3 increased the sensitivity for predicting disease recurrence from 22.4 % to 47.1 %. The finding was validated in the external cohort (5-year DFS 0.65 vs. 0.72, p < 0.01; sensitivity of stage N3 increased from 14.0 % to 41.9 % for disease recurrence).

CONCLUSION

Results from two centre cohorts confirmed that the radiological advanced ENE should be considered as a criterion for stage N3 disease in NPC.

Depletion of SLC7A11 Sensitizes Nasopharyngeal Carcinoma Cells to Ionizing Radiation

BACKGROUND

Radiotherapy is the primary treatment choice for Nasopharyngeal Carcinoma (NPC). However, its efficacy is compromised due to radioresistance. Ferroptosis, a novel iron-dependent regulated cell death induced by Ionizing Radiation (IR), plays a role in promoting cancer cell death. Yet, the relationship between enhanced ferroptosis and increased sensitivity of NPC cells to IR remains poorly understood.

OBJECTIVE

This study aimed to explore the association between IR and ferroptosis in NPC, as well as the role of the ferroptosis repressor SLC7A11 in IR-treated NPC cells.

METHODS

CNE1 and HNE-2 NPC cells were subjected to IR treatment. We performed qPCR and western blotting to evaluate the expression of ferroptosis-related genes in both control and IR-treated NPC cells. Additionally, we used the MTT assay to measure the viability of these NPC cells. JC-1 and DCFH-DA staining were employed to assess mitochondrial membrane potential and Reactive Oxygen Species (ROS) levels in both control and IR-treated NPC cells. Furthermore, we examined the levels of Fe2+, Malondialdehyde (MDA), reduced Glutathione (GSH), and oxidized glutathione (GSSG) in these cells. Moreover, we depleted SLC7A11 in IR-treated NPC cells to investigate its impact on the ferroptosis of these cells.

RESULTS

IR upregulated the expression of ferroptosis-related genes, including SLC7A11, ACSL4, COX2, FTH1, and GPX4, in CNE1 and HNE-2 cells. IR treatment also resulted in decreased cell viability, disrupted mitochondrial membrane potential, increased ROS levels, altered glutathione levels, and elevated Fe2+ levels. Knockdown of SLC7A11 enhanced the sensitivity of NPC cells to IR.

CONCLUSION

IR may induce ferroptosis in NPC cells, and stimulating ferroptosis could potentially serve as a therapeutic strategy to enhance the efficacy of IR in treating NPC patients.

Regional lymph node density-based nomogram predicts prognosis in nasopharyngeal carcinoma patients without distant metastases

BACKGROUND

Nasopharyngeal carcinoma (NPC) is a relatively common type of cancer in Southern China, with local recurrence or distant metastases even after radical treatment; consequently, it is critical to identify the patients at higher risk for these events beforehand. This study aimed to assess the prognostic value of regional lymph node density (RLND) associated nomograms in NPC and to evaluate the utility of nomograms in risk stratification.

METHODS

A total of 610 NPC patients without distant metastases (425 in the training and 185 in the validation cohort) were enrolled. The MRI-identified nodal features and clinical characteristics were documented, and the RLND was calculated. Cox analyses were conducted to identify prognostic-associated factors. Nomograms were generated based on the multivariate analysis results. The predictive accuracy and discriminative ability of the nomogram models were determined using the concordance index (C-index), receiver operating characteristic (ROC) curve, and calibration curve; the results were compared with those of the tumor-node-metastasis (TNM) classification. Decision curve analysis (DCA) and C-index were used to assess the prognostic effect and added discriminative ability of RLND. We also estimated the optimal RLND-based nomogram score cut-off values for survival prediction.

RESULTS

RLND was an independent predictor of overall survival (OS) and disease-free survival (DFS), with hazard ratios of 1.36 and 1.30, respectively. RLND was utilized in the construction of nomograms, alongside other independent prognostic factors. The RLND-based nomogram models presented a more effective discriminative ability than the TNM classification for predicting OS (C-index, 0.711 vs. 0.680) and DFS (C-index, 0.681 vs. 0.669), with favorable calibration and consistency. The comparison of C-index values between the nomogram models with and without RLND provided substantiation of the crucial role RLND plays in these models. DCA confirmed the satisfactory clinical practicability of RLND. Moreover, the nomograms were used to categorize the patients into three groups (high-, middle-, and low-risk), and the Kaplan-Meier curves showed significant differences in prognosis between them (p < 0.05). These results were verified in the validation cohort.

CONCLUSION

RLND stands as a robust prognostic factor in NPC. The RLND-based nomograms excel in predicting survival, surpassing the TNM classification.

Efficacy of induction chemotherapy in lymph node-positive stage III nasopharyngeal carcinoma and identification of beneficiaries based on clinical features: A propensity score matching analysis

PURPOSE

To investigate the role of induction chemotherapy (IC) in lymph node-positive (LN-positive) stage III nasopharyngeal carcinoma (NPC) receiving concurrent chemoradiotherapy (CCRT).

METHODS

In total, 627 patients with newly diagnosed LN-positive stage III NPC receiving CCRT or IC plus CCRT were included. The primary endpoint was progression-free survival (PFS). Propensity-score matching (PSM) was conducted to balance the intergroup covariates. Kaplan-Meier method with log-rank test was employed to compare survival curves. Subgroup analyses were conducted based on baseline characteristics.

RESULTS

After 1:1 PSM, 414 patients were identified (207 patients per group). Compared with CCRT, IC plus CCRT provided better survival (5-year PFS 88.4% vs. 78.6%, P = 0.01; overall survival [OS] 94.8% vs. 85.3%, P = 0.003; and distant metastasis-free survival [DMFS] 93.1% vs. 85.6%, P = 0.03). The IC beneficial effects on PFS were mainly present in patients with grade 2-3 ENE, elevated serum lactate dehydrogenase (LDH > 170U/L), and N2 disease. Patients with grade 2 CNN had comparable PFS benefits to those with grade 0-1 CNN. For patients with grade 0-1 ENE combined with LDH ≤ 170U/L, survival between the two groups was similar with 5-year PFS 93.6% vs. 90.4% (P = 0.50), OS 94.2% vs. 93.0% (P = 0.72), and DMFS 98.6% vs. 97.7% (P = 0.98).

CONCLUSION

Adding IC before CCRT improved survival in LN-positive stage III NPC patients. Additional IC did not provide better survival for patients with grade 0-1 ENE combined with LDH ≤ 170U/L and could be avoided in this population. CNN may not be a good risk factor for tailoring a personalized treatment plan.

Prognostic Value of Lymph Node Necrosis at Different N Stages in Patients with Nasopharyngeal Carcinoma

Background: Lymph node necrosis (LNN), including retropharyngeal nodal necrosis and cervical nodal necrosis, which is related to radiotherapy/ chemotherapy resistance, is a common phenomenon in nasopharyngeal carcinoma (NPC). This study was to assess the prognostic value of LNN at different N stages in NPC patients. Materials and Methods: In total, 1,665 newly diagnosed NPC patients at stage TxN1-3M0 from two centers were enrolled. Univariate and multivariate models were constructed to assess the association between LNN and long-term survival outcomes. The propensity score matching method was performed to balance treatment groups for baseline characteristics. Results: Of the 1,665, 540 patients (540/1665, 32.4%) were diagnosed with LNN, of which 54.1% (292/540) patients were at stage N1, 31.3% (169/540) at stage N2, and 14.6% (79/540) at stage N3. Univariate and multivariate analyses indicated LNN as an independent predictor for progression‑free survival (PFS), overall survival (OS), distant metastasis-free survival (DMFS), and locoregional relapse-free survival (LRRFS) in stage N1-3 patients (all P<0.001). When patients were analyzed according to stage, similar findings were observed for N1 patients (all P<0.001); for N2 patients, LNN independently predicted PFS (P=0.003), OS (P=0.011), and DMFS (P=0.004), and for stage N3, LNN only independently predicted LRRFS (P=0.019). 123 pairs of patients who received induction chemotherapy plus concurrent chemoradiotherapy or only concurrent chemoradiotherapy were matched, adding induction chemotherapy improved 5-year OS, PFS and LRFFS, but the results were not statistically significant. Conclusions: In NPC patients, LNN could independently predict poor prognosis at all N1-3 stages and at each N stage (N1 to N3). The value of adding induction chemotherapy to concurrent chemoradiotherapy in patients with LNN still requires further prospective studies.

Normal size of benign upper neck nodes on MRI: parotid, submandibular, occipital, facial, retroauricular and level IIb nodal groups

PURPOSE

Nodal size is an important imaging criterion for differentiating benign from malignant nodes in the head and neck cancer staging. This study evaluated the size of normal nodes in less well-documented nodal groups in the upper head and neck on magnetic resonance imaging (MRI).

METHODS

Analysis was performed on 289 upper head and neck MRIs of patients without head and neck cancer. The short axial diameters (SAD) of the largest node in the parotid, submandibular, occipital, facial, retroauricular and Level IIb of the upper internal jugular nodal groups were documented and compared to the commonly used threshold of ≥ 10 mm for diagnosis of a malignant node.

RESULTS

Normal nodes in the parotid, occipital, retroauricular and Level IIb groups were small with a mean SAD ranging from 3.8 to 4.4 mm, nodes in the submandibular group were larger with a mean SAD of 5.5 mm and facial nodes were not identified. A size ≥ 10 mm was found in 0.8% of submandibular nodes. Less than 10% of the other nodal group had a SAD of ≥ 6 mm and none of them had a SAD ≥ 8 mm.

CONCLUSION

To identify malignant neck nodes in these groups there is scope to reduce the size threshold of ≥ 10 mm to improve sensitivity without substantial loss of specificity.

Prognostic value of the cervical lymph node necrosis ratio in nasopharyngeal carcinoma

PURPOSE

Whether cervical lymph node necrosis (CNN) is an independent adverse prognostic factor in nasopharyngeal carcinoma (NPC) has not been determined. In this study, the CNN ratio was graded quantitatively to explore the prognostic value in NPC.

PARTICIPANTS AND METHODS

We retrospectively reviewed a total of 648 pathologically confirmed as NPC. We outlined metastatic lymph nodes and necrotic area of lymph nodes slice by slice on the magneticresonanceimages (MRI) cross section, and calculated the corresponding CNN ratio.

RESULTS

The median CNN ratio (17.37 %) was taken as the cut-off point, 256 (39.51 %) patients were divided into CNN1 group (<17.37 %, n = 128) and CNN2 group (≥17.37 %, n = 128), 392 (60.49 %) patients without lymph nodes necrosis were CNN0. Among the CNN0, CNN1 and CNN2 groups, five-year overall survival (OS) was 82.4 %, 76.6 % and 71.1 %, locoregional recurrence-free survival (LRRFS) was 91.3 %, 91.1 % and 90.5 %, distant metastasis-free survival (DMFS) was 83.7 %, 78.5 % and 68.7 %, progression-free survival (PFS) was 78.3 %, 71.7 % and 61.6 % respectively. By multivariate analysis, CNN was an independent prognostic factor for OS (P = 0.003), DMFS (P = 0.019) and PFS (P = 0.007). More than 3 cycles of chemotherapy significantly increased OS (P = 0.024) and DMFS (P = 0.015) in the CNN1 group.

CONCLUSIONS

This study indicated that CNN is one of the factors with the negative prognosis of NPC. The CNN ratio might be used as one of the reference factors in the formulation of individualized treatment plan.