CT-diagnosed severe skull base bone destruction predicts distant bone metastasis in early N-stage nasopharyngeal carcinoma

Dual-energy CT for the detection of skull base invasion in nasopharyngeal carcinoma: comparison of simulated single-energy CT and MRI

BACKGROUND

Skull base invasion in nasopharyngeal carcinoma (NPC) was shown to be a poor negative prognostic factor, and dual-energy CT (DECT) has heralded a new approach to detect this condition. The study aims to evaluate the value of DECT for detection of skull base invasion in NPC and compare the diagnostic performance of DECT with those of simulated single-energy CT (SECT) and MRI.

METHODS

The imaging findings of 50 NPC patients and 31 participants in control group which underwent DECT examinations were assessed in this retrospective study. The skull base invasions were evaluated using 5-point scale by two blind observers. ROC analysis, Mcnemar test, paired t test, weighted K statistics and intraclass correlation coefficient were performed to evaluate the diagnostic performance of simulated SECT, MRI and DECT.

RESULTS

Quantitative analysis of DECT parameters showed higher normalized iodine concentration and effective atomic number values in sclerosis and lower values in erosion than those in normal bones (both p < 0.05). Compared with simulated SECT and MRI, the diagnostic sensitivity for DECT was significantly improved from 75% (simulated SECT) and 84.26% (MRI) to 90.74% (DECT) (both p < 0.001), specificity from 93.23% and 93.75% to 95.31 (both p < 0.001), accuracy from 86.67% and 90.33% to 93.67%, and AUC from 0.927 and 0.955 to 0.972 (both p < 0.05), respectively.

CONCLUSIONS

DECT demonstrates better diagnostic performance than simulated SECT and MRI for detecting skull base invasions in NPC, even those slight bone invasions in early stage, with higher sensitivity, specificity and accuracy.

Predicting Bone Metastasis Risk Based on Skull Base Invasion in Locally Advanced Nasopharyngeal Carcinoma

Objective

To develop and validate a bone metastasis prediction model based on skull base invasion (SBI) in patients with locally advanced nasopharyngeal carcinoma (LA-NPC).

Methods

This retrospective cohort study enrolled 290 patients with LA-NPC who received intensity-modulated radiation therapy in two hospitals from 2010 to 2020. Patient characteristics were grouped by SBI and hospital. Both unadjusted and multivariate-adjusted models were used to determine bone metastasis risk based on SBI status. Subgroup analysis was performed to investigate heterogeneity using a forest graph. Cox proportional hazard regression analysis was used to screen for risk factors of bone metastasis-free survival (BMFS). A nomogram of BMFS based on SBI was developed and validated using C-index, receiver operating characteristic curve, calibration curves, and decision curve analysis after Cox proportional hazard regression analysis.

Results

The incidence of bone metastasis was 14.83% (43/290), 20.69% (24/116), and 10.92% (19/174) in the overall population, SBI-positive group, and SBI-negative group, respectively. In the unadjusted model, SBI was associated with reduced BMFS [HR 2.43 (1.32–4.47), P = 0.004], and the results remained stable after three continuous adjustments (P <0.05). No significant interaction was found in the subgroup analyses (P for interaction >0.05). According to Cox proportional hazard regression analysis and clinical value results, potential risk factors included SBI, Karnofsky performance status, TNM stage, induction chemotherapy, concurrent chemoradiotherapy, and adjuvant chemotherapy. Using a training C-index of 0.80 and a validation C-index of 0.79, the nomogram predicted BMFS and demonstrated satisfactory prognostic capability in 2, 3, and 5 years (area under curve: 83.7% vs. 79.6%, 81.7% vs. 88.2%, and 79.0% vs. 93.8%, respectively).

Conclusion

Skull base invasion is a risk factor for bone metastasis in patients with LA-NPC. The SBI-based nomogram model can be used to predict bone metastasis and may assist in identifying LA-NPC patients at the highest risk of bone metastasis.

The evolution of bone marrow signal changes at the skull base in nasopharyngeal carcinoma patients treated with radiation therapy

BACKGROUND

Clival infiltration is frequently seen in nasopharyngeal carcinoma (NPC) and the resultant bone marrow signal changes (BMSC) can persist even after complete tumor response to the radiation therapy (RT). The differentiation of those residual BMSC from recurrent/persistent disease may be challenging. We performed serial analysis of the clival BMSC after RT, to define an expected temporal evolution of those signal changes during the follow-up.

MATERIALS AND METHODS

Serial MRI studies of 50 NPC patients (with or without initial clival infiltration) who had undergone RT were retrospectively examined. Abnormal clival BMSC and contrast enhancement (CE) were evaluated on each follow-up scan. Duration of BMSC/CE was correlated with the degree of baseline clival involvement (BCID), RT dose, and primary mass volume (PMV).

RESULTS

Clival BMSC persisted without any evidence of recurrence, for a mean of 66.5 (max. 137) months (with accompanying CE for up to 125 months) in 26 patients with clival infiltration at diagnosis. Duration of BMSC and CE showed statistical correlations with PMW (p < 0.05), but not with RT dose or BCID. The rate of recurrence in clivus was 14%. New clival lesions that occurred within the first 12 months after RT (in six patients) did not develop recurrence suggesting radiation osteitis (12%).

CONCLUSION

After RT, residual clival medullary signal change/enhancement is seen in most NPC patients and can persist even years without recurrence.

Nasopharyngeal carcinoma among the pediatric patients in a non-endemic region: our experience at a tertiary care teaching hospital in Eastern India

Background

Nasopharyngeal carcinoma (NPC) is an extremely rare malignant lesion among the pediatric age group. The relative rarity of pediatric NPC makes the diagnosis difficult. This rarity is often associated with delayed diagnosis which may lead to advanced loco-regional disease. Here, we study the clinical presentations, investigations, and treatment of nasopharyngeal carcinoma in the pediatric age group in a non-endemic region.

Result

This is a retrospective study where 21 pediatric patients were enrolled with age under 18 years. They were managed at a tertiary care teaching hospital between December 2010 and January 2019. Majority of the patients in this study were boys (66.7%). All children diagnosed with NPC were treated with radiotherapy covering entire nasopharynx and some children with chemotherapy. Until the patient is in a late stage, most children diagnosed with NPC were presenting with symptoms of neck mass (90.5%), bleeding from the nose (66.7%), nasal blockage (57.1%), and hearing loss (47.6%). Pathological report revealed WHO type III in the majority of the patients. All patients were treated with radiotherapy to primary and enlarged neck nodes.

Conclusion

Children with NPC have excellent survival except for those with distant metastatic disease. NPC in the pediatric age is usually not suspected clinically until patient in late stage. The TNM staging has the most relevant prognostic factor. Unfortunately, NPC tends to be locally advanced at the time of diagnosis in the pediatric age group and is sometimes associated with distant metastasis. In our study, most children were diagnosed with NPC along with neck node enlargement and were treated with radiotherapy. The diagnosis of pediatric NPC should prompt timely treatment.

Superiority of intensity-modulated radiation therapy in nasopharyngeal carcinoma with skull-base invasion

PURPOSE

To compare the clinical results and functional outcomes between two-dimensional conventional radiation therapy (2DRT) and intensity-modulated radiation therapy (IMRT) in nasopharyngeal carcinoma (NPC) with skull-base invasion.

METHODS

A total of 1258 patients were subclassified into two groups: mild skull-base invasion group (792; 63%) and severe skull-base invasion group (466; 37%). Patients were pair matched (1:1 ratio) using six clinical factors into 2DRT or IMRT groups. The Kaplan-Meier method and Cox regression model were performed to assess overall survival (OS), disease-free survival (DFS), locoregional relapse-free survival (LRRFS) and distant metastasis-free survival (DMFS). Toxicities were evaluated.

RESULTS

IMRT significantly improved four-year OS compared with 2DRT (65.6% vs. 81.8%, P = 0.000), DFS (57.3% vs. 73.3%, P = 0.000) and LRRFS (76.5% vs. 87.5%, P = 0.003) in NPC with severe skull-base invasion, but similar results were observed in patients with mild skull-base invasion (P > 0.05). In patients with severe invasion, radiation therapy techniques were found to be an independent prognostic factor for OS (HR = 0.457, P = 0.000), DFS (HR = 0.547, P = 0.000) and LRRFS (HR = 0.503, P = 0.004). IMRT was associated with better OS. In subgroups analysis, IMRT group also had a better survival in OS, DFS (P < 0.05 for all rates) for patients received concurrent chemotherapy and sequential chemotherapy compared to 2DRT in the severe invasion group. The IMRT group displayed lower incidence of mucositis, xerostomia, trismus (< 1 cm) and temporal lobe necrosis than the 2DRT group.

CONCLUSIONS

IMRT significantly improved patient survival compared with 2DRT in NPC patients with severe skull-base invasion, but a similar survival rate was noted in mild invasion patients. Chemotherapy can improve survival in NPC patients with severe invasion. Among the two therapies, IMRT significantly decreased therapy-related toxicity.

Human nasopharyngeal carcinoma can be radiosensitized by trichosanthin via inhibition of the PI3K pathway

Nasopharyngeal carcinoma (NPC) is a prevalent tumor that affects the head and neck. Radiation therapy is typically used to treat NPC; however, poor prognoses and distant metastases are common due to radiation resistance. The antitumor activities of trichosanthin (TCS) have been reported in several types of tumors. The aim of the present study was to investigate whether TCS may serve as a potential radiosensitizer in the treatment of NPC tumors. In the present study, NPC cells were treated with radiation alone or together with TCS and radiosensitivity was compared. Clonogenic assay, flow cytometry and an animal study were performed to assess cell death in NPC. The clonogenic assay demonstrated that TCS had a significant radiosensitizing effect on NPC cells. Western blotting indicated that phosphorylated protein kinase B and signal-regulated kinase [phosphoinositide 3-kinase (PI3K) pathway] were downregulated, and that cleaved caspase-3 was upregulated by combined treatment with TCS and radiation. Furthermore, TCS potently radiosensitized NPC xenografts in vivo. In conclusion, TCS radiosensitized NPC in vitro and in vivo via downregulation of PI3K pathways and the upregulation of cleaved caspase-3.

Diagnostic value of diffusion-weighted magnetic resonance imaging for local and skull base recurrence of nasopharyngeal carcinoma after radiotherapy

Tumor recurrence is a major cause of nasopharyngeal carcinoma (NPC) treatment failure. Diffusion-weighted imaging (DWI) is used for a variety of cancers, but few data are available for NPC.The aim of the study was to investigate the DWI features of recurrent NPC after radiotherapy and apparent diffusion coefficient (ADC) thresholds for the diagnosis of recurrent NPC.This was a retrospective study of 160 patients with NPC treated by radiotherapy at the Cancer Hospital affiliated to Guangxi Medical University from May 2012 to March 2015. The patients were divided into the local recurrence (n = 39), fibrosis (n = 51), clivus recurrence (n = 22), and clivus nonrecurrence (n = 48) groups. The patients underwent magnetic resonance imaging (MRI), enhanced MRI, and DWI. Receiver operating characteristics curves were used to determine sensitivity, specificity, and negative predictive values.ADC values were significantly different between the recurrence and fibrosis groups (P < .0001). Using ADC threshold values of 0.887 × 10 mm/s for local recurrence, the area under the curve (AUC) of DWI was 0.967 (87.2% sensitivity and 94.1% specificity), compared with 0.732 for routine MRI (71.8% sensitivity and 74.5% specificity) (P < .001). Using ADC threshold values of 1.018 × 10 mm/s for the diagnosis of clivus recurrent NPC, the AUC of DWI was 0.984 (95.5% sensitivity and 91.7% specificity) compared with 0.558 for routine MRI (63.6% sensitivity and 47.9% specificity) (P < .001).DWI has a higher diagnostic value for recurrent NPC than MRI. DWI can increase the diagnosis sensitivity and specificity of locally recurrent NPC.