Intensity modulated radiation therapy in nasopharyngeal carcinoma

The Role of Circulating Tumor Cells in the Prognosis of Local Recurrence and Local Residual Nasopharyngeal Carcinoma Undergoing Endoscopic Resection

Purpose

To investigate the role of circulating tumor cells in the prognosis of local recurrence and local residual nasopharyngeal carcinoma undergoing endoscopic surgery.

Methods

A total of 56 patients with locally residual nasopharyngeal carcinoma (NPC) who underwent nasal endoscopic surgery from August 2018 to December 2021 were included. The status of circulating tumor cells (CTC) before and after surgery was detected, and its relationship with clinical characteristics and postoperative survival was analyzed.

Results

After nasal endoscopy, the positive rates of CTC and mesenchymal CTC (MCTC) detected in patients with nasopharyngeal carcinoma were significantly lower than those before treatment (P=0.0376; P=0.0212). Before nasal endoscopy, the status of CTC and MCTC was significantly correlated with the T stage (P < 0.05). After nasal endoscopy, the status of CTC and MCTC was significantly correlated with the TNM stage, T stage, and first radiotherapy mode (P < 0.05). The PFS of patients with different clinical characteristics was analyzed, and the results showed that the PFS of NPC patients with CTC (+) was significantly shorter than that of CTC (−) patients (18.71 vs. 22.47, P < 0.05) and the PFS of NPC patients with MCTC (+) was significantly shorter than that of MCTC (−) patients (18.22 vs. 22.30, P < 0.05). The PFS of NPC patients in TNM stage (I-II) was significantly longer than that in TNM stage (III) patients (22.53 vs. 18.57, P < 0.05). The PFS of NPC patients whose first radiotherapy mode was conventional was significantly longer than that of patients whose first radiotherapy mode was enhanced (22.14 vs. 16.85, P < 0.05). The COX analysis showed that MCTC and TNM stages were independent risk factors affecting the prognosis of local recurrence or local residual nasopharyngeal carcinoma after endoscopic resection (P < 0.05).

Conclusion

The detection of CTC is helpful for the prognosis evaluation of local recurrence or local residual NPC after endoscopic resection of NPC. The MCTC is an important factor affecting the prognosis of NPC patients.

Parotid Gland Stem Cell Preservation during Intensity-Modulated Radiotherapy for Nasopharyngeal Carcinoma: Dosimetric Analysis and Feasibility

Objective. Parotid gland (PG) is a radiosensitive organ, and xerostomia (XS) is a key factor affecting patients’ life quality after conventional radiotherapy for head and neck tumors. In this study, dosimetry analysis was performed on PG stem cell preservation in intensity-modulated radiotherapy (IMRT) for nasopharyngeal carcinoma (NPC). Methods. All clinical data of 80 NPC patients diagnosed pathologically in the Radiotherapy Department of Taizhou Hospital of Zhejiang Province Affiliated with Wenzhou Medical University from August 2017 to September 2019 were retrospectively analyzed. Patients were assigned to a regular group and a restricted group according to different IMRT plans, in which a dose limitation for the parotid duct was added in the restricted group in addition to the conventional plan used in the regular group to minimize the parotid duct radiation dose. The differences in planning target volume (PTV) dose distribution, organ at risk (OAR) dose, and dose to the PG and its ducts were compared between the two groups. Results. Significantly higher mean irradiation doses of the brainstem, mandible, and oral cavity were determined in the restricted group compared with the regular group ( $P>0.05$ ), but there was no significant difference in the mean dose of other OARs irradiated ( $P>0.05$ ). As compared to the irradiation of bilateral PGs, no statistical differences were found in the mean irradiation dose and V30 between regular and restricted groups ( $P>0.05$ ), but lower V20 and higher V45 were determined in the restricted group ( $P<0.05$ ). The mean irradiation dose, V15, V20, and V26 of bilateral parotid ducts were lower in the restricted group as compared to the regular group ( $P<0.05$ ). Conclusion. IMRT for NPC can effectively reduce the mean irradiation dose and play a PG stem cell preservation role by giving specific dose limitation conditions to the parotid duct area without affecting PTV dose distribution and OAR irradiation dose, which has certain feasibility.

Effect of Standardized Nutritional Intervention in Patients with Nasopharyngeal Carcinoma Receiving Radiotherapy Complicated with Diabetes Mellitus

Objective

To evaluate the effect of standardized nutritional intervention in patients with nasopharyngeal carcinoma receiving radiotherapy complicated with diabetes mellitus and the impact on quality of life.

Methods

From January 2019 to December 2020, 100 diabetic patients with nasopharyngeal carcinoma receiving radiotherapy were assessed for eligibility and recruited. They were concurrently and randomly assigned (1 : 1) to receive either conventional nursing (control group) or standardized nutritional intervention (observation group). The outcomes include clinical efficacy and quality of life.

Results

Standardized nutritional intervention was associated with significantly lower levels of fasting blood glucose (FBG), 2 h postprandial blood glucose (2hPBG), and glycated hemoglobin (HbA1c) versus conventional nursing (P < 0.001). The patients given standardized nutritional intervention showed significantly higher hemoglobin (Hb), prealbumin (PA), and albumin (ALB) levels versus those given conventional nursing at 4 weeks after the start of radiotherapy and at the end of radiotherapy (P < 0.001). The two groups showed similar Morisky scores before intervention (P > 0.05). After intervention, the observation group outperformed the control group in terms of treatment compliance (P < 0.05). Standardized nutritional intervention provided patients with a significantly better quality of life versus conventional nursing (P < 0.05). Standardized nutritional intervention was associated with a significantly lower incidence of adverse events and higher nursing satisfaction versus conventional nursing (P < 0.05).

Conclusion

Standardized nutritional intervention for patients with nasopharyngeal carcinoma given radiotherapy complicated with diabetes mellitus can efficiently restore the normal nutritional status of patients, reduce the complications of radiotherapy, and improve the quality of life of patients, so it is worthy of wide clinical application.

Prognostic significance of MRI-based late-course tumor volume in locoregionally advanced nasopharyngeal carcinoma

Background

To validate tumor volume-based imaging markers for predicting local recurrence-free survival (LRFS) in locoregionally advanced nasopharyngeal carcinoma patients, who underwent induction chemotherapy followed by definitive intensity-modulated radiotherapy.

Methods

We enrolled 145 patients with stage III–IVA nasopharyngeal carcinoma in this retrospective study. Pre-treatment tumor volume (V_pre) and late-course volume (LCV) were measured based on the MRIs scanned before treatment and during the first 3 days in the sixth week of radiotherapy, respectively. The volume regression rate (VRR) was calculated according to V_pre and LCV. Receiver operating characteristic (ROC) curves were used to identify the cut-off best separating patient subgroups in assessing the prognostic value of V_pre, LCV and VRR. The Kaplan–Meier method was used for survival analysis. Prognostic analyses were performed using univariate and multivariate COX proportional hazard models.

Results

The LCV was 5.3 ± 0.5 (range 0–42.1) cm³; The VRR was 60.4 ± 2.2% (range 2.9–100.0). The median follow-up period was 36 months (range 6–98 months). The cut-off value of LCV determined by the ROC was 6.8 cm³ for LRFS prediction (sensitivity 68.8%; specificity 79.8%). The combination of LCV and VRR for LRFS prediction (AUC = 0.79, P < 0.001, 95% CI 0.67–0.90), LCV (AUC = 0.74, P = 0.002, 95% CI 0.60–0.88) and V_pre (AUC = 0.71, P = 0.007, 95% CI 0.56–0.85) are better than T category (AUC = 0.64, P = 0.062, 95% CI 0.50–0.79) alone. Patients with LCV ≤ 6.8 cm³ had significantly longer LRFS (P < 0.001), disease-free survival (DFS, P < 0.001) and overall survival (OS, P = 0.005) than those with LCV > 6.8 cm³. Multivariate Cox regression showed LCV was the only independent prognostic factor for local control (HR = 7.80, 95% CI 2.69–22.6, P < 0.001).

Conclusions

LCV is a promising prognostic factor for local control and chemoradiosensitivity in patients with locoregionally advanced NPC. The LCV, and the combination of LCV with VRR are more robust predictors for patient survival than T category.

Failure Patterns of Recurrence and Metastasis After Intensity-Modulated Radiotherapy in Patients With Nasopharyngeal Carcinoma: Results of a Multicentric Clinical Study

Purpose

This study aimed to explore factors associated with recurrence and metastasis after intensity-modulated radiotherapy (IMRT) in patients with nasopharyngeal carcinoma (NPC) and provide evidence for NPC treatment.

Methods

We retrospectively analysed the treatment dose and survival outcomes of 645 patients with nasopharyngeal carcinoma without distant metastases treated with IMRT for the first time at three treatment centres in the Guangxi Zhuang Autonomous Region, China, between January 2009 and December 2012.

Results

There were 9.3% of patients (60/645) had recurrence and 17.5% (113/645) had distant metastasis 5 years after treatment. The 1-year, 3-year and 5-year local recurrence rates were 0.9%, 6.5% and 9.0% respectively. And the 1-year, 3-year and 5-year distant metastasis rates were 3.4%, 10% and 17.2%, respectively. In the 60 patients with recurrence, the in-field, marginal-field, and out-field recurrence rates were 93.3% (56/60), 5.0% (3/60) and 1.7% (1/60), respectively. Recurrence failures occurring within the first three years after treatment accounted for 81.7% (49/60). In the 113 patients with metastasis, the size of the cervical lymph node, the presence of lower cervical lymph node metastasis, the residual cervical lymph node size and the time of residual cervical lymph node complete response (CR) were independent prognostic factors for DMFS (P <0.05).

Conclusion

Most recurrences occured in the first three years after IMRT. In-field recurrence was the most common pattern for loco-regional failure of NPC treatment. The risk of distant metastasis was positively correlated with higher N stage, lower neck nodal metastasis, larger size of cervical lymph nodes, and longer time to response for residual NPC in cervical adenopathy.

Incidence and Demographics of Nasopharyngeal Carcinoma in Cheung Chau Island of Hong Kong-A Distinct Geographical Area With Minimal Residential Mobility and Restricted Public Healthcare Referral Network

Background

Nasopharyngeal carcinoma (NPC) is endemic in Hong Kong with a skewed geographical and ethnic distribution. We performed an epidemiological study of NPC in Cheung Chau Island, a fishing village with very minimal residential mobility, and compared its demographics and survival with the rest of Hong Kong.

Methods

NPC data in Cheung Chau and non–Cheung Chau residents between 2006 and 2017 treated in our tertiary center were collected. The incidence, stage distribution, and mortality of Cheung Chau NPC residents were compared with those of their counterparts in the whole Hong Kong obtained from the Hong Kong Cancer Registry. Propensity score matching (PSM) was performed between Cheung Chau and non–Cheung Chau cases in a 1:4 ratio. Overall survival (OS), progression-free survival (PFS), and cancer-specific survival (CSS) were compared between these two cohorts by product limit estimation and log-rank tests.

Results

Sixty-one patients residing in Cheung Chau were identified between 2006 and 2017. There was a significantly higher NPC incidence (P < .001) but an insignificant difference in the mortality rate in Cheung Chau compared to the whole Hong Kong data. After PSM with 237 non–Cheung Chau patients, the Cheung Chau cohort revealed a stronger NPC family history (P < .001). However, there were no significant differences in OS (P = .170), PFS (P = .053), and CSS (P = .160) between these two cohorts.

Conclusion

Our results revealed that Cheung Chau had a higher NPC incidence but similar survival outcomes compared to the whole of Hong Kong. Further prospective studies are warranted to verify this finding and to explore the possible underlying mechanisms.

Evaluation of daily dose accumulation with deformable image registration method using helical tomotherapy images for nasopharyngeal carcinoma

Aim:

Nasopharyngeal carcinoma (NPC) patients may have anatomical variations during their radiotherapy treatment course. In this study, we determine the daily accumulated dose by the deformable image registration (DIR) process for comparing with the planned dose and explore the number of fractions which the daily accumulated dose significantly changed from the planned dose.

Methods:

The validation of the DIR process in MIM software has been tested. One hundred and sixty-five daily megavoltage computed tomography (MVCT) images of NPC patients who were treated by helical tomotherapy were exported to MIM software to determine the daily accumulated dose and then compared with the planned dose.

Results:

The MIM software illustrated the acceptable validation for clinical application. The accumulated dose (D50%) of the planning target volume (PTV70) showed a decrease from the planned dose with an average of 0.5 ± 0.27% at the end of the treatment and was significantly different from the planned dose after the second fraction of the treatment (p-value = 0.008). In contrast, the accumulated dose of organ at risk (OAR) tended to increase from the planned dose and was significantly different after the fifth fraction (left parotid), the twelfth fraction (right parotid) and the second fraction (spinal cord).

Findings:

The inter-fractional anatomic changes cause the actual dose to be different from the planned dose. The dose differences and the number of fractions were varied in each target and OAR. The dose accumulation explored the necessary information for the radiation oncologist to consider adaptive treatment strategies to increase the efficiency of treatment.

Quantitative Comparisons of Deep-learning-based and Atlas-based Auto-segmentation of the Intermediate Risk Clinical Target Volume for Nasopharyngeal Carcinoma

BACKGROUND

Manual segment target volumes were time-consuming and inter-observer variability couldn't be avoided. With the development of computer science, auto-segmentation had the potential to solve this problem.

OBJECTIVE

To evaluate the accuracy and stability of Atlas-based and deep-learning-based auto-segmentation of the intermediate risk clinical target volume, composed of CTV2 and CTVnd, for nasopharyngeal carcinoma quantitatively.

METHODS AND MATERIALS

A cascade-deep-residual neural network was constructed to automatically segment CTV2 and CTVnd by deep learning method. Meanwhile, a commercially available software was used to automatically segment the same regions by Atlas-based method. The datasets included contrast computed tomography scans from 102 patients. For each patient, the two regions were manually delineated by one experienced physician. The similarity between the two auto-segmentation methods was quantitatively evaluated by Dice similarity coefficient, the 95th Hausdorff distance, volume overlap error and relative volume difference, respectively. Statistical analyses were performed using the ranked Wilcoxon test.

RESULTS

The average Dice similarity coefficient (±standard deviation) given by the deep-learning-based and Atlas-based auto-segmentation were 0.84(±0.03) and 0.74(±0.04) for CTV2, 0.79(±0.02) and 0.68(±0.03) for CTVnd, respectively. For the 95th Hausdorff distance, the corresponding values were 6.30±3.55mm and 9.34±3.39mm for CTV2, 7.09±2.27mm and 14.33±3.98mm for CTVnd. Besides, volume overlap error and relative volume difference could also predict the same situations. Statistical analyses showed significant difference between the two auto-segmentation methods (p<0.01).

CONCLUSIONS

Compared with the Atlas-based segmentation approach, the deep-learning-based segmentation method performed better both in accuracy and stability for meaningful anatomical areas other than organs at risk.

The evolution of the nasopharyngeal carcinoma staging system over a 10-year period: implications for future revisions

BACKGROUND

The classification criteria and staging groups for nasopharyngeal carcinoma described in the Union for International Cancer Control/American Joint Committee on Cancer (UICC/AJCC) staging system have been revised over time. This study assessed the proportion of patients whose staging and treatment strategy have changed due to revisions of the UICC/AJCC staging system over the past 10 years (ie, from the sixth edition to the eighth edition), to provide information for further refinement.

METHODS

We retrospectively reviewed 1901 patients with non-metastatic nasopharyngeal carcinoma treated in our cancer center between November 2009 and June 2012. The Akaike information criterion and Harrell concordance index were applied to evaluate the performance of the staging system.

RESULTS

In total, 25 (1.3%) of the 1901 patients who were staged as T2a according to the sixth edition system were downgraded to T1 in the eighth edition; 430 (22.6%) staged as N0 in the sixth edition were upgraded to N1 in the eighth edition; 106 (5.6%) staged as N1/2 in the sixth edition were upgraded to N3 in the eighth edition. In addition, 51 (2.7%) and 25 (1.3%) of the study population were upstaged from stage I to stage II and stage II to stage IVa, respectively; 10 (0.5%) was downgraded from stage II to stage I. The survival curves of adjacent N categories and staging groups defined by eighth classification system were well-separated. However, there was no significant difference in the locoregional failure-free survival (P = 0.730) and disease-free survival (P = 0.690) rates between the T2 and T3 categories in the eighth edition classification system.

CONCLUSIONS

Modifications to the tumor-node-metastasis staging system over the past 10 years have resulted in N classification changes in numerous cases. Although the eighth edition tumor-node-metastasis staging system better predicts survival outcomes, the T classification could be simplified in future revisions.

Weight Change Trajectory in Patients With Locally Advanced Nasopharyngeal Carcinoma During the Peri-Radiation Therapy Period

OBJECTIVES

To analyze the weight change trajectory in patients with locally advanced nasopharyngeal carcinoma (LANPC) before, during, and after radiation therapy for a time span of 40 weeks.

SAMPLE & SETTING

147 patients from a university-affiliated medical center in China were included.

METHODS & VARIABLES

Body weight was measured weekly during intensive treatment and biweekly after radiation therapy.

RESULTS

All 147 patients experienced critical weight loss during the peri-radiation therapy period. Overall, body weight remained basically unchanged during induction chemotherapy, followed by a sharp and severe decrease during radiation therapy. At 20 weeks after radiation therapy, body weight had increased only slightly from the lowest point.

IMPLICATIONS FOR NURSING

A time-tailored intervention based on the weight change trajectory is necessary for patients with LANPC. According to the weight change trajectory, relevant interventions for maintaining body weight should be initiated as early as the second week of radiation therapy and no later than the fourth week of radiation therapy, and these interventions should continue for at least four weeks after radiation therapy.

Comparison of different images in gross target volume delineating on VX2 nasopharyngeal transplantation tumor models

Background: To determine the optimum conditions for diagnosis of nasopharyngeal carcinoma, we established VX2 rabbit model to delineate gross target volume (GTV) in different imaging methods. Methods: The orthotopic nasopharyngeal carcinoma (NPC) was established in sixteen New Zealand rabbits. After 7-days inoculation, the rabbits were examined by CT scanning and then sacrificed for pathological examination. To achieve the best delineation, different GTVs of CT, MRI, ¹⁸F-FDG PET/CT, and ¹⁸F-FLT PET/CT images were correlated with pathological GTV (GTVp). Results: We found 45% and 60% of the maximum standardized uptake value (SUV_max) as the optimal SUV threshold for the target volume of NPC in ¹⁸F-FDG PET/CT and ¹⁸F-FLT PET/CT images, respectively (GTV_FDG45% and GTV_FLT60%). Moreover, the GTV_MRI and GTV_CT were significantly higher than the GTVp (P ≤ 0.05), while the GTV_FDG45% and especially GTV_FLT60% were similar to the GTVp (R = 0.892 and R = 0.902, respectively; P ≤ 0.001). Conclusions: Notably, the results suggested that ¹⁸F-FLT PET/CT could reflect the tumor boundaries more accurately than ¹⁸F-FDG PET/CT, MRI and CT, which makes ¹⁸F-FLT PET-CT more advantageous for the clinical delineation of the target volume in NPC.

Six fractions weekly as accelerated fraction radiotherapy: Is it applicable for nasopharyngeal cancer? A review

Standard therapy for nasopharyngeal cancer (NPC) is concurrent chemoradiation. Nevertheless, therapeutic outcomes are often unsatisfactory particularly for locally advanced stage. To enhance the therapeutic outcome, we may consider using altered fraction radiotherapy. Altered fraction radiotherapy is divided into two large groups for the therapy of NPC: hyperfraction radiotherapy and accelerated fraction radiotherapy. One of the accelerated fraction regimens suitable for NPC therapy is an accelerated regimen of six radiotherapy fractions weekly. This regimen is considered safe whether using conventional 2D planning technique or advance technique. Response to radiotherapy is better owing to the decrease in overall treatment time (OTT). Furthermore, acute or late side effects for this therapy are not very different to those of standard therapy. The conclusion is that we recommend the use of an accelerated regimen of six radiotherapy fractions weekly for locally advanced stage NPC with contraindication to concurrent chemoradiation, due to the high degree of clinical outcome as well as better tolerated side effect for NPC patients, particularly for those with locally advanced stage NPC.

The evolution of nasopharyngeal carcinoma staging

The prevalence of nasopharyngeal carcinoma is characterized by an unbalanced distribution: the disease is particularly prevalent in East and Southeast Asia. In this article, we review the evolution of the International Union Against Cancer/American Joint Committee on Cancer staging system for nasopharyngeal carcinoma. With the increasing using of newer imaging methods, more advanced radiotherapy techniques and systemic chemotherapy, we also discuss newer clinical features that might affect staging. Finally, we propose the future direction of staging and potential prognostic factors that have a major influence on the treatment outcomes of this disease.

The development and external validation of simplified T category classification for nasopharyngeal carcinoma to improve the prognostic value in the intensity-modulated radiotherapy era

Background

Intensity‐modulated radiotherapy (IMRT) provides excellent local control in nasopharyngeal carcinoma (NPC). We investigated whether simplifying 8th American Joint Committee on Cancer staging system T categories improves prognostic value.

Methods

We used 2191 NPC patients as a training set and 414 patients separately as an independent, external validation cohort.

Results

In the training set, local relapse‐free survival (LRFS), disease‐free survival (DFS), and overall survival (OS) were not significantly different between the 8th edition T2/T3 (P = 0.610, 0.380 and 0.353, respectively). Merging T2 and T3 to proposed T2 (proT2) provided significant differences in LRFS, DFS, and OS between proposed T categories. Proposed T categories had similar c‐indices for LRFS, DFS, and OS (vs the 8th edition), which was validated in the external cohorts. Moreover, for DFS, the adjusted HRs of the proT2N0 (3.8), proT1N1 (3.8), and proT2N1 (6.0) subsets were similar; the adjusted HRs of the proT3N0 (7.0), proT3N1 (11.4), proT1N2 (11.0), proT2N2 (11.6), and proT3N2 (13.3) subsets were similar; the adjusted HRs of the proT1N3 (17.8), proT2N3 (15.3), and proT3N3 (26.4) subsets were similar; the results of the adjusted HRs for OS had the same rule. Defining proT1N0 as stage I; proT1N1/proT2N0‐1 as stage II; proT3N0‐2/proT1‐2N2 as stage III; and proT1‐3N3 as stage IVa generated orderly, significant differences in DFS and OS between stages in the training set and external validation cohort.

Conclusions

In the IMRT era, three T categories are more reasonable (merging T2/T3 into T2) and proT3N0‐2 (the 8th edition T4N0‐2) should be down‐staged to stage III.

Reirradiation for Recurrent Nasopharyngeal Carcinomas: Experience From an Academic Tertiary Center in a Low- to Middle-Income Country

PURPOSE

The objectives of this study were to report the oncologic outcomes and the treatment-related toxicities after reirradiation (re-RT) for recurrent nasopharyngeal carcinoma (rNPC) at our institution and to apply a recently published prognostic model for survival in rNPC in our cohort.

PATIENTS AND METHODS

Thirty-two patients with rNPC treated at the authors' institution with re-RT were retrospectively reviewed. Treatment modalities for re-RT were intensity-modulated radiotherapy (n = 14), three-dimensional conformal radiotherapy (n = 9), single-fraction stereotactic radiosurgery (n = 6), fractionated stereotactic radiotherapy (n = 2), and high dose rate intracavitary brachytherapy (n = 1). Twenty-seven patients received re-RT with curative intent, whereas five patients were treated palliatively.

RESULTS

Median follow-up time was 15.5 months (range, 1 to 123 months) for the entire cohort and 20 months (range, 3 to 123 months) for patients treated with curative intent. For the entire cohort, median locoregional recurrence-free survival (LRRFS) was 14 months, with actuarial 1- and 2-year LRRFS estimates of 67.5% and 44.0%, respectively. Median overall survival (OS) time was 38 months, with actuarial 1- and 2-year estimates of 74.2% and 57.2%, respectively. For patients treated with curative intent, median LRRFS was not reached. Actuarial 1- and 2-year LRRFS estimates were 68.2% and 54.5%, respectively. Median OS time after curative intent re-RT was 42 months, with actuarial 1- and 2-year estimates of 75.4% and 63.8%, respectively. One- and 2-year OS estimates based on risk stratification were 68.6% for high risk compared with 80.8% for low risk and 34.3% for high risk compared with 70.7% for low risk, respectively (P = .223). Three patients (9.4%) developed symptomatic temporal lobe necrosis. There was no reported grade 5 treatment-related toxicity.

CONCLUSION

Results of the study suggest that re-RT is an effective and safe salvage treatment strategy for rNPC. Re-RT to a maximum equivalent dose in 2-Gy fractions of 60 Gy may yield good LRRFS and translate to prolonged OS.

Comparison of intensity modulated radiotherapy with simultaneous integrated boost (IMRT-SIB) and a 3-dimensional conformal parotid gland-sparing radiotherapy (ConPas 3D-CRT) in treatment of nasopharyngeal carcinoma: a mono-institutional experience

AIM

To compare intensity modulated radiotherapy with simultaneous integrated boost (IMRT-SIB) and a 3-dimensional conformal parotid gland-sparing radiotherapy (ConPas 3D-CRT) in treatment of nasopharyngeal carcinoma with regard to outcomes and dose distribution to the planning target volumes (PTVs) and to the organs at risk (OARs).

METHODS

The treatment records of 24 patients with histologically proven carcinoma of the nasopharynx treated with ConPas 3D-CRT or IMRT-SIB technique between May 2009 and December 2016 were assessed.

RESULTS

The mean dose and dose to 50% parotid glands volume as well as the maximal dose to the spinal cord were significantly lower in the IMRT-SIB than in the ConPas 3-CRT group (p < 0.05; p < 0.05; p < 0.01, respectively). IMRT-SIB was also superior in coverage of PTVs. The 3-year overall survival (OS) and disease-free survival (DFS) of patients in the IMRT-SIB and ConPas 3D-CRT groups were 77 and 81% (p = 0.93), 51.9 and 70.7% (p = 0.83), respectively.

CONCLUSION

IMRT-SIB provided additional spearing to parotid glands and spinal cord in comparison to ConPas 3D-CRT technique but without improvement of OS and DFS.

Application of intensity-modulated radiation therapy in the treatment of nasopharyngeal carcinoma

The objective of the present study was to investigate the application values of the intensity-modulated radiation therapy (IMRT) and the three-dimensional conformal radiation therapy (3D-CRT) in the treatment of nasopharyngeal carcinoma (NPC). A total of 124 patients diagnosed with nasopharyngeal carcinomas were included into the study and randomly divided into the control group and the observation group, with 62 patients in each group. The 3D-CRT combined with postoperative chemotherapy were performed on the control group and the observation group received IMRT combined with postoperative chemotherapy, and then were followed up for a median duration of 25.5 months. Comparison of the survival analysis of the two groups showed no differences between them in terms of the total effective rate and effectiveness (P>0.05), or radiotherapy complications (P>0.05). In addition, no significant differences between the two groups were found in the follow-up local tumor control probability (TCP), regional lymph node control rate, distant metastasis-free rate, tumor-free survival rate, recurrence rate and overall survival rate (P>0.05). Furthermore, there was no difference between the two groups in the overall score of quality of life (P>0.05). The present study concludes that the IMRT and the 3D-CRT have almost the same short-term and long-term clinical effects in the treatment of nasopharyngeal carcinoma and both of them have high effectiveness and safety.

Pretreatment Nomograms for Local and Regional Recurrence after Radical Radiation Therapy for Primary Nasopharyngeal Carcinoma

Background: The aim of this study was to build nomograms to predict local recurrence (LR) and regional recurrence (RR) in patients with nasopharyngeal carcinoma (NPC) underwent intensity-modulated radiation therapy (IMRT).

Patients and Methods: A total of 1811 patients with non-metastatic NPC treated with IMRT (with or without chemotherapy) between October 2009 and February 2012 at our center were involved for building the nomograms. Nomograms for LR-free rate and RR-free rate at 3- and 5- year were generated as visualizations of Cox proportional hazards regression models, and validated using bootstrap resampling, estimating discrimination and calibration.

Results: With a median follow up of 49.50 months, the 3- and 5- year LR-free rate were 95.43% and 94.30% respectively; the 3- and 5- year RR-free rate were 95.94% and 95.41% respectively. The final predictive model for LR included age, the neutrophil/leukocyte ratio (NWR), pathological type, primary gross tumor volume, maxillary sinus invasion, ethmoidal sinus invasion and lacerated foramen invasion; the model for RR involved NWR, plasma Epstein-Barr virus (EBV) DNA copy number, cervical lymph node volume and N category. The models showed fairly good discriminatory ability with concordance indices (c-indices) of 0.76 and 0.74 for predicting LR and RR, respectively, as well as good calibration. The proposed stratification of risk groups based on the nomograms allowed significant distinction between Kaplan-Meier curves for LR and RR.

Conclusions: The proposed nomograms resulted in more-accurate prognostic prediction for LR and RR with a high concordance, hence to inform patients with high risk of recurrence on more aggressive therapy. The prognostic nomograms could better stratify patients into different risk groups.

Validation of the 8th edition of the UICC/AJCC staging system for nasopharyngeal carcinoma treated with intensity-modulated radiotherapy

An accurate TNM staging system is crucial for treatment guidance and prognosis prediction in nasopharyngeal carcinoma (NPC) patients. In this retrospective study, we evaluated the 8th edition of the Union for International Cancer Control/American Joint Committee on Cancer (UICC/AJCC) staging system for NPC treated with intensity-modulated radiotherapy (IMRT). A total of 608 patients with biopsy-proven, non-metastatic NPC, treated with IMRT between January 2008 and March 2010, were enrolled. The 5-year overall survival (OS), disease-free survival (DFS), local relapse-free survival (LRFS), and distant metastasis-free survival (DMFS) rates were 81.5%, 80.1%, 86.0%, and 81.1%, respectively. The LRFS rates of patients with stages T1 vs. T2, T2 vs. T3, and T1 vs. T3 did not differ between the 7th and 8th editions. By contrast, the DMFS rates of patients with N0 vs. N1, N1 vs. N2, and N2 vs. N3 differed between the 8th and the 7th editions, though no difference was observed between N3a and N3b, according to the 7th edition. The difference in OS between stages II and III, and between stages III and IVa, was larger according to the 8th edition than the 7th edition. There was no difference in the OS between stages I and II. These data indicate that in the IMRT era, the 8th edition staging system can predict the prognosis of NPC patients more accurately than the 7th edition.