Prognostic factors on overall survival of newly diagnosed metastatic nasopharyngeal carcinoma

Individualized radiology screening for newly diagnosed nasopharyngeal carcinoma

OBJECTIVES

Current guidelines recommend universal PET/CT screening for metastases staging in newly diagnosed nasopharyngeal carcinoma (NPC) despite the low rate of synchronous distant metastasis (SDM). The study aims to achieve individualized screening recommendations of NPC based on the risk of SDM.

METHODS AND MATERIALS

18 pre-treatment peripheral blood indicators was retrospectively collected from 2271 primary NPC patients. A peripheral blood risk score (PBRS) was constructed by indicators associated with SDM on least absolute shrinkage and selection operator (LASSO) regression. The PBRS-based distant metastases (PBDM) model was developed from features selected by logistic regression analyses in the training cohort and then validated in the validation cohort. Receiver operator characteristic curve analysis, calibration curves, and decision curve analysis were applied to evaluate PBDM model performance.

RESULTS

Pre-treatment Epstein-Barr viral DNA copy number, percentage of total lymphocytes, serum lactate dehydrogenase level, and monocyte-to-lymphocyte ratio were most strongly associated with SDM in NPC and used to construct the PBRS. Sex (male), T stage (T3-4), N stage (N2-3), and PBRS (≥1.076) were identified as independent risk factors for SDM and applied in the PBDM model, which showed good performance. Through the model, patients in the training cohort were stratified into low-, medium-, and high-risk groups. Individualized screening recommendations were then developed for patients with differing risk levels.

CONCLUSION

The PBDM model offers individualized recommendations for applying PET/CT for metastases staging in NPC, allowing more targeted screening of patients with greater risk of SDM compared with current recommendations.

An Exploratory Study of Refining TNM-8 M1 Categories and Prognostic Subgroups Using Plasma EBV DNA for Previously Untreated De Novo Metastatic Nasopharyngeal Carcinoma

(1) Background: NPC patients with de novo distant metastasis appears to be a heterogeneous group who demonstrate a wide range of survival, as suggested by growing evidence. Nevertheless, the current 8th edition of TNM staging (TNM-8) grouping all these patients into the M1 category is not able to identify their survival differences. We sought to identify any anatomic and non-anatomic subgroups in this study. (2) Methods: Sixty-nine patients with treatment-naive de novo M1 NPC (training cohort) were prospectively recruited from 2007 to 2018. We performed univariable and multivariable analyses (UVA and MVA) to explore anatomic distant metastasis factors, which were significantly prognostic of overall survival (OS). Recursive partitioning analysis (RPA) with the incorporation of significant factors from MVA was then performed to derive a new set of RPA stage groups with OS segregation (Set 1 Anatomic-RPA stage groups); another run of MVA was performed with the addition of pre-treatment plasma EBV DNA. A second-round RPA with significant prognostic factors of OS identified in this round of MVA was performed again to derive another set of stage groups (Set 2 Prognostic-RPA stage groups). Both sets were then validated externally with an independent validation cohort of 67 patients with distant relapses of their initially non-metastatic NPC (rM1) after radical treatment. The performance of models in survival segregation was evaluated by the Akaike information criterion (AIC) and concordance index (C-index) under 1000 bootstrapping samples for the validation cohort; (3) Results: The 3-year OS and median follow-up in the training cohort were 36.0% and 17.8 months, respectively. Co-existence of liver-bone metastases was the only significant prognostic factor of OS in the first round UVA and MVA. Set 1 RPA based on anatomic factors that subdivide the M1 category into two groups: M1a (absence of co-existing liver-bone metastases; median OS 28.1 months) and M1b (co-existing liver-bone metastases; median OS 19.2 months, p = 0.023). When pre-treatment plasma EBV DNA was also added, it became the only significant prognostic factor in UVA (p = 0.001) and MVA (p = 0.015), while co-existing liver-bone metastases was only significant in UVA. Set 2 RPA with the incorporation of pre-treatment plasma EBV DNA yielded good segregation (M1a: EBV DNA ≤ 2500 copies/mL and M1b: EBV DNA > 2500 copies/mL; median OS 44.2 and 19.7 months, respectively, p < 0.001). Set 2 Prognostic-RPA groups (AIC: 228.1 [95% CI: 194.8−251.8] is superior to Set 1 Anatomic-RPA groups (AIC: 278.5 [254.6−301.2]) in the OS prediction (p < 0.001). Set 2 RPA groups (C-index 0.59 [95% CI: 0.54−0.67]) also performed better prediction agreement in the validation cohort (vs. Set 1: C-index 0.47 [95% CI: 0.41−0.53]) (p < 0.001); (4) Conclusions: Our Anatomic-RPA stage groups yielded good segregation for de novo M1 NPC, and prognostication was further improved by incorporating plasma EBV DNA. These new RPA stage groups for M1 NPC can be applied to countries/regions regardless of whether reliable and sensitive plasma EBV DNA assays are available or not.

Refining TNM-8 M1 categories with anatomic subgroups for previously untreated de novo metastatic nasopharyngeal carcinoma

PURPOSE

To propose a refined M1 classification in de novo metastatic nasopharyngeal carcinoma (NPC) based on pooled data from two academic institutions.

METHODS

Previously untreated de novo M1 NPC patients prospectively treated at The University of Hong Kong (N = 69) and Fujian Cancer Hospital (N = 114) between 2007 and 2016 were recruited and randomized in a 2:1 ratio to generate training (N = 120) and validation (N = 63) cohorts, respectively. Multivariable analysis (MVA) was performed for the training and validation cohorts to identify anatomic prognostic factors for overall survival (OS). Recursive partitioning analysis (RPA) was performed which incorporated the anatomic prognostic factors identified in the MVA to derive Anatomic-RPA groups which stratified OS in the training cohort, and were then validated in the validation cohort.

RESULTS

Median follow-up for the training and validation cohorts was 27.2 and 30.2 months with 3-year OS of 51.6% and 51.1%, respectively. MVA revealed that co-existing liver-bone metastases was the only factor prognostic for OS in both the training and validation cohorts. Anatomic-RPA separated M1 disease into M1a (no co-existing liver-bone metastases) and M1b (co-existing liver-bone metastases) with median OS 39.5 and 23.7 months, respectively (p = 0.004) in the training cohort. RPA for the validation cohort also confirmed good segregation with co-existing liver-bone metastases with median OS 47.7 and 16.0 months, respectively (p = 0.008).

CONCLUSION

Our proposal to subdivide de novo M1 NPC into M1a (no co-existing liver-bone metastases) vs. M1b (co-existing liver-bone metastases) provides better OS segregation.

Gemcitabine Plus Platinum versus Docetaxel Plus Platinum as First-Line Therapy for Metastatic Nasopharyngeal Carcinoma: A Randomized Clinical Study

Background:

A well-established first-line chemotherapy standard for metastatic nasopharyngeal carcinoma is yet lacking.

Objectives:

To compare the efficacy and safety of gemcitabine plus platinum versus docetaxel plus platinum regimen as first-line therapies for distal metastatic nasopharyngeal carcinoma.

Study Design and Participants:

A single center, randomized, open-label, parallel-arm study. The study included 120 patients with metastatic nasopharyngeal carcinoma who met the study requirements.

Interventions:

Participants were randomized in a 1:1 ratio through a sealed envelope selection. Gemcitabine 1000 mg/m²/d intravenously (IV) for >30 min (days 1 and 8) or docetaxel 75 mg/m²/d IV for 1 h (day 1) were administered to the respective group participants. Nedaplatin 75 mg/m²/d, IV (day 1), cisplatin 75 mg/m²/d IV (day 1) or carboplatin (area under the curve set as 5) IV (day 1) were used in both groups. One cycle duration was 21 days, with 4–6 cycles for all participants.

Outcomes:

The primary assessed outcomes were progression-free survival (PFS) and overall survival (OS), and the secondary outcomes were short-term efficacy [i.e., response rate (RR) and disease control rate (DCR)] and safety.

Results:

Seven patients withdrew from the study, and efficacy and adverse reactions were obtained for 113 patients (gemcitabine: 56; docetaxel: 57). Compared with the docetaxel plus platinum group, the gemcitabine plus platinum group had significantly higher RR (71.4% vs. 52.6%, P < 0.05); mPFS (9.7 vs. 7.8 months, P < 0.05), and mOS (20.6 vs. 16.8 months, P < 0.01). The significance was not associated with increased adverse reactions, as both groups showed similar Grades 3 and 4 adverse reactions (P > 0.05). DCR was non-significantly higher in the gemcitabine group (85.7% vs. 75.4%, P > 0.05). Multivariable analysis revealed that time to disease progression, number of involved organs, liver metastasis, and grouping were associated with mPFS and mOS (all P < 0.05).

Conclusion:

The combination of gemcitabine with platinum is likely superior to that of docetaxel with platinum as first-line treatment for metastatic nasopharyngeal carcinoma.

Metastatic characteristics associated with survival of synchronous metastatic nasopharyngeal carcinoma in non-epidemic areas

INTRODUCTION

The current metastatic category (M) of nasopharyngeal carcinoma (NPC) is a "catch-all" category, we previously successfully established a M1 subdivision system based on prognostic metastatic characteristics in epidemic areas. We aimed to figure out metastatic characteristics associated with survival outcomes of NPC in non-epidemic areas.

METHODS

A total of 428 newly diagnosed de novo metastatic NPC patients from 2010 to 2016 were analyzed from the population-based Surveillance, Epidemiology, and End Results program. Cox proportional hazard ratios (HRs) were used to identify independent prognostic factors for survival.

RESULTS

The most frequently involved metastatic locations were the bones (53.04%), the lungs (36.68%), the livers (29.21%) and the distant lymph nodes (24.07%). Univariate analysis indicated that bone involvement (HR = 1.39, 95% CI = 1.09-1.77), liver involvement (HR = 1.44, 95% CI = 1.12-1.85) and multiple metastatic locations (HR = 1.32, 95% CI = 1.04-1.67) were negative prognostic factors of overall survival (OS) for patients with synchronous metastasis. We established a new M1 subdivision system based on metastatic characteristics: M1a, without bone and liver involvement; M1b, single bone or liver involvement; M1c, multiple metastatic locations including bone and/or liver. Multivariate analysis confirmed that our new subcategories were associated with significantly different OS (M1b vs M1a: HR = 1.54, 95% CI = 1.11-2.16; M1c vs M1a: HR = 2.03, 95% CI = 1.47-2.78).

CONCLUSIONS

Synchronous metastatic NPC patients with multiple metastatic locations involved bone and/or liver were prone to suffer from dismal OS and might need more attentions for selection of treatment modality.

Prognostic factors in metastatic nasopharyngeal carcinoma

Introduction

Nasopharyngeal carcinoma has the highest metastatic potential of all head and neck cancers. The survival time of patients with nasopharyngeal carcinoma has improved significantly in the last decades due to the use of combination of chemotherapy and radiotherapy, as well as advances in radiotherapy techniques. However, appropriately 30% of patients with nasopharyngeal carcinoma suffer a poor prognosis, mainly due to distant metastasis.

Objective

The study aimed to identify the survival and prognostic factors in metastatic nasopharyngeal carcinoma.

Methods

A retrospective analysis was conducted in patients treated for synchronous metastatic nasopharyngeal carcinoma or metachronous metastatic nasopharyngeal carcinoma for 14 years (2003–2016). Overall survival was analyzed using the Kaplan-Meier method and compared using the log-rank test for the whole population and both groups of patients. Multivariate analysis was performed using the Cox model; p-values < 0.05 were considered to indicate statistical significance.

Results

One hundred and twelve patients with metastatic nasopharyngeal carcinoma were included (51 patients with metastatic nasopharyngeal carcinoma, and 61 patients with metachronous metastatic nasopharyngeal carcinoma). In the whole population, the median overall survival was 10 months (1–156 months). In the multivariate analysis, female gender, poor performance status (WHO > 1) and metachronous metastasis were independent prognostic factors. In the metastatic nasopharyngeal carcinoma patients, the median overall survival was 13 months (1–156 months). In multivariate analysis, independent prognostic factors were non-oligometastatic disease, severe (G3‒G4) chemotherapy toxicity and the lack of nasopharyngeal and metastatic site irradiation. In the metachronous metastatic nasopharyngeal carcinoma patients, the median overall survival was 7 months (1–41 months). In multivariate analysis, the poor performance status (WHO > 1) was an independent metastatic nasopharyngeal carcinoma prognostic factor.

Conclusion

Oligometastatic patients with synchronous metastatic nasopharyngeal carcinoma had better survival. The locoregional treatment of primitive nasopharyngeal carcinoma improved survival in patients with metastatic nasopharyngeal carcinoma who responded to induction chemotherapy. Local irradiation of metastatic sites improved survival of metastatic nasopharyngeal carcinoma patients. Grade 3 or 4 chemotherapy toxicity altered survival among patients with synchronous metastatic nasopharyngeal carcinoma.

Prognostic value of retropharyngeal lymph node metastasis laterality in nasopharyngeal carcinoma and a proposed modification to the UICC/AJCC N staging system

BACKGROUND AND PURPOSE

Metastasis laterality is used for N classification of cervical lymph nodes, but not retropharyngeal lymph nodes (RLNs). This study explored the prognostic value of laterality of RLN metastasis to provide suggestions for a better N standard classification.

MATERIALS AND METHODS

This retrospective study evaluated 1225 patients with new biopsy-confirmed nasopharyngeal carcinoma (NPC). Univariable and multivariable Cox regression models were used to assess overall survival (OS), progression-free survival (PFS), and distant metastasis-free survival (DMFS). A new N classification system was developed and compared to the 8th AJCC system. Kaplan-Meier methods with log-rank tests were used to compare OS, PFS, and DMFS between our proposed N stage and the AJCC N stages.

RESULTS

The incidence of RLN metastasis was 38.7% (unilateral) and 27.5% (bilateral). In the N1 subgroup, metastasis laterality was associated with significant differences in the 5-year rates of OS (89.4% vs. 82.6%, p = 0.016), DMFS (91.5% vs. 82.9%, p = 0.004), and PFS (80.3% vs. 71.2%, p = 0.016). However, no significant differences in these outcomes were observed when we compared N2 disease to N1 bilateral RLN metastasis. Multivariate analysis confirmed that bilateral RLN metastasis independently predicted OS, DMFS, and PFS. The proposed classification broadened the differences in OS, DMFS, PFS between N1 and N2 disease.

CONCLUSION

Patients with NPC and unilateral RLN metastasis had better survival than did patients with bilateral RLN metastasis. Upgrading cases with bilateral RLN metastasis from N1 to N2 may help improve prognostication using the 8th AJCC system.

A Prognostic Score for Nasopharyngeal Carcinoma with Bone Metastasis: Development and Validation from Multicenter

Background: To establish a prognostic score based on clinical routine factors to stratify nasopharyngeal carcinoma patients with bone metastasis into risk groups with different survival rates. Materials and Methods: Total 276 patients from multicenter were retrospectively analyzed. Kaplan-Meier method and Cox regression were used to confirm independent risk factors, which were checked for internal validity by bootstrapping method. The prognostic score, deriving from the corresponding regression coefficients in Cox model, classified patients into low and high risk groups. Finally, two independent cohorts were used for external validation. Results: In development cohort, six risk factors were identified: age>46 year-old (point=1), N>0 stage (point=2), anemia (point=2), bone metastasis free interval≤12 months (point=1), without radiotherapy to primary sites (point=1), and without radiotherapy to first metastasis sites (point=1). The derived prognostic score divided patients into low (score, 0-4) and high (score, 5-8) risk groups, with highly significant differences of 5-year overall survival rates (high vs. low risk: 24.6% vs. 58.2%, HR 3.47, P<0.001). Two external validations presented congruent results. Conclusion: A feasible and applicative prognostic score was successfully established and validated to discriminate bone metastatic nasopharyngeal carcinoma into low/high risk groups, which will be useful for individual treatment.

The Ratio of C-Reactive Protein/Albumin is a Novel Inflammatory Predictor of Overall Survival in Cisplatin-Based Treated Patients with Metastatic Nasopharyngeal Carcinoma

The C-reactive protein/albumin (CRP/Alb) ratio has been recently identified as a prognostic factor in various cancers, whereas its role remains unclear in metastatic nasopharyngeal carcinoma (NPC). The current study retrospectively analyzed 148 patients with metastatic NPC who underwent cisplatin-based chemotherapy and further evaluated the prognostic value of the CRP/Alb ratio and its association with clinical characteristics in these patients. The optimal cut-off value was 0.189 for the CRP/Alb ratio. The high CRP/Alb ratio was significantly associated with elevated NLR, platelet-to-lymphocyte ratio (PLR), and EBV-DNA levels and decreased haemoglobin level (all p < 0.05). The results of multivariate analysis showed that the CRP/Alb ratio was an independent prognostic factor of overall survival. Patients with a high CRP/Alb ratio (≥0.189) had a 1.867 times (p = 0.024, 95% CI = 1.085–3.210) greater risk of mortality compared with those with a low CRP/Alb ratio (<0.189). In addition, combining the CRP/Alb ratio with GPS could accurately discriminate the prognosis of our patients. Our results suggested that the CRP/Alb ratio is a feasible and inexpensive tool for predicting survival outcomes and is a valuable coadjutant for the GPS to further identify differences in survivals of patients with metastatic NPC.

Higher N stage and serum ferritin, but lower serum albumin levels are associated with distant metastasis and poor survival in patients with nasopharyngeal carcinoma following intensity-modulated radiotherapy

Purpose

To evaluate the potential risk factors for distant metastasis of nasopharyngeal carcinoma in Chinese patients following standard intensity-modulated radiotherapy and chemotherapy.

Methods

The potential risk factors for distant metastasis in 622 patients with newly-diagnosed primary nasopharyngeal carcinoma following standard radiotherapy and chemotherapy were evaluated retrospectively by stratification, univariate and multivariate analyses. The 5-year overall survival, distant metastasis-free survival, local recurrence-free survival and progression-free survival rates were determined.

Results

Univariate and multivariate analyses indicated that N2-3 stage, serum ferritin > 300 μg/L and serum albumin < 42 g/L were independent risk factors for distant metastasis of nasopharyngeal carcinoma (P < 0.001, P = 0.013, P = 0.002, respectively). A risk prediction model was developed as follows: 1) low-risk group: 0-1 risk factor; and 2) high-risk group: 2-3 risk factors. Compared with low-risk group, the high-risk group had significantly lower 5-year distant metastasis-free survival (76.4% vs. 89.6%, P < 0.001), overall survival (76% vs. 85.9%,P < 0.001), local recurrence-free survival (88% vs. 92.4%, P = 0.029) and progression-free survival rates (68.2% vs. 83.7%, P < 0.001). In the high-risk group, patients with three risk factors had the lowest distant metastasis-free survival rate (P = 0.036).

Conclusions

Combination of higher N stage, serum ferritin and lower serum albumin levels may be valuable for predicting distant metastasis of nasopharyngeal carcinoma patients following standard intensity-modulated radiotherapy and chemotherapy.

microRNA-125b reverses the multidrug resistance of nasopharyngeal carcinoma cells via targeting of Bcl-2

Multidrug resistance (MDR) is a major clinical obstacle in the successful treatment of patients with metastatic nasopharyngeal carcinoma (NPC). Results from previous studies suggest that microRNAs (miRNA) may be involved in promoting MDR in multiple cancer types. However, the role of miR‑125b in modulating the MDR of NPC is elusive. In the present study, miR‑125b expression in cisplatin (DDP) ‑resistant CNE2 cells (CNE2/DDP) was compared with parental counterparts, using reverse transcription‑quantitative polymerase chain reaction. A >3‑fold reduction in miR‑125b expression levels was observed in CNE2/DDP cells compared with parental CNE2 cells. Ectopic expression of miR‑125b by transfecting CNE2/DDP cells with miR-125b mimics, increased DDP‑induced cytotoxicity, apoptosis and chemosensitivity. By contrast, suppression of miR-125b by transfecting CNE2 cells with miR‑125b inhibitors, reduced DDP‑induced cytotoxicity and apoptosis, and facilitated cisplatin resistance. The results suggest that miR‑125b may regulate the sensitivity of NPC cells to DDP by modulating the expression levels of antiapoptotic factor B-cell CLL/lymphoma 2. Collectively, the results of the present study highlight miR‑125b as a potential therapeutic target for reversing MDR in NPC.

Intensity-modulated radiotherapy controls nasopharyngeal carcinoma distant metastasis and improves survival of patients

BACKGROUND

This study evaluated the distant metastatic outcomes in nasopharyngeal carcinoma (NPC) patients treated with intensity-modulated radiotherapy (IMRT) plus chemotherapy.

METHODS

530 Non-metastatic NPC patients were retrospectively collected and reviewed after receiving IMRT with or without chemotherapy between June 2006 and December 2011. Patients were treated with one fraction of IMRT daily for 5 days a week for 69.96-74.09 Gy, while 473 (89.2 %) of patients also received chemotherapy.

RESULTS

Patients were followed up for a median follow-up duration of 49 months (range from 5 to 98 months). After treatment, 91 (17.3 %) patients developed distant metastasis. Distant metastasis after treatment was significantly associated with advanced 2010 Union for International Cancer Control (UICC)/American Joint Committee on Cancer (AJCC) T staging (p = 0.034), N stage (p < 0.001), 2010 UICC/AJCC stage (p < 0.001), and tumor recurrence (p = 0.029). However, chemotherapy failed to reduce cancer distant metastasis in early stage patients, the distant metastasis rate was 17.5 % in stage III and 24.2 % in stage IVA-B diseases, after IMRT and chemotherapy. The multivariate analysis showed that cancer remission duration, treatment modality, and metastatic site (p < 0.001, p = 0.027 and p = 0.022, respectively) were all independent predictors for overall survival of NPC patients after IMRT and chemotherapy.

CONCLUSIONS

This study provided insight into the effects of IMRT plus chemotherapy in the treatment of NPC. Future studies will explore the efficacy of more aggressive systemic therapies for high-risk patients with distant metastasis.

Solitary splenic metastasis from nasopharyngeal carcinoma: a case report and systematic review of the literature

Background

Solitary splenic metastases are a rare occurrence, and the nasopharyngeal carcinoma represents one of the most uncommon primary sources. The present study aimed to describe a rare case of a solitary single splenic metastasis from nasopharyngeal carcinoma and to assess the number of cases of isolated nasopharyngeal carcinoma metastases to the spleen reported in the literature.

Main body

We describe the case of a 56-year-old man with a history of nasopharyngeal carcinoma and complete remission after chemo-radiotherapy. Three months after complete remission, positron emission tomography/computed tomography scan revealed a hypermetabolic splenic lesion without increased metabolic activity in other areas. After laparoscopic splenectomy, the pathology report confirmed a single splenic metastasis from undifferentiated carcinoma of the nasopharyngeal type. The postoperative period was uneventful. We also performed a systematic review of the literature using MEDLINE and Google Scholar databases. All articles reporting cases of splenic metastases from nasopharyngeal carcinoma, with or without histologic confirmation, were evaluated. The literature search yielded 15 relevant articles, which were very heterogeneous in their aims and methods and described only 25 cases of splenic metastases from nasopharyngeal carcinoma.

Conclusion

The present review shows that solitary splenic metastases from nasopharyngeal carcinoma are a rare event, but it should be considered in patients presenting with splenic lesions at imaging and a history of primary or recurrent nasopharyngeal carcinoma. No evidence supports a negative impact of splenectomy in patients with solitary splenic metastasis from nasopharyngeal carcinoma.

Development and External Validation of Nomograms for Predicting Survival in Nasopharyngeal Carcinoma Patients after Definitive Radiotherapy

The distant metastasis free survival (DMFS) and overall survival (OS) differ significantly among individuals even within the same clinical stages. The purpose of this retrospective study was to build nomograms incorporating plasma EBV DNA for predicting DMFS and OS of nasopharyngeal carcinoma (NPC) patients after definitive radiotherapy. A total of 1168 non-metastatic NPC patients from two institutions were included to develop the nomograms. Seven and six independent prognostic factors were identified to build the nomograms for OS and DMFS, respectively. The models were externally validated by a separate cohort of 756 NPC patients from the third institutions. For predicting OS, the c-index of the nomogram was significantly better than that of the TNM staging system (Training cohort, P = 0.005; validation cohort, P = 0.03). The c-index of nomogram for DMFS in the training and validation set were both higher than that of TNM classification with marginal significance (P = 0.048 and P = 0.057, respectively). The probability of 1-, 3-, and 5-year OS and DMFS showed optimal agreement between nomogram prediction and actual observation. The proposed stratification of risk groups based on the nomograms allowed significant distinction between Kaplan-Meier curves for survival outcomes. The prognostic nomograms could better stratify patients into different risk groups.

Subdivision of M category for nasopharyngeal carcinoma with synchronous metastasis: time to expand the M categorization system

INTRODUCTION

The current metastatic category (M) of nasopharyngeal carcinoma (NPC) is a "catch-all" classification, covering a heterogeneous group of tumors ranging from potentially curable to incurable. The aim of this study was to design an M categorization system that could be applied in planning the treatment of NPC with synchronous metastasis.

METHODS

A total of 505 NPC patients diagnosed with synchronous metastasis at Sun Yat-sen University Cancer Center between 2000 and 2009 were involved. The associations of clinical variables, metastatic features, and a proposed M categorization system with overall survival (OS) were determined by using Cox regression model.

RESULTS

Multivariate analysis showed that Union for International Cancer Control (UICC) N category (N1-3/N0), number of metastatic lesions (multiple/single), liver involvement (yes/no), radiotherapy to primary tumor (yes/no), and cycles of chemotherapy (>4/≤4) were independent prognostic factors for OS. We defined the following subcategories based on liver involvement and the number of metastatic lesions: M1a, single lesion confined to an isolated organ or location except the liver; M1b, single lesion in the liver and/or multiple lesions in any organs or locations except the liver; and M1c, multiple lesions in the liver. Of the 505 cases, 74 (14.7%) were classified as M1a, 296 (58.6%) as M1b, 134 (26.5%) as M1c, and 1 was not specified. The three M1 subcategories showed significant difference in OS [M1b vs. M1a, hazard ratio (HR) = 1.69, 95% confidence interval (CI) = 1.16-2.48, P = 0.007; M1c vs. M1a, HR = 2.64, 95% CI = 1.75-3.98, P < 0.001].

CONCLUSIONS

We developed an M categorization system based on the independent factors related to the prognosis of patients with metastatic NPC. This system may be helpful to further optimize individualized care for NPC patients.