Whether Primary Bone-Only Oligometastatic Nasopharyngeal Carcinoma Patients Benefit From Radiotherapy to the Bones on the Basis of Palliative Chemotherapy Plus Locoregional Radiotherapy?-A Large-Cohort Retrospective Study

OBJECTIVES

Whether to perform local radiotherapy on metastatic bone for primary bone-only oligometastatic nasopharyngeal carcinoma (NPC) patients remains unclear. Therefore, we analyzed the treatment methods and their survival and developed a prognostic model to predict outcomes and guide personalized treatment.

MATERIALS AND METHODS

We studied 308 primary bone-only oligometastatic NPC patients who were treated with either palliative chemotherapy (PCT) alone, PCT combined with locoregional radiotherapy (LRRT), or PCT, LRRT, and radiotherapy to metastatic bones (bRT). The primary endpoint was overall survival (OS). Cox regression was utilized to identify independent prognostic factors, leading to the construction of a nomogram model. Patients were stratified into two risk groups based on median prognostic scores, and treatment modalities were compared using log-rank test while employing the inverse probability of treatment weighting (IPTW) to balance baseline characteristics and adjust for sample size differences between risk groups.

RESULTS

The best OS was observed in the group treated with PCT, LRRT, and bRT (HR = 0.60, 95% CI: 0.45-0.81, p = 0.002). Multivariable analysis revealed that age, N stage, pre-treatment levels of LDH, and EBV DNA were independent prognostic factors for OS. In total, 155 patients were in low-risk group while 153 were in high-risk group. Before and after IPTW, the high-risk group benefited from the PCT, LRRT, and bRT regimen (adjusted HR = 0.53, 95% CI: 0.42-0.67, p < 0.001; unadjusted HR = 0.59, 95% CI: 0.42-0.83, p = 0.007), while the low-risk group did not (adjusted HR = 0.79, 95% CI: 0.56-1.11, p = 0.345; unadjusted HR = 0.65, 95% CI: 0.37-1.14, p = 0.309).

CONCLUSION

Best outcomes of the whole cohort were seen with PCT + LRRT + bRT. Our study identified age, N stage, pre-treatment LDH levels, and EBV DNA levels as independent prognostic factors for OS. The high-risk group demonstrated a longer OS when treated with PCT + LRRT + bRT, whereas the low-risk group did not benefit from the combinatorial treatment.

Establishing M1 subdivision for de novo nasopharyngeal carcinoma patients receiving immuno-chemotherapy: A multicenter, retrospective cohort study

OBJECTIVES

This study aims to better manage de novo metastatic nasopharyngeal carcinoma (NPC) patients receiving palliative immuno-chemotherapy (PICT), thereby easily determining individual survival outcomes.

MATERIALS AND METHODS

Patients with de novo metastatic NPC from four centers who received first-line PICT were included. We developed a nomogram for the pretherapy overall survival (OS) prediction using a logistic regression model in the training cohort (n = 296). We assessed the performance of this nomogram in a validation cohort.

RESULTS

A total of 592 patients were included. The median follow-up time was 29.83 months. Bone metastasis (HR, 2.46; 95 % CI, 1.01-6.21; p = 0.049) and the number of metastatic lesions > 3 (HR, 2.78; 95 % CI, 1.24-6.24; p = 0.013) were independent prognostic indicators. A new two-category M1 subdivision was generated: M1a, defined by the absence of co-existing bone metastasis and the presence of more than three metastatic lesions; and M1b, characterized by the presence of co-existing bone metastasis and the presence of more than three metastatic lesions. The 3-year OS rates of patients with M1a vs. M1b were 87.1 % vs. 60.3 % (p < 0.001). The C-indexes were 0.652 and 0.581 in the training and validation cohorts. The 1-, 2-, and 3-year areas under the curve (AUC) were 0.69, 0.68, 0.68 in the training cohort and 0.64, 0.6, 0.6 in the validation cohort. DCA curves also indicated that the nomogram has good clinical utility.

CONCLUSION

The proposed M1 subdivision provides good OS segregation for patients receiving PICT.

Enhancing efficacy and reducing toxicity: Therapeutic optimization in locoregionally advanced nasopharyngeal carcinoma

When applied as the standard therapeutic modality, intensity-modulated radiotherapy (IMRT) improves local control and survival rates in patients with nasopharyngeal carcinoma (NPC). However, distant metastasis continues to be the leading cause of treatment failure. Here, we review the most recent optimization strategies for combining chemotherapy with IMRT in high-risk patients with locoregionally advanced NPC. We focus on major clinical trials on induction chemotherapy and metronomic adjuvant chemotherapy, emphasizing their efficacy in mitigating distant metastasis and prognosis. We also highlight innovations in reducing toxicity in low-risk patients, particularly through approaches of excluding chemotherapy, adopting equivalent low-toxicity drugs, or selectively exempting lymph nodes with low metastatic risk from irradiation. These approaches have provided positive treatment outcomes and significantly enhanced patients' quality of life. Finally, we provide an overview of the evolving immunotherapy landscape, with a focus on the ongoing trials and future potential of immune checkpoint inhibitors in advanced NPC treatment.

Establishing subdivisions of M1 stage nasopharyngeal carcinoma based on decision tree classification: A multicenter retrospective study

OBJECTIVES

To meet the demand for personalized treatment, effective stratification of patients with metastatic nasopharyngeal carcinoma (mNPC) is essential. Hence, our study aimed to establish an M1 subdivision for prognostic prediction and treatment planning in patients with mNPC.

MATERIALS AND METHODS

This study included 1239 patients with mNPC from three medical centers divided into the synchronous mNPC cohort (smNPC, n = 556) to establish an M1 stage subdivision and the metachronous mNPC cohort (mmNPC, n = 683) to validate this subdivision. The primary endpoint was overall survival. Univariate and multivariate Cox analyses identified covariates for the decision-tree model, proposing an M1 subdivision. Model performance was evaluated using time-dependent receiver operating characteristic curves, Harrell's concordance index, calibration plots, and decision curve analyses.

RESULTS

The proposed M1 subdivisions were M1a (≤5 metastatic lesions), M1b (>5 metastatic lesions + absent liver metastases), and M1c (>5 metastatic lesions + existing liver metastases) with median OS of 34, 22, and 13 months, respectively (p < 0.001). This M1 subdivision demonstrated superior discrimination (C-index = 0.698; 3-year AUC = 0.707) and clinical utility over those of existing staging systems. Calibration curves exhibited satisfactory agreement between predictions and actual observations. Internal and mmNPC cohort validation confirmed the robustness. Survival benefits from local metastatic treatment were observed in M1a, while immunotherapy improved survival in patients with M1b and M1c disease.

CONCLUSION

This novel M1 staging strategy provides a refined approach for prognostic prediction and treatment planning in patients with mNPC, emphasizing the potential benefits of local and immunotherapeutic interventions based on individualized risk stratification.

Refining the 8th edition TNM classification for EBV related nasopharyngeal carcinoma

The AJCC/UICC TNM classification describes anatomic extent of tumor progression and guides treatment decisions. Our comprehensive analysis of 8,834 newly diagnosed patients with non-metastatic Epstein-Barr virus related nasopharyngeal carcinoma (NPC) from six Chinese centers indicates certain limitations in the current staging system. The 8th edition of the AJCC/UICC TNM classification inadequately differentiates patient outcomes, particularly between T2 and T3 categories and within the N classification. We propose reclassifying cases of T3 NPC with early skull-base invasion as T2, and elevating N1-N2 cases with grade 3 image-identified extranodal extension (ENE) to N3. Additionally, we suggest combining T2N0 with T1N0 into a single stage IA. For de novo metastatic (M1) NPC, we propose subdivisions of M1a, defined by 1-3 metastatic lesions without liver involvement, and M1b, characterized by >3 metastatic lesions or liver involvement. This proposal better reflects responses of NPC patients to the up-to-date treatments and their evolving risk profiles.

Comprehensive integrated analysis of MR and DCE-MR radiomics models for prognostic prediction in nasopharyngeal carcinoma

Although prognostic prediction of nasopharyngeal carcinoma (NPC) remains a pivotal research area, the role of dynamic contrast-enhanced magnetic resonance (DCE-MR) has been less explored. This study aimed to investigate the role of DCR-MR in predicting progression-free survival (PFS) in patients with NPC using magnetic resonance (MR)- and DCE-MR-based radiomic models. A total of 434 patients with two MR scanning sequences were included. The MR- and DCE-MR-based radiomics models were developed based on 289 patients with only MR scanning sequences and 145 patients with four additional pharmacokinetic parameters (volume fraction of extravascular extracellular space (ve), volume fraction of plasma space (vp), volume transfer constant (Ktrans), and reverse reflux rate constant (kep) of DCE-MR. A combined model integrating MR and DCE-MR was constructed. Utilizing methods such as correlation analysis, least absolute shrinkage and selection operator regression, and multivariate Cox proportional hazards regression, we built the radiomics models. Finally, we calculated the net reclassification index and C-index to evaluate and compare the prognostic performance of the radiomics models. Kaplan-Meier survival curve analysis was performed to investigate the model's ability to stratify risk in patients with NPC. The integration of MR and DCE-MR radiomic features significantly enhanced prognostic prediction performance compared to MR- and DCE-MR-based models, evidenced by a test set C-index of 0.808 vs 0.729 and 0.731, respectively. The combined radiomics model improved net reclassification by 22.9%-52.6% and could significantly stratify the risk levels of patients with NPC (p = 0.036). Furthermore, the MR-based radiomic feature maps achieved similar results to the DCE-MR pharmacokinetic parameters in terms of reflecting the underlying angiogenesis information in NPC. Compared to conventional MR-based radiomics models, the combined radiomics model integrating MR and DCE-MR showed promising results in delivering more accurate prognostic predictions and provided more clinical benefits in quantifying and monitoring phenotypic changes associated with NPC prognosis.

M1 stage subdivisions based on 18F-FDG PET-CT parameters to identify locoregional radiotherapy for metastatic nasopharyngeal carcinoma

Purpose

To establish a risk classification of de novo metastatic nasopharyngeal carcinoma (mNPC) patients based on ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG PET-CT) radiomics parameters to identify suitable candidates for locoregional radiotherapy (LRRT).

Methods

In all, 586 de novo mNPC patients who underwent ¹⁸F-FDG PET-CT prior to palliative chemotherapy (PCT) were involved. A Cox regression model was performed to identify prognostic factors for overall survival (OS). Candidate PET-CT parameters were incorporated into the PET-CT parameter score (PPS). Recursive partitioning analysis (RPA) was applied to construct a risk stratification system.

Results

Multivariate Cox regression analyses revealed that total lesion glycolysis of locoregional lesions (LRL-TLG), the number of bone metastases (BMs), metabolic tumor volume of distant soft tissue metastases (DSTM-MTV), pretreatment Epstein-Barr virus DNA (EBV DNA), and liver involvement were independent prognosticators for OS. The number of BMs, LRL-TLG, and DSTM-MTV were incorporated as the PPS. Eligible patients were divided into three stages by the RPA-risk stratification model: M1a (low risk, PPS_low + no liver involvement), M1b (intermediate risk, PPS_low + liver involvement, PPS_high + low EBV DNA), and M1c (high risk, PPS_high + high EBV DNA). PCT followed by LRRT displayed favorable OS rates compared to PCT alone in M1a patients (p < 0.001). No significant survival difference was observed between PCT plus LRRT and PCT alone in M1b and M1c patients (p > 0.05).

Conclusions

The PPS-based RPA stratification model could identify suitable candidates for LRRT. Patients with stage M1a disease could benefit from LRRT.

Oligometastatic Head and Neck Cancer: Challenges and Perspectives

Simple Summary

Oligometastasis represents a disease state and an opportunity for cure when metastases emerge. Emerging evidence supports that most head and neck cancer patients with oligometastatic disease are likely to benefit from curative intent local ablative therapy if appropriate selection criteria are applied. Biomarkers to predict development of oligometastasis, as well as to identify which patients could benefit from a radical intent approach, are under investigation. This review summarizes recent knowledge about the characteristics, investigational efforts, and evidence for local ablation regarding oligometastasis in head and neck cancer. We also describe the challenges and opportunities in patient selection and discuss the role of radiotherapy and immunotherapy combinations to enhance anti-tumor immunity.

Abstract

A minority of patients with metastatic head and neck squamous cell carcinoma (HNSCC) present with oligometastatic disease. Oligometastasis not only reflects a disease state, but might also present an opportunity for cure in the metastatic setting. Radical ablation of all oligometastatic sites may confer prolonged survival and possibly achieve cure in some patients. However, substantial debate remains about whether patients with oligometastatic disease could benefit from curative intent therapy or whether aggressive treatments expose some patients to futile toxicity. Optimal selection of patients, carefully balancing the currently known prognostic factors against the risks of toxicity is critical. Emerging evidence suggests that patients with a limited burden of disease, viral-related pharyngeal cancer, metachronous metastasis and lung-only metastasis may benefit most from this approach. Efforts are underway to identify biomarkers that can detect oligometastasis and better select patients who would derive the maximum benefit from an aggressive radical approach. The combination of radiotherapy and immunotherapy promises to enhance the anti-tumoral immune response and help overcome resistance. However, optimization of management algorithms, including patient selection, radiation dose and sequencing, will be critical in upcoming clinical trials. This review summarizes recent knowledge about the characteristics and investigational efforts regarding oligometastasis in HNSCC.

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.

Local radiotherapy versus nonradiotherapy to distant lesions for metastatic nasopharyngeal carcinoma: A retrospective cohort study

BACKGROUND

To evaluate the efficiency of local radiotherapy to metastatic lesions in patients with metastatic nasopharyngeal carcinoma (mNPC).

METHODS

The overall survival was observed and compared for mNPC patients who received local radiotherapy versus nonradiotherapy to metastatic lesions by using the Kaplan-Meier method and Cox analysis.

RESULTS

One hundred and nine patients with NPC were involved in this study, with 61 (56.0%) received radiotherapy to metastatic sites and 48 (44.0%) did not receive radiotherapy to metastatic sites. The 2- and 5-year OS for patients who received local radiotherapy to metastatic lesions were 65.8% and 35.7%, and for patients who did not receive radiotherapy to metastatic lesions were 45.3% and 26.2%. The multivariable adjusted hazard radios for local radiotherapy versus nonradiotherapy to metastatic lesions were 0.482 (95% confidence interval is 0.278-0.834, p = 0.009).

CONCLUSIONS

Local radiotherapy to metastatic lesions might be a protective factor for patients with mNPC.

Subphrenic Lymph Node Metastasis Predicts Poorer Prognosis for Nasopharyngeal Carcinoma Patients With Metachronous Metastasis

Aim

We retrospectively analyzed the distribution of distant lymph node metastasis and its impact on prognosis in patients with metastatic NPC after treatment.

Methods

From 2010 to 2016, 219 NPC patients out of 1,601 (182 from the Affiliated Cancer Hospital and Institute of Guangzhou Medical University, and 37 from the Affiliated Dongguan Hospital, Southern Medical University) developed distant metastasis after primary radiation therapy. Metastatic lesions were divided into groups according to location: bones above the diaphragm (supraphrenic bone, SUP-B); bones below the diaphragm (subphrenic bone, SUB-B); distant lymph nodes above the diaphragm (supraphrenic distant lymph nodes, SUP-DLN); distant lymph nodes below the diaphragm (subphrenic distant lymph nodes, SUB-DLN), liver, lung, and other lesions beyond bone/lung/distant lymph node above the diaphragm (supraphrenic other lesions, SUP-OL); other lesions beyond bone/liver/distant lymph node below the diaphragm (subphrenic other lesions, SUB-OL); the subtotal above the diaphragm (supraphrenic total lesions, SUP-TL); and the subtotal below the diaphragm (subphrenic total lesions, SUB-TL). Kaplan–Meier methods were used to estimate the probability of patients’ overall survival (OS). Univariate and multivariate analyses were applied using the Cox proportional hazard model to explore prediction factors of OS.

Results

The most frequent metastatic locations were bone (45.2%), lung (40.6%), liver (32.0%), and distant lymph nodes (20.1%). The total number of distant lymph node metastasis was 44, of which 22 (10.0%) were above the diaphragm, 18 (8.2%) were below the diaphragm, and 4 (1.8%) were both above and below the diaphragm. Age (HR: 1.02, 95% CI: 1.00, 1.03, p = 0.012), N stage (HR: 1.26, 95% CI: 1.04, 1.54, p = 0.019), number of metastatic locations (HR: 1.39, 95% CI: 1.12, 1.73, p = 0.003), bone (HR: 1.65, 95% CI: 1.20, 2.25, p = 0.002), SUB-B (HR: 1.51, 95% CI: 1.07, 2.12, p = 0.019), SUB-DLN (HR: 1.72, 95% CI: 1.03, 2.86, p = 0.038), and SUB-O L(HR: 4.46, 95% CI: 1.39, 14.3, p = 0.012) were associated with OS. Multivariate analyses revealed that a higher N stage (HR: 1.23, 95% CI: 1.00, 1.50, p = 0.048), SUB-DLN (HR: 1.72, 95% CI: 1.02, 2.90, p = 0.043), and SUB-OL (HR: 3.72, 95% CI: 1.14, 12.16, p = 0.029) were associated with worse OS.

Conclusion

Subphrenic lymph node metastasis predicts poorer prognosis for NPC patients with metachronous metastasis; however, this needs validation by large prospective studies.

Prognostic Factors for Overall Survival in Nasopharyngeal Cancer and Implication for TNM Staging by UICC: A Systematic Review of the Literature

This study aims to identify prognostic factors in nasopharyngeal carcinoma (NPC) to improve the current 8th edition TNM classification. A systematic review of the literature reported between 2013 and 2019 in PubMed, Embase, and Scopus was conducted. Studies were included if (1) original clinical studies, (2) ≥50 NPC patients, and (3) analyses on the association between prognostic factors and overall survival. The data elements of eligible studies were abstracted and analyzed. A level of evidence was synthesized for each suggested change to the TNM staging and prognostic factors. Of 5,595 studies screened, 108 studies (44 studies on anatomical criteria and 64 on non-anatomical factors) were selected. Proposed changes/factors with strong evidence included the upstaging paranasal sinus to T4, defining parotid lymph node as N3, upstaging N-category based on presence of lymph node necrosis, as well as the incorporation of non-TNM factors including EBV-DNA level, primary gross tumor volume (GTV), nodal GTV, neutrophil-lymphocyte ratio, lactate dehydrogenase, C-reactive protein/albumin ratio, platelet count, SUVmax of the primary tumor, and total lesion glycolysis. This systematic review provides a useful summary of suggestions and prognostic factors that potentially improve the current staging system. Further validation studies are warranted to confirm their significance.

Liquid biopsy posttreatment surveillance in endemic nasopharyngeal carcinoma: a cost-effective strategy to integrate circulating cell-free Epstein-Barr virus DNA

BACKGROUND

The optimal posttreatment surveillance strategy for nasopharyngeal carcinoma (NPC) remains unclear. Circulating cell-free Epstein-Barr virus (cfEBV) DNA has been recognized as a promising biomarker to facilitate early detection of NPC recurrence. Therefore, we aim to determine whether integrating circulating cfEBV DNA into NPC follow-up is cost-effective.

METHODS

For each stage of asymptomatic nonmetastatic NPC patients after complete remission to primary NPC treatment, we developed a Markov model to compare the cost-effectiveness of the following surveillance strategies: routine follow-up strategy, i.e., (1) routine clinical physical examination; routine imaging strategies, including (2) routine magnetic resonance imaging plus computed tomography plus bone scintigraphy (MRI + CT + BS); and (3) routine 18F-fluorodeoxyglucose positron emission tomography/computed tomography (PET/CT); cfEBV DNA-guided imaging strategies, including (4) cfEBV DNA-guided MRI + CT + BS and (5) cfEBV DNA-guided PET/CT. Clinical probabilities, utilities, and costs were derived from published studies or databases. Sensitivity analyses were performed.

RESULTS

For all disease stages, cfEBV DNA-guided imaging strategies demonstrated similar survival benefits but were considerably more economical than routine imaging strategies. They only required approximately one quarter of the number of imaging studies compared with routine imaging strategies to detect one recurrence. Specifically, cfEBV DNA-guided MRI + CT + BS was most cost-effective for stage II (incremental cost-effectiveness ratio [ICER] $57,308/quality-adjusted life-year [QALY]) and stage III ($46,860/QALY) patients, while cfEBV DNA-guided PET/CT was most cost-effective for stage IV patients ($62,269/QALY). However, routine follow-up was adequate for stage I patients due to their low recurrence risk.

CONCLUSIONS

The cfEBV DNA-guided imaging strategies are effective and cost-effective follow-up methods in NPC. These liquid biopsy-based strategies offer evidence-based, stage-specific surveillance modalities for clinicians and reduce disease burden for patients.

Consensus of Minimally Invasive and Multidisciplinary Comprehensive Treatment for Hepatocellular Carcinoma - 2020 Guangzhou Recommendations

In China, the majority of patients with hepatocellular carcinoma (HCC) result from long-term infection of hepatitis B. Pathologically, HCC is characterized by rich blood supply, multicentric origins, early vascular invasion and intrahepatic metastasis. Therefore, HCC is not a local disease but a systemic disease at the beginning of its occurrence. For this reason, a comprehensive treatment strategy should be adopted in the management of HCC, including local treatments (such as surgical resection, radiofrequency ablation, microwave ablation, chemical ablation and cryoablation, etc.), organ-level treatments [such as transcatheter arterial infusion of chemotherapy and transcatheter arterial chemoembolization (TACE)], and systemic treatments (such as immunotherapy, antiviral therapy and molecular targeted therapy, etc.). This consensus sets forth the minimally-invasive and multidisciplinary comprehensive guideline of HCC, focusing on the following eight aspects (1) using hepaticarteriography, CT hepatic arteriography (CTHA), CT arterial portography (CTAP), lipiodol CT (Lp-CT), TACE-CT to find the intrahepatic lesion and make precise staging (2) TACE combined with ablation or ablation as the first choice of treatment for early stage or small HCC, while other therapies are considered only when ablation is not applicable (3) infiltrating HCC should be regarded as an independent subtype of HCC (4) minimally-invasive comprehensive treatment could be adopted in treating metastatic lymph nodes (5) multi-level subdivision of M-staging should be used for individualized treatment and predicting prognosis (6) HCC with severe hepatic decompensation is the only candidate criterion for liver transplantation (7) bio-immunotherapy, traditional Chinese medicine therapy, antiviral therapy, and psychosocial and psychopharmacological interventions should be advocated through the whole course of HCC treatment (8) implementation of multicenter randomized controlled trials of minimally-invasive therapy versus surgery for early and intermediate stage HCC is recommended.

Prognostic value of pretreatment F-18 fluorodeoxyglucose PET/CT in colorectal cancer with unresectable metastasis

PURPOSE

The aim of the study was to assess the prognostic value of pretreatment PET/computed tomography (CT) scans in colorectal cancer (CRC) patients with unresectable metastasis.

MATERIALS AND METHODS

We retrospectively reviewed the pretreatment PET/CT images of 82 CRC patients with unresectable metastasis and their medical records. On PET/CT images, maximum standardized uptake value (SUVmax) of primary tumor, highest SUVmax of metastatic tumors and number of metastatic organs were identified. The patients were further divided into single and multiple organ metastases groups according to the extent of disease. Survival analysis was performed with the clinical variables and metabolic parameters from PET/CT.

RESULTS

In a total of 82 patients, the age of patients, highest SUVmax of metastatic tumors and number of metastatic organs were independent prognostic factors for overall survival (OS) (all P < 0.05), whereas the SUVmax of primary tumor was not. On multivariate analysis, only the SUVmax of metastatic tumor was a significant prognostic factor in the single organ metastasis group (P = 0.047), whereas the age and highest SUVmax of metastatic tumors were independent prognostic factors in the multiple organ metastases group (all P < 0.05).

CONCLUSION

The highest SUVmax of metastatic tumors was an independent prognostic factor for OS in CRC patients with unresectable metastasis.

Induction Chemotherapy Combined With Intensity-Modulated Radiotherapy for 129 Nasopharyngeal Carcinoma Patients With Synchronous Metastases: A Retrospective Study

Objective

To analyze the therapeutic effect and prognostic factors of nasopharyngeal carcinoma (NPC) patients with distant metastases at initial diagnosis receiving induction chemotherapy with intensity-modulated radiotherapy (IMRT).

Methods

A total of 129 patients who underwent platinum-based induction chemotherapy followed by definitive IMRT with or without concurrent or adjuvant chemotherapy for newly diagnosed distant metastatic NPC in our center between March 2008 and November 2018 were retrospectively analyzed. 41 patients underwent local therapy for metastatic sites. Kaplan-Meier method was used to estimate survival rates, Log-rank test and Cox proportional hazards model were used to figure out independent prognostic factors of overall survival (OS).

Results

A total of 66 patients had been dead (median follow-up time, 51.5 months). The median overall survival (OS) time was 54.2 months (range, 7-136 months), and the 1-year, 2-year, 3-year, 5-year overall survival rates were 88.0%,71.0%,58.0%, and 47.0%. Multivariate analysis found that the factors correlated with poor overall survival were pre-treatment serum lactate dehydrogenase (SLDH) >180U/L, chemotherapy cycles<4, and M1 stage subdivision (M1b, single hepatic metastasis and/or multiple metastases excluding the liver; and M1c, multiple hepatic metastases). The 5-year OS rates for M1a, M1b and M1c were 62.6%,40.4% and 0%, respectively.

Conclusion

Platinum-containing induction chemotherapy combined with IMRT seemed to be advantageous to prolong survival for some NPC patients with synchronous metastases at initial diagnosis. The independent factors to prognosticate OS were pre-treatment SLDH, number of chemotherapy cycles, and M1 subcategories. Prospective clinical trials are needed to confirm the result.

Local treatment of metastases plus systemic chemotherapy on overall survival of patients with metastatic nasopharyngeal carcinoma

Background

To investigate the effect of local treatment of metastases on overall survival (OS) of patients with metastatic nasopharyngeal carcinoma (NPC).

Methods

One hundred and forty‐seven patients were included. The association between local treatment and OS was examined with propensity score matching (PSM) method.

Results

In entire cohort, the median OS was significantly longer in patients with local treatment of metastases plus chemotherapy compared to those with chemotherapy alone (71.7 vs. 16.2 months; p < 0.001). In PSM cohort, similar OS benefit of patients with local treatment was observed (55.6 vs. 17.6 months; p = 0.011). The survival benefit of local treatment remained regardless of the number of metastatic lesions and metastatic sites. Patients received radiation doses of >60 Gy had longer OS than those who received less.

Conclusions

Local treatment of metastases could improve OS of patients with metastatic NPC and could be considered in their treatment in addition to chemotherapy.

Synchronous Metastatic Nasopharyngeal Carcinoma: Characteristics and Survival of Patients Adding Definitive Nasopharyngeal-Neck Radiotherapy to Systematic Chemotherapy

Purpose

To determine the M1 sub-staging in synchronous metastatic nasopharyngeal carcinoma (smNPC) and to examine the effect of nasopharyngeal-neck radiotherapy (RT) and local treatment of metastases on overall survival (OS) of smNPC patients.

Patients and Methods

A total of 150 patients with smNPC were included. Metastatic characteristics associated with their potential prognostic significance were analyzed. Then, a stratification system of the M1 sub-staging in smNPC was provided according to metastatic features. Moreover, the OS of patients with or without nasopharyngeal-neck RT was compared by Log rank test. The OS of patients who received or did not receive local treatment of metastases was also analyzed.

Results

We successfully divided the M1 stage into three sub-staging: M1a (a single site with a single lesion), M1b (a single site with multiple lesions), and M1c (multiple sites with multiple lesions). The median OS was 53.2, 25.8, and 18.9 months for M1a, M1b, and M1c, respectively (p < 0.001). Nasopharyngeal-neck RT plus systematic chemotherapy (CT) significantly improved OS compared to systematic CT (median OS, 34.0 vs 15.2 months, p = 0.002). However, incorporation of local treatment of metastases did not bring survival benefit to smNPC patients who received nasopharyngeal-neck RT plus systematic CT (median OS, 25.8 vs 35.1 months, p = 0.374).

Conclusion

The sub-staging of the M1 stage in smNPC had promising prognostic value. Adding nasopharyngeal-neck RT on the basis of systematic CT markedly improved the survival of smNPC patients, while addition of local treatment of metastases to nasopharyngeal-neck RT plus systematic CT for smNPC needed further exploration.

Subdivision of M1 Stage for De Novo Metastatic Breast Cancer to Better Predict Prognosis and Response to Primary Tumor Surgery

BACKGROUND

Patients with de novo metastatic breast cancer (MBC) constitute a heterogeneous group with different clinicopathologic characteristics and survival outcomes. Despite controversy regarding its prognostic value, primary tumor surgery may improve survival for selected patients.

PATIENTS AND METHODS

Patients with de novo MBC were identified using the SEER database and were then divided randomly into training and validation sets. A Fine-Gray competing risks model was developed to identify the variables associated with increased cancer-specific mortality in the training set. The M1 subdivision system was established based on the independent prognostic factors. Cumulative incidence curves were estimated and compared using Gray's test.

RESULTS

Involvement of brain or liver and number of metastatic sites were identified as independent prognostic factors in multivariate analysis. The M1 category was subdivided into 3 subcategories: M1a, single site involvement except brain and liver; M1b, liver involvement only, or multiple site involvement except brain and liver; and M1c, brain involvement regardless of number of metastatic sites, or liver and other sites involvement except brain (M1b vs M1a: subdistribution hazard ratio [SHR], 1.48; 95% CI, 1.29-1.68; M1c vs M1a: SHR, 2.45; 95% CI, 2.18-2.75). Patients with the M1a subtype benefited most from primary tumor surgery in the adjusted competing risks model (M1a: SHR, 0.57; 95% CI, 0.48-0.67, M1b: SHR, 0.62; 95% CI, 0.47-0.83, and M1c: SHR, 0.59; 95% CI, 0.44-0.80), whereas benefits conferred by treatment with chemotherapy alone increased with the upstaging of metastatic disease (M1a: SHR, 0.72; 95% CI, 0.62-0.83, M1b: SHR, 0.54; 95% CI, 0.44-0.68, and M1c: SHR, 0.53; 95% CI, 0.45-0.61).

CONCLUSIONS

Subdivision of M1 stage facilitates prognosis prediction and treatment planning for patients with de novo MBC. Treatment offered should be decided in a coordinated multidisciplinary setting. Primary tumor surgery may play an important role in the management of selected patients.

An optimal posttreatment surveillance strategy for cancer survivors based on an individualized risk-based approach

The optimal post-treatment surveillance strategy that can detect early recurrence of a cancer within limited visits remains unexplored. Here we adopt nasopharyngeal carcinoma as the study model to establish an approach to surveillance that balances the effectiveness of disease detection versus costs. A total of 7,043 newly-diagnosed patients are grouped according to a clinic-molecular risk grouping system. We use a random survival forest model to simulate the monthly probability of disease recurrence, and thereby establish risk-based surveillance arrangements that can maximize the efficacy of recurrence detection per visit. Markov decision-analytic models further validate that the risk-based surveillance outperforms the control strategies and is the most cost-effective. These results are confirmed in an external validation cohort. Finally, we recommend the risk-based surveillance arrangement which requires 10, 11, 13 and 14 visits for group I to IV. Our surveillance strategies might pave the way for individualized and economic surveillance for cancer survivors.

Intensive Local Radiotherapy Is Associated With Better Local Control and Prolonged Survival in Bone-Metastatic Nasopharyngeal Carcinoma Patients

Objective: To compare the survival outcomes brought by different radiation dose schedules to bone lesions and different chemotherapy regimens in bone metastatic nasopharyngeal carcinoma (NPC).

Background: The current treatment strategy for bone metastatic NPC patients was empirically given and poorly studied before. It is of necessity to optimize the treatment for bone metastasis to enhance the therapeutic effect and increase the proportion of long-term survived patients.

Methods: Three hundred patients who received chemoradiotherapy from 2002 to 2018 were involved in the study. Demographics, laboratory results, and detailed treatment plans were recorded. Radiotherapy plans were classified into three categories based on the intensity, and the survival analysis was performed using log-rank test. Multivariable analysis was made by the Cox proportional regression model.

Results: Patients who received 60–75 Gy/30–35 fractions of radiation to the metastatic bones had significantly longer bone relapse-free survival (BRFS) (HR, 0.53, 95% CI, 0.37–0.78, P = 0.003), overall survival (OS) (HR, 0.63, 95% CI, 0.46–0.84, P = 0.007), and progression-free survival (PFS) (HR, 0.80, 95% CI, 0.67–0.95, P = 0.041). The administration of paclitaxel, cisplatin and 5-fluorouracil regimen was also associated with better BRFS (HR, 0.27, 95% CI, 0.10–0.75, P = 0.007), PFS (HR, 0.60, 95% CI, 0.42–0.87, P = 0.007), and OS with borderline significance (HR, 0.54, 95% CI, 0.29–1.03, P = 0.058). In multivariable analysis, the post-treatment EBV DNA level and radical radiation dose were proved as independent prognostic factors for both BRFS and OS.

Conclusions: Radiotherapy to metastatic bones with palliative dose prescription should not be considered in bone metastatic NPC patients. TPF chemotherapy regimen might help to improve the survivals in NPC patients but failed to be an independent protective factor.

Evaluation of the National Comprehensive Cancer Network and European Society for Medical Oncology Nasopharyngeal Carcinoma Surveillance Guidelines

Purpose: The National Comprehensive Cancer Network (NCCN) and European Society for Medical Oncology (ESMO) provide surveillance guidelines for nasopharyngeal carcinoma (NPC). We evaluated the ability of these guidelines to capture disease recurrence.

Materials and methods: All 749 NPC patients were stratified for analysis by T and N stage. We evaluated the guidelines by calculating the percentage of relapses detected when following the 2018 NCCN, 2015 NCCN, and 2012 ESMO surveillance guidelines, and related surveillance costs were compared.

Results: At a median follow-up of 100.8 months, 168 patients (22.4%) had experienced recurrence. Nineteen recurrences (11.3%) were detected using the 2018 NCCN, 53 (31.5%) using the 2015 NCCN and 46 (27.4%) using the ESMO guidelines. To capture 95% recurrences, surveillance would be required for 85.57 months for T1/2, 67.45 months for T3/4, 83.57 months for N0/1, and 55.80 months for N2/3 disease. In T1/2 disease, Medicare surveillance costs per patient were US$1642.66 using 2018 NCCN or ESMO and US$2179.81 using 2015 NCCN. Costs per recurrence detected were US$42,578.64, 62,088.70, and 73,329.76 using 2018 NCCN, 2015 NCCN, and ESMO, respectively.

Conclusions: If strictly followed, the NCCN and ESMO guidelines will miss more than two-thirds recurrences. Improved surveillance algorithms to balance patient benefit against costs are needed.

Establishing M1 stage subdivisions by incorporating radiological features and Epstein-Barr virus DNA for metastatic nasopharyngeal carcinoma

Background

Significance of plasma Epstein-Barr virus deoxyribonucleic acid (EBV DNA)-a proven robust indicator for nasopharyngeal carcinoma (NPC)-is not yet clarified in risk stratification of metastatic NPC (mNPC). We aim to establish effective M1 stage subdivisions in mNPC by integrating radiological features and EBV DNA at diagnosis of metastasis (mEBV DNA).

Methods

The study comprised 1,007 mNPC patients, including 817 metachronous mNPC (mmNPC) patients randomized into training (n=613) and internal validation (n=204) cohorts, and 190 synchronous mNPC (smNPC) patients defined as smNPC validation cohort. Primary clinical end-point was overall survival (OS). Covariate inclusion to recursive partitioning analysis (RPA)-generated risk stratification was qualified by a multivariable two-sided P<0.05. Performances of different models were compared using area under ROC curve (AUC), Harrell's concordance index (c-index) and Akaike information criterion (AIC).

Results

Compared with other simply image-based models, the ultimate RPA-EBV-stage presented a best performance [c-index =0.68 (training), 0.70 (internal validation), 0.64 (smNPC validation); AUC =0.69 (training), 0.72 (internal validation), 0.70 (smNPC validation)]: M1a (low mEBV DNA + oligo lesion), M1b (low mEBV DNA + multiple lesions), M1c (high mEBV DNA + no liver involvement), and M1d (high mEBV DNA + liver involvement). Corresponding 3-year OS rates were 49.9%, 33.4%, 22.6%, and 6.7%, respectively (P<0.001). In mmNPC patients, compared with chemotherapy alone, addition of local treatment demonstrated superiority in M1a and M1b; systemic therapy combined with targeted therapy conferred benefit on patients of M1c and M1d (P<0.05).

Conclusions

This RPA-EBV-stage provided favorable prognostic value for survival outcomes and could assist clinical and investigative management. Low-risk patients are considered suitable candidate for curative local treatment, and high-risk patients are recommended to undergo intensive systemic treatment.

Prognostic value of early radiological response to first-line platinum-containing chemotherapy in patients with metastatic nasopharyngeal carcinoma

Background

To explore the prognostic value of early radiological response (ERR) to first‐line platinum‐containing chemotherapy in patients with metastatic nasopharyngeal carcinoma (mNPC), as well as its correlation with the best radiological response (BRR).

Patients and methods

A total of 756 mNPC patients with measurable lesions who received first‐line platinum‐containing chemotherapy were enrolled in this study. ERR was defined as complete or partial response after 6 weeks of chemotherapy according to the Response Evaluation Criteria in Solid Tumors (RECIST) 1.1. We performed survival analyses according to the radiological response after repeated chemotherapy. Log‐rank test and Cox regression were used to analyze the survival data.

Results

About 470 patients achieved ERR and 78 patients achieved subsequent response (objective response after repeated chemotherapy). ERR patients had better OS (P < .001, median OS: 34.3 vs 22.2 months) and PFS (P < .001, median PFS: 10.2 vs 7.4 months) than non‐ERR ones. ERR (OS: HR = 0.591, 95% CI, 0.495‐0.705, P < .001, PFS: HR = 0.586, 95% CI, 0.500‐0.686, P < .001) was independently prolonged survival compared with non‐ERR ones. Besides, ERR was significantly correlated with the BRR (Kappa: 0.73; Pearson: 0.74, P < .001), and had significantly longer OS and PFS than patients with subsequent response, respectively.

Conclusion

ERR is an independent prognostic factor in determining survival in mNPC patients received first‐line platinum‐containing chemotherapy, which may be a more sensitive predictor to assess overall efficacy of systemic treatment than BRR in mNPC. Prospective validation studies are needed.

Modern radiotherapy for head and neck cancer

Radiation therapy (RT) plays a key role in curative-intent treatments for head and neck cancers. Its use is indicated as a sole therapy in early stage tumors or in combination with surgery or concurrent chemotherapy in advanced stages. Recent technologic advances have resulted in both improved oncologic results and expansion of the indications for RT in clinical practice. Despite this, RT administered to the head and neck region is still burdened by a high rate of acute and late side effects. Moreover, about 50% of patients with high-risk disease experience loco-regional recurrence within 3 years of follow-up. Therefore, in recent decades, efforts have been dedicated to optimize the cost/benefit ratio of RT in this subset of patients. The aim of the present review was to highlight modern concepts of RT for head and neck cancers considering both the technological advances that have been achieved and recent knowledge that has informed the biological interaction between radiation and both tumor and healthy tissues.

Nasopharyngeal carcinoma

Nasopharyngeal carcinoma is characterised by distinct geographical distribution and is particularly prevalent in east and southeast Asia. Epidemiological trends in the past decade have shown that its incidence has declined gradually but progressively, and mortality has been reduced substantially. These findings probably reflect lifestyle and environmental changes, enhanced understanding of the pathogenesis and risk factors, population screening, advancements in imaging techniques, and individualised comprehensive chemoradiotherapy strategies. In particular, plasma Epstein-Barr virus (EBV) DNA has been used for population screening, prognostication, predicting treatment response for therapeutic adaptation, and disease surveillance. Moreover, the widespread application of intensity-modulated radiotherapy and optimisation of chemotherapy strategies (induction, concurrent, adjuvant) have contributed to improved survival with reduced toxicities. Among the existing developments in novel therapeutics, immune checkpoint therapies have achieved breakthroughs for treating recurrent or metastatic disease and represent a promising future direction in nasopharyngeal carcinoma.

Establishment and validation of a nomogram for predicting survival in patients with de novo metastatic nasopharyngeal carcinoma

BACKGROUND AND PURPOSE

No nomogram has been established for de novo metastatic NPC patients previously. Thus, we retrospectively involved 502 de novo NPC patients to develop a practical clinical tool by combining prognostic biomarkers to estimate individual risk.

METHODS

The nomogram was based on a primary cohort involving 353 patients from 2007 to 2013; all independent prognostic factors were integrated for inclusion in the model. The predictive accuracy of the model was evaluated by concordance index (C-index). A calibration curve was used to compare predicted and observed survival. We confirmed the results using a validation cohort study on 149 patients enrolled from 2014 to 2016.

RESULTS

Five independent prognostic factors derived from multivariable analysis were entered into the nomogram. The C-index of the nomogram was 0.724. The calibration curves for probability of 3- and 5-year overall survival (OS) showed satisfactory agreement between predicted survival and actual observed survival. The Kaplan-Meier survival curves showed a significant difference in survival among different risk groups according to the total score. All results were confirmed in the validation cohort.

CONCLUSION

We established a convenient nomogram that provides individual prediction of OS for patients with de novo metastatic NPC.

Role of radiotherapy in the treatment of metastatic head and neck cancer

In metastatic or locally advanced head and neck tumors that present in frail patients or after chemotherapy progression, radiotherapy is normally used as a palliative treatment, with a high rate of symptom palliation and improvement in quality of life. However, there is controversy about what the optimal regimen is. Moreover, despite the poor prognosis of metastatic head and neck cancer, different retrospective studies have shown that a minority of patients with oligometastatic disease experience prolonged disease-free survival after adding curative radiotherapy treatment to the metastatic disease and/or primary tumor. Different retrospective studies have identified clinical prognostic factors that may be used to select candidate patients with metastatic head and neck cancer for a radical approach with radiotherapy. The purpose of this manuscript is to review the role of radiotherapy in metastatic and locally advanced head and neck tumors.

Percutaneous CT-guided radiofrequency ablation for patients with extrahepatic oligometastases of hepatocellular carcinoma: long-term results

BACKGROUND

The aim of this study was to evaluate the therapeutic outcome of percutaneous computed tomography (CT)-guided radiofrequency ablation (RFA) for extrahepatic oligometastases of hepatocellular carcinoma (HCC).

METHODS

Institutional review board approval was obtained for this retrospective study, and all patients provided written informed consent. Between April 2004 and December 2015, 116 oligometastases (diameter, 5-50 mm; 20.3 ± 10.4) in 79 consecutive HCC patients (73 men and 6 women; average age, 50.3 years ±13.0) were treated with RFA. We focussed on patients with 1-3 extrahepatic metastases (EHM) confined to 1-2 organs (including the lung, adrenal gland, bone, lymph node and pleura/peritoneum) who were treated naïve with curative intent. Survival, technical success and safety were evaluated. The log-rank test and Cox proportional hazards regression models were used to analyse the survival data.

RESULTS

No immediate technical failure occurred, and at 1 month, the technique effectiveness rate was determined to be 95.8%. After a median follow-up time of 28.0 months (range, 6-108 months), the 1-, 2- and 3-year overall survival (OS) rates were 91, 70 and 48%, respectively, with a median survival time of 33.5 months. Time to unoligometastatic progression (TTUP) of less than 6 months (p < 0.001) and a Child-Pugh score of more than 5 (p = 0.001) were significant indicators of shorter OS. The 1-, 2- and 3-year disease free survival (DFS) rates were 34, 21 and 8%, respectively, with a median DFS time of 6.8 months. DFS was better for those with lung metastases (p = 0.006). Major complication occurred in nine (9.5%, 9/95) RFA sessions without treatment-related mortality.

CONCLUSIONS

CT-guided RFA for oligometastatic HCC may provide favourable efficacy and technical success with a minimally invasive approach.

Establishment and validation of M1 stage subdivisions for de novo metastatic nasopharyngeal carcinoma to better predict prognosis and guide treatment

BACKGROUND

To better manage patients with de novo metastatic NPC (mNPC) including easily identifying individuals' survival outcomes and accurately choosing the most suitable treatment.

MATERIALS AND METHODS

Three independent cohorts of mNPC patients (a training set of n = 462, an internal prospective validation set of n = 272 and an external prospective validation set of n = 243) were studied. The radiological characteristics of distant metastases, including number of metastatic locations, number of metastatic lesions and size of metastatic lesions, were carefully defined based on imaging data. These three factors and other potential prognostic factors were comprehensively analysed and were further integrated into new subdivisions of stage M1 using a Cox proportional hazards model.

RESULTS

We successfully subdivided the M1 stage into three categories: M1a, oligo metastasis without liver involvement; M1b, multiple metastases without liver involvement; and M1c, liver involvement irrespective of metastatic lesions. The 3-year overall survival ranged from 54.5% to 72.8%, from 34.3% to 41.6% and from 22.6.0%-23.6% for M1a, M1b and M1c, respectively (P < 0.001). Systemic chemotherapy combined with radical loco-regional radiotherapy may benefit patients in M1a and M1b, not in M1c. Further aggressive treatment of metastatic lesions based on systemic chemotherapy and definitive loco-regional radiotherapy showed no survival benefit, even for patients in M1a (P > 0.05).

CONCLUSION

The subdividing of M1 provided promising prognostic value and could aid clinicians in choosing the most suitable treatment for de novo mNPC patients.