18F-FMISO PET-guided dose escalation with multifield optimization intensity-modulated proton therapy in nasopharyngeal carcinoma.

PURPOSE: The purpose of this study was to evaluate the radiotherapy planning feasibility of dose escalation with intensity-modulated proton therapy (IMPT) to hypoxic tumor regions identified on 18F-Fluoromisonidazole (FMISO) positron emission tomography and computed tomography (PET-CT) in NPC. MATERIALS AND METHODS: Nine patients with stages T3-4N0-3M0 NPC underwent 18F-FMISO PET-CT before and during week 3 of radiotherapy. The hypoxic volume (GTVhypo) is automatically generated by applying a subthresholding algorithm within the gross tumor volume (GTV) with a tumor to muscle standardized uptake value (SUV) ratio of 1.3 on the 18F-FMISO PET-CT scan. Two proton plans were generated for each patient, a standard plan to 70 Gy and dose escalation plan with upfront boost followed by standard 70GyE plan. The stereotactic boost was planned with single-field uniform dose optimization using two fields to deliver 10 GyE in two fractions to GTVhypo. The standard plan was generated with IMPT with robust optimization to deliver 70GyE, 60GyE in 33 fractions using simultaneous integrated boost technique. A plan sum was generated for assessment. RESULTS: Eight of nine patients showed tumor hypoxia on the baseline 18F-FMISO PET-CT scan. The mean hypoxic tumor volume was 3.9 cm3 (range .9-11.9cm3 ). The average SUVmax of the hypoxic volume was 2.2 (range 1.44-2.98). All the dose-volume parameters met the planning objectives for target coverage. Dose escalation was not feasible in three of eight patients as the D0.03cc of temporal lobe was greater than 75GyE. CONCLUSIONS: The utility of boost to the hypoxic volume before standard course of radiotherapy with IMPT is dosimetrically feasible in selected patients. Clinical trials are warranted to determine the clinical outcomes of this approach.

Comparison of radiomics tools for image analyses and clinical prediction in nasopharyngeal carcinoma.

OBJECTIVE: Radiomics pipelines have been developed to extract novel information from radiological images, which may help in phenotypic profiling of tumours that would correlate to prognosis. Here, we compared two publicly available pipelines for radiomics analyses on head and neck CT and MRI in nasopharynx cancer (NPC). METHODS AND MATERIALS: 100 biopsy-proven NPC cases stratified by T- and N-categories were enrolled in this study. Two radiomics pipeline, Moddicom (v. 0.51) and Pyradiomics (v. 2.1.2) were used to extract radiomics features of CT and MRI. Segmentation of primary gross tumour volume was performed using Velocity v. 4.0 by consensus agreement between three radiation oncologists. Intraclass correlation between common features of the two pipelines was analysed by Spearman's rank correlation. Unsupervised hierarchical clustering was used to determine association between radiomics features and clinical parameters. RESULTS: We observed a high proportion of correlated features in the CT data set, but not for MRI; 76.1% (51 of 67 common between Moddicom and Pyradiomics) of CT features and 28.6% (20 of 70 common) of MRI features were significantly correlated. Of these, 100% were shape-related for both CT and MRI, 100 and 23.5% were first-order-related, 61.9 and 19.0% were texture-related, respectively. This interpipeline heterogeneity affected the downstream clustering with known prognostic clinical parameters of cTN-status and GTVp. Nonetheless, shape features were the most reproducible predictors of clinical parameters among the different radiomics modules. CONCLUSION: Here, we highlighted significant heterogeneity between two publicly available radiomics pipelines that could affect the downstream association with prognostic clinical factors in NPC. ADVANCES IN KNOWLEDGE: The present study emphasized the broader importance of selecting stable radiomics features for disease phenotyping, and it is necessary prior to any investigation of multicentre imaging datasets to validate the stability of CT-related radiomics features for clinical prognostication.

Clinical and dosimetric predictors of physician and patient reported xerostomia following intensity modulated radiotherapy for nasopharyngeal cancer - A prospective cohort analysis.

BACKGROUND AND PURPOSE: To compare physician and patient reported xerostomia and correlate xerostomia with dosimetric and clinical parameters for nasopharyngeal cancer (NPC) patients treated with intensity modulated radiotherapy (IMRT) and chemotherapy. PATIENTS AND METHODS: We analyzed the data of 172 patients with locally advanced NPC. Xerostomia was evaluated via physician-rated xerostomia based on RTOG morbidity score (E1), patient-rated dry mouth (E2) and patient-rated sticky saliva (E3) based on EORTC QLQ-HN35 questionnaire. Primary endpoint was the presence of moderate to severe xerostomia at 2-year after completion of IMRT. RESULTS: The levels of physician reported xerostomia (E1) were consistently lower than patient reported dry mouth (E2) over time. The incidence of patients with xerostomia at 3-month post RT was 58% based on E1, 70% based on E2, and 51% based on E3. The corresponding incidence rates at 2-year post RT was 26% (E1), 36% (E2) and 21% (E3). The incidence of patients with xerostomia at 1-year post RT was close to that at 2-year post RT for all the 3 endpoints. The average Dmean of parotid glands was 41.5 Gy (range: 31.0 Gy-65.9 Gy, median: 40.7 Gy). No dosimetric parameters were significantly associated with xerostomia. CONCLUSION: Significant proportion of patients still experienced long term xerostomia with IMRT. Dose-effect relationships between xerostomia and the parotid glands were not observed in this study.

Intra-patient and inter-patient comparisons of DNA damage response biomarkers in Nasopharynx Cancer (NPC): analysis of NCC0901 randomised controlled trial of induction chemotherapy in locally advanced NPC.

BACKGROUND: Inter-patient heterogeneity in radiation-induced DNA damage responses is proposed to reflect intrinsic variations in tumour and normal tissue radiation sensitivity, but the prediction of phenotype by a molecular biomarker is influenced by clinical confounders and assay reproducibility. Here, we characterised the intrapatient and inter-patient heterogeneity in biomarkers of DNA damage and repair and radiation-induced apoptosis. METHODS: We enrolled 85 of 172 patients with locally advanced nasopharynx cancer from a randomised controlled phase II/III trial of induction chemotherapy added to chemo-radiotherapy. G0 blood lymphocytes were harvested from these patients, and irradiated with 1, 4, and 8 Gy ex vivo. DNA damage induction (1 Gy 0.5 h) and repair (4 Gy 24 h) were assessed by duplicate γH2AX foci assays in 50-100 cells. Duplicate FLICA assays performed at 48 h post-8 Gy were employed as surrogate of radiation-induced apoptosis; %FLICA-positive cells were quantified by flow cytometry. RESULTS: We observed limited intrapatient variation in γH2AX foci and %FLICA readouts; median difference of duplicate foci scores was - 0.37 (IQR = - 1.256-0.800) for 1 Gy 0.5 h and 0.09 (IQR = - 0.685-0.792) for 4 Gy 24 h; ICC of ≥0.80 was observed for duplicate %FLICA0Gy and %FLICA8Gy assays of CD4+ and CD8+ T lymphocytes. As expected, we observed wide inter-patient heterogeneity in both assays that was independent of intrapatient variation and clinical covariates, with the exception of age, which was inversely correlated with %FLICAbackground-corrected (Spearman R = - 0.406, P < 0.001 [CD4+]; R = - 0.220, P = 0.04 [CD8+]). Lastly, an exploratory case-control analysis indicates increased levels of γH2AX foci at 4 Gy 24 h in patients with severe late radiotherapy-induced xerostomia (P = 0.05). CONCLUSION: Here, we confirmed the technical reproducibility of DNA damage response assays for clinical implementation as biomarkers of clinical radiosensitivity in nasopharynx cancer patients.

Neutrophil-to-lymphocyte ratio as a prognostic marker in locally advanced nasopharyngeal carcinoma: A pooled analysis of two randomised controlled trials.

PURPOSE: To assess the prognostic value of neutrophil-to-lymphocyte ratio (NLR) in patients with International Union Against Cancer (UICC)-staged III/IVA,B nasopharyngeal carcinoma (NPC), who were enrolled into two randomised controlled trials of concurrent/adjuvant chemotherapy when added to radiotherapy (SQNP01), and induction chemotherapy when added to chemoradiotherapy (NCC0901). MATERIAL AND METHODS: A post hoc analysis of pooled cohorts from SQNP01 (N = 221) and NCC0901 (N = 172) was performed. We employed a threshold of pre-treatment NLR = 3.0 (median) to stratify patients. Survival outcomes were compared using log-rank test. Multivariable Cox regression analyses were performed to assess association between NLR and overall survival (OS), disease-free survival (DFS), distant metastasis-free survival (DMFS), and locoregional recurrence-free survival (LRFS). RESULTS: High NLR (≥3.0) was associated with advanced T-status (p = 0.002), N-status (p = 0.002), overall UICC stage (p = 0.004), and high pre-treatment Epstein-Barr virus DNA titre (p = 0.001). High NLR was not associated with OS (0.94 [0.67-1.32], p = 0.7), DFS (0.98 [0.73-1.33], p = 0.9), DMFS (1.02 [0.66-1.57], p = 0.9), and LRFS (1.37 [0.84-2.22], p = 0.2) on univariable and multivariable analyses, while conventional clinical indices (T-status, N-status, and overall UICC stage) were prognostic of clinical outcomes. High NLR also did not predict for a treatment effect with the experimental arms in both trials. CONCLUSION: Our pooled analyses that were confined to a homogenous patient population of locally advanced NPC do not suggest that NLR adds prognostic value to conventional clinical indices in identifying patients with unfavourable disease.

Recommendation for a contouring method and atlas of organs at risk in nasopharyngeal carcinoma patients receiving intensity-modulated radiotherapy.

BACKGROUND AND PURPOSE: To recommend contouring methods and atlas of organs at risk (OARs) for nasopharyngeal carcinoma (NPC) patients receiving intensity-modulated radiotherapy, in order to help reach a consensus on interpretations of OARs delineation. METHODS AND MATERIALS: Two to four contouring methods for the middle ear, inner ear, temporal lobe, parotid gland and spinal cord were identified via systematic literature review; their volumes and dosimetric parameters were compared in 41 patients. Areas under the receiver operating characteristic curves for temporal lobe contouring were compared in 21 patients with unilateral temporal lobe necrosis (TLN). RESULTS: Various contouring methods for the temporal lobe, middle ear, inner ear, parotid gland and spinal cord lead to different volumes and dosimetric parameters (P<0.05). For TLN, D1 of PRV was the most relevant dosimetric parameter and 64Gy was the critical point. We suggest contouring for the temporal lobe, middle ear, inner ear, parotid gland and spinal cord. A CT-MRI fusion atlas comprising 33 OARs was developed. CONCLUSIONS: Different dosimetric parameters may hinder the dosimetric research. The present recommendation and atlas, may help reach a consensus on subjective interpretation of OARs delineation to reduce inter-institutional differences in NPC patients.

Late toxicities after conventional radiation therapy alone for nasopharyngeal carcinoma.

BACKGROUND AND PURPOSE: We sought to evaluate the nature and frequency of late toxicities in a cohort of nasopharyngeal cancer (NPC) patients treated with conventional radiotherapy alone. METHODS AND MATERIALS: Seven-hundred and ninety-six consecutive NPC patients treated using conventional radiotherapy at a single center from 1992 to 1995 were retrospectively analyzed. Patients with histology proven, completely staged, Stage I-IVB World Health Organization Type I-III NPC and completed radical radiotherapy were included. Patients with incomplete staging investigations, distant metastases at diagnosis, previous treatment, and incomplete radiotherapy were excluded. Radiotherapy-related complications were categorized using the RTOG Late Radiation Morbidity Scoring Criteria. RESULTS: Median follow-up was 7.2 years. The 5-year overall survival and disease free survival were 69% and 56%, respectively, and the corresponding 10-year rates were 52% and 44%. Among 771 patients with at least 3 months of follow-up post treatment, 565 (73%) developed RT-related complications. Diagnosed neurological complications were cranial nerve palsies (n=70; 9%), temporal lobe necrosis (n=37; 5%), Lhermitte's syndrome (n=7; 1%), and brachial plexopathy (n=2; 0.3%). Non-neurological complications included xerostomia (n=353; 46%), neck fibrosis (n=169; 22%), hypo-pituitarism (n=48; 6%), hearing loss (n=120; 16%), dysphagia (n=116; 15%), otorrhea (n=101; 13%), tinnitus (n=94; 12%), permanent tube feeding (n=61; 8%), trismus (n=45; 6%), second malignancies within treatment field (n=17; 2%), and osteo-radionecrosis (n=13; 2%). CONCLUSIONS: While radiotherapy is curative in NPC, many patients suffer significant late treatment morbidities with conventional radiotherapy techniques.

Is nasopharyngeal cancer really a "Cantonese cancer"?

Nasopharyngeal cancer (NPC) is endemic in Southern China, with Guandong province and Hong Kong reporting some of the highest incidences in the world. The journal Science has called it a "Cantonese cancer". We propose that in fact NPC is a cancer that originated in the Bai Yue ("proto Tai Kadai" or "proto Austronesian" or "proto Zhuang") peoples and was transmitted to the Han Chinese in southern China through intermarriage. However, the work by John Ho raised the profile of NPC, and because of the high incidence of NPC in Hong Kong and Guangzhou, NPC became known as a Cantonese cancer. We searched historical articles, articles cited in PubMed, Google, monographs, books and Internet articles relating to genetics of the peoples with high populations of NPC. The migration history of these various peoples was extensively researched, and where possible, their genetic fingerprint identified to corroborate with historical accounts. Genetic and anthropological evidence suggest there are a lot of similarities between the Bai Yue and the aboriginal peoples of Borneo and Northeast India; between Inuit of Greenland, Austronesian Mayalo Polynesians of Southeast Asia and Polynesians of Oceania, suggesting some common ancestry. Genetic studies also suggest the present Cantonese, Minnans and Hakkas are probably an admixture of northern Han and southern Bai Yue. All these populations have a high incidence of NPC. Very early contact between southern Chinese and peoples of East Africa and Arabia can also account for the intermediate incidence of NPC in these regions.

Weak expression of cyclooxygenase-2 is associated with poorer outcome in endemic nasopharyngeal carcinoma: analysis of data from randomized trial between radiation alone versus concurrent chemo-radiation (SQNP-01).

BACKGROUND: Over-expression of cyclooxygenase-2 (COX-2) enzyme has been reported in nasopharyngeal carcinoma (NPC). However, the prognostic significance of this has yet to be conclusively determined. Thus, from our randomized trial of radiation versus concurrent chemoradiation in endemic NPC, we analyzed a cohort of tumour samples collected from participants from one referral hospital. METHODS: 58 out of 88 patients from this institution had samples available for analysis. COX-2 expression levels were stratified by immunohistochemistry, into negligible, weak, moderate and strong, and correlated with overall and disease specific survivals. RESULTS: 58% had negligible or weak COX-2 expression, while 14% and 28% had moderate and strong expression respectively. Weak COX-2 expression conferred a poorer median overall survival, 1.3 years for weak versus 6.3 years for negligible, 7.8 years, strong and not reached for moderate. There was a similar trend for disease specific survival. CONCLUSION: Contrary to literature published on other malignancies, our findings seemed to indicate that over-expression of COX-2 confer a better prognosis in patients with endemic NPC. Larger studies are required to conclusively determine the significance of COX-2 expression in these patients.

Treatment of nasopharyngeal carcinoma using intensity-modulated radiotherapy-the national cancer centre singapore experience.

PURPOSE: The aim of this study was to determine the efficacy and acute toxicity of our early experience with treating nasopharyngeal carcinoma (NPC) patients with intensity-modulated radiotherapy (IMRT). METHODS AND MATERIALS: A review was conducted on case records of 195 patients with histologically proven, nonmetastatic NPC treated with IMRT between 2002 and 2005. MRI of the head and neck was fused with CT simulation images. All plans had target volumes at three dose levels, with a prescribed dose of 70 Gy to the gross disease, in 2.0-2.12 Gy/fraction over 33-35 fractions. Cisplatin-based chemotherapy was offered to Stage III/IV patients. RESULTS: Median patient age was 52 years, and 69% were male. Median follow-up was 36.5 months. One hundred and twenty-three patients had Stage III/IV disease (63%); 50 (26%) had T4 disease. One hundred and eighty-eight (96%) had complete response; 7 (4%) had partial response. Of the complete responders, 10 (5.3%) had local recurrence, giving a 3-year local recurrence-free survival estimate of 93.1% and a 3-year disease-free survival of 82.1%. Fifty-one patients (26%) had at least one Grade 3 toxicity. CONCLUSIONS: Results from our series are comparable to those reported by other centers. Acute toxicity is common. Local failure or persistent disease, especially in patients with bulky T4 disease, are issues that must be addressed in future trials.

Comparison of 4 modalities for distant metastasis staging in endemic nasopharyngeal carcinoma.

BACKGROUND: Endemic nasopharyngeal carcinoma (NPC) commonly metastasizes to the lungs, liver, and bones. This study aims to assess the efficacy of 4 distant metastasis staging modalities, namely (1) conventional work-up comprising chest X-ray, liver ultrasound, and skeletal scintigraphy, (2) CT of the thorax, abdomen, and skeletal scintigraphy, (3) (18)F-fluorodeoxyglucose positron emission tomography (FDG-PET), and (4) integrated FDG-PET/CT. METHODS: Seventy-eight consecutive patients diagnosed with NPC were enrolled and followed up for a minimum of 6 months to confirm the staging at diagnosis. RESULTS: Six patients (7.7%) had distant metastases at diagnosis. The sensitivities and specificities of conventional work-up, combined CT and skeletal scintigraphy, FDG-PET, and FDG-PET/CT were 33.3%, 66.7%, 83.3%, and 83.3%; and 90.3%, 91.7%, 94.4%, and 97.2%, respectively. The corresponding accuracies were 85.9%, 89.7%, 93.6%, and 96.2%. CONCLUSIONS: FDG-PET/CT is the most sensitive, specific, and accurate modality for distant metastasis staging of endemic NPC.

Phenotypic and functional alterations of Vgamma2Vdelta2 T cell subsets in patients with active nasopharyngeal carcinoma.

INTRODUCTION: Human Vgamma2Vdelta2 T cells play important role in immunity to infection and cancer by monitoring self and foreign isoprenoid metabolites with their gammadelta T cell antigen receptors. Like CD4 and CD8 alphabeta T cells, adult peripheral Vgamma2Vdelta2 T cells represent a pool of heterogeneous cells with distinct functional capabilities. PURPOSE: The aim of this study was to characterize the phenotypes and functions of various Vgamma2Vdelta2 T cell subsets in patients with nasopharyngeal carcinoma (NPC). We sought to develop a better understanding of the role of these cells during the course of disease and to facilitate the development of immunotherapeutic strategies against NPC. RESULTS: Although similar total percentages of peripheral blood Vgamma2Vdelta2 T cells were found in both NPC patients and normal donors, Vgamma2Vdelta2 T cells from NPC patients showed decreased cytotoxicity against tumor cells whereas Vgamma2Vdelta2 T cells from normal donors showed potent cytotoxicity. To investigate further, we compared the phenotypic characteristics of Vgamma2Vdelta2 T cells from 96 patients with NPC and 54 healthy controls. The fraction of late effector memory Vgamma2Vdelta2 T cells (T(EM RA)) was significantly increased in NPC patients with corresponding decreases in the fraction of early memory Vgamma2Vdelta2 T cells (T(CM)) compared with those in healthy controls. Moreover, T(EM RA) and T(CM) Vgamma2Vdelta2 cells from NPC patients produced significantly less IFN-gamma and TNF-alpha, potentially contributing to their impaired cytotoxicity. Radiotherapy or concurrent chemo-radiotherapy further increased the T(EM RA) Vgamma2Vdelta2 T cell population but did not correct the impaired production of IFN-gamma and TNF-alpha observed for T(EM RA) Vgamma2Vdelta2 T cells. CONCLUSION: We have identified distinct alterations in the Vgamma2Vdelta2 T cell subsets of patients with NPC. Moreover, the overall cellular effector function of gammadelta T cells is compromised in these patients. Our data suggest that the contribution of Vgamma2Vdelta2 T cells to control NPC may depend on the activation state and differentiation of these cells.