Post-radiation primary hypothyroidism in patients with head and neck cancer: External validation of thyroid gland dose-volume constraints with long-term endocrine outcomes.

BACKGROUND: Post-radiation primary hypothyroidism is a common late complication in head and neck cancer (HNC) survivors. No radiation dose-volume constraint of the thyroid gland has been externally validated for predicting long-term thyroid function outcomes. MATERIALS AND METHODS: This external validation study evaluated the diagnostic properties of 22 radiation dose-volume constraints of the thyroid gland proposed in the literature. Radiation dosimetric data from 488 HNC patients who underwent neck irradiation from January 2013 to December 2015 at two tertiary oncology centers were reviewed. The diagnostic metrics of candidate constraints were computed by inverse probability of censoring weighting and compared using time-dependent receiver operating characteristic (ROC) curves with death designated as a competing event. Multivariable regression analyses were performed using the Fine-Gray sub-distribution hazard model. RESULTS: Over a median follow-up period of 6.8 years, 205 (42.0 %) patients developed post-radiation primary hypothyroidism. The thyroid volume spared from 60 Gy (VS60) had the largest area under ROC curve of 0.698 at 5 years after radiotherapy. Of all evaluated constraints, VS60 at a cutoff value of 10 cc had the highest F-score of 0.53. The 5-year hypothyroidism risks of patients with thyroid VS60 ≥ 10 cc and < 10 cc were 14.7 % and 38.2 %, respectively (p < 0.001). The adjusted sub-hazard ratio for post-radiation primary hypothyroidism for VS60 < 10 cc was 1.87 (95 % confidence interval, 1.22-2.87; p < 0.001). CONCLUSION: Thyroid VS60 is the best radiation dose-volume parameter to predict the long-term risk of primary hypothyroidism in patients with HNC who underwent neck irradiation. VS60 ≥ 10 cc is a robust constraint that limits the 5-year primary hypothyroidism risk to less than 15 % and should be routinely employed during radiotherapy optimization.

EGFR mutation-guided use of afatinib, erlotinib and gefitinib for advanced non-small-cell lung cancer in Hong Kong - A cost-effectiveness analysis.

INTRODUCTION: Tyrosine kinase inhibitors (TKIs) therapy targets at epidermal growth factor receptor (EGFR) gene mutations in non-small-cell lung cancer (NSCLC). We aimed to compare the EGFR mutation-guided target therapy versus empirical chemotherapy for first-line treatment of advanced NSCLC in the public healthcare setting of Hong Kong. METHODS: A Markov model was designed to simulate outcomes of a hypothetical cohort of advanced (stage IIIB/IV) NSCLC adult patients with un-tested EGFR-sensitizing mutation status. Four treatment strategies were evaluated: Empirical first-line chemotherapy with cisplatin-pemetrexed (empirical chemotherapy group), and EGFR mutation-guided use of a TKI (afatinib, erlotinib, and gefitinib). Model outcome measures were direct medical cost, progression-free survival, overall survival, and quality-adjusted life-years (QALYs). Incremental cost per QALY gained (ICER) was estimated. Sensitivity analyses were performed to examine robustness of model results. RESULTS: Empirical chemotherapy and EGFR mutation-guided gefitinib gained lower QALYs at higher costs than the erlotinib group. Comparing with EGFR mutation-guided erlotinib, the afatinib strategy gained additional QALYs with ICER (540,633 USD/QALY). In 10,000 Monte Carlo simulations for probabilistic sensitivity analysis, EGFR mutation-guided afatinib, erlotinib, gefitinib and empirical chemotherapy were preferred strategy in 0%, 98%, 0% and 2% of time at willingness-to-pay (WTP) 47,812 USD/QALY (1x gross domestic product (GDP) per capita), and in 30%, 68%, 2% and 0% of time at WTP 143,436 USD/QALY (3x GDP per capita), respectively. CONCLUSIONS: EGFR mutation-guided erlotinib appears to be the cost-effective strategy from the perspective of Hong Kong public healthcare provider over a broad range of WTP.

Nasopharyngeal carcinoma MHC region deep sequencing identifies HLA and novel non-HLA TRIM31 and TRIM39 loci.

Despite pronounced associations of major histocompatibility complex (MHC) regions with nasopharyngeal carcinoma (NPC), causal variants underlying NPC pathogenesis remain elusive. Our large-scale comprehensive MHC region deep sequencing study of 5689 Hong Kong Chinese identifies eight independent NPC-associated signals and provides mechanistic insight for disrupted transcription factor binding, altering target gene transcription. Two novel protective variants, rs2517664 (Trs2517664 = 4.6%, P = 6.38 × 10-21) and rs117495548 (Grs117495548 = 3.0%, P = 4.53 × 10-13), map near TRIM31 and TRIM39/TRIM39-RPP21; multiple independent protective signals map near HLA-B including a previously unreported variant, rs2523589 (P = 1.77 × 10-36). The rare HLA-B*07:05 allele (OR < 0.015, P = 5.83 × 10-21) is absent in NPC, but present in controls. The most prevalent haplotype lacks seven independent protective alleles (OR = 1.56) and the one with additional Asian-specific susceptibility rs9391681 allele (OR = 2.66) significantly increased NPC risk. Importantly, this study provides new evidence implicating two non-human leukocyte antigen (HLA) genes, E3 ubiquitin ligases, TRIM31 and TRIM39, impacting innate immune responses, with NPC risk reduction, independent of classical HLA class I/II alleles.

Clinical utility of serial analysis of circulating tumour cells for detection of minimal residual disease of metastatic nasopharyngeal carcinoma.

BACKGROUND: Nasopharyngeal carcinoma (NPC) is an important cancer in Hong Kong. We aim to utilise liquid biopsies for serial monitoring of disseminated NPC in patients to compare with PET-CT imaging in detection of minimal residual disease. METHOD: Prospective serial monitoring of liquid biopsies was performed for 21 metastatic patients. Circulating tumour cell (CTC) enrichment and characterisation was performed using a sized-based microfluidics CTC chip, enumerating by immunofluorescence staining, and using target-capture sequencing to determine blood mutation load. PET-CT scans were used to monitor NPC patients throughout their treatment according to EORTC guidelines. RESULTS: The longitudinal molecular analysis of CTCs by enumeration or NGS mutational profiling findings provide supplementary information to the plasma EBV assay for disease progression for good responders. Strikingly, post-treatment CTC findings detected positive findings in 75% (6/8) of metastatic NPC patients showing complete response by imaging, thereby demonstrating more sensitive CTC detection of minimal residual disease. Positive baseline, post-treatment CTC, and longitudinal change of CTCs significantly associated with poorer progression-free survival by the Kaplan-Meier analysis. CONCLUSIONS: We show the potential usefulness of application of serial analysis in metastatic NPC of liquid biopsy CTCs, as a novel more sensitive biomarker for minimal residual disease, when compared with imaging.

Recombinant human thyrotropin versus thyroid hormone withdrawal in an Asian population.

CONTEXT: To prepare for radioactive iodine therapy in post total thyroidectomy patients with well-differentiated thyroid cancer (WDTC), either thyroid hormone withdrawal (THW) or administration of recombinant human thyrotropin (rhTSH) can be performed. OBJECTIVE: Our objective is to compare quality of life (QoL) parameters using the SF-36v2 questionnaire (Short Form health survey) and a self-evaluated item, and the hypothyroid status using modified Billewicz scores in an Asian population undergoing either THW or rhTSH for remnant ablation or adjuvant treatment following total thyroidectomy for WDTC. We will also assess the proportion of patients achieving TSH level of >30 mU/L after 4 weeks of thyroid hormone withdrawal. RESULTS: Patients in the rhTSH group were better in the QoL domains of physical functioning, role functioning/physical and bodily pain, while patients in THW group were better in mental health. This was however, not statistically significant. Modified Billewicz scores were higher in patients in THW group as compared with rhTSH group and statistically significant. A total of 96.3% of patients achieved TSH level >30 mU/L after 4 weeks of THW. CONCLUSION: Clinical symptoms and signs of hypothyroidism as assessed with modified Billewicz scores were statistically significantly higher in the THW group. However, there was no statistically significant difference in QoL in the rhTSH group.

Whole-exome sequencing identifies multiple loss-of-function mutations of NF-κB pathway regulators in nasopharyngeal carcinoma.

Nasopharyngeal carcinoma (NPC) is an epithelial malignancy with a unique geographical distribution. The genomic abnormalities leading to NPC pathogenesis remain unclear. In total, 135 NPC tumors were examined to characterize the mutational landscape using whole-exome sequencing and targeted resequencing. An APOBEC cytidine deaminase mutagenesis signature was revealed in the somatic mutations. Noticeably, multiple loss-of-function mutations were identified in several NF-κB signaling negative regulators NFKBIA, CYLD, and TNFAIP3 Functional studies confirmed that inhibition of NFKBIA had a significant impact on NF-κB activity and NPC cell growth. The identified loss-of-function mutations in NFKBIA leading to protein truncation contributed to the altered NF-κB activity, which is critical for NPC tumorigenesis. In addition, somatic mutations were found in several cancer-relevant pathways, including cell cycle-phase transition, cell death, EBV infection, and viral carcinogenesis. These data provide an enhanced road map for understanding the molecular basis underlying NPC.

Local and regional control in patients with papillary thyroid carcinoma: specific indications of external radiotherapy and radioactive iodine according to T and N categories in AJCC 6th edition.

To identify indications for external radiotherapy (EXT) and radioactive iodine (RAI) in papillary thyroid carcinoma (PTC), we conducted a retrospective study of local and regional control in 1297 patients diagnosed with PTC in a tertiary referral center. Managed by surgery alone, patients with bilateral thyroidectomy had a lower rate of local relapse compared with lobectomy (P=0.02). EXT improved locoregional (LR) failure-free survival (FFS) (P<0.001) and survival (P=0.01) in patients with gross postoperative LR residual disease. EXT also improved local FFS in patients with pathologically confirmed positive resection margins (P<0.001) and reduced local failures in patients with T4 disease (P=0.002). In patients with lymph nodes (LN) metastasis, more extensive surgery by functional or radical neck dissection resulted in less LN relapse compared with excision alone (P<0.001). EXT improved 10-year LN FFS in patients with N1b disease (P=0.005) and patients with LN metastasis of size>2 cm (P=0.02). RAI was effective in improving local control in patients with T2 to T4 diseases and LN control in patients with N0, N1a, and N1b categories. Local or LN relapses were associated with worse survival (P<0.001 and P<0.0001). The survival of patients with PTC could be improved by reducing local or LN relapses. RAI is indicated in patients with T2 to T4 disease. EXT is indicated in patients with gross postoperative disease, positive resection margins or T4 disease, N1b, or a LN size of >2 cm. LN relapse can be reduced by RAI in N0, N1a, and N1b disease.