Multi-gene Liquid Biopsy to Detect Resistance to First-line Osimertinib in Patients With EGFR-mutated Lung Adenocarcinoma.

BACKGROUND/AIM: Osimertinib is currently used as a first-line treatment for EGFR-mutated non-small cell lung cancer, and the emergence of drug resistance poses a substantial challenge. Liquid biopsy with a multi-gene panel can examine both the molecular mechanisms and possibility of early resistance diagnosis. PATIENTS AND METHODS: We used a molecular barcode library construction kit (Archer® LiquidPlex™) that allowed the analysis of multiple cancer-related genes using cell-free DNA from the plasma samples of patients. We collected plasma from 17 consecutive patients with lung adenocarcinoma at our hospital at various time points and cell-free DNA was extracted and subjected to LiquidPlex analysis. RESULTS: Plasma DNA concentration was not associated with the presence or absence of resistance to osimertinib. The pathological mutations detected using next-generation sequencing in the resistant specimens were in MAP2K1, PIK3CA, TP53, BRAF, and EGFR. Among the recurrent cases, EGFR mutations identified at the initial diagnosis were detected within 6 months before relapse confirmation in four cases (average 88 days). Many of the recurrent cases without detection of known EGFR mutations in the liquid biopsy showed a longer interval between the detection of relapse and the last blood draw for the liquid biopsy (average 255 days). CONCLUSION: Frequent liquid biopsies are useful for identifying known EGFR mutations as markers for early detection of relapse. Several cancer driver mutations were observed, suggesting a variety of mechanisms of resistance in first-line osimertinib-treated lung adenocarcinoma.

A Prospective Cohort Study Assessing the Relationship between Plasma Levels of Osimertinib and Treatment Efficacy and Safety.

Osimertinib is a standard treatment for patients with EGFR-mutated non-small cell lung carcinoma (NSCLC). We evaluated the relationship between plasma osimertinib concentrations and treatment outcome in patients with NSCLC for this cohort study. The plasma levels of osimertinib and its metabolite AZ5104 were measured a week after the start of treatment (P1). The primary endpoint was to evaluate the correlation between plasma concentration and adverse events (AEs). The correlation with treatment efficacy was one of the secondary endpoints. In patients with CNS metastases, the concentration in the cerebrospinal fluid was also measured. Forty-one patients were enrolled. The frequency of AEs was highest for rash, followed by anorexia and thrombocytopenia. Thirty-eight cases provided measurements for P1. The median plasma concentration of osimertinib was 227 ng/mL, and that of AZ5104 was 16.5 ng/mL. The mean CNS penetration rate of two cases was 3.8%. The P1 in the group with anorexia was significantly higher than that in the group without anorexia (385.0 ng/mL vs. 231.5 ng/mL, p = 0.009). Divided into quartiles by P1 trough level, Q2 + Q3 (164-338 ng/mL) had longer PFS, while Q1 and Q4 had shorter PFS. An appropriate plasma level of osimertinib may avoid some adverse events and induce long PFS. Further large-scale trials are warranted.

Detection of multiple druggable mutations of lung cancer from cytology specimens by MINtS: An advanced medicine A trial.

Most multigene mutation tests require tissue specimens. However, cytological specimens are easily obtained in the clinical practice and provide high-quality DNA and RNA. We aimed to establish a test that utilizes cytological specimens and performed a multi-institutional study to investigate the performance of MINtS, a test based on next-generation sequencing. A standard procedure for specimen isolation was defined. The specimens were considered suitable for the test if >100 ng DNA and >50 ng RNA could be extracted from them. In total, 500 specimens from 19 institutions were investigated. MINtS detected druggable mutations in 63% (136 of 222) of adenocarcinomas. Discordant results between MINtS and the companion diagnostics were observed in 14 of 310 specimens for the EGFR gene, and 6 of 339 specimens for the ALK fusion genes. Confirmation by other companion diagnostics for the EGFR mutations or the clinical response to an ALK inhibitor all supported the results obtained by MINtS. MINtS along with the isolation procedure presented in the current study will be a platform to establish multigene mutation tests that utilize cytological specimens. UMIN000040415.

Hydrogen Generation from Organic Hydrides under Continuous-Flow Conditions Using Polymethylphenylsilane-Aluminum Immobilized Platinum Catalyst.

Hydrogen is an important resource for realizing the goal of a hydrogen-based society as well as for synthetic organic chemistry. Catalytic dehydrogenation of organic hydrides such as methyl cyclohexane is attractive for hydrogen storage and transportation in terms of reversibility and selectivity of catalytic reactions and hydrogen storage density. We developed a highly active polymethylphenylsilane-aluminum immobilized platinum catalyst (Pt/MPPSi-Al2 O3 ) for dehydrogenation of organic hydrides. Organic hydrides were fully converted into the corresponding aromatic compounds under reactive distillation conditions at 200 °C or under circulation-flow conditions using the Pt/MPPSi-Al2 O3 catalyst packed in a column at 260 °C. The dehydrogenation reaction reached a maximum conversion at equilibrium (ca. 60%) under continuous-flow conditions at 260 °C. This catalytic continuous-flow dehydrogenation was applied to a formal hydrogen transfer from organic hydrides to unsaturated organic substrates under sequential and continuous-flow conditions for practical flow hydrogenation reactions by connecting two different heterogeneous catalysts packed in columns.

Phase II Study of Low-Dose Afatinib Maintenance Treatment Among Patients with EGFR-Mutated Non-Small Cell Lung Cancer: North Japan Lung Cancer Study Group Trial 1601 (NJLCG1601).

LESSONS LEARNED: Low-dose afatinib maintenance treatment among patients with EGFR-mutated NSCLC achieved long-time to treatment failure with fewer treatment-related AEs without detracting from the therapeutic efficacy. This modified regimen represents a practical usage that balances effectiveness and safety. BACKGROUND: Although afatinib is an effective therapy for patients with EGFR-mutated non-small cell lung cancer (NSCLC), drug-related adverse events (AEs) have often necessitated dose reductions. In a post hoc analysis of the LUX-Lung 3 and 6 trials, there was no difference in median progression-free survival (PFS) between patients who had the dose of afatinib reduced and those who did not. We thus evaluated the efficacy and tolerability of low-dose afatinib maintenance treatment among patients with NSCLC harboring EGFR mutations who had not been previously treated. METHODS: Eligible patients received afatinib 40 mg orally once daily. When prescribed grade ≥ 2 AEs, rash of grade ≥ 3, or unacceptable toxicity occurred, the afatinib dose was reduced from 40 to 30 mg and if needed from 30 to 20 mg. The primary endpoint was the 1-year PFS rate. Secondary endpoints were PFS, overall response rate (ORR), and toxicity. RESULTS: Among 30 patients, 93% had adenocarcinoma, 53% had exon 19 deletion, 37% had L858R, and 10% had minor mutations. The 1-year PFS rate was 50% (95% confidence interval [CI], 31.3-66.1) and the median PFS was 11.8 months (95% CI, 7.1-21.4). The incidence rate of grade ≥ 3 toxicities was 57%, including elevated aspartate aminotransferase/alanine aminotransferase level (13%), diarrhea (10%), and paronychia (10%). CONCLUSION: Low-dose afatinib maintenance treatment reduced treatment-related AEs without detracting from the therapeutic efficacy.

Rare metastatic pancreatic tumors from lung cancer with cystic changes resembling intraductal papillary mucinous neoplasm: a case report.

BACKGROUND: Metastatic pancreatic tumors from lung cancer (MPTLC) constitute 3% of all metastatic pancreatic tumors. We present an extremely rare case of cystic MPTLC that was difficult to distinguish from intraductal papillary mucinous neoplasm (IPMN). CASE PRESENTATION: The patient was a 74-year-old woman who underwent lobectomy of lung cancer 2 years before presentation to our hospital. She was referred to our department for resection of cystic pancreatic tumors, which were diagnosed as IPMN with high-risk stigmata. Abdominal computed tomography (CT) showed a 37-mm-wide cystic tumor with a contrasted solid nodule in the pancreatic head and a 17-mm-wide cystic tumor in the pancreatic tail. We performed a total pancreatectomy for these lesions. According to histopathological and immunohistochemical findings, the tumors were diagnosed as metastatic pancreatic tumors from lung cancer. CONCLUSION: In this case, the cystic morphology was formed by eosinophilic secretions from tumor cells, and it was difficult to distinguish from IPMN with high-risk stigmata. We consider this case, based on the variable clinical findings, an extremely rare variant of MPTLC.

EGFR Mutation Analysis of Circulating Tumor DNA Using an Improved PNA-LNA PCR Clamp Method.

Introduction. Rebiopsies have become more crucial in non-small cell lung cancer (NSCLC). Instead of invasive biopsies, development of collecting biological data of the tumor from blood samples is expected. We conducted a prospective study to assess the feasibility of detection of epidermal growth factor receptor (EGFR) mutation in plasma samples. Method. NSCLC patients harboring EGFR activating mutations, who were going to receive EGFR-tyrosine kinase inhibitors (TKIs) as first-line treatment, were enrolled in this study. Plasma EGFR activating mutations and the T790M resistance mutation were analyzed by an improved PNA-LNA PCR clamp method, characterized by a 10-fold or more sensitivity compared with the original methods. Result. Six patients with wild-type EGFR and 24 patients with EGFR mutations were enrolled in this study. Pretreatment plasma samples achieved sensitivity of 79%. The 6 patients with wild-type EGFR were all negative for plasma EGFR mutations. At the time of disease progression, plasma T790M mutation was detected in 8 of 16 cases. Absence of T790M before and during TKI treatment and disappearance of activating mutations during TKI treatment were considered as predictors of EGFR-TKIs efficacy. Conclusion. We were able to detect EGFR mutations in plasma samples by using an improved PNA-LNA PCR clamp method.

Alternate-day Treatment with Crizotinib for Drug-induced Esophagitis and Liver Damage in a Patient with EML4-ALK Fusion Gene-positive Lung Adenocarcinoma.

A 44-year-old woman who was diagnosed with anaplastic lymphoma kinase-positive lung adenocarcinoma developed brain metastases, multiple spinal metastases and meningeal dissemination. Crizotinib was administered after the failure of first-line chemotherapy. Esophagitis and liver damage were induced by the twice-daily administration of crizotinib at 250 mg and 200 mg, respectively. The alternate-day administration of crizotinib (250 mg, twice daily) was able to control disease progression without any adverse effects for several months. We evaluated the relationship between the serum concentration of crizotinib and the development of esophagitis and liver damage. The alternate-day administration of crizotinib is one of the strategies for managing the severe toxicity of crizotinib.

Olig2 labeling index is correlated with histological and molecular classifications in low-grade diffuse gliomas.

Diagnosis of low-grade diffuse gliomas based on morphology is highly subjective and, therefore, is often difficult, with significant intra- and interobserver variability. Here, we investigated WHO grade II diffuse astrocytomas, oligoastrocytomas and oligodendrogliomas for immunohistochemical expression of Olig2, measuring its labeling index (LI), and evaluated the significance of Olig2 LI in the histological and molecular classifications. The means of Olig2 LI in glioma cells were 43.7 % in diffuse astrocytomas, 59.3 % in oligoastrocytomas and 76.1 % in oligodendrogliomas. There was a statistically significant difference between all pairs of histological types. The mean of Olig2 LI of gliomas with 1p/19q loss ± IDH1/2 mutation, the majority of them being oligodendrogliomas, was significantly higher than the means of those with TP53 mutation ± IDH1/2 mutation and IDH1/2 mutation only, the majority of which were diffuse astrocytomas (70.1 vs. 47.2 and 46.5 %, respectively). When categorized according to the classification of Jiao et al., Olig2 LI of I-CF gliomas (cases with IDH and one or more of CIC, FUBP1 or combined 1p/19q loss; mean 71.0 %) was significantly higher than that of I-A gliomas (cases with IDH and ATRX alterations; mean 45.3 %). These molecular classifications were reported to correlate well with clinical outcome. However, borderlines of Olig2 LI were broad and could not clearly distinguish genotypes in the molecular classifications. In conclusion, Olig2 LI cannot be taken as a complete surrogate marker for molecular genotype, but could possibly provide some ancillary information when molecular assay is not availabe.

The combination of functional metagenomics and an oil-fed enrichment strategy revealed the phylogenetic diversity of lipolytic bacteria overlooked by the cultivation-based method.

Metagenomic screening and conventional cultivation have been used to exploit microbial lipolytic enzymes in nature. We used an indigenous forest soil (NS) and oil-fed enriched soil (OS) as microbial and genetic resources. Thirty-four strains (17 each) of lipolytic bacteria were isolated from the NS and OS microcosms. These isolates were classified into the (sub)phyla Betaproteobacteria, Gammaproteobacteria, Firmicutes, and Actinobacteria, all of which are known to be the main microbial resources of commercially available lipolytic enzymes. Seven and 39 lipolytic enzymes were successfully retrieved from the metagenomic libraries of the NS and OS microcosms, respectively. The screening efficiency (a ratio of positive lipolytic clones to the total number of environmental clones) was markedly higher in the OS microcosm than in the NS microcosm. Moreover, metagenomic clones encoding the lipolytic enzymes associated with Alphaproteobacteria, Deltaproteobacteria, Acidobacteria, Armatimonadetes, and Planctomycetes and hitherto-uncultivated microbes were recovered from these libraries. The results of the present study indicate that functional metagenomics can be effectively used to capture as yet undiscovered lipolytic enzymes that have eluded the cultivation-based method, and these combined approaches may be able to provide an overview of lipolytic organisms potentially present in nature.

Alpha-internexin and altered CIC expression as a supportive diagnostic marker for oligodendroglial tumors with the 1p/19q co-deletion.

α-Internexin (INA) has been proposed as a biomarker of oligodendroglial tumors with the 1p/19q co-deletion. On the other hand, sequence studies have recently linked the CIC mutation and subsequent altered CIC expression to the 1p/19q co-deletion in oligodendroglial tumors. We assessed the usability of combination immunohistochemical analysis using CIC and INA as a surrogate tool for the 1p/19q status in 39 cases of oligodendroglial tumors. The positive expression of INA was observed in 10 cases (52 %) of oligodendroglial tumors with the 1p/19q co-deletion, and in only 3 cases of oligodendroglial tumors without the 1p/19q co-deletion (15 %, P = 0.012). The lack of CIC expression was detected in 13 cases (68 %) of oligodendroglial tumors with the 1p/19q co-deletion, and in only 1 case of oligodendroglial tumors without the 1p/19q co-deletion (5 %, P < 0.0001). Combined immunohistochemical analysis assessed by INA expression and/or the lack of CIC expression was strongly associated with the 1p/19q co-deletion in oligodendroglial tumors, indicating a potential surrogate marker of the 1p/19q state. Although combined immunohistochemical analysis cannot be totally replaced by molecular genetic analysis as a definitive diagnostic technique, it may contribute to a steady morphological diagnosis by predicting the 1p/19q state in oligodendroglial tumors.

Anaplastic ependymoma with ependymoblastic multilayered rosettes.

Anaplastic ependymoma, World Health Organization grade III, is a malignant glioma with ependymal differentiation characterized by high mitotic activity often accompanied by microvascular proliferation and necrosis, where, generally, much fewer ependymal rosettes are found than in ependymoma, World Health Organization grade II. Ependymal rosettes, forming a single layer of tumor cells, differ from ependymoblastic multilayered rosettes, which are characteristic histologic features of ependymoblastoma, a variant of central nervous system primitive neuroectodermal tumor. Here, we report an autopsy case involving a 24-year-old woman with a frontal lobe tumor, which showed the aggregation of true rosettes with multilayering of tumor cells resembling the ependymoblastoma histology. Molecular and cytogenetic analyses revealed the absence of 19q13.42 amplification, a specific molecular hallmark of ependymoblastoma and embryonal tumor with abundant neuropil and true rosettes, supporting the diagnosis of anaplastic ependymoma.

A phase II study of amrubicin as a third-line or fourth-line chemotherapy for patients with non-small cell lung cancer: Hokkaido Lung Cancer Clinical Study Group Trial (HOT) 0901.

Amrubicin, a third-generation synthetic anthracycline agent, has favorable clinical activity and acceptable toxicity for the treatment of patients with non-small cell lung cancer (NSCLC) and small cell lung cancer. We conducted this study to evaluate the efficacy and safety of amrubicin for advanced NSCLC patients as a third- or fourth-line therapy. Eligible patients had recurrent or refractory advanced NSCLC after second- or third-line therapy. Patients received amrubicin, 35 mg/m(2) i.v. on days 1-3 every 3 weeks. The primary endpoint was the disease control rate (DCR). Secondary endpoints were the overall survival (OS) time, progression-free survival (PFS) time, response rate, and toxicity profile. Of the 41 patients enrolled, 26 received amrubicin as a third-line and 15 received it as a fourth-line therapy. The median number of treatment cycles was two (range, 1-9). Objective responses were complete response (n = 0), partial response (n = 4), stable disease (n = 21), progressive disease (n = 15), and not evaluable (n = 1), resulting in a DCR of 61.0% (95% confidence interval, 46.0%-75.9%). The overall response rate was 9.8% (95% confidence interval, 0.6%-18.8%). The median PFS interval was 3.0 months, median OS time was 12.6 months, and 1-year survival rate was 53.7%. Grade 3 or 4 hematological toxicities were neutropenia (68%), anemia (12%), thrombocytopenia (12%), and febrile neutropenia (17%). Nonhematological toxicities were mild and reversible. No treatment-related deaths were observed. Amrubicin showed significant clinical activity with manageable toxicities as a third- or fourth-line therapy for patients with advanced NSCLC. This study provides relevant data for routine practice and future prospective trials evaluating third- or fourth-line treatment strategies for patients with advanced NSCLC.

The novel mutant scl of the medaka fish, Oryzias latipes, shows no secondary sex characters.

A new mutant that has neither male nor female secondary sex characters was found in the medaka, Oryzias latipes. Both XX and XY mature mutants had gonads with many spermatozoa, but spawning did not occur when the mutants were paired with normal males or normal females. F1 progeny were successfully obtained by artificial insemination using unfertilized eggs from wild-type females and spermatozoa of the XY mutant. The mutant phenotype did not occur in the F1 progeny from this cross. Incrossing among the F1 progeny produced 17 mutant offspring out of 68 progeny (25%), demonstrating that the mutant phenotype is caused by a single recessive mutation. This mutant was named scl (sex character-less). Because papillary processes, a male secondary sex character, were induced in the XY mutants by androgen administration, it seems that the androgen receptor is functioning normally. We found a loss-of-function type mutation in the P450c17 gene of the mutant; this gene encodes a steroidogenic enzyme required for the production of estrogen and androgen. The scl phenotype was completely linked to the mutant genotype of P450c17, strongly suggesting that mutation at the P450c17 locus is responsible for the scl mutant phenotype.

Dax1 suppresses P450arom expression in medaka ovarian follicles.

Dax1 is a member of an unusual orphan nuclear receptor family, and is known to regulate P450arom in mammals and is involved in sex differentiation in some vertebrates. To investigate whether Dax1 is involved in the regulation of the steroidogenic pathway for estrogen biosynthesis in medaka ovarian follicles, we isolated Dax1 cDNA from adult medaka ovaries and analyzed its expression pattern in medaka gonads. In adult ovaries, Dax1 mRNA was detected only in postvitellogenic follicles and was not detected in previtellogenic and vitellogenic follicles. In adult testis, Dax1 mRNA was not detected. We compared the expression pattern of Dax1 with that of Foxl2, Ad4BP/Sf-1, P450c17, and P450arom by in situ hybridization using adjacent sections. In contrast to Dax1 expression, these genes were co-expressed in vitellogenic follicles but were not detected in postvitellogenic follicles. Thus, in medaka ovarian follicles, Dax1 did not show any overlapping expression patterns against Foxl2, Ad4BP/Sf-1, P450c17, and P450arom. Moreover, co-transfection experiments demonstrated that Dax1 inhibits Ad4BP/Sf-1- and Foxl2-mediated P450arom expression. On the other hand, during early sex differentiation, Dax1 mRNA was not detected in both males and females. Our results suggest that Dax1 down-regulates Ad4BP/Sf-1- and Foxl2-mediated P450arom expression in medaka ovarian follicles.

Knock-down of DMY initiates female pathway in the genetic male medaka, Oryzias latipes.

DMY is the second vertebrate sex-determining gene identified from the fish, Oryzias latipes. In this study, we used two different ways of sex reversal, DMY knock-down and estradiol-17beta (E2) treatment, to determine the possible function of DMY during early gonadal sex differentiation in XY medaka. Our findings revealed that the mitotic and meiotic activities of the germ cells in the 0 day after hatching (dah) DMY knock-down XY larvae were identical to those of the normal XX larvae, suggesting the microenvironment of these XY gonads to be similar to that of the normal XX gonad, where DMY is naturally absent. Conversely, E2 treatment failed to initiate mitosis in the XY gonad, possibly due to an active DMY, even though it could initiate meiosis. Present study is the first to prove that the germ cells in the XY gonad can resume the mitotic activity, if DMY was knocked down.

Effects of estradiol-17beta on germ cell proliferation and DMY expression during early sexual differentiation of the medaka Oryzias latipes.

Sex reversal of XY male to functional females was induced by estrogen treatment during the embryonic period in the medaka Oryzias latipes. The present study aimed to examine whether exogenous estrogen (estradiol-17beta; E(2)) affects early sex differentiation, paying particular attention to DMY expression and proliferation activity of germ cells in estrogen treated XY individuals. Our results showed that germ cell number was not affected by E(2) treatment at hatching, and that DMY expression was not suppressed under conditions of sex reversal. Therefore, male differentiation of germ cells, which is triggered by the expression of DMY in the supporting cell lineage, proceeds even in E(2) treated XY individuals until hatching, and early sex differentiation is not altered by estrogen. However, sex reversal occurred after hatching probably because of estrogen remaining in the yolk. Interestingly, DMY expression was also detected in the large follicle layer of E(2 )treated XY ovary. These results suggested that DMY regulates male determination in early embryonic stage but does not suppress female follicle development.

Presence of somatic hypermutation and activation-induced cytidine deaminase in acute lymphoblastic leukemia L2 with t(14;18)(q32;q21).

AIM: Acute lymphoblastic leukemia (ALL) with L2 (FAB) morphology has rarely been reported to show t(14;18)(q32;q21). We aimed to delineate the stage at which this type of ALL is derived in B-lineage differentiation. METHODS: The somatic hypermutation (SHM) of the variable region of immunoglobulin heavy chain (IgV(H)) gene and the expression of terminal deoxynucleotidyl transferase (TdT), recombination-activating gene 1 and 2 (RAG-1 and -2), and activation-induced cytidine deaminase (AID) were investigated in three cell lines and two fresh samples, including a pair of matched fresh and cell line cells. RESULTS: TdT, RAG-1, and RAG-2 were variably expressed. AID was expressed in four of five samples. SHM of the IgV(H) gene was found in all samples with high average frequency (11.84%) comparable with that in follicular lymphoma. Ongoing mutation was seen in two fresh samples. CONCLUSION: As AID and SHM are generally regarded as properties exhibited by mature B cells, the presence of AID and SHM in this study seems to be incompatible with the general understanding of the early stage derivation of ALL in B-lineage differentiation. The results here give some insight into the relationship between disease type (ALL or lymphoma) and derivation stage, the overlapping of the early stage phenotype and the mature genomic characteristics, and the probable relationship between the mechanism of the occurrence of t(14;18)(q32;q21) and the machinery causing SHM.

Correlation between angiogenesis and reduction ratio measured using 201Tl chloride single photon emission computed tomography in patients with oral cavity squamous cell carcinoma.

OBJECTIVE: The aim of this study is to examine the correlation between tumor angiogenesis and response to preoperative radiotherapy evaluated using 201Tl single photon emission computed tomography (Tl SPECT) in oral cavity squamous cell carcinoma (SCC). METHODS: Tl SPECTs before and after preoperative radiotherapy were obtained from 11 patients diagnosed with SCC in oral cavity. Regions of interest were set around the tumor and scalp respectively, and the ratio of mean counts in the tumor to those in the scalp was calculated (T/N). Immunohistochemical staining for investigating microvessel density of pre-treatment biopsy specimen was performed using CD31 monoclonal antibody. We compared microvessel density with semi-quantitative parameters obtained using Tl SPECT (T/N at pre- an post-treatment, reduction ratio) and prognosis. RESULTS: The subgroup with higher microvessel density showed a significantly higher reduction ratio than the one with lower microvessel density. Regarding prognosis, the subgroup with locoregional recurrent disease exhibited a significantly higher microvessel density than the one without recurrence. CONCLUSIONS: In SCC of the oral cavity, there was a significant correlation between microvessel density and response to preoperative radiotherapy. Namely, it was revealed that change of 201Tl uptake after preoperative radiotherapy correlated with tumor angiogenesis of oral cavity SCC.

Evaluation of mandibular invasion by head and neck cancers using 99mTc-methylene diphosphonate or 99mTc-hydroxymethylene diphosphonate and 201Tl chloride dual isotope single photon emission computed tomography.

Whether a patient with head and neck cancer has mandibular invasion or not is important in determining the method of resection surgery. But, no modality is adequately reliable when used alone in the evaluation of mandibular invasion. Therefore, to more accurately diagnose mandibular invasion in head and neck cancer, we used a new modality, namely, 99mTc methylene diphosphonate (MDP) or 99mTc hydroxymethylene diphosphonate (HMDP) and 201Tl chloride dual isotope single photon emission computed tomography (Tc/Tl SPECT). The aim of this study is to disclose the usefulness of Tc/Tl SPECT in the assessment of mandibular invasion by head and neck cancers. 99mTc-MDP or -HMDP SPECT (Tc SPECT)s and 201Tl chloride SPECT (Tl SPECT)s were performed in 34 patients with suspected mandibular involvement of head and neck cancer. Thirty of 34 cases underwent both TcMTl SPECT and CT examination. Tc/Tl SPECT fusion images were obtained using the Automatic Registration Tool (ART, TOSHIBA, Japan) system. In the diagnosis of mandibular invasion on Tc/Tl SPECT fusion images, a problem was that the range of Tc and Tl uptake was changed by the condition of display used in the reconstruction and expression of the images. Then, prior to clinical evaluation, to reveal the most appropriate upper window level for display, a phantom study was performed. In a clinical study, the upper window level was set at 40 or 50%, which were verified to be the proper values in the preliminary study. The diagnostic accuracy obtained using Tc SPECT, TcMTl SPECT and CT was compared with the histopathological findings. Tc/Tl SPECT at 40 and 50% upper window level had higher specificity, accuracy, and positive predictive value (73.3%, 85.3%, 81.8%) than Tc SPECT alone (21.4%, 67.6%, 64.5%) and higher sensitivity and negative predictive value (94.7%, 91.7%) than CT (70.6%, 72.2%) for detecting mandibular invasion. Tc/Tl SPECT was a useful diagnostic procedure for the assessment of mandibular invasion by head and neck cancers.