Chung-Jan Kang

Prospective Study of [18F]Fluorodeoxyglucose Positron Emission Tomography and Computed Tomography and Magnetic Resonance Imaging in Oral Cavity Squamous Cell Carcinoma With Palpably Negative Neck

PURPOSE To assess the clinical usefulness of [(18)F]fluorodeoxyglucose positron emission tomography ([18F]FDG PET) as well as computed tomography (CT) or magnetic resonance imaging (MRI) in oral squamous cell carcinoma (SCC) patients with palpably negative neck. PATIENTS AND METHODS In total, 134 oral SCC patients with palpably negative neck were prospectively evaluated with [18F]FDG PET, CT/MRI, and their visual correlation. Histopathologic analysis was used as the gold standard for assessment of these imaging techniques. RESULTS Thirty-five (26.1%) of our 134 patients were found to have neck metastases. On a level-by-level basis, the sensitivity of [18F]FDG PET for nodal metastases was two-fold higher than that of CT/MRI (41.2% v 21.6%, respectively; P = .021). Visual correlation of [(18)F]FDG PET and CT/MRI yielded slightly higher sensitivity and specificity than [18F]FDG PET alone (47.1% v 41.2%, P = .25; 98.0% v 96.8%, P = .125, respectively). On a patient-by-patient basis, the sensitivity of [18F]FDG PET for neck metastases was 51.4% and increased to 57.1% after visual correlation with CT/MRI. The probabilities of occult neck metastasis after using [(18)F]FDG PET were 6.7% in T1 tumors, 10.8% in T2 tumors, 13.3% in T3 tumors, and 25% in T4 tumors and decreased to 3.3% in T1 tumors and to 9.2% in T2 tumors after visual correlation with CT/MRI. CONCLUSION [(18)F]FDG PET was superior to CT/MRI for detecting palpably occult neck metastasis of oral SCC. Because [(18)F]FDG PET could reduce the probability of occult neck metastasis to less than 15% in T1 to T3 tumors, it should be indicated for evaluation of these subpopulations.

Surgical outcome of T4a and resected T4b oral cavity cancer.

The American Joint Committee on Cancer (AJCC) 2002 staging system (AJCC 2002) suggested that squamous cell carcinoma of the oral cavity (OSCC) with T4b is unresectable. The current retrospective results show that selected T4b patients were resectable with favorable outcomes.

Neck treatment of patients with early stage oral tongue cancer : comparison between observation, supraomohyoid dissection, and extended dissection

The role of elective and therapeutic selective neck dissection in patients with early stage cancer of the oral tongue remains controversial. The purpose was to investigate the role of neck treatment in the management of this condition.

[18F]Fluorodeoxyglucose Positron Emission Tomography Is More Sensitive Than Skeletal Scintigraphy for Detecting Bone Metastasis in Endemic Nasopharyngeal Carcinoma at Initial Staging

PURPOSE Bone metastasis occurs frequently in patients with endemic nasopharyngeal carcinoma (NPC). The main objective of this study is to evaluate positron emission tomography (PET) using fluorine-18-labeled fluorodeoxyglucose ([18F]FDG) and conventional skeletal scintigraphy (SS) for detecting bone metastasis at initial staging. Auxiliary objectives are to identify risk factors for bone metastasis and features associated with poor survival in patients with bone metastasis. PATIENTS AND METHODS Patients with endemic NPC before initiation of treatment were enrolled. PET and SS were performed at initial staging and compared using McNemars paired-sample test. Bone metastasis was considered to be present if there was any reliable evidence identified within 1 year after primary diagnosis. Multiple logistic regression and Coxs proportional hazards models were used for auxiliary objectives. RESULTS Thirty (15%) of 202 eligible patients were found to have bone metastasis. [18F]FDG PET was found to be more sensitive than SS in the patient-based analysis (P = .006) and in the region-based analysis at the spine (P = .001). Advanced N stage was the only significant risk factor (P < .0001), and the coexistence of hepatic metastasis was a prognosticator of poor survival (P = .017). The survival was not significantly better for patients with bone metastasis undetected at primary staging than for those with initially detectable bone metastasis (P = .620). CONCLUSION [18F]FDG PET is more sensitive than SS for detecting bone metastasis in endemic NPC at initial staging, whereas SS can be considered as supplementary in this setting.

Neck dissection field and lymph node density predict prognosis in patients with oral cavity cancer and pathological node metastases treated with adjuvant therapy

Pathological lymph node metastases (pN+) are an established prognostic factor in oral cavity squamous cell carcinoma (OSCC). We retrospectively examined the prognostic significance of lymph node (LN) density in pN+ OSCC patients who underwent neck dissection (ND) and postoperative adjuvant therapy. We examined 309 pN+ patients who underwent levels I-III ND and 148 pN+ patients treated with levels I-V ND. The 5-year control and survival rates served as the main outcome measures. The 5-year rates for patients treated with levels I-III and I-V NDs were as follows: local control, 79%, 74% (p=0.0630); neck control, 81%, 68% (p=0.0014); distant metastasis, 21%, 36% (p=0.0003); disease-free survival (DFS), 59%, 43% (p=0.0001); disease-specific survival (DSS), 66%, 46% (p<0.0001); and overall survival (OS), 49%, 37% (p=0.0048), respectively. Multivariate analysis demonstrated that an LN density ≥0.16 was an independent prognostic factor for 5-year neck control (all data presented as p, hazard ratio [95% confidence interval]) (0.003, 2.691 [1.412-5.128]), distant metastases (0.001, 2.831 [1.520-5.270]), DFS (<0.001, 2.464 [1.571-3.866]), and DSS (0.036, 1.781 [1.040-3.052]) in levels I-III ND patients. An LN density ≥0.048 was an independent predictor of 5-year local control (0.004, 4.871 [1.654-14.344]), neck control (0.002, 24.738 [3.367-181.771]), DFS (<0.001, 4.151 [2.264-7.610]), DSS (<0.001, 3.791 [2.017-7.125]), and OS (<0.001, 2.806 [1.706-4.613]) in levels I-V ND patients. Our findings demonstrate the prognostic value of LN density for guiding treatment strategies in OSCC patients who are to receive adjuvant therapy.

The comparison between weekly and three-weekly cisplatin delivered concurrently with radiotherapy for patients with postoperative high-risk squamous cell carcinoma of the oral cavity

BackgroundThe aim of this study was to compare the outcomes of postoperative adjuvant concomitant chemoradiotherapy using two different schedules of cisplatin for patients with high-risk oral squamous cell carcinoma (OSCC).MethodsFrom Feb. 2008 to Aug. 2010, 55 patients with high-risk OSCC were included in this study. Patients were randomized into treatment groups that either received 100 mg/m2 cisplatin once every 3 weeks (arm A) or 40 mg/m2 cisplatin once per week (arm B). All patients were irradiated with 66 Gy in 33 fractions.ResultsOf the 50 eligible patients, 26 were assigned to arm A, and 24 were assigned to arm B. Both groups of patients received the same mean doses of radiotherapy and cisplatin. However, 88.5% of patients in arm A and 62.5% of those in arm B (p = 0.047) received ≥ 200 mg/m2 of cisplatin in total. The overall toxicity was significantly greater in arm B (p = 0.020), and all of the grade 4 toxicities occurred in patients in arm B.ConclusionsThree-weekly high-dose cisplatin treatment showed higher compliance, and lower acute toxicity compared to weekly low-dose cisplatin treatment.

Thermal measurements and analyses of low-cost high-power LED packages and their modules

Abstract The thermal behaviors of high-power light emitting diode (LED) chip-on-plate (COP) package and module are investigated by experimental measurements (with LED junction temperature ( T j ) tester, thermocouples, and thermal imager), a thermal resistance circuit (TRC) method, a commercial finite element code (ANSYS), and a computational fluid dynamics code (CFdesign). Based on the experimental results, the thermal resistance of the COP package was found to be comparable to those for the commercial packages. Furthermore, it was also found that the T j and thermal resistances of the COP package and module, calculated from 2D ANSYS, 3D TRC and 3D CFdesign, are consistent well with those from the experiments. Besides, the uncertain equation-based convection coefficients used in ANSYS and TRC for the thermal analysis of the COP module were closely examined and discussed in detail by comparing with those from CFdesign analysis. Moreover, the validated ANSYS and CFdesign models were used for parametric studies of the COP module and further provided useful design parameters. Finally, the COP module under natural and forced convection conditions was studied, and the results showed that the junction-to-air thermal resistances are sensitive to the flow conditions, but not for thermal resistances from the junction to aluminum substrate and to heat sink.

PET and PET/CT of the Neck Lymph Nodes Improves Risk Prediction in Patients with Squamous Cell Carcinoma of the Oral Cavity

We prospectively evaluated the sensitivity and specificity of 18F-FDG PET in the detection of neck lymph node metastases in patients with oral cavity squamous cell carcinoma (OSCC). We also sought to evaluate whether pretreatment PET visual scores in the neck lymph nodes may improve risk stratification. Methods: We enrolled 473 OSCC patients (445 men and 28 women; mean age ± SD, 50.9 ± 11.7 y) without distant metastases. All participants underwent 18F-FDG PET within 2 wk before surgery and neck dissection. Histopathology was taken as the reference standard for neck lymph node status. The duration of follow-up was at least 24 mo in all surviving patients. Results: 18F-FDG PET correctly diagnosed 164 of 211 patients with neck metastases and 152 of 262 subjects without pathologic neck metastases, resulting in a patient-based sensitivity and specificity of 77.7% and 58.0%, respectively. In Cox models adjusting for age, sex, traditional risk factors, and treatment modality, PET results at the neck lymph nodes were significantly and independently associated with rates of neck control, distant metastasis, disease-free survival, disease-specific survival, and overall survival. Notably, the results of the c-statistics demonstrated that PET score improved the accuracy of risk prediction in terms of overall and disease-free survival rates. Conclusion: PET findings at the neck lymph nodes have limited sensitivity and specificity for primary staging of OSCC but improve risk stratification beyond that of traditional risk factors.

Refining the role of preoperative C‐reactive protein by neutrophil/lymphocyte ratio in oral cavity squamous cell carcinoma

Elevated inflammatory biomarkers such as C‐reactive protein (CRP) and the recently identified neutrophil/lymphocyte ratio (NLR) were demonstrated to be associated with prognosis in human cancers. The aim of our present study is to analyze the relationship of preoperative levels of CRP and NLR with clinicopathological factors and prognosis in oral squamous cell carcinoma (OSCC) patients.

Comparison of PET/CT and MRI for the detection of bone marrow invasion in patients with squamous cell carcinoma of the oral cavity

Our aim was to retrospectively assess the diagnostic performance from combined positron emission tomography/computed tomography (PET/CT) and magnetic resonance imaging (MRI) for the detection of bone marrow invasion of the mandible or maxilla in patients with oral cavity squamous cell carcinoma (OCSCC). A total of 114 patients with OCSCC, arising from or abutting the upper or lower alveolar ridge, underwent staging PET/CT and MRI studies before surgery. The possibility of bone marrow invasion on PET/CT and MRI was graded retrospectively on a 5-point score. Histopathology was taken as the reference standard. Sensitivity, specificity, predictive values and likelihood ratios were calculated. Clinical factors affecting the performance, like tumor origin and dentate status were also explored. PET/CT was found to be more specific than MRI (83% vs. 61%, respectively, p=0.0015) but less sensitive (78% vs. 97%, respectively, p=0.0391). Dentate status and tumor origin affected the diagnostic performance of PET/CT. In patients with positive MRI, sensitivity and specificity of PET/CT were 78% and 100% in dentate patients with alveolar ridge tumors, 75% and 80% in dentate patient with buccal tumors, 90% and 33% in edentulous patients with alveolar ridge tumors and 0% and 63% for edentulous patients with buccal tumors, respectively. PET/CT is more specific than MRI and can be used to complement the role of MRI. A negative MRI result can confidently exclude the presence of bone marrow invasion, while in patients with positive MRI findings, a negative PET/CT may be useful to rule out bone marrow invasion in dentate patients.