研究者詳細 - 加茂　憲一

論文 - 加茂　憲一

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Selection Method for Height-Diameter Curves and Its Application to the Data of Sugi (<i>Cryptomeria japonica</i>) in Japan

Ken-ichi Kamo, Tetsuji Tonda, Masayoshi Takahashi, Naoto Matsumura

FORMATH ( FORMATH Research Group ) 22 n/a - n/a 2023年12月

DOI

Strength estimation for moving iodine-125 source for brachytherapy; application to source link loader”

K.Tanaka, T.Kajimoto, O.Asanuma, M.Hori, K.Kamo, T.Suzuki, I.Sumida, Y.Takahashi, G.Bengua, K.Sakata, S.Endo

Bulletin of Kyoto Pharmaceutical University 4 167 - 174 2023年12月 [査読有り]

DOI

Cost-effectiveness of preventive aspirin use and intensive downstaging polypectomy in patients with familial adenomatous polyposis: A microsimulation modeling study.

Eiko Saito, Michihiro Mutoh, Hideki Ishikawa, Kenichi Kamo, Keisuke Fukui, Megumi Hori, Yuri Ito, Yichi Chen, Byron Sigel, Masau Sekiguchi, Osamu Hemmi, Kota Katanoda

Cancer medicine 2023年08月 [査読有り] [国際誌]

OBJECTIVE: Although there is increasing evidence to suggest the cost-effectiveness of aspirin use to prevent colorectal cancer (CRC) in the general population, no study has assessed cost-effectiveness in patients with familial adenomatous polyposis (FAP), who are at high risk of developing CRC. We examined the cost-effectiveness of preventive use of low-dose aspirin in FAP patients who had undergone polypectomy in comparison with current treatment practice. DESIGN: We developed a microsimulation model that simulates a hypothetical cohort of the Japanese population with FAP for 40 years. Three scenarios were created based on three intervention strategies for comparison with no intervention, namely intensive downstaging polypectomy (IDP) of colorectal polyps at least 5.0 mm in diameter, IDP combined with low-dose aspirin, and total proctocolectomy with ileal pouch-anal anastomosis (IPAA). Cost-effective strategies were identified using a willingness-to-pay threshold of USD 50,000 per QALY gained. RESULTS: Compared with no intervention, all strategies resulted in extended QALYs (21.01-21.43 QALYs per individual) and showed considerably reduced colorectal cancer mortality (23.35-53.62 CRC deaths per 1000 individuals). Based on the willingness-to-pay threshold, IDP with low-dose aspirin was more cost-effective than the other strategies, with an incremental cost-effectiveness ratio of $57 compared with no preventive intervention. These findings were confirmed in both one-way sensitivity analyses and probabilistic sensitivity analyses. CONCLUSION: This study suggests that the strategy of low-dose aspirin with IDP may be cost-effective compared with IDP-only or IPAA under the national fee schedule of Japan.

DOI PubMed

Statistical Inference for Diameter-Height Curves using Varying Coefficient Model

Tetsuji Tonda, Ken-ichi Kamo, Masayoshi Takahashi

FORMATH ( FORMATH Research Group ) 22 n/a - n/a 2023年

DOI

How much can screening reduce colorectal cancer mortality in Japan? Scenario-based estimation by microsimulation.

Ken-Ichi Kamo, Keisuke Fukui, Yuri Ito, Tomio Nakayama, Kota Katanoda

Japanese journal of clinical oncology 52 ( 3 ) 221 - 226 2021年12月 [査読有り] [国際誌]

担当区分：筆頭著者 , 責任著者

BACKGROUND: Screening is one of the effective interventions for the reduction of colorectal cancer mortality. Though the Japanese government recommends faecal occult blood test and colonoscopy as a follow-up examination following a diagnosis, both participation rates have not been so high and the national mortality rate has not shown a clear decreasing trend. METHODS: Microsimulation models simulate the life histories of a large population of individuals under various scenarios. In this study, we applied a microsimulation model to estimate the reduction of colorectal cancer mortality based on screening scenarios. RESULTS: The effect of reducing the age-standardized mortality rate for colorectal cancer was estimated at 9.4% for men and 6.0% for women under the scenario which calls for 50% participation in faecal occult blood test and 90% participation of follow-up examination. This scenario corresponds to the goal setting for screening in the third-term of the Basic Plan to Promote Cancer Control Programs in Japan. CONCLUSIONS: Our microsimulation model was found to be useful in estimating the mortality reduction effect of cancer control policy. Such modelling techniques can be utilized to develop effective and optimal cancer control programs.

DOI PubMed

Ridge Estimate Application to Growth Function

Ken-ichi Kamo, Hirokazu Yanagihara

FORMATH ( FORMATH Research Group ) 20 n/a - n/a 2021年09月 [査読有り]

担当区分：筆頭著者 , 責任著者

DOI

Assessing the Immediate Impact of Surrounding Land Uses on the Extents of Freshwater Body over Time in Madagascar - A Demonstrative Case Study of Itasy Lake -

Masashi Konoshima, Tetsuji Tonda, Ken-ichi Kamo, Bam H.N. Razafindrabe

FORMATH ( FORMATH Research Group ) 20 n/a - n/a 2021年09月 [査読有り]

DOI

Gamma Regression Model with Nuisance Baseline for Tree Growth Data

Tetsuji Tonda, Ken-ichi Kamo, Masayoshi Takahashi

FORMATH ( FORMATH Research Group ) 20 n/a - n/a 2021年09月 [査読有り]

DOI

がん対策立案・評価における意思決定に寄与するマイクロシミュレーションの構築：大腸がんを事例に

加茂憲一, 福井敬祐, 坂本亘, 伊藤ゆり

計量生物学 ( The Biometric Society of Japan ) 41 ( 2 ) 93 - 115 2021年05月 [査読有り]

担当区分：筆頭著者 , 責任著者

DOI J-GLOBAL

A modified GAP model for East-Asian populations with idiopathic pulmonary fibrosis

Hirotaka Nishikiori, Hirofumi Chiba, Sang Hoon Lee, Shun Kondoh, Ken-ichi Kamo, Koshi Nakamura, Kimiyuki Ikeda, Koji Kuronuma, Man Pyo Chung, Yasuhiro Kondoh, Sakae Homma, Naohiko Inase, Moo Suk Park, Hiroki Takahashi

Respiratory Investigation ( Elsevier BV ) 58 ( 5 ) 395 - 402 2020年09月 [査読有り] [国際誌]

BACKGROUND: The easy-to-calculate gender, age, and lung physiology (GAP) model shows good predictive and discriminative performance in the prognosis of idiopathic pulmonary fibrosis (IPF). However, the GAP model was not effective in predicting the prognosis accurately in previous Japanese and Korean IPF cohort studies. Therefore, we developed a modified GAP model for the East-Asian populations by weighing the GAP variables. The validity of the modified GAP model was subsequently evaluated in East-Asian IPF patients. METHODS: The derivation cohort comprised 326 patients with IPF. Weights of the variables were adjusted on the basis of coefficients derived from Cox regression models. The total points were distributed to the three stages of the disease so that the number of patients included in each stage was appropriate. The validity of the modified model was analyzed in another Japanese cohort of 117 patients with IPF and a nationwide cohort of Korean patients with IPF. RESULTS: Predicted survival rates differed significantly in the derivation cohort using the modified GAP model for each stage of IPF (log-rank test: stage I vs. stage II, p < 0.001; stage II vs. stage III, p < 0.001). Model performance improved according to Harrell's C-index (at three years: 0.696 in the original GAP model to 0.738 in the modified model). The performance of the modified model was validated in the Japanese validation and Korean national cohorts. CONCLUSIONS: Our modification of the original GAP model showed improved performance in East-Asian IPF patient populations.

DOI PubMed

Lateral Position With Gantry Tilt Further Improves Computed Tomography Image Quality Reconstructed Using Single-Energy Metal Artifact Reduction Algorithm in the Oral Cavity

Maki Onodera, Kazunori Aratani, Takaharu Shonai, Keishi Ogura, Ken-ichi Kamo, Kazuhiro Ogi, Atsushi Kondo, Masamitsu Hatakenaka

Journal of Computer Assisted Tomography ( Ovid Technologies (Wolters Kluwer Health) ) 44 ( 4 ) 553 - 558 2020年07月 [査読有り]

DOI

Statistical inference for estimating the incidence of cancer at the prefectural level in Japan

Tanabe Ryunosuke, Kamo Ken-ichi, Fukui Keisuke, Imori Shinpei

JAPANESE JOURNAL OF CLINICAL ONCOLOGY 49 ( 5 ) 481 - 485 2019年05月 [査読有り]

担当区分：責任著者

DOI

A New Approach to Classify Growth Patterns Based on Growth Function Selection and K-means Method

Ken-ichi Kamo

FORMATH ( FORMATH Research Group ) 18 ( 0 ) n/a - n/a 2019年04月 [査読有り]

担当区分：筆頭著者 , 責任著者

DOI

Simulation Models in Gastric Cancer Screening: A Systematic Review

Ayako Matsuda, Kumiko Saika, Rina Tanaka, Yuri Ito, Keisuke Fukui, Ken-ichi Kamo

Asian Pacific journal of cancer prevention : APJCP 19 ( 12 ) 3321 - 3334 2018年12月 [査読有り] [国際誌]

担当区分：最終著者

Background: Together with such high-quality approaches as randomized controlled trials and large-scale cohort studies, simulation models are often employed to evaluate the effect of cancer screening methods and decide on their appropriateness. This study aimed to evaluate all effects of gastric cancer screening that have been assessed using simulation models, including cost-effectiveness, mortality reduction, and early-stage detection. Methods: We performed a systematic review using PubMed and Web of Science. We evaluated the effect of screening related to cost, such as incremental cost-effectiveness and incremental cost-effectiveness ratios; we also separately assessed effects other than cost, such as quality-adjusted life-years, number of deaths prevented, life-years saved, relative risk of mortality from gastric cancer, life expectancy, and incidence reduction. The methods targeted for evaluation were Helicobacter pylori testing or endoscopy. Results: We identified 19 studies dealing with simulation models in gastric cancer screenings: 14 examined H. pylori screening and 7 focused on endoscopy. Among those studies, two assessed both H. pylori and endoscopy screening. Most of the studies adopted a Markov model, and all the studies evaluated cost-effectiveness. Of the 14 H. pylori screening studies, 13 demonstrated cost-effectiveness and 11 also showed good results other than cost-effectiveness, such as extension of life-years and increase in early-stage detection. In three of the five endoscopy studies, the target population was patients; all five studies obtained good results for cost-effectiveness and four observed good results other than for cost-effectiveness. Conclusions: In this study, we showed that the H. pylori screening test was cost-effective in terms of simulation model investigations. However, the H. pylori screening test should not ordinarily be recommended since there is insufficient evidence that it reduces gastric cancer mortality. In Japan, simulation modeling should be employed to plan for cancer control, and the appropriate use of simulation models should be examined for future use.

PubMed

Long-term prognosis of patients with HHV-6 reactivation following allogeneic HSCT

K.Iesato, T.Hori, Y.Yoto, M.Yamamoto, N.Inazawa, K.Kamo, H.Ikeda, S.Iyama, N.Hatakeyama, A.Iguchi, J.Sugita, R.Kobayashi, N.Suzuki, H.Tsutsumi

Pediatrics International 60 547 - 552 2018年 [査読有り]

An in vitro verification of strength estimation for moving an 125iodine source during implantation in brachytherapy

K.Tanaka, T.Kajimoto, T.Hayashi, O.Asanuma, M.Hori, K.Kamo, I.Sumida, Y.Takahashi, K.Tateoka, G.Bengua, K.Sakata, S.Endo

Journal of Radiation Research 59 ( 4 ) 484 - 489 2018年 [査読有り]

A STUDY ON THE BIAS-CORRECTION EFFECT OF THE AIC FOR SELECTING VARIABLES IN NORMAL MULTIVARIATE LINEAR REGRESSION MODELS UNDER MODEL MISSPECIFICATION

Hirokazu Yanagihara, Ken-ichi Kamo, Shinpei Imori, Mariko Yamamura

REVSTAT-STATISTICAL JOURNAL ( INST NACIONAL ESTATISTICA-INE ) 15 ( 3 ) 299 - 332 2017年07月 [査読有り]

By numerically comparing a variable-selection method using the crude AIC with those using the bias-corrected AICs, we find out knowledge about what kind of bias correction gives a positive effect to variable selection under model misspecification. Actually, since all the variable-selection methods considered in this paper asymptotically choose the same model as the best model, we conduct numerical examinations using small and moderate sample sizes. Our results show that bias correction under assumption that the mean structure is misspecified gives a better effect to a variable-selection method than that under the assumption that the distribution of the model is misspecified.

Growth analysis using nuisance baseline

K.Kamo, T.Tonda, K.Satoh

FORMATH 16 1 - 10 2017年 [査読有り]

担当区分：筆頭著者 , 責任著者

The signal intensity ratio of the optic nerve to ipsilateral frontal white matter is of value in the diagnosis of acute optic neuritis

Maki Onodera, Naoya Yama, Masato Hashimoto, Takaharu Shonai, Kazunori Aratani, Hiroyuki Takashima, Ken-ichi Kamo, Hiroshi Nagahama, Hiroshi Ohguro, Masamitsu Hatakenaka

EUROPEAN RADIOLOGY ( SPRINGER ) 26 ( 8 ) 2640 - 2645 2016年08月 [査読有り]

To evaluate the usefulness of the signal intensity ratio (SIR) of the optic nerve to the white matter (WM) on short tau inversion recovery (STIR) images to diagnose acute optic neuritis (AON). The 405 consecutive patients with suspected orbital diseases underwent orbital magnetic resonance imaging (MRI) using a 3-T scanner between June 2008 and August 2011. Among them, 108 optic nerves (33 AON and 75 control) were retrospectively analysed. The averaged SIR (SIRave) and maximum SIR (SIRmax) were defined as the averaged signal intensity (SI) of the optic nerve divided by that of WM, and the maximum SI of the optic nerve divided by averaged SI of WM, respectively. These values were compared between AON and control using the Mann-Whitney U test. A P < 0.05 was considered statistically significant. SIRave and SIRmax were significantly (P < 0.001) higher in the AON compared to the control. At a cut-off SIRave value of 1.119, the sensitivity, specificity and accuracy were 0.939, 0.840, and 0.870; and at a cut-off SIRmax value of 1.281, these were 1.000, 0.720 and 0.806, respectively. The SIR of the optic nerve to WM on STIR images is of value in diagnosing AON. aEuro cent We propose a method of diagnosing acute optic neuritis using 3-T MRI. aEuro cent Our method is simple and objective and requires no novel imaging techniques. aEuro cent Our method shows high diagnostic accuracy.

DOI

Quantification of the increase in thyroid cancer prevalence in Fukushima after the nuclear disaster in 2011-a potential overdiagnosis?

Kota Katanoda, Ken-Ichi Kamo, Shoichiro Tsugane

JAPANESE JOURNAL OF CLINICAL ONCOLOGY ( OXFORD UNIV PRESS ) 46 ( 3 ) 284 - 286 2016年03月 [査読有り]

A thyroid ultrasound examination programme has been conducted in Fukushima Prefecture, Japan, after the nuclear disaster in 2011. Although remarkably high prevalence of thyroid cancer was observed, no relevant quantitative evaluation was conducted. We calculated the observed/expected (O/E) ratio of thyroid cancer prevalence for the residents aged a parts per thousand currency sign20 years. Observed prevalence was the number of thyroid cancer cases detected by the programme through the end of April 2015. Expected prevalence was calculated as cumulative incidence by a life-table method using the national estimates of thyroid cancer incidence rate in 2001-10 (prior to the disaster) and the population of Fukushima Prefecture. The underlying assumption was that there was neither nuclear accident nor screening intervention. The observed and estimated prevalence of thyroid cancer among residents aged a parts per thousand currency sign20 years was 160.1 and 5.2, respectively, giving an O/E ratio of 30.8 [95% confidence interval (CI): 26.2, 35.9]. When the recent increasing trend in thyroid cancer was considered, the overall O/E ratio was 22.2 (95% CI: 18.9, 25.9). The cumulative number of thyroid cancer deaths in Fukushima Prefecture, estimated with the same method (annual average in 2009-13), was 0.6 under age 40. Combined with the existing knowledge about radiation effect on thyroid cancer, our descriptive analysis suggests the possibility of overdiagnosis. Evaluation including individual-level analysis is required to further clarify the contribution of underlying factors.

DOI

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