Rikiya Taoka

Dr. Rikiya Taoka

orcid

Research Focus & Metrics

Academic Career Length

11Years (2016-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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1 July 2017 in Asian Journal of Urology
Verified
Journal Article
Open access
RTRikiya Taoka
Rikiya Taoka
YKYoshiyuki Kakehi
Yoshiyuki Kakehi
Benign prostatic hyperplasia (BPH) is a condition that greatly affects the quality of life of middle-aged and elderly men. Histopathologically, hyperplastic changes frequently occur in the prostate tissue of elderly men, the incidence of which has been reported to reach approximately 80% in men in their 70s. In clinical practice, approximately 25% of men with histologic BPH are assumed to experience lower urinary tract symptoms (LUTS) and receive some kind of treatment. In other words, there are some men with histologic BPH who do not exhibit LUTS. For that reason, many factors, such as the change in hormonal environment, the immune or autoimmune response, the alteration of gene expression, and so on, are thought to affect the onset and progression of LUTS in men with histologic BPH. One such factor that has long drawn attention is the presence of asymptomatic histological inflammation, which very often accompanies symptomatic BPH. Recent studies have suggested that asymptomatic histological inflammation causes repeated destruction, healing, and regeneration of the prostate tissue, leading to the enlargement of prostatic nodules, while at the same time causing stromal tissue-predominant remodeling of the prostate tissue, which can increase urination resistance and result in the condition changing from asymptomatic BPH to symptomatic BPH. In future, the biomolecular clarification of the significance of asymptomatic histological inflammation in the prostate tissue could help develop new treatment strategies for BPH accompanied by LUTS.

11 March 2021 in BMC Cancer
Verified
Journal Article
Open access
PDF file
OGon behalf of the Japanese Urological Oncology Group
on behalf of the Japanese Urological Oncology Group
Makito MiyakeMakito Miyake
Makito Miyake
KIKota Iida
Kota Iida
NNNobutaka Nishimura
Nobutaka Nishimura
TMTatsuki Miyamoto
Tatsuki Miyamoto
HNHiroyuki Nishiyama
Hiroyuki Nishiyama
Background: To explore possible solutions to overcome chronic Bacillus Calmette–Guérin (BCG) shortage affecting seriously the management of non-muscle invasive bladder cancer (NMIBC) in Europe and throughout the world, we investigated whether non-maintenance eight-dose induction BCG (iBCG) was comparable to six-dose iBCG plus maintenance BCG (mBCG). Methods: This observational study evaluated 2669 patients with high- or highest-risk NMIBC who treated with iBCG with or without mBCG during 2000–2019. The patients were classified into five groups according to treatment pattern: 874 (33%) received non-maintenance six-dose iBCG (Group A), 405 (15%) received six-dose iBCG plus mBCG (Group B), 1189 (44%) received non-maintenance seven−/eight-dose iBCG (Group C), 60 (2.2%) received seven−/eight-dose iBCG plus mBCG, and 141 (5.3%) received only ≤5-dose iBCG. Recurrence-free survival (RFS), progression-free survival, and cancer-specific survival were estimated and compared using Kaplan–Meier analysis and the log-rank test, respectively. Propensity score-based one-to-one matching was performed using a multivariable logistic regression model based on covariates to obtain balanced groups. To eliminate possible immortal bias, 6-, 12-, 18-, and 24-month conditional landmark analyses of RFS were performed. Results: RFS comparison confirmed that mBCG yielded significant benefit following six-dose iBCG (Group B) in recurrence risk reduction compared to iBCG alone (groups A and C) before (P < 0.001 and P = 0.0016, respectively) and after propensity score matching (P = 0.001 and P = 0.0074, respectively). Propensity score-matched sequential landmark analyses revealed no significant differences between groups B and C at 12, 18, and 24 months, whereas landmark analyses at 6 and 12 months showed a benefit of mBCG following six-dose iBCG compared to non-maintenance six-dose iBCG (P = 0.0055 and P = 0.032, respectively). There were no significant differences in the risks of progression and cancer-specific death in all comparisons of the matched cohorts. Conclusions: Although non-maintenance eight-dose iBCG was inferior to six-dose iBCG plus mBCG, the former might be an alternative remedy in the BCG shortage era. To overcome this challenge, further investigation is warranted to confirm the real clinical value of non-maintenance eight-dose iBCG.

4 April 2022 in Photodiagnosis and Photodynamic Therapy
Verified
Journal Article
Open access
RTRikiya Taoka
Rikiya Taoka
YMYuki Matsuoka
Yuki Matsuoka
MYMari Yamasaki
Mari Yamasaki
NKNaoya Kani
Naoya Kani
THTomoko Honda
Tomoko Honda
MSMikio Sugimoto
Mikio Sugimoto
5-aminolevulinic acid is a protoporphyrin IX precursor used for photodynamic diagnosis. We aimed to clarify the therapeutic benefits of orally administered 5-aminolevulinic acid for photodynamic diagnosis in transurethral resection for non-muscle-invasive bladder cancer in a real-world setting. From January 2009 to December 2020, patients with non-muscle-invasive bladder cancer who have undergone visually complete resection by initial transurethral surgery were included. Histopathologically confirmed residual and intravesical recurrent bladder cancer was retrospectively investigated and compared with transurethral resection using photodynamic diagnosis and conventional white light. One hundred and fifteen patients who underwent photodynamic diagnosis-transurethral resection were compared with 346 patients who underwent white light-transurethral resection. The second transurethral resection revealed that the proportion of residual T1 and Ta bladder cancer was lower in the photodynamic diagnosis group than in the white light group (10.3% vs. 33.8%, P = 0.001). Additionally, the proportion of intravesical recurrence was lower in the photodynamic diagnosis group than in the white light group (9.6% vs. 41.9%, P < 0.001). Using 5-aminolevulinic acid-photodynamic diagnosis during transurethral resection of bladder tumor improved the cumulative intravesical recurrence-free survival (log-rank test: P < 0.001). Furthermore, multivariate analyses indicated that not using 5-aminolevulinic acid-photodynamic diagnosis was an independent predictive factor for residual bladder cancer (odds ratio, 6.16; 95% confidence interval, 2.10-18.0; P < 0.001) and intravesical recurrence (hazard ratio, 2.01; 95% confidence interval, 1.05-3.83, P = 0.034). Introducing 5-aminolevulinic acid-photodynamic diagnosis into transurethral resection reduces residual bladder cancer and improves the cumulative intravesical recurrence-free survival in patients with non-muscle-invasive bladder cancer, indicating its possible therapeutic benefits.

28 February 2024 in International Journal of Clinical Oncology
Verified
Journal Article
Closed access
PDF file
RTRikiya Taoka
Rikiya Taoka
MKMasaki Kamada
Masaki Kamada
KIKazuyoshi Izumi
Kazuyoshi Izumi
RTRyuta Tanimoto
Ryuta Tanimoto
KDKei Daizumoto
Kei Daizumoto
MSMikio Sugimoto
Mikio Sugimoto

5 April 2022 in BMC Urology
Verified
Journal Article
Open access
PDF file
MYMari Yamasaki
Mari Yamasaki
RTRikiya Taoka
Rikiya Taoka
KKKazuya Katakura
Kazuya Katakura
TMToru Matsunaga
Toru Matsunaga
NKNaoya Kani
Naoya Kani
MSMikio Sugimoto
Mikio Sugimoto
Background: The Paris System (TPS) for reporting urinary cytology differs from conventional systems (CS) in that it focuses on the diagnosis of high-grade urothelial carcinoma (HGUC). This study investigated the impact of TPS implementation on the diagnostic accuracy of HGUC by comparing it with our institutional CS. Methods: A total of 649 patients who underwent transurethral resection of bladder tumor (TURBT) between January 2009 and December 2020 were included in this study. Our institution adopted TPS to report urinary cytology in February 2020. The diagnostic accuracy of HGUC in preoperative urinary cytology was compared with the presence or absence of HGUC in resected specimens of TURBT before and after TPS implementation. Results: After implementing TPS in urinary cytology, 89 patients were reviewed and compared with 560 patients whose urinary cytology was diagnosed by CS. TPS and CS for detecting HGUC had 56.0% and 58.2% sensitivity, 97.8% and 91.2% specificity, and 93.3% and 87.9% positive predictive values, respectively. There were no significant differences between TPS and CS in terms of sensitivity, specificity, and positive predictive value for HGUC (P = 0.83, 0.21, 1.00). On the other hand, the negative predictive value for HGUC using TPS was 80.0%, which was significantly higher than that of CS (66.4%, P = 0.04) The multivariate logistic regression analysis indicated that not using TPS was one of the independent predictive factors associated with false-negative results for HGUC (odds ratio, 2.26; 95% confidence interval, 1.08–4.77; P = 0.03). Conclusion: In instances where urinary cytology is reported as negative for HGUC by TPS, there is a low probability of HGUC, indicating that TPS has a potential diagnostic benefit.

19 March 2021 in International Journal of Urology
Verified
Journal Article
Closed access
PDF file
RTRikiya Taoka
Rikiya Taoka
HTHiroyuki Tsunemori
Hiroyuki Tsunemori
YMYuki Matsuoka
Yuki Matsuoka
KKKana Kohashiguchi
Kana Kohashiguchi
TMTakayoshi Miura
Takayoshi Miura
MSMikio Sugimoto
Mikio Sugimoto