Abstract
Introduction: Dose-dense methotrexate, vinblastine, doxorubicin, and cisplatin (ddMVAC) therapy is indicated as first-line or neoadjuvant chemotherapy (NAC) for patients with advanced or metastatic urothelial carcinoma (UC). However, no studies reported ddMVAC therapy with pegfilgrastim (3.6 mg) in Japanese patients. We investigated the safety and efficacy of ddMVAC therapy with pegfilgrastim in patients with advanced or metastatic UC. Methods: A total of 43 patients received ddMVAC therapy with pegfilgrastim (3.6 mg) from February 2021 to December 2023. Among them, 25 and 18 patients received this regimen as first-line chemotherapy and NAC, respectively. We assessed toxicity and efficacy using Common Terminology Criteria for Adverse Events version 4.0 and Response Evaluation Criteria in Solid Tumors version 1.1, respectively. Results: The median number of ddMVAC therapy cycles was 3 (range: 1–5), with a total of 131 cycles. Cisplatin at the full dose without reduction was administered to 24 (56%) patients. Grade ≥3 hematologic toxicity occurred in 15 (35%) patients. Among them, anemia, neutropenia, thrombocytopenia, and febrile neutropenia were 13.9%, 9.3%, 11.7%, and 7.0%, respectively. Regarding non-hematologic toxicity, grade 3 appetite loss was observed in 2 (5%) patients. Complete response was observed in 7 (16%) patients and partial response in 26 patients (60%), yielding an objective response rate of 76%. Pathologic complete response (pCR; ypT0pN0) was observed in 3 (16.7%) patients and downstaging occurred in 13 (72.2%) patients. The median progression-free survival and overall survival of first-line treatment with ddMVAC were 18.6 months and not reached, respectively. Conclusion: The ddMVAC with pegfilgrastim (3.6 mg) reduced injection-related patient burden, caused fewer grade ≥3 adverse events, and demonstrated similar efficacy when compared to the original ddMVAC regimen that used granulocyte colony-stimulating factor for 7 consecutive days.
Introduction
Cisplatin-based combination chemotherapy regimens are standard treatment for advanced or metastatic urothelial carcinoma (UC). In 1985, Sternberg et al. [1] first reported the methotrexate, vinblastine, doxorubicin, and cisplatin (MVAC) regimen for advanced or metastatic UC. This classic MVAC regimen demonstrated a high response rate but was administered without preventative granulocyte colony-stimulating factor (G-CSF), causing frequent severe toxicity, including sepsis, myelosuppression, and drug-related deaths [2].
Dose-dense MVAC (ddMVAC) was designed to improve upon the classic MVAC regimen by reducing toxicity and enhancing treatment benefits. The ddMVAC regimen administers methotrexate at 30 mg/m2 on day 1, vinblastine at 3 mg/m2, doxorubicin at 30 mg/m2, and cisplatin at 70 mg/m2 on day 2, with G-CSF administered on days 4–10 every 2 weeks [3, 4]. This modified regimen reduced severe toxicity rates and statistically significantly improved overall survival (OS) compared to the classic MVAC regimen [5]. Additionally, ddMVAC improved 3-year progression-free survival (PFS) over gemcitabine and cisplatin for patients who received neoadjuvant chemotherapy (NAC) in the VESPER trial [6].
Pegfilgrastim is a long-acting conjugation of polyethylene glycol (PEGylated) form of the recombinant human G-CSF analog filgrastim. Masuda et al. [7] assessed the optimal dose of pegfilgrastim in a phase II clinical trial that involved Japanese patients with breast cancer who underwent docetaxel, doxorubicin, and cyclophosphamide therapy. Patients received 1.8, 3.6, or 6.0 mg of pegfilgrastim once per chemotherapy cycle. This phase II clinical trial revealed that a 3.6-mg pegfilgrastim administration may be safe and effective for Japanese patients, and the appropriate pegfilgrastim dose for Japanese patients was 3.6 mg. Pegfilgrastim was approved in Japan in 2014 and is used in the chemotherapy of various cancer types for preventing the onset of febrile neutropenia (FN) [8‒13]. Additionally, pegfilgrastim is used in ddMVAC therapy for advanced UC, with a standard dose of 6.0 mg overseas [14, 15]. No study reported ddMVAC therapy with pegfilgrastim (3.6 mg) for advanced or metastatic UC in Japanese patients; thus, we have retrospectively investigated its safety and efficacy.
Patients and Methods
Patients
We retrospectively reviewed clinical data for 43 patients with advanced or metastatic UC who received ddMVAC therapy with pegfilgrastim (3.6 mg) from February 2021 to December 2023 at Kitasato University Hospital. Among them, 25 (58%) and 18 (42%) patients received this regimen as first-line chemotherapy and NAC, respectively. Of the patients who underwent first-line chemotherapy, 17 (68%) and 8 (32%) had bladder cancer and upper tract UC (UTUC), respectively. Conversely, among those who underwent NAC, 15 (83%) and 3 (17%) underwent radical cystectomy and radical nephroureterectomy, respectively. Tables 1 and 2 present the clinical characteristics of all patients.
Characteristics of patients who received ddMVAC as first-line chemotherapy
Variable . | Patients, n (%) . |
---|---|
Age, years | |
Median (range) | 72 (49–82) |
Sex | |
Male | 16 (64) |
Female | 9 (36) |
ECOG PS | |
0 | 22 (88) |
1 | 2 (8) |
2 | 1 (4) |
Primary tumor | |
bladder | 17 (68) |
UTUC | 8 (32) |
Disease site | |
Primary | 19 (76) |
Lymph node | 13 (52) |
Lung | 2 (8) |
Liver | 2 (8) |
Bone | 3 (12) |
Adrenal | 2 (8) |
Peritoneal dissemination | 1 (4) |
eGFR (mL/min/1.73 m2) | |
≥60 | 14 (56) |
45–59 | 10 (40) |
<45 | 1 (4) |
Variable . | Patients, n (%) . |
---|---|
Age, years | |
Median (range) | 72 (49–82) |
Sex | |
Male | 16 (64) |
Female | 9 (36) |
ECOG PS | |
0 | 22 (88) |
1 | 2 (8) |
2 | 1 (4) |
Primary tumor | |
bladder | 17 (68) |
UTUC | 8 (32) |
Disease site | |
Primary | 19 (76) |
Lymph node | 13 (52) |
Lung | 2 (8) |
Liver | 2 (8) |
Bone | 3 (12) |
Adrenal | 2 (8) |
Peritoneal dissemination | 1 (4) |
eGFR (mL/min/1.73 m2) | |
≥60 | 14 (56) |
45–59 | 10 (40) |
<45 | 1 (4) |
ddMVAC, dose-dense methotrexate, vinblastine, doxorubicin, and cisplatin; ECOG, Eastern Cooperative Oncology Group; PS, performance status; eGFR, estimated glomerular filtration rate; UTUC, upper tract urothelial carcinoma.
Characteristics of patients receiving ddMVAC as neoadjuvant chemotherapy
Variable . | Patients, n (%) . |
---|---|
Age, years | |
Median (range) | 74 (54–86) |
Sex | |
Male | 15 (83) |
Female | 3 (17) |
ECOG PS | |
0 | 17 (94) |
1 | 1 (6) |
Primary tumor | |
Bladder | 15 (83) |
UTUC | 3 (17) |
cT stage | |
T1 | 2 (11) |
T2 | 8 (44) |
T3 | 7 (39) |
T4 | 1 (6) |
cN stage | |
N0 | 15 (83) |
N1 | 1 (6) |
N2 | 2 (11) |
cM stage | |
M0 | 17 (94) |
M1 | 1 (6) |
eGFR (mL/min/1.73 m2) | |
≥60 | 10 (56) |
45–59 | 6 (33) |
<45 | 2 (11) |
Variable . | Patients, n (%) . |
---|---|
Age, years | |
Median (range) | 74 (54–86) |
Sex | |
Male | 15 (83) |
Female | 3 (17) |
ECOG PS | |
0 | 17 (94) |
1 | 1 (6) |
Primary tumor | |
Bladder | 15 (83) |
UTUC | 3 (17) |
cT stage | |
T1 | 2 (11) |
T2 | 8 (44) |
T3 | 7 (39) |
T4 | 1 (6) |
cN stage | |
N0 | 15 (83) |
N1 | 1 (6) |
N2 | 2 (11) |
cM stage | |
M0 | 17 (94) |
M1 | 1 (6) |
eGFR (mL/min/1.73 m2) | |
≥60 | 10 (56) |
45–59 | 6 (33) |
<45 | 2 (11) |
ddMVAC, dose-dense methotrexate, vinblastine, doxorubicin, and cisplatin; ECOG, Eastern Cooperative Oncology Group; PS, performance status; eGFR, estimated glomerular filtration rate; UTUC, upper tract urothelial carcinoma.
Chemotherapy Plan
This study administered the dosage of each drug at the same levels as the original ddMVAC in cycles of 14 days. However, pegfilgrastim (3.6 mg) was administered only once on day 3 at least 24 h after chemotherapy administration. The administration cycles were standardized at 4–6 and 4 cycles for first-line chemotherapy and NAC, respectively. The cisplatin dose was reduced based on renal function. Estimated glomerular filtration rates (eGFR) of <45 mL/min/1.73 m2, 45–60 mL/min/1.73 m2, and >60 mL/min/1.73 m2 were administered 50%, 75%, and 100% (standard dose) cisplatin, respectively.
Treatment Evaluation
This study primarily aimed to evaluate the safety of ddMVAC therapy with pegfilgrastim (3.6 mg). Objective response rate (ORR), pathological response, PFS, and OS were the secondary endpoints.
Safety was evaluated for all 43 patients who received at least one ddMVAC therapy dose. Toxicity data were retrospectively monitored according to the National Cancer Institute Common Terminology Criteria for Adverse Events version 4.0. Blood cell counts and serum chemistry tests were conducted before the start of each cycle and on days 3 and 6 during the chemotherapy.
Generally, ORR was conducted every four cycles using computed tomography or magnetic resonance imaging, based on response evaluation criteria in solid tumors version 1.1. Patients who received first-line chemotherapy were recommended for maintenance therapy with avelumab after achieving stable disease or better in the efficacy assessment [16]. Pembrolizumab was indicated as a second-line treatment in cases of progressive disease [17]. Conversely, all patients who received NAC were scheduled for radical surgery. Additionally, surgical specimens were processed under standard pathological procedures at our hospital. Moreover, adjuvant therapy with nivolumab was recommended based on postoperative pathological results [18].
Statistical Analyses
PFS and OS times were calculated based on patients’ medical records. Bladder recurrence after radical nephroureterectomy was not considered in the PFS rate analysis. PFS time was calculated from radical surgery or first-line chemotherapy to disease progression or death date. OS time was the period from radical surgery or first-line chemotherapy to death. The Kaplan-Meier method was used to estimate survival curves. All analyses were conducted using Stata version 13 for Windows (Stata Corp, College Station, TX, USA).
Results
The median age of all patients who received ddMVAC chemotherapy was 74 years (range: 49–86 years). Of the 43 patients, 31 (72%) were male and 12 (28%) were female, with 39 (91%), 3 (7%), and 1 (2%) having performance status (PS) of 0, 1, and 2, respectively. The median number of treatment cycles was 3 (range: 1–5), with a total of 131 cycles. Cisplatin at 100% (full dose without reduction), 75%, and 50% of the dose was administered to 24 (56%), 16 (37%), and 3 (7%) patients, respectively. The median number of treatment cycles was 3 (range: 1–4) in first-line chemotherapy. Cisplatin at 100%, 75%, and 50% of dosage was administered to 14 (56%), 10 (40%), and 1 (4%) patients, respectively. Conversely, the median number of treatment cycles was 3 cycles (range: 1–5) in the NAC group. Cisplatin at 100%, 75%, and 50% of dosage was administered to 10 (56%), 6 (33%), and 2 (11%), respectively. The median dose intensity and relative dose intensity were 11.1 mg/m2/week and 74.3% for methotrexate, 1.3 mg/m2/week and 85.6% for vinblastine, 13.8 mg/m2/week and 91.7% for doxorubicin, and 27.3 mg/m2/week and 77.9% for cisplatin, respectively. In this study, the dosage of each drug was adjusted by the respective urologist based on the patient’s age, PS, renal function, and other factors. As a result, the RDI varied for each drug.
Table 3 lists the adverse events encountered during ddMVAC chemotherapy. This study reported no treatment-related deaths, with no cases of patients who were unable to undergo definitive radical surgery as planned due to adverse events. Grade 3 or 4 hematologic toxicity occurred in 15 (35%) patients. Among them, the most common toxicity was anemia (14%), and 4 patients (9%) received blood transfusions. Grade 4 neutropenia occurred in 4 (9%) patients; among them, 3 (7%) developed FN. Grade 4 and 3 thrombocytopenia occurred in 3 (7%) and 2 (5%) patients, respectively. One patient received a platelet transfusion. Grade ≥3 hyponatremia, hypokalemia, and hyperkalemia occurred in 3 (7%), 5 (12%), and 1 (2%) patients, respectively. Regarding non-hematologic toxicity, grade 3 appetite loss was observed in 2 (5%) patients. All patients received conservative treatment.
Treatment-related toxicity
Adverse event, n (%) . | Grade 1 . | Grade 2 . | Grade 3 . | Grade 4 . |
---|---|---|---|---|
Anemia | 13 (30.2) | 17 (39.5) | 5 (11.6) | 1 (2.3) |
Leukopenia | 0 (0) | 1 (2.3) | 3 (7.0) | 4 (9.3) |
Neutropenia | 1 (2.3) | 0 (0) | 0 (0) | 4 (9.3) |
Febrile neutropenia | 0 (0) | 0 (0) | 3 (7.0) | 0 (0) |
Thrombocytopenia | 22 (51.2) | 5 (11.6) | 3 (7.0) | 2 (4.7) |
Creatinine increased | 19 (44.2) | 4 (9.3) | 0 (0) | 0 (0) |
AST increased | 13 (30.2) | 0 (0) | 0 (0) | 0 (0) |
ALT increased | 11 (25.6) | 0 (0) | 0 (0) | 0 (0) |
Hyponatremia | 27 (62.8) | 5 (11.6) | 3 (7.0) | 0 (0) |
Hypokalemia | 15 (34.9) | 0 (0) | 4 (9.3) | 1 (2.3) |
Hyperkalemia | 9 (20.9) | 1 (2.3) | 1 (2.3) | 0 (0) |
Hypocalcemia | 5 (11.6) | 0 (0) | 0 (0) | 0 (0) |
Nausea/vomiting | 8 (18.6) | 6 (14.0) | 0 (0) | 0 (0) |
Appetite loss | 13 (30.2) | 5 (11.6) | 2 (4.7) | 0 (0) |
Adverse event, n (%) . | Grade 1 . | Grade 2 . | Grade 3 . | Grade 4 . |
---|---|---|---|---|
Anemia | 13 (30.2) | 17 (39.5) | 5 (11.6) | 1 (2.3) |
Leukopenia | 0 (0) | 1 (2.3) | 3 (7.0) | 4 (9.3) |
Neutropenia | 1 (2.3) | 0 (0) | 0 (0) | 4 (9.3) |
Febrile neutropenia | 0 (0) | 0 (0) | 3 (7.0) | 0 (0) |
Thrombocytopenia | 22 (51.2) | 5 (11.6) | 3 (7.0) | 2 (4.7) |
Creatinine increased | 19 (44.2) | 4 (9.3) | 0 (0) | 0 (0) |
AST increased | 13 (30.2) | 0 (0) | 0 (0) | 0 (0) |
ALT increased | 11 (25.6) | 0 (0) | 0 (0) | 0 (0) |
Hyponatremia | 27 (62.8) | 5 (11.6) | 3 (7.0) | 0 (0) |
Hypokalemia | 15 (34.9) | 0 (0) | 4 (9.3) | 1 (2.3) |
Hyperkalemia | 9 (20.9) | 1 (2.3) | 1 (2.3) | 0 (0) |
Hypocalcemia | 5 (11.6) | 0 (0) | 0 (0) | 0 (0) |
Nausea/vomiting | 8 (18.6) | 6 (14.0) | 0 (0) | 0 (0) |
Appetite loss | 13 (30.2) | 5 (11.6) | 2 (4.7) | 0 (0) |
Table 4 shows the clinical response rates of all patients who received ddMVAC chemotherapy and each group. Complete response (CR) and partial response (PR) were observed in 7 (16%) and 26 (60%) patients, respectively, yielding an objective response rate of 76%. Table 5 lists pathological response rates of patients who underwent radical surgery after NAC. Pathologic complete response (pCR; ypT0pN0) was observed in 3 (16.7%) patients, and downstaging occurred in 13 (72.2%) patients. Among 25 patients who received ddMVAC as first-line therapy, 11 (44%) and 5 (20%) received avelumab as maintenance therapy and pembrolizumab as second-line therapy, respectively. The median follow-up was 15.6 months. The median PFS and OS of first-line treatment with ddMVAC were 18.6 months and not reached, respectively. The 1-year and 2-year OS were 81.3% and 71.1%, respectively (Fig. 1). Conversely, among 18 patients who underwent radical surgery after NAC with ddMVAC, 4 (22%) experienced recurrence.
Clinical response rates of all patients receiving ddMVAC therapy and for each group
Response . | All patients (%) . | First-line (%) . | NAC (%) . |
---|---|---|---|
Complete response (CR) | 7 (16) | 5 (20) | 2 (11) |
Partial response (PR) | 26 (60) | 13 (52) | 13 (72) |
Stable disease (SD) | 5 (12) | 3 (12) | 2 (11) |
Progressive disease (PD) | 5 (12) | 4 (16) | 1 (6) |
Objective response rate (CR+PR) | 33 (76) | 18 (72) | 15 (83) |
Response . | All patients (%) . | First-line (%) . | NAC (%) . |
---|---|---|---|
Complete response (CR) | 7 (16) | 5 (20) | 2 (11) |
Partial response (PR) | 26 (60) | 13 (52) | 13 (72) |
Stable disease (SD) | 5 (12) | 3 (12) | 2 (11) |
Progressive disease (PD) | 5 (12) | 4 (16) | 1 (6) |
Objective response rate (CR+PR) | 33 (76) | 18 (72) | 15 (83) |
ddMVAC, dose-dense methotrexate, vinblastine, doxorubicin, and cisplatin; NAC, neoadjuvant chemotherapy.
Pathological response rates of patients undergoing radical surgery after NAC
Response . | Patients, n . | (%) . |
---|---|---|
ypT0 N0 | 3 | 16.7 |
ypTis, Ta, or T1 and ypN0 | 7 | 38.9 |
≥ypT2 and ypN0 | 5 | 27.7 |
ypN+ | 3 | 16.7 |
Down stage | 13 | 72.2 |
Response . | Patients, n . | (%) . |
---|---|---|
ypT0 N0 | 3 | 16.7 |
ypTis, Ta, or T1 and ypN0 | 7 | 38.9 |
≥ypT2 and ypN0 | 5 | 27.7 |
ypN+ | 3 | 16.7 |
Down stage | 13 | 72.2 |
NAC, neoadjuvant chemotherapy.
Kaplan-Meier curves for PFS (a) and OS (b) in patients treated with dose-dense methotrexate, vinblastine, doxorubicin, and cisplatin therapy as first-line chemotherapy.
Kaplan-Meier curves for PFS (a) and OS (b) in patients treated with dose-dense methotrexate, vinblastine, doxorubicin, and cisplatin therapy as first-line chemotherapy.
Discussion
Recently, the ddMVAC regimen has been administered not only as first-line chemotherapy for metastatic UC but also as NAC and adjuvant therapy [3, 5, 6, 14, 15, 19]. The use of ddMVAC in NAC has been increasing domestically since the publication of the VESPER Trial results [6]. However, reports of ddMVAC using pegfilgrastim are limited [14, 15], with no studies conducted on ddMVAC using the 3.6 mg of pegfilgrastim formulation.
Sternberg et al. [3] conducted a randomized controlled trial comparing ddMVAC therapy using 7 consecutive days of G-CSF as first-line chemotherapy with classic MVAC for advanced UC [5]. The incidence of grade ≥3 hematologic toxicity in the ddMVAC arm, such as leukopenia, thrombocytopenia, and FN, was 20%, 22%, and 10%, respectively. Moreover, the toxic death rate was 3%. VESPER Trial compared ddMVAC therapy using the same G-CSF regimen with gemcitabine and cisplatin therapy as perioperative chemotherapy for patients with non-metastatic muscle-invasive bladder cancer [6]. Of them, 88% were NAC cases. The incidence of grade ≥3 anemia, neutropenia, thrombocytopenia, and FN in the ddMVAC arm was 22%, 39%, 20%, and 6.5%, respectively. Chemotherapy-related deaths occurred in 3 (1.2%) patients. One phase II study and one retrospective study revealed the outcomes of ddMVAC using the 6 mg pegfilgrastim formulation as NAC [14, 20]. They revealed the incidence of grade ≥3 anemia, neutropenia, thrombocytopenia, and FN of 2.5%–4.0%, 0%–4.0%, 0%–2.5%, and 4.0%–7.6%, respectively. No treatment-related deaths were reported.
No studies have compared the safety of different G-CSF preparations used with ddMVAC. Patient backgrounds differ and various biases occur, but ddMVAC using pegfilgrastim may be associated with a lower incidence of grade ≥3 hematologic toxicity compared to ddMVAC using G-CSF for 7 consecutive days. A meta-analysis comparing “once per cycle” pegfilgrastim with “once daily” filgrastim for other cancer types revealed a significantly lower incidence of FN following primary prophylaxis with pegfilgrastim than with filgrastim [21]. The present study revealed the incidence of grade ≥3 hematologic toxicity, such as anemia, neutropenia, thrombocytopenia, and FN of 13.9%, 9.3%, 11.7%, and 7.0%, respectively, which may be lower than those reported above for ddMVAC using G-CSF for 7 consecutive days. Pegfilgrastim of 6 mg may have less hematologic toxicity than 3.6 mg, but only the 3.6 mg dose is available in Japan.
We then consider the secondary endpoints of ORR, pathological response, PFS, and OS. The clinical outcomes of first-line treatment with the original ddMVAC were an ORR of 72% (CR: 25% and PR: 48%), and the 2-year PFS and OS rates were 24.7% and 35.3%, respectively [3, 5]. The present study revealed that the ORR was 72% (CR: 20% and PR: 52%), and the 2-year PFS and OS were 38% and 71%, respectively, for the first-line treatment group. Research on NAC using the original ddMVAC regimen or ddMVAC with pegfilgrastim has demonstrated that the pCR (ypT0pN0) rate ranges from 26% to 42%, and the ypT1 rate or less ranges from 49% to 63% [6, 14, 15]. The pCR and ≤ypT1 rates were 17% and 56% in our study, respectively. Variations in G-CSF formulations exhibited no significant effect concerning secondary endpoints, such as ORR, pathological response, PFS, and OS, and our results were similar to previous reports.
Our study has several limitations. This was a retrospective analysis of medical records, which may be subjected to various selection biases and potentially less accurate than prospective studies. Next, the small number of patients and the short follow-up period are notable limitations. However, in terms of safety, which is our primary endpoint, we were able to assess 131 cycles of ddMVAC chemotherapy. Each cycle required a 1-week hospitalization, enabling detailed confirmation of hematologic toxicity at the start, on days 3 and 6, and of non-hematologic toxicity, which is noteworthy. Conversely, PFS and OS, which are our secondary endpoints, warrant a longer follow-up. Additionally, this study administered pegfilgrastim (3.6 mg), which is approved in Japan, making it difficult to draw direct comparisons with international studies that use pegfilgrastim (6 mg). Finally, the EV-302 trial reported last year demonstrated that the combination therapy of enfortumab vedotin and pembrolizumab significantly improved OS compared to platinum-based chemotherapy [22]. In the NCCN guidelines, the combination therapy is recommended as a preferred regimen for advanced or metastatic UC. It was approved in Japan in September 2024, and in the future, ddMVAC therapy may no longer be the standard first-line regimen for advanced or metastatic UC. However, the combination therapy of enfortumab vedotin and pembrolizumab is not indicated for NAC.
Conclusion
This study indicated that ddMVAC with pegfilgrastim (3.6 mg) lessened patient burden, causing fewer grade ≥3 adverse events, and maintained similar efficacy when compared to the original ddMVAC regimen that used G-CSF for 7 consecutive days. In the future, we will investigate a greater number of cases and evaluate the safety and efficacy of long-term follow-up.
Acknowledgments
The authors would like to thank all the participants who contributed to this study.
Statement of Ethics
This study was conducted in accordance with the Declaration of Helsinki and its amendments and with the approval of the Ethics Committee of Kitasato University School of Medicine and Hospital (Approval No. B22-013). Due to the retrospective design of the study, the Ethics Committee waived the requirement for written informed consent. The patients had the option of opting out of the study.
Conflict of Interest Statement
The authors have no conflicts of interest to declare.
Funding Sources
There are no funding sources to declare.
Author Contributions
Takahiro Harano and Masaomi Ikeda designed the study and wrote the manuscript. Shuhei Hirano, Soichiro Shimura, Masayoshi Toyoda, Satoshi Okuda, Dai Koguchi, Hideyasu Tsumura, and Daisuke Ishii contributed to the patient collection and data acquisition. Masaomi Ikeda and Kazumasa Matsumoto performed statistical analysis and interpreted the data. All authors read and approved the final manuscript.
Data Availability Statement
The datasets used and/or analyzed during the current study are not publicly available due to their containing information that could compromise the privacy of research participants, but are available from the corresponding author on reasonable request.