Abstract
Background/Aim: The effect of multidisciplinary therapy conducted at the sarcoma center of our hospital was examined to determine whether therapy undertaken here improved the prognosis of patients with soft-tissue sarcoma. Patients and Methods: The clinical findings and prognoses of patients treated before the establishment of the sarcoma center (72 patients from April 2016 to March 2018) and those treated after (155 patients from April 2018 to March 2021) were compared. Results: The mean number of patients increased from 36.0 to 51.7 per year after the establishment of the sarcoma center. The proportion of patients with stage IV disease also increased from 8.3% to 12.9% after establishment of the sarcoma center. The 3-year survival rate of patients, considering all stages, decreased from 80.0% to 78.3% after establishment of the sarcoma center rather than showing an increase. The 3-year survival rate of patients with stage II and III disease increased from 78.6% to 84.7%, and that of stage III patients with retroperitoneal sarcoma increased from 70.0% to 86.7% after establishment of the sarcoma center. However, no statistically significant difference was observed in the survival curves. Conclusion: The establishment of a sarcoma center has contributed to centralizing treatment for soft-tissue sarcoma. Multidisciplinary therapy at sarcoma centers may improve the prognosis of patients with soft-tissue sarcomas.
Soft-tissue sarcoma is characterized by its rarity and diversity (1, 2). Therefore, centralizing patients is essential for treatment. It is also important to treat patients with soft-tissue sarcoma using a specific and multidisciplinary approach based on the clinical practice guidelines (3-6). Surgical treatments conducted at centers specialized in soft-tissue sarcoma have been reported to be effective in reducing the recurrence of and fatality risk associated with the disease (7). A sarcoma center was established in our hospital in 2018. Here, patients with soft-tissue sarcomas are treated cross-departmentally and following a multidisciplinary approach according to diverse practice guidelines (3-5, 8). In this study, multidisciplinary treatment conducted at the sarcoma center of our hospital was examined to determine whether it improved the prognosis of patients with soft-tissue sarcoma.
Patients and Methods
The participants were patients with soft-tissue sarcoma who visited our hospital for the first time and received treatment for 5 years from April 2016 to March 2021. Patients seen only for palliative treatment or for a second opinion were excluded. Patients were divided into two groups: Those who received treatment from April 2016 to March 2018, before the establishment of the sarcoma center (group A) and those treated later, from April 2018 to March 2021 (group B).
The clinical data and prognosis of the patients in each group were collected from medical charts for comparative investigation. The endpoint was set as overall survival. Survival time was defined as the period from the first visit to the last follow-up. The TNM classification of the American Joint Committee on Cancer (ver. 8) was used for stage classification (9).
Description of the sarcoma center. A sarcoma center specializing in treating patients with soft-tissue sarcoma was established in April 2018 at the Chiba Cancer Center. Medical staff members from all clinical and core departments (including research centers) relevant to soft-tissue sarcoma treatment are a part of the sarcoma center. ‘Regular’ conferences are held four times per year to discuss soft-tissue sarcoma cases with diagnostic and treatment difficulties. Furthermore, ‘special’ conferences are held incidentally, when necessary (approximately 20 times per year), to discuss treatment plans for patients with soft-tissue sarcoma.
Thus, a treatment system capable of providing patients with soft-tissue sarcoma with specialized and multidisciplinary medical treatment following clinical practice guidelines for soft-tissue sarcoma (3, 5, 6, 8) through cross-clinical departmental conferences was established.
Statistical analysis. EZR (10) was used to compute overall survival rates, plot Kaplan–Meier survival curves, and estimate the significance of the survival curve (log-rank test). Statistical significance was set at a p-value of 0.05.
Ethical consideration. In accordance with Japanese ethical guidelines, written consent is not obtained, instead, an opt-out method was used (11).
Results
There were 72 patients (average 36.0 patients per year) who were treated before the sarcoma center was established. They were aged 29 to 91 years (median age=68 years; mean age=63.3 years). There were 38 men (52.8%) and the duration of the follow-up observation ranged from 2 to 77 months (median=59.0 months; mean duration=50.8 months).
The number of patients treated after the establishment of the sarcoma center was 155 (an average of 51.7 patients per year), 80 of whom were men (51.6%). These patients were aged 15 to 92 years (median=68 years; mean=63.5 years). The duration of the follow-up observation ranged from 2 to 55 months (median=28.0 months; mean=31.0 months).
Table I and Table II depict the clinical characteristics of the patients in each group. There were no significant differences in clinical characteristics other than staging between the two groups.
Clinical characteristics of patients treated before the establishment of the sarcoma center (n=72).
Clinical characteristics of patients treated after the establishment of the sarcoma center (n=155).
The 3-year survival rate of patients considering all stages was 80.0% in the [95% confidence interval (CI)=0.685-0.876] and 78.3% (95% CI=0.702-0.844) in those treated before and after the establishment of the center, respectively (Figure 1). Patients with stage II and III disease had 3-year survival rates of 78.6% (95% CI=64.6-87.5%) and 84.7% (95% CI=75.8-90.5%), respectively (Figure 2). The corresponding rates for patients with stage III retroperitoneal sarcoma were 70.0% (95% CI=32.9-89.2%) and 86.7% (95% CI=56.4-96.5%), respectively (Figure 3).
Survival curve of patients (all stages) treated before (group A) and after (group B) the establishment of the sarcoma center. No significant difference in survival was confirmed between these two groups (p=0.757).
Survival curve of patients with stage II and stage III treated before (group A) and after (group B) the establishment of the sarcoma center. No significant difference in survival was confirmed between these two groups (p=0.544).
Survival curve of patients with stage III retroperitoneal sarcoma treated before (group A) and after (group B) the establishment of the sarcoma center. No significant difference in survival was confirmed between these two groups (p=0.555).
Discussion
The mean number of patients with soft-tissue sarcoma increased from 36.0 to 51.7 per year following the establishment of the sarcoma center, which reflects the centralization of the treatment of this disease. The Orthopedic Surgery Department treated the most patients, followed by Hepatobiliary Pancreatic Surgery, Gynecology, and Urology. The order did not differ before and after the establishment of the sarcoma center. The Department of Orthopedic Surgery has implemented chemotherapy for soft-tissue sarcoma cases since the establishment of the sarcoma center; thus, the patient proportion seen by this department increased from 79.2% to 83.9% (Table I and Table II).
The sites of occurrence were, in order of frequency, soft tissue/extremities, soft tissue/trunk, retroperitoneum, and uterus; the order and frequency did not change after sarcoma center establishment. The histopathological types noted increased from 15 to 22 after the establishment of the sarcoma center; following center establishment, tumors with more diverse histological types were treated. The proportion of patients with stage IV disease increased from 8.3% to 12.9% after sarcoma center establishment (Table I and Table II). An increasing tendency for referral of patients with advanced disease to the center was noted following its establishment.
Blay et al. reported that “relapse-free survival was significantly better in patients presented to a multidisciplinary tumor board…before initiation of treatment” (12). The 3-year survival rate of patients (regardless of stage) declined from 80.0% to 78.3% in our study following the establishment of the sarcoma center (Figure 1). This decline was probably the result of the increase in the proportion of patients with stage IV disease from 8.3% to 12.9% after sarcoma center establishment. The 3-year survival rate of those with stage II and stage III disease increased from 78.6% to 84.7% after sarcoma center establishment. However, no statistically significant difference was observed in these survival curves (Figure 2).
Bonvalot et al. reported that “the prognoses of retroperitoneal sarcoma patients were more significantly superior for patients who underwent surgery within the specialized sarcoma center network than those treated in an out-of-network center” (13). At our sarcoma center, the Department of Hepatobiliary Pancreatic Surgery conducts surgery and the Department of Orthopedic Surgery administers chemotherapy for patients with retroperitoneal sarcoma. The 3-year survival rate of patients with stage III retroperitoneal sarcoma increased from 70.0% to 86.7% after the establishment of the sarcoma center. However, no significant differences were observed in the survival curves (Figure 3).
Research limitations. This study was a single-institute investigation, and the number of cases was relatively small; thus, no statistical significance was confirmed for differences in the survival curves. The duration of follow-up after sarcoma center establishment was also short, and comparison of long-term prognosis was impossible.
Conclusion
The establishment of a sarcoma center contributed to centralizing the treatment of soft-tissue sarcoma cases. After sarcoma center establishment, patients with advanced soft-tissue sarcomas were frequently referred to the center. The 3-year survival rate of patients with stage II and stage III disease was higher after sarcoma center establishment, suggesting that the multidisciplinary therapy provided at the center has improved the prognosis of patients with soft-tissue sarcoma.
- Received February 3, 2023.
- Revision received February 17, 2023.
- Accepted February 23, 2023.
- Copyright © 2023 International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.
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