Demographics, stage distribution, and relative roles of surgery and radiotherapy on survival of persons with primary prostate sarcomas

Adult Prostate Sarcoma: Demographics, Treatment Patterns, and Survival

BACKGROUND

This study aimed to examine clinicopathologic characteristics, treatment patterns, and survival rates in a contemporary population-based cohort of adult prostate sarcoma patients.

METHODS

In the Surveillance, Epidemiology, and End Results database (2004-2020), adult patients with prostate sarcoma were identified. Descriptive statistics, Kaplan-Meier analyses, smoothed cumulative incidence plots, and Cox regression models were used.

RESULTS

Of 125 patients, 45 (36%) harbored leiomyosarcoma, 17 (14%) had rhabdomyosarcoma, 15 (12%) had stromal sarcoma, 17 (14%) had sarcoma not otherwise specified (NOS), and 31 (25%) had other sarcoma subtypes. Metastatic stage was most common in the rhabdomyosarcoma patients (44%) and least common in the leiomyosarcoma (21%) and stromal sarcoma (20%) patients. Most of the rhabdomyosarcoma patients received the combination of systemic and radiation therapy with (24%) or without radical surgery (35%), whereas most of the leiomyosarcoma and stromal sarcoma patients underwent radical surgery with (22 and 13%) or without (22 and 47%) radiation. In the overall population, the median overall survival was 27 months. The 5-years overall versus cancer-specific versus other-cause mortality rates were respectively 71 versus 58 versus 13%. In the multivariable Cox regression models, the highest overall mortality was exhibited by the patients with metastatic disease (hazard ratio [HR] 2.87; 95% confidence interval [CI] 1.55-5.31; p < 0.001) or unknown disease stage (HR 2.94; 95% CI 2.20-7.21; p = 0.019). Conversely, of all the histologic subtypes, only stromal sarcoma distinguished itself by lower overall mortality (HR 0.41; 95% CI 0.18-0.96; p = 0.039).

CONCLUSIONS

Four major histologic subtypes were identified. Among most adult sarcoma patients, treatment patterns vary according to histology, from multimodal therapy to radical prostatectomy alone. These treatment differences reflect equally important heterogeneity in survival patterns.

Comparison of Outcomes and Toxicity Between Extreme and Moderate Radiation Therapy Hypofractionation in Localized Prostate Cancer: A Propensity Score Analysis

PURPOSE

To compare clinical outcomes and toxicities of 2 radiation therapy (RT) schemes for localized prostate cancer (PCa): extreme hypofractionation (EH; fractions of 6.5-7 Gy to a total dose of 32.5-35 Gy) and the moderate hypofractionation (MH; 26 fractions of 2.7 Gy to a total dose of 70.2 Gy). A propensity score method was used to compare the EH-RT and MH-RT groups.

METHODS AND MATERIALS

Our analysis included a total of 421 patients divided in 2 groups: 227 treated with MH-RT and 194 treated with EH-RT (43 and 30 months median follow-up, respectively). Propensity matching created comparable cohorts. Statistical evaluations were performed on the whole cohort, stratifying the analyses by risk strata factors identified with the propensity scores, and on a subgroup of patients matched by propensity score. Multivariate proportional hazard Cox models were used to compare the 2 groups, mainly for gastrointestinal and genitourinary toxicity and secondarily for clinical progression-free survival, biochemical progression-free survival, and overall survival.

RESULTS

Considering the whole population, acute genitourinary and gastrointestinal greater than grade 1 was significantly more frequent in the whole MH-RT group (P < .001 and P < .002, respectively). A borderline significantly greater late genitourinary was confirmed with the multivariate analysis (P = .07). Concerning tumor outcome, no statistically significant differences were observed. After propensity score matching, 226 patients were included in the analysis. The 2 obtained propensity score matched groups did not differ for any of the clinical and pathologic variables considered for the analysis, resulting in well-balanced cohorts. The results obtained on the whole population were confirmed in the matched groups.

CONCLUSIONS

EH-RT yields a decreased risk of acute or late toxicities compared with MH-RT, and oncologic outcomes were comparable. Our data indicate that EH-RT might be considered as a treatment modality of choice for select patients with PCa.

Epidemiology, Incidence, and Survival of Rhabdomyosarcoma Subtypes: SEER and ICES Database Analysis

Rhabdomyosarcoma is the most common soft-tissue sarcoma in children and adolescents and accounts for 3% of all pediatric tumors. Subtypes include alveolar, spindle cell, embryonal, mixed-type, pleomorphic, and rhabdomyosarcoma with ganglionic differentiation. The National Cancer Institute's Surveillance, Epidemiology, and End Results (SEER) database was queried for patients diagnosed with any type of rhabdomyosarcoma between 1973 and 2014. Patient demographics, tumor characteristics, and incidence were studied with χ² analysis. Survival was modeled with Kaplan-Meier survival curves and Cox proportional hazards models were used to assess the effect of age and gender on survival. Pleomorphic subtype had higher grade and larger sized tumors compared to other subtypes (p < 0.05). Pleomorphic and alveolar rhabdomyosarcoma had the worst overall survival with a 26.6% and 28.9% 5-year survival, respectively. Embryonal rhabdomyosarcoma had the highest 5-year survival rate (73.9%). Tumor size was negatively correlated with survival months, indicating patients with larger tumors had shorter survival times (p < 0.05). Presence of higher-grade tumors and metastatic disease at presentation were negatively correlated with survival months (p < 0.05). No significant differences in the survival were found between gender or race between all of the subtypes (p > 0.05). This study highlights key differences in the demographic and survival rates of the different types of rhabdomyosarcoma that can be used for more tailored patient counseling. We also demonstrate that large, population-level databases provide sufficient data that can be used in the analysis of rare tumors. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 37:2226-2230, 2019.

Demographics, stage distribution, and relative roles of surgery and radiotherapy on survival of persons with primary prostate sarcomas

Background

Primary prostate sarcomas (PPS) are rare. Outcomes for this cancer have not been well characterized.

Materials and Methods

Subjects with a PPS diagnosed between 1973 and 2014 were identified in the SEER database. Subjects were stratified by disease stage and types of therapies received. Disease‐specific survival (DSS) and Overall survival (OS) was estimated by Kaplan‐Meier analysis and cohorts were compared with a univariate and multivariable Cox regression.

Results

The incidence of PPS among all prostate cancer diagnoses was 0.02%. Subjects younger than age 26 years at diagnosis represented 29% of cases, and 32% of primary prostate sarcomas were rhabdomyosarcoma histology.

Rhabdomyosarcoma Histologies

The median age at diagnosis was 9 years. Between age 0‐25 years rhabdomyosarcoma accounted for 96.4% of primary prostate sarcoma diagnoses, after age 25 rhabdomyosarcoma represented 15% of new diagnoses. The 10‐year DSS and OS for rhabdomyosarcoma was 47% and 44%.

Non‐Rhabdomyosarcoma Histologies

The median age at diagnosis was 71 years. The most common diagnoses were leiomyosarcoma (33%) and carcinosarcoma (28%). Localized, regional, or distant disease occurred in 40%, 34%, and 26% of cases. The 10‐year DSS and OS were 26% and 14%. In locally advanced cases, RT added to surgery trended toward improved DSS (P = 0.10).

Conclusions

Disease‐specific survival and OS for non‐rhabdomyosarcoma histologies appear inferior to those of rhabdomyosarcoma. The addition of RT to surgical resection may improve DSS in locally advanced non‐rhabdomyosarcoma. This is the largest report of the incidence, stage distribution, and survival for this extremely rare urologic malignancy providing valuable prognostic information.