Complete pathological response to neoadjuvant treatment is associated with better survival outcomes in patients with soft tissue sarcoma: Results of a retrospective multicenter study

The impact of CT-based adipose tissue distribution and sarcopenia on treatment outcomes in patients with high-risk soft tissue sarcoma

BACKGROUND

The prognostic and predictive value of obesity and sarcopenia remains poorly defined in patients with high-risk soft tissue sarcoma (HR-STS). We sought to correlate clinical outcomes with CT-based body composition parameters in patients with HR-STS undergoing a multimodal preoperative therapy. The impact of radiologic and histopathologic response to preoperative treatment was correlated with individual fat and muscle distribution.

METHODS

Patients with locally advanced non-abdominal HR-STS and treatment with preoperative chemotherapy + regional hyperthermia (RHT) +/- radiotherapy (RT) followed by surgery between 2015 and 2022 were retrospectively evaluated. Body composition parameters measured on baseline CT scans were correlated with clinical outcomes including event-free survival (EFS) and overall survival (OS) as well as radiologic and histopathologic treatment response.

RESULTS

A total of 85 patients were included. Body composition parameters showed no significant correlation with radiologic or histopathologic treatment response. High total fat indices such as the total fat index (TFI, HR 3.56, p = 0.005) and high total fat to muscle ratio (FMR, HR 3.22, p = 0.020) were strongly associated with poor OS. Parameters for sarcopenia including skeletal muscle index (SMI) were not significantly linked to survival outcomes.

CONCLUSION

High fat indices and a high FMR are strong predictors of poor OS in patients with HR-STS. Larger studies are warranted to further clarify the prognostic impact of sarcopenia and the predictive value of body composition parameters on preoperative treatment response.

Comparison of Pathologic Tumor Necrosis of Conventional Versus Ultrahypofractionated Preoperative Radiation Therapy in Localized Extremity Soft Tissue Sarcoma and Its Correlation With Clinical Outcomes

PURPOSE

We aimed to determine if ultrahypofractionated radiation therapy (UHYPO-RT) delivering 6 Gy x 5 fractions yields similar tumor necrosis compared with conventional radiation therapy (CONV-RT) with 2 Gy x 25 fractions in soft tissue sarcoma. The clinical significance of tumor necrosis on loco-regional recurrence-free survival (LRFS), distant disease-free survival (DDFS), and overall survival (OS) were assessed.

METHODS AND MATERIALS

Patients with localized soft tissue sarcoma treated with CONV-RT or UHYPO-RT followed by surgery were included. Good response was defined as tumor necrosis ≥90%, and poor response as <90%. The Mann-Whitney U test compared median tumor necrosis. χ2 analysis was used for categorical variables. The Kaplan-Meier function estimated LRFS, DDFS, and OS.

RESULTS

A total of 64 patients received CONV-RT, and 45 received UHYPO-RT. The median tumor size was 7.0 cm, with the lower extremity being the most common site (55%). Myxofibrosarcoma (39%) and undifferentiated pleomorphic sarcoma (16%) were the most frequent histologies. The median time from radiation therapy to surgery was 35 days. There was a significant difference in median tumor necrosis between CONV-RT and UHYPO-RT, with rates of 40% and 60%, respectively (P = .022). Patients receiving UHYPO-RT had a higher percentage of tumor necrosis at the 90% cutoff, achieving 27% compared with 6% for CONV-RT (P = .003). At a median follow-up of 32 months, 12 patients (9%) experienced loco-regional recurrence, 24 patients (19%) faced distant failure, and 19 patients (15%) died of metastatic disease. Patients with <90% necrosis had higher rates of loco-regional (13% vs 0%, P = .207) and distant failure (25% vs 0%, P = .021). Three-year LRFS was 86% for <90% necrosis and 100% for ≥90% necrosis (P = .160). DDFS was 75% for <90% necrosis versus 100% for ≥90% (P = .036). OS rates were 79% and 93%, respectively (P = .290).

CONCLUSIONS

Preoperative RT with UHYPO-RT was associated with a higher rate of tumor necrosis ≥90% than CONV-RT. Our data suggest that more extensive necrosis is associated with better clinical outcomes.

Heterogeneity in response to neoadjuvant radiotherapy between soft tissue sarcoma histotypes: associations between radiology and pathology findings

OBJECTIVE

To investigate imaging biomarkers of tumour response by describing changes in imaging and pathology findings after neoadjuvant radiotherapy (nRT) and exploring their correlations.

MATERIALS AND METHODS

Tumour diameter, volume, and tumour-to-muscle signal intensity (SI) ratio were collected before and after radiotherapy in a cohort of 107 patients with intermediate/high-grade STS and were correlated with post-radiotherapy pathology findings (percentage of necrosis, viable cells, and fibrosis) using Spearman Rank test. Pathological complete response (pCR) was defined as no residual viable cells present, whereas the presence of < 10% viable cells was defined as near-complete pathologic response (near-pCR).

RESULTS

Median amount of necrosis, viable cells, and fibrosis after nRT were 10%, 30%, and 25%, respectively. 7% of patients achieved pCR and 22% near-pCR. No changes in tumour volume were found except for subtypes myxoid liposarcoma (mLPS) -Δ54.47%, undifferentiated pleomorphic sarcoma (UPS) +Δ24.22% and dedifferentiated liposarcoma (dLPS) +Δ35.91%. The median change of tumour-to-muscle SI ratio was -19.7% for the entire population, whereas it was -19.55% and -36.26% for UPS and mLPS, respectively. Correlations (positive and negative) were found between change in volume and the presence of necrosis or fibrosis (rs = 0.44; rs = -0.44), as well as between tumour-to-muscle SI ratio and viable cells (rs = 0.33) or fibrosis (rs = -0.28).

CONCLUSION

STS displays extensive heterogeneity in response patterns after nRT. In some subgroups, particularly UPS and mLPS, tumour size changes or tumour-to-muscle SI ratio are significantly linked with the percentage of viable cells, fibrosis, or necrosis.

KEY POINTS

Question How do primary soft tissue sarcomas (STS) respond to neoadjuvant therapy, and what correlations exist between pathological findings and imaging characteristics in assessing treatment response? Findings mLPS shrank post-nRT; undifferentiated pleomorphic and dLPSs enlarged. Volume increase correlated with higher necrosis and lower fibrosis; tumour-to-muscle intensity ratio correlated with viable cells. Clinical relevance These findings emphasise the extensive heterogeneity in STS response to nRT across different subtypes. Preoperative correlations between tumour volume and SI changes with necrosis, fibrosis, and viable cells can aid in more precise treatment assessment and prognostication.

Paradoxical Response to Neoadjuvant Therapy in Undifferentiated Pleomorphic Sarcoma: Increased Tumor Size on MRI Associated with Favorable Pathology

Background/Objectives: To correlate size changes in undifferentiated pleomorphic sarcoma (UPS) on magnetic resonance imaging (MRI) after neoadjuvant chemoradiation therapy (nCRT) with pathological response, risk of local recurrence, and therapeutic regimens. Methods: This retrospective study analyzed clinical, pathological, and imaging data from 39 biopsy-proven UPS subjects. Four readers measured the tumor dimensions before and after nCRT, including two perpendicular axial diameters and the longest coronal/sagittal diameter. Three cross-sectional areas and bounding volume were also calculated. Responders (pR) were defined as having ≤10% viable cells and non-responders (pNR) as having more. Inter-reader agreement was evaluated using Kendall's concordance coefficient. Changes in tumor size were compared between pR and pNR using one-way ANOVA and Tukey's HSD test for multiple comparisons of means. Results: pR showed a greater increase in size across all measurements compared to pNR. For the longest axial diameter, the mean increase was 30% ± 35% for pR and 14% ± 31% for pNR, with a mean difference (pR-pNR) of 16% (95% CI: 6-27%, p = 0.003). In tumors treated with radiotherapy alone, pR exhibited larger size increases in all dimensions compared to pNR. In contrast, in the chemoradiation group, pR showed a slight increase, while pNR generally shrank, although these differences did not reach statistical significance. Notably, pNR with local recurrence exhibited a reduction in all tumor dimensions compared to pNR without local recurrence. Conclusions: This exploratory study suggests that tumor size changes may predict pathological response and local recurrence after nCRT in UPS; however, the small sample size limits the generalizability of these findings.

Long-term survival of participants in the PASART-1 and PASART-2 trials of neo-adjuvant pazopanib and radiotherapy in soft tissue sarcoma

OBJECTIVE

This study aims to assess the long-term safety and efficacy of adding pazopanib to neo-adjuvant radiotherapy followed by surgery in patients with high-risk non-metastatic soft tissue sarcoma of the trunk and extremities treated in the PASART-1 and PASART-2 trials, as well as to compare the PASART cohorts to a control cohort receiving standard treatment during the same time period from the Netherlands Cancer Registry (IKNL) to investigate if adding pazopanib improves Overall Survival (OS).

METHODS

Updated follow-up data on disease control, survival and long-term toxicities of the PASART-trials were extracted from electronic patient records. The effect of adding pazopanib to neo-adjuvant radiotherapy on OS was investigated by comparing the combined PASART cohorts to the IKNL cohort via direct comparison and exact matching analysis.

RESULTS

PASART-trials included 34 patients, IKNL cohort included 487 patients. After a median follow-up of 75.4 months (range: 30-131 months) the 1-year, 2-year and 5-year OS in the PASART-trials were 97% (95% confidence interval [CI]: 91.5-100), 85.3% (95% CI: 74.2-98.1), 79.3% (95% CI: 66.8-94.2), respectively. Matching resulted in 23 PASART and 89 IKNL patients. Adding pazopanib did not significantly improve OS when compared to standard treatment (IKNL) in a direct comparison (hazard ratio [HR]: 0.58; 95% CI: 0.30-1.13) or matched analysis (HR: 0.70; 95% CI: 0.29-1.73). Long-term toxicities, mainly fibrosis (n = 6) and edema (n = 2), were observed in 11 PASART patients and comparable to historical controls.

INTERPRETATION

The addition of pazopanib had tolerable long-term toxicity but did not improve OS when compared to a control cohort receiving standard treatment.

Hypofractionated Preoperative Radiation Therapy for Soft Tissue Sarcoma: A Systematic Review

PURPOSE

Hypofractionated radiation therapy is being used more frequently for many common cancer sites. Conventionally fractionated radiation therapy treatment regimens have remained the standard of care when radiation therapy is indicated for soft tissue sarcoma (STS). The aim of this study was to systematically review published data on the use of preoperative hypofractionated radiation therapy as part of a curative treatment paradigm in patients with STS. Herein, we summarize current evidence for the use of hypofractionated radiation therapy in the preoperative treatment of STS.

METHODS AND MATERIALS

We conducted a database search for prospectively or retrospectively collected data on patients with a diagnosis of STS treated with hypofractionated radiation therapy. Studies evaluating STS of all histologic subtypes affecting extremities or trunks were included in the search. Articles were screened by 2 independent reviewers for inclusion in this review. Patient, treatment, toxicity, and outcome data were recorded and collated from selected studies.

RESULTS

Twenty-five articles are included in this review. Nine prospective trials have been published since 2020. Dose fractionations range from 25 to 40 Gy in 5 fractions or 28-42.75 Gy in 8-15 fractions. Local control and overall survival outcomes are consistent with historical data for conventionally fractionated radiation therapy. Acute toxicity and wound complication rates are in keeping with acceptable results. Late toxicity data are limited and require longer follow-up. Rates of pathologic complete response are promising across all studies.

CONCLUSIONS

There is a growing body of evidence supporting hypofractionation as safe and effective in the preoperative treatment of STS. This review highlights potential areas that could be further investigated to optimize preoperative treatment for STS.

What Is the Prognostic Value of the Pathologic Response after Neoadjuvant Radiotherapy in Soft Tissue Sarcoma? An Institutional Study Using the EORTC-STBSG Response Score

Background/Objectives: The relationship between pathologic findings in soft tissue sarcoma (STS) after neoadjuvant treatment and oncological outcomes remains uncertain due to varying evaluation methods and cut-off values. This study aims to assess pathologic findings after neoadjuvant radiotherapy in STS using the EORTC-STBSG response score and evaluate its prognostic value. Methods: Clinical and outcome data from 44 patients were reviewed. Resected specimens were re-evaluated to measure viable cells, necrosis, fibrosis, and hyalinization. Local recurrence-free survival (LRFS), distant metastasis-free survival (DMFS), and overall survival (OS) were analyzed using Kaplan-Meier survival analysis. Cox proportional hazards regression was used for univariate and multivariate analyses to correlate outcomes with pathologic response. Results: The median percentages of viable cells, necrosis, and fibrosis/hyalinization were 20%, 11%, and 40%, respectively. A pathologic complete response (pCR), defined as ≤5% viable cells, was achieved in 25% of cases. Local recurrence occurred in 33% of cases, with a significantly higher rate of 64% after R1 resection compared to 22% after R0 resection. Distant metastases were observed in 42% of patients, primarily in the lungs. The 3-year rates for LRFS, DMFS, and OS were 65%, 54%, and 67%, respectively. A correlation between outcomes and tumor size, grade and histological subtype was observed. Classifying pathologic response by the EORTC-STBSG score failed to show an association with outcomes. Patients achieving pCR showed lower risk of LR and improved OS. Conclusions: While the EORTC-STBSG score did not show a prognostic value, resection specimens with ≤5% viable cells were linked to improved LRFS and OS.

Local relapse patterns after preoperative radiotherapy of limb and trunk wall soft tissue sarcomas: Prognostic role of imaging and pathologic response factors

Purpose

To retrospectively identify clinical, pathologic, or imaging factors predictive of local relapse (LR) after preoperative radiotherapy (RT) for soft tissue sarcomas (STS).

Methods and Materials

This is a retrospective multicenter study of patients who underwent preoperative RT and surgery for limb or trunk wall STS between 2007 and 2018 in French Sarcoma Group centers and were enrolled in the "Conticabase". Patterns of LR were investigated taking into account the multimodal response after preoperative RT. Diagnostic and surgical samples were compared after systematic review by expert pathologists and patients were stratified by tumor grade. Log-rank tests and Cox models were used to identify prognostic factors for radiation response and LR.

Results

257 patients were included; 17 % had low-grade (LG), 72.5 % had high-grade (HG) sarcomas. In HG group, tumors were larger, mostly undifferentiated, and displayed more necrosis and perilesional edema after RT. Median follow-up was 32 months. Five-year cumulative incidence of LR was 20.3 % in the HG group versus 9.7 % in the LG group (p = 0.026). In multivariate analysis, trunk wall location (HR 6.79, p = 0.012) and proportion of viable tumor cellularity ≥ 20 % (HR 3.15, p = 0.018) were associated with LR. After adjusting for tumor location, combination of histotype and cellularity rate significantly correlated with LR. We described three prognostic subgroups for HG sarcomas, listed from the highest to lowest risk: undifferentiated sarcoma (US) with cellularity rates ≥ 20 %; non-US (NUS) with cellularity rates ≥ 20 % or US with cellularity rates < 20 %; and NUS with cellularity rates < 20 %, which shared similar prognostic risks with LG sarcomas.

Conclusions

HG and LG tumors have different morphological and biological behaviors in response to RT. Combination of cellularity rate with histotype could be a major prognostic for LR. Patients with undifferentiated HG sarcomas with cellularity rates ≥ 20 % after preoperative RT had the highest risk of LR and disease-specific death.

Spatial distribution of tumour immune infiltrate predicts outcomes of patients with high-risk soft tissue sarcomas after neoadjuvant chemotherapy

BACKGROUND

Anthracycline-based neoadjuvant chemotherapy (NAC) may modify tumour immune infiltrate. This study characterized immune infiltrate spatial distribution after NAC in primary high-risk soft tissue sarcomas (STS) and investigate association with prognosis.

METHODS

The ISG-STS 1001 trial randomized STS patients to anthracycline plus ifosfamide (AI) or a histology-tailored (HT) NAC. Four areas of tumour specimens were sampled: the area showing the highest lymphocyte infiltrate (HI) at H&E; the area with lack of post-treatment changes (highest grade, HG); the area with post-treatment changes (lowest grade, LG); and the tumour edge (TE). CD3, CD8, PD-1, CD20, FOXP3, and CD163 were analyzed at immunohistochemistry and digital pathology. A machine learning method was used to generate sarcoma immune index scores (SIS) that predict patient disease-free and overall survival (DFS and OS).

FINDINGS

Tumour infiltrating lymphocytes and PD-1+ cells together with CD163+ cells were more represented in STS histologies with complex compared to simple karyotype, while CD20+ B-cells were detected in both these histology groups. PD-1+ cells exerted a negative prognostic value irrespectively of their spatial distribution. Enrichment in CD20+ B-cells at HI and TE areas was associated with better patient outcomes. We generated a prognostic SIS for each tumour area, having the HI-SIS the best performance. Such prognostic value was driven by treatment with AI.

INTERPRETATION

The different spatial distribution of immune populations and their different association with prognosis support NAC as a modifier of tumour immune infiltrate in STS.

FUNDING

Pharmamar; Italian Ministry of Health [RF-2019-12370923; GR-2016-02362609]; 5 × 1000 Funds-2016, Italian Ministry of Health; AIRC Grant [ID#28546].

Evaluation of the Prognostic Value of Pretherapeutic Magnetic Resonance Imaging in Predicting Soft Tissue Sarcoma Radiation Response: A Retrospective Study from a Large Institutional Sarcoma Imaging Database

Background: RT-induced hyalinization/fibrosis was recently evidenced as a significant independent predictor for complete response to neoadjuvant radiotherapy (RT) and survival in patients with soft tissue sarcoma (STS). Purpose: Non-invasive predictive markers of histologic response after neoadjuvant RT of STS are expected. Materials and Methods: From May 2010 to April 2017, patients with a diagnosis of STS who underwent neoadjuvant RT for limb STS were retrieved from a single center prospective clinical imaging database. Tumor Apparent Diffusion Coefficients (ADC) and areas under the time-intensity perfusion curve (AUC) were compared with the histologic necrosis ratio, fibrosis, and cellularity in post-surgical specimens. Results: We retrieved 29 patients. The median ADC value was 134.3 × 10-3 mm2/s. ADC values positively correlated with the post-treatment tumor necrosis ratio (p = 0.013). Median ADC values were lower in patients with less than 50% necrosis and higher in those with more than 50% (120.3 × 10-3 mm2/s and 202.0 × 10-3 mm2/s, respectively (p = 0.020). ADC values higher than 161 × 10-3 mm2/s presented a 95% sensitivity and a 55% specificity for the identification of tumors with more than 50% tumor necrosis ratio. Tumor-to-muscle AUC ratios were associated with histologic fibrosis (p = 0.036). Conclusions: ADC and perfusion AUC correlated, respectively, with radiation-induced tumor necrosis and fibrosis.

Moderate hypofractionated radiation therapy and pathologic response for soft tissue sarcomas (STS) of limbs and trunk: experience from a tertiary cancer center

BACKGROUND

Preoperative radiation therapy following by limb-sparing or conservative surgery is a standard approach for limb and trunk STS. Data supporting hypofractionated radiotherapy schedules are scarce albeit biological sensitivity of STS to radiation would justify it. We sought to evaluate the impact of moderate hypofractionation on pathologic response and its influence on oncologic outcomes.

MATERIAL AND METHODS

From October 2018 to January 2023, 18 patients with limb or trunk STS underwent preoperative radiotherapy at a median dose of 52.5 Gy (range 49.5-60 Gy) in 15 fractions of 3.5 Gy (3.3-4 Gy) with or without neoadjuvant chemotherapy. A favorable pathologic response (fPR) was considered as ≥ 90% tumor necrosis on specimen examination.

RESULTS

All patients completed planned preoperative radiotherapy. Eleven patients (61.1%) achieved a fPR, and 7 patients (36.8%) a complete pathologic response with total disappearance of tumor cells. Nine patients (47%) developed grade 1-2 acute skin toxicity, and 7 patients (38.8%) had wound complications on follow-up. With a median follow-up of 14 months (range 1-40), no cases of local relapse were observed, and actuarial 3-year overall survival (OS) and distant metastases-free survival (DMFS) are 87% and 76.4%, respectively. In the univariate analysis, the presence of a favorable pathologic response (fPR) was associated with improved 3-year OS (100% vs. 56.03%, p = 0.058) and 3-year DMFS (86.91% vs. 31.46%, p = 0.002). Moreover, both complete or partial RECIST response and radiological stabilization of the tumor lesion showed a significant association with higher rates of 3-year distant metastasis-free survival (DMFS) (83% vs. 83% vs. 56%, p < 0.001) and 3-year overall survival (OS) (100% vs. 80% vs. 0, p = 0.002).

CONCLUSIONS

Preoperative moderate hypofractionated radiation treatment for STS is feasible and well tolerated and associates encouraging rates of pathologic response that could have a favorable impact on final outcomes.

[Predictive factors assessment of pathological response to neoadjuvant radiotherapy of soft tissue sarcomas]

PURPOSE

Conserving surgery combined with radiotherapy in presence of local recurrence risk factors is standard treatment of soft tissue sarcomas, a group of rare and heterogeneous tumours. Radiotherapy is performed before or after surgery. In neoadjuvant setting, late radiation-induced toxicity is reduced and pathological response to radiotherapy could be achieved. A complete pathological response to radiotherapy has recently been shown to predict better survival. Our study aims at identifying predictive factors of pathological response to neoadjuvant radiotherapy (clinical, radiological or histological) of soft tissue sarcomas.

PATIENTS AND METHODS

Clinical, imaging (MRI: perilesional oedema, necrosis, tumour heterogeneity, vasculonervous relationships) and pathological (pathological subtype, tumour grade, anticipated/obtained resection quality) data were retrospectively collected. Tumour response (imaging and pathological), patient outcome, acute and late radiation-induced toxicity, predictive factors of pathological response to neoadjuvant radiotherapy were studied. The 2-test or exact-Fisher test (qualitative variables) and by Student's t-test or Kruskal-Wallis test (quantitative variables) were used for statistical analysis.

RESULTS

From April 2017 to April 2021, neoadjuvant radiotherapy (50Gy in 25 fractions) followed by surgical excision was performed to 36 consecutive patients with liposarcomas (n=17/36), or undifferentiated sarcomas (n=8/36). MRI response was complete in 1 patient, partial in 9 patients (n=9/36, 25%), stable in 21 patients (n=21/36, 58%) or in progression in 5 patients (n=5/36, 14%). Pathological response was observed in 22 patients (61%). No grade 3-4 acute radiation-induced toxicity was observed. Regarding late toxicity, 28% of patients had grade 1-2 oedema (n=10/36), 39% had a grade 1 fibrosis (n=14/36), and 30% grade 1 pain (n=11/36). No predictive factors of response to radiotherapy was statistically significant.

CONCLUSIONS

Neoadjuvant radiotherapy is well-tolerated. No clinical, radiological or pathological predictive factors was identified for radiotherapy tumour response.

Pathological and radiological response following neoadjuvant treatments in primary localized resectable myxofibrosarcoma and undifferentiated pleomorphic sarcoma of the extremities and trunk wall

BACKGROUND

To explore the correlation between pathological and radiological response to preoperative treatments and outcome in surgically treated patients with myxofibrosarcoma (MFS) and undifferentiated pleomorphic sarcoma (UPS).

METHODS

All consecutive patients with primary localized MFS and UPS of the extremities and trunk wall surgically treated with curative intent at our center (2005-2021) were included. Clinical data including residual visible tumor (VT%) on surgical specimen and Response Evaluation Criteria in Solid Tumor (RECIST) were retrieved. Kaplan-Meier curves for overall survival and disease-free survival, and cumulative incidence of local relapse and distant metastasis were estimated in a competing risk framework according to RECIST and VT%, overall and by treatment group. Cox and Fine and Gray multivariable models were performed.

RESULTS

Of 693 patients affected by primary MFS and UPS, 233 (66 MFS and 167 UPS) were treated by neoadjuvant chemotherapy (naChT), radiotherapy (naRT), or both (naChT-RT). VT% was ≤5% in 13/46 (28.2%), 24/99 (24.2%), and 40/88 (45.4%) patients, respectively. There were 11/46 (29.7%), 22/99 (22.7%), and 23/88 (26.1%) RECIST partial responses and 18/46 (48.6%), 59/99 (60.8%), and 60/88 (68.2%) RECIST stable disease, respectively. In naChT, a trend for a better survival was observed when VT% ≤5% (p = .09), whereas RECIST partial responses and stable disease had the same outcome. VT% was not associated with outcome in naRT or naChT-RT, whereas RECIST response was.

CONCLUSION

In primary localized MFS and UPS treated with neoadjuvant therapies, VT% seems more relevant than size reduction after naChT, whereas the opposite is true when naRT is administered alone or concurrent to ChT.

Case Report: An exceptional response to neoadjuvant radiotherapy and chemotherapy in undifferentiated pleomorphic sarcoma following checkpoint inhibitor use

Undifferentiated pleomorphic sarcoma (UPS), a subtype of soft tissue sarcoma (STS), is an uncommon malignancy associated with a poor prognosis. As with other forms of sarcoma, surgical resection remains the only form of treatment with curative potential. The role of perioperative systemic therapy has not been definitively elucidated. Due to high recurrence rates and metastatic potential, management of UPS can pose a difficult task for clinicians. In cases of unresectable UPS due to anatomic limitations and in patients with comorbidities and poor performance status (PS), management options are limited. We describe a patient with UPS involving the chest wall with poor PS who achieved complete response (CR) following neoadjuvant chemotherapy and radiation in the setting of prior immune-checkpoint inhibitor (ICI) therapy.

The Prognostic Relevance of MRI Characteristics in Myxofibrosarcoma Patients Treated with Neoadjuvant Radiotherapy

To improve local control, neoadjuvant radiotherapy (nRT) followed by surgery is the standard of care in myxofibrosarcoma (MFS) because of its infiltrative growth pattern. Nevertheless, local recurrence rates are high. Data on prognostic factors for poor clinical outcomes are lacking. This retrospective study thus investigates the prognostic relevance of magnetic resonance imaging (MRI) characteristics before and after nRT in 40 MFS patients, as well as their association with disease-free survival (DFS) and overall survival (OS). A vascular pedicle, defined as extra-tumoral vessels at the tumor periphery, was observed in 12 patients (30.0%) pre-nRT and remained present post-nRT in all cases. Patients with a vascular pedicle had worse DFS (HR 5.85; 95% CI 1.56-21.90; p = 0.009) and OS (HR 9.58; 95% CI 1.91-48.00; p = 0.006). An infiltrative growth pattern, referred to as a tail sign, was observed in 22 patients (55.0%) pre-nRT and in 19 patients (47.5%) post-nRT, and was associated with worse DFS post-nRT (HR 6.99; 95% CI 1.39-35.35; p = 0.019). The percentage of tumor necrosis estimated by MRI was increased post-nRT, but was not associated with survival outcomes. The presence of a tail sign or vascular pedicle on MRI could support the identification of patients at risk for poor clinical outcomes after nRT.

Effectiveness and Safety of Trabectedin and Radiotherapy for Patients With Myxoid Liposarcoma: A Nonrandomized Clinical Trial

Importance

Preclinical data about the synergistic activity of radiotherapy (RT) and trabectedin have been reported. The combination of trabectedin and RT in treating myxoid liposarcomas appears worth exploring.

Objective

To explore the effectiveness and safety of trabectedin combined with RT.

Design, Setting, and Participants

This international, open-label, phase 2 nonrandomized clinical trial including 46 patients with myxoid liposarcoma was conducted in 4 centers in Spain, 1 in Italy, and 2 in France from July 1, 2016, to September 30, 2019. Eligible patients had to have a histologic, centrally reviewed diagnosis of localized resectable myxoid liposarcoma arising from an extremity or the trunk wall.

Interventions

Trabectedin was administered at the recommended dose stemming from the phase 1 trial (1.5 mg/m2), with intravenous infusion during 24 hours every 21 days for a total of 3 cycles. Radiotherapy was started after completion of the first trabectedin infusion (cycle 1, day 2). Patients received 25 fractions of radiation for a total of 45 Gy. Surgery was planned 3 to 4 weeks after the administration of the last preoperative cycle and not until 4 weeks after the end of preoperative RT. Pathologic specimens were mapped in tumor sections to estimate the histologic changes and the percentage of viable tumor after neoadjuvant treatment.

Main Outcomes and Measures

The primary objective of the phase 2 part of the study was overall response. Secondary objectives were effectiveness measured by relapse-free survival and activity measured by functional imaging and pathologic response.

Results

A total of 46 patients were enrolled. Four patients were not evaluable. The median age was 43 years (range, 18-77 years), and 31 patients were male (67%). Overall, 9 of 41 patients (22%) achieved a partial response with neoadjuvant treatment with trabectedin and RT, with 5 of 39 patients (13%) achieving a complete pathologic response and 20 of 39 patients (51%) having 10% or less of a viable remaining tumor. Partial responses according to Choi criteria were observed in 24 of 29 evaluable patients (83%), and no patient had disease progression. Treatment was well tolerated.

Conclusions and Relevance

Although the primary end point of this phase 2 nonrandomized clinical trial was not met (Response Evaluation Criteria in Solid Tumors response in ≥70% of patients), results suggest this combination was well tolerated and effective in terms of pathologic response. Thus, trabectedin plus RT might be a treatment option regarding tolerability; further evidence should be generated in this setting.

Clinical course and features of soft tissue sarcomas in geriatric patients: a single-center experience

OBJECTIVE

This study was performed to examine the disease course in geriatric patients with soft tissue sarcoma and determine the risk factors for mortality.

METHODS

We retrospectively analyzed patients who were treated at Istanbul University Oncology Institute from January 2000 to August 2021.

RESULTS

Eighty patients were included in the study. The patients' median age was 69 years (range, 65-88 years). The median overall survival of patients diagnosed between the ages of 65 and 74 years was 70 months, and that of patients diagnosed at the age of ≤75 years was significantly lower at 46 months. The median survival of patients who did and did not undergo surgical resection was 66 and 11 months, respectively, with a significant difference. The median overall survival of patients with positive and negative surgical margins was 58 and 96 months, respectively, also with a significant difference. Age at diagnosis and recurrence/metastasis significantly affected mortality. A 1-year increase in the age at diagnosis increased mortality by 1.147 times.

CONCLUSION

Age of >75 years, inability to undergo surgery, positive surgical margins, and head and neck location may be associated with a poor prognosis in geriatric patients with soft tissue sarcoma.

Neoadjuvant Radiation Therapy with Interdigitated High-Dose LRT for Voluminous High-Grade Soft-Tissue Sarcoma

Purpose

To report a case of large extremity soft tissue sarcoma (2933 cc), safely treated with a novel approach of interdigitating high-dose LATTICE radiation therapy (LRT) with standard radiation therapy as a neoadjuvant treatment to surgery.

Patients and Methods

Four sessions of high-dose LRT were delivered in a weekly interval, interdigitated with standard radiation therapy. The LRT plan consisted of 15 high-dose vertices receiving a dose >12 Gy per session, with 2-3 Gy to the peripheral margin of the tumor. The patient underwent surgical excision 2 months after the new regimen of induction radiation therapy.

Results and Discussion

The patient tolerated the radiation therapy regimen well. The post-operative assessment revealed a negative surgical margin and over 95% necrosis of the total tumor volume. The post-surgical wound complication was mitigated by outpatient wound care. Interdigitating multiple sessions of high-dose LATTICE radiation treatments with standard neoadjuvant radiation therapy as a neoadjuvant therapy for soft tissue sarcoma was feasible and did not incur additional toxicity in this clinical case. A phase-I/II trial will be conducted to further evaluate the toxicity and efficacy of the new treatment strategy with the intent to increase the rate of pathologic necrosis, which has been shown to positively correlate with the overall survival.

Effect of Favorable Pathologic Response After Neoadjuvant Radiation Therapy Alone in Soft-tissue Sarcoma

Purpose

Whether the therapeutic response of soft-tissue sarcoma to neoadjuvant treatment is predictive for clinical outcomes is unclear. Given the rarity of this disease and the confounding effects of chemotherapy, this study analyzes whether a favorable pathologic response (fPR) after neoadjuvant radiation therapy (RT) alone is associated with clinical benefits.

Methods and Materials

An institutional review board-approved retrospective review was conducted on a database of patients with primary soft-tissue sarcoma treated at our institution between 1987 and 2015 with neoadjuvant RT alone followed by surgical resection. Time-to-event outcomes estimated with a Kaplan-Meier analysis included overall survival, progression-free survival (PFS), locoregional control, and distant control (DC). Cox regression analyses were performed to determine prognostic variables associated with clinical outcomes.

Results

Of the overall cohort of 315 patients, 181 patients (57%) were included in the primary analysis with documented pathologic necrosis (PN) rates (mean: 59%) and a median follow up from diagnosis of 48 months (range, 4-170 months). The median neoadjuvant RT dose was 50 Gy (range, 40-60 Gy), and the majority of patients had negative surgical margins (79%). Only 35 patients (19%) achieved a fPR (PN ≥95%), which was associated with a higher R0 resection rate (94% vs. 75%; P = .013), a significant 5-year PFS benefit (74% vs. 43%; P = .014), and a nonsignificant 5-year DC benefit (76% vs. 62%; P = .12) compared with PN <95%. On multivariable analysis, fPR was an independent predictor for PFS (hazard ratio: 0.47; 95% confidence interval, 0.25-0.90; P = .022).

Conclusions

Achieving fPR with neoadjuvant RT alone is associated with a higher R0 resection rate and possible DC benefit, translating into a significant improvement in PFS. Further studies to improve pathologic response rates and prospectively validate this endpoint are warranted.

Correlation of radiological and histopathological response after neoadjuvant radiotherapy in soft tissue sarcoma

BACKGROUND

The aim of this study was to assess the association between radiological and histopathological response after neoadjuvant radiotherapy (nRT) in soft tissue sarcoma (STS), as well as the prognostic value of the different response evaluation methods on the oncological outcome.

METHODS

A retrospective cohort of patients with localized STS of the extremity and trunk wall, treated with nRT followed by resection were included. The radiological response was assessed by RECIST 1.1 (RECIST) and MR-adapted Choi (Choi), histopathologic response was evaluated according to the EORTC-STBSG recommendations. Oncological outcome parameters of interest were local recurrence-free survival (LRFS), disease metastases-free survival (DMFS), and overall survival (OS).

RESULTS

For 107 patients, complete pre- and postoperative pathology and imaging datasets were available. Most tumors were high-grade (77%) and the most common histological subtypes were undifferentiated pleomorphic sarcoma/not otherwise specified (UPS/NOS, 40%), myxoid liposarcoma (MLS, 21%) and myxofibrosarcoma (MFS, 16%). When comparing RECIST to Choi, the response was differently categorized in 58%, with a higher response rate (CR + PR) with Choi. Radiological responders showed a significant lower median percentage of viable cells (RECIST p = .050, Choi p = .015) and necrosis (RECIST p < .001), and a higher median percentage of fibrosis (RECIST p = .005, Choi p = .008), compared to radiological non-responders (SD + PD). RECIST, Choi, fibrosis, and viable cells were not significantly associated with altered oncological outcome, more necrosis was associated with poorer OS (p = .038).

CONCLUSION

RECIST, Choi and the EORTC-STBSG response score show incongruent results in response evaluation. The radiological response was significantly correlated with a lower percentage of viable cells and necrosis, but a higher percentage of fibrosis. Apart from necrosis, radiological nor other histopathological parameters were associated with oncologic outcomes.

Predicting pathological complete response of neoadjuvant radiotherapy and targeted therapy for soft tissue sarcoma by whole-tumor texture analysis of multisequence MRI imaging

OBJECTIVES

To construct effective prediction models for neoadjuvant radiotherapy (RT) and targeted therapy based on whole-tumor texture analysis of multisequence MRI for soft tissue sarcoma (STS) patients.

METHODS

Thirty patients with STS of the extremities or trunk from a prospective phase II trial were enrolled for this analysis. All patients underwent pre- and post-neoadjuvant RT MRI examinations from which whole-tumor texture features were extracted, including T₁-weighted with fat saturation and contrast enhancement (T₁FSGd), T₂-weighted with fat saturation (T₂FS), and diffusion-weighted imaging (DWI) sequences and their corresponding apparent diffusion coefficient (ADC) maps. According to the postoperative pathological results, the patients were divided into pathological complete response (pCR) and non-pCR (N-pCR) groups. pCR was defined as less than 5% of residual tumor cells by postoperative pathology. Delta features were defined as the percentage change in a texture feature from pre- to post-neoadjuvant RT MRI. After data reduction and feature selection, logistic regression was used to build prediction models. ROC analysis was performed to assess the diagnostic performance.

RESULTS

Five of 30 patients (16.7%) achieved pCR. The Delta_Model (AUC 0.92) had a better predictive ability than the Pre_Model (AUC 0.78) and Post_Model (AUC 0.76) and was better than AJCC staging (AUC 0.52) and RECIST 1.1 criteria (AUC 0.52). The Combined_Model (pre, post, and delta features) had the best predictive performance (AUC 0.95).

CONCLUSION

Whole-tumor texture analysis of multisequence MRI can well predict pCR status after neoadjuvant RT and targeted therapy in STS patients, with better performance than RECIST 1.1 and AJCC staging.

KEY POINTS

• MRI multisequence texture analysis could predict the efficacy of neoadjuvant RT and targeted therapy for STS patients. • Texture features showed incremental value beyond routine clinical factors. • The Combined_Model with features at multiple time points showed the best performance.

Nomograms predicting local and distant recurrence and disease-specific mortality for R0/R1 soft tissue sarcomas of the extremities

Background

Prognostic models for patients with soft tissue sarcoma (STS) of the extremities have been developed from large multi-institutional datasets with mixed results. We aimed to develop predictive nomograms for sarcoma-specific survival (SSS) and, for the first time, long-term local recurrence (LR) and distant recurrence (DR) in patients with STS of the extremities treated at our institution.

Patients and methods

Data from patients treated at Humanitas Cancer Center from 1997 to 2015 were analyzed. Variable selection was based on the clinical knowledge and multivariable regression splines algorithm. Perioperative treatments were always included in the model. Prognostic models were developed using Cox proportional hazards model, and model estimates were plotted in nomograms predicting SSS at 5 and 10 years and LR and DR at 2, 5, and 10 years. Model performance was estimated internally via bootstrapping, in terms of optimism-corrected discrimination (Harrell C-index) and calibration (calibration plots).

Results

Data on 517 patients were analyzed. At 5 and 10 years, SSS was 68.1% [95% confidence interval (CI), 63.8-72.1] and 55.6% (50.5-60.3), respectively. LR was 79.1% (95% CI, 75.3-82.4), 71.1% (95% CI, 66.7-75.1), and 66.0% (95% CI, 60.7-70.7) at 2, 5, and 10 years, respectively, whereas DR was 65.9% (95% CI, 61.6-69.9), 57.5% (95% CI, 53.0-61.8), and 52.1% (95% CI, 47.1-56.8) at 2, 5, and 10 years, respectively. SSS nomogram included age, gender, margins, tumor size, grading, and histotype. LR and DR nomograms incorporated mostly the same variables, except for age for DR; LR nomogram did not include gender but included anatomic site. The optimism-corrected C-indexes were 0.73 and 0.72 for SSS at 5 and 10 years, respectively; 0.65, 0.64, and 0.64 for LR at 2, 5, and 10 years, respectively; and 0.68 for DR at 2, 5, and 10 years. Predicted probabilities were close to the observed ones for all outcomes.

Conclusions

We developed and validated three nomograms for STS of the extremities predicting the probability of SSS at 5 and 10 years and LR and DR at 2, 5, and 10 years. By accounting for the perioperative treatment, these models allow prediction for future patients who had no perioperative treatment, thus being useful in the clinical decision-making process.

Final safety and HRQoL results of the phase II/III Act.In.Sarc study with preoperative NBTXR3 plus radiotherapy versus radiotherapy in locally advanced soft-tissue sarcoma

PURPOSE

XXXX(Anonymized) demonstrated that the first-in-class radioenhancer NBTXR3, activated by preoperative radiotherapy, doubled the rate of pathological complete response after resection compared with preoperative radiotherapy alone in adult patients with locally advanced soft tissue sarcoma of the extremity or trunk wall (16.1% versus 7.9%, P=0.045), and more patients achieved R0 resections (77.0% versus 64.0%, P=0.042). These are the toxicity and health-related quality of life (HRQoL) results.

METHODS AND MATERIALS

XXXX(Anonymized) randomized eligible patients 1:1 to either NBTXR3 (single intratumoral injection, volume equivalent to 10% of baseline tumor volume, at 53.3 g/L) activated by external-beam radiotherapy (EBRT) (Arm A) or EBRT alone (Arm B) (50 Gy in 25 fractions), followed by surgery in both arms. Here, we report the safety analyses in the all-treated population with a long-term follow-up of at least two-years, and HRQoL in the intention-to-treat full analysis set.

RESULTS

During the on-treatment period serious adverse events (SAEs) of all grades related to NBTXR3 occurred in 10.1% (9/89) of patients (Arm A), SAEs related to radiotherapy occurred in 5.6% (5/89) (Arm A) versus 5.6% (5/90) (Arm B); and post-surgery hospitalization due to SAEs occurred in 15.7% (14/89) (Arm A) versus 24.4% (22/90) (Arm B). During the follow-up period, post-treatment SAEs (regardless of relationship) occurred in 13.5% (12/89) (Arm A) versus 24.4% (22/90) (Arm B). NBTXR3 did not negatively impact on HRQoL, during the follow-up period, there was an improvement in most mean Toronto Extremity Salvage Score, EuroQol-5 Dimension (EQ-5D), EQ5D02-EQ Visual Analog Scale, Reintegration to Normal Living Index, and Musculoskeletal Tumor Rating Scale scores.

CONCLUSIONS

NBTXR3 did not negatively impact safety or HRQoL. Long-term safety results reinforce the favorable benefit-risk ratio of NBTXR3 plus radiotherapy.

Virtual Biopsy in Soft Tissue Sarcoma. How Close Are We?

A shift in radiology to a data-driven specialty has been unlocked by synergistic developments in imaging biomarkers (IB) and computational science. This is advancing the capability to deliver "virtual biopsies" within oncology. The ability to non-invasively probe tumour biology both spatially and temporally would fulfil the potential of imaging to inform management of complex tumours; improving diagnostic accuracy, providing new insights into inter- and intra-tumoral heterogeneity and individualised treatment planning and monitoring. Soft tissue sarcomas (STS) are rare tumours of mesenchymal origin with over 150 histological subtypes and notorious heterogeneity. The combination of inter- and intra-tumoural heterogeneity and the rarity of the disease remain major barriers to effective treatments. We provide an overview of the process of successful IB development, the key imaging and computational advancements in STS including quantitative magnetic resonance imaging, radiomics and artificial intelligence, and the studies to date that have explored the potential biological surrogates to imaging metrics. We discuss the promising future directions of IBs in STS and illustrate how the routine clinical implementation of a virtual biopsy has the potential to revolutionise the management of this group of complex cancers and improve clinical outcomes.

Soft Tissue Sarcomas: The Role of Quantitative MRI in Treatment Response Evaluation

BACKGROUND

Although curative surgery remains the cornerstone of the therapeutic strategy in patients with soft tissue sarcomas (STS), neoadjuvant radiotherapy and chemotherapy (NART and NACT, respectively) are increasingly used to improve operability, surgical margins and patient outcome. The best imaging modality for locoregional assessment of STS is MRI but these tumors are mostly evaluated in a qualitative manner.

OBJECTIVE

After an overview of the current standard of care regarding treatment for patients with locally advanced STS, this review aims to summarize the principles and limitations of (i) the current methods used to evaluate response to neoadjuvant treatment in clinical practice and clinical trials in STS (RECIST 1.1 and modified Choi criteria), (ii) quantitative MRI sequences (i.e., diffusion weighted imaging and dynamic contrast enhanced MRI), and (iii) texture analyses and (delta-) radiomics.

Different HSP90 Inhibitors Exert Divergent Effect on Myxoid Liposarcoma In Vitro and In Vivo

The therapeutic options for patients with relapsed or metastatic myxoid liposarcoma (MLS) remain scarce and there is currently no targeted therapy available. Inhibition of the HSP90 family of chaperones has been suggested as a possible therapeutic option for patients with MLS. However, the clinical effect of different HSP90 inhibitors vary considerably and no comparative study in MLS has been performed. Here, we evaluated the effects of the HSP90 inhibitors 17-DMAG, AUY922 and STA-9090 on MLS cell lines and in an MLS patient-derived xenograft (PDX) model. Albeit all drugs inhibited in vitro growth of MLS cell lines, the in vivo responses were discrepant. Whereas 17-DMAG inhibited tumor growth, AUY922 surprisingly led to increased tumor growth and a more aggressive morphological phenotype. In vitro, 17-DMAG and STA-9090 reduced the activity of the MAPK and PI3K/AKT signaling pathways, whereas AUY922 led to a compensatory upregulation of downstream ERK. Furthermore, all three tested HSP90 inhibitors displayed a synergistic combination effect with trabectidin, but not with doxorubicin. In conclusion, our results indicate that different HSP90 inhibitors, albeit having the same target, can vary significantly in downstream effects and treatment outcomes. These results should be considered before proceeding into clinical trials against MLS or other malignancies.

Could Five Be the New Twenty-Five? Long-term Oncologic Outcomes from a Phase II, Prospective, 5-Fraction Pre-operative Radiation Therapy Trial in Patients with Localized Soft Tissue Sarcoma

Purpose

Management of adult soft tissue sarcomas entails a multidisciplinary approach with surgery and radiation therapy with or without chemotherapy. The use of preoperative irradiation has been well established, and although conventional fractionation involves daily treatments over the course of 5 weeks, higher doses per fraction may be beneficial due to the radiobiologic profile of sarcoma. In this study we report long-term oncologic outcomes from a single-institution, phase II study evaluating a 5-fraction hypofractionated course of preoperative radiation.

Methods and materials

Preoperative hypofractionated radiation therapy was administered to 35 Gy in 5 fractions every other day followed by resection 4 to 6 weeks later. If given, chemotherapy consisted of a doxorubicin-ifosfamide-based regimen delivered neoadjuvantly. The primary endpoint was local control. Additional survival and pathologic outcomes, including overall and distant metastasis-free survival, tumor, and treatment-related pathology, as well as acute and late toxicity were examined.

Results

Thirty-two patients were enrolled in this prospective, single-arm phase II trial. At a median follow-up of 36.4 months (range, 3-56), no patient developed a local recurrence, and the 3-year overall and distant metastasis-free survival was 82.2% and 69%, respectively. Major acute postoperative wound complications occurred in 25% of patients. Grade 2 and 3 fibrosis occurred in 21.7% and 13% of patients, respectively. The 2-year median and mean Musculoskeletal Tumor Society score for all patients was 28 and 27.4, respectively.

Conclusions

A condensed course of preoperative hypofractionated radiation therapy leads to excellent rates of local control and survival with acceptable toxicity profiles. Potential studies ideally with phase II or III randomized trials would help corroborate these findings and other preoperative hypofractionated results in soft tissue sarcomas.

Implementing a Machine Learning Strategy to Predict Pathologic Response in Patients With Soft Tissue Sarcomas Treated With Neoadjuvant Chemotherapy

PURPOSE

Neoadjuvant chemotherapy (NAC) has been increasingly used in patients with locally advanced high-risk soft tissue sarcomas in the past decade, but definition and prognostic impact of a good histologic response (GHR) are lacking. Our aim was to investigate which histologic feature from the post-NAC surgical specimen independently correlated with metastatic relapse-free survival (MFS) in combination with clinical, radiologic, and pathologic features using a machine learning approach.

METHODS

This retrospective study included 175 consecutive patients (median age: 59 years, 75 women) with resectable disease, treated with anthracycline-based NAC between 1989 and 2015 in our sarcoma reference center, and with quantitative histopathologic analysis of the surgical specimen. The outcome of interest was the MFS. A multimodel, multivariate survival analysis was used to define GHR. The added prognostic value of GHR was investigated through the comparisons with the standard model (including histologic grade, size, and depth) and SARCULATOR nomogram using concordance indices (c-index) and Monte-Carlo cross-validation.

RESULTS

Seventy-two patients (72 of 175, 41.1%) had a metastatic relapse. Stepwise Cox regression, random survival forests, and least absolute shrinkage and selection operator-penalized Cox regression all converged toward the same definition for GHR, ie, < 5% stainable tumor cells. The five-year MFS probability was 1 (95% CI, 1 to 1) in patients with GHR versus 0.73 (95% CI, 0.65 to 0.81) in patients without GHR (log-rank P = .0122). The final prognostic model incorporating the GHR was significantly better than the standard model and SARCULATOR (average c-index in testing sets = 0.72 [95% CI, 0.61 to 0.82] v 0.57 [95% CI, 0.44 to 0.70] and 0.54 [95% CI, 0.45 to 0.64], respectively; P = .0414 and .0091).

CONCLUSION

Histologic response to NAC improves the prediction of MFS in patients with soft tissue sarcoma and represents a possible end point in future studies exploring innovative regimens in the neoadjuvant setting.

Clinical Outcomes for Primary and Radiation-Associated Angiosarcoma of the Breast with Multimodal Treatment: Long-Term Survival Is Achievable

BACKGROUND

The optimal management of primary angiosarcoma (PAS) and radiation-associated angiosarcoma (RAAS) of the breast remains undefined. Available data show persistently poor survival outcomes following treatment with surgery or chemotherapy alone. The objective of this study was to evaluate long-term outcomes in patients treated with multimodality therapy.

METHODS

Patients diagnosed with stage I-III PAS or RAAS of the breast were identified from our local tumor registry (2010-2020). Patient demographics, tumor characteristics, and treatment were collected. Primary outcomes were local recurrence (LR), distant recurrence (DR), and median overall survival (OS). A secondary outcome was pathologic complete response (pCR) following neoadjuvant chemotherapy (NAC). Mann-Whitney U, chi-squared, or Fisher exact tests were used to analyze data. Kaplan-Meier curves compared OS for PAS and RAAS.

RESULTS

Twenty-two patients met inclusion criteria, including 11 (50%) with RAAS and 11 (50%) with PAS. Compared to PAS patients, RAAS patients were older and had more comorbidities. For RAAS patients, median time from radiation to diagnosis was 6 years (IQR: 5-11). RAAS patients were more likely to have a pCR to NAC (40% vs. 20%, p = 0.72). RAAS patients had a higher LR rate (43% vs. 38%, p = 0.83), and PAS patients were more likely to develop a DR (38% vs. 0%, p = 0.07). Median OS was 81 months in PAS patients and 90 months in RAAS patients (p = 1.00).

DISCUSSION

Long-term survival can be achieved in patients with PAS and RAAS who undergo multimodality treatment. NAC can result in pCR. The long-term clinical implications of pCR warrant further investigation.

Impact of histological subtype on radiological and pathological response after neoadjuvant radiotherapy in soft tissue sarcoma

BACKGROUND

Evaluation of response to neoadjuvant radiotherapy (NART) does not consider soft tissue sarcoma (STS) heterogeneity. We aimed to investigate radiological and pathological response of 4 major histotypes.

METHODS

Extremity or trunk STS patients who received 50 Gy NART between 2009 and 2020 were retrospectively included. Relative variation in tumor size (RVTS) and pathological response were reported in the overall population and in undifferentiated pleomorphic sarcoma (UPS), myxofibrosarcoma (MFS), myxoid liposarcoma (MLS) and synovial sarcoma (SS) patients to identify response modalities of each histotype.

RESULTS

Among the 121 included patients, 49, 19, 13 and 11 presented UPS, MFS, MLS and SS. Median RVTS were 0% (IQR -18-+18), +8% (IQR 0-+24), -12% (IQR -20-3) and -11% (IQR -15-9), respectively (p = 0.001). Median viable cells were 10%, 60%, 20% and 70% (p = 0.007). In overall population, pathological complete response and median necrosis were 27.7% and 10% without significant correlation to histotype (p = 0.18 and 0.06). Nineteen (38.8%) UPS specimens presented cysts that were emptied during the sampling process and distorted the microscopic response evaluation. Infiltrative growth pattern was observed in 28% and 38.9% UPS and MFS patients. Five (38.5%) MLS presented mature adipocytes without proven prognostic value. Cysts were observed in 36% of SS specimens. In the absence of initial tumor limits, the great viable cellularity of SS may be overestimated by their nodular aspect.

CONCLUSION

After NART, we highlighted disparate response of UPS, frequent progression of MFS, and confirmed MLS and SS radiosensitivity. Response must be interpreted with caution and consider the histotype-specific patterns.

A moderate dose of preoperative radiotherapy may improve resectability in myxoid liposarcoma

BACKGROUND

Histotype specific neoadjuvant therapy response data is scarce in soft tissue sarcomas. This study aimed to assess the impact of a moderate radiotherapy (RT) dose on resectability and to correlate MRI parameters to pathological treatment response in Myxoid Liposarcoma (MLS).

METHODS

This prospective, multicenter, single-arm, phase 2 trial assessed the radiological effects of 36 Gy of preoperative radiotherapy in primary non-metastatic MLS (n=34). Distance of the tumor to the neurovascular bundle, tumor dimensions, fat fraction, enhancing fraction were determined on MRI scans at baseline, after 8 and 16 fractions, and preoperatively. Pathological response was established by central pathology review.

RESULTS

Preoperative radiotherapy resulted in a median increase of 2 mm (IQR 0 to 6) of the distance of the tumor to the neurovascular bundle. As compared to baseline, the median change of the tumor volume, craniocaudal diameter and axial diameter at preoperative MRI were -60% (IQR -74 to -41), -19% (IQR -23 to -7) and -20% (IQR -29 to -12), respectively. The median fat fraction of 0.1 (IQR 0.0-0.1) and enhancing fraction of 0.8 (IQR 0.6 to 0.9) at baseline, changed to 0.2 (IQR 0.1 to 0.5) and to 0.5(IQR 0.4 to 0.9) preoperatively, respectively. Radiological signs of response in terms of volume, enhancing fraction and fat fraction were correlated with specific pathological signs of response like hyalinization, necrosis and fatty maturation.

CONCLUSIONS

A moderate dose of preoperative radiotherapy may improve resectability in MLS and could facilitate achievement of clear margins and function preservation. MRI features which were predictive for expressions of pathological response, can play a role in further personalization of neoadjuvant treatment strategies in order to improve outcome in MLS.