Radiation Therapy in Adult Soft Tissue Sarcoma-Current Knowledge and Future Directions: A Review and Expert Opinion

Radiation therapy improves survival in elderly patients with localized extremity soft tissue sarcoma

BACKGROUND

This study aims to evaluate the efficacy of radiation therapy in enhancing survival outcomes among elderly patients diagnosed with localized extremity soft tissue sarcomas (STSs). Furthermore, it seeks to explore whether the survival benefits conferred by radiation therapy differ according to tumor characteristics and treatment modalities.

METHODS

We conducted a retrospective analysis using the Surveillance, Epidemiology, and End Results (SEER) database to identify patients aged 80 years and older diagnosed with localized extremity STSs. The study assessed 1498 eligible patients, analyzing cancer-specific survival (CSS) and overall survival (OS) through Kaplan-Meier survival analysis and Cox proportional hazards modeling. Propensity score matching was employed to adjust for potential confounders.

RESULTS

Among the analyzed patients, 773 patients underwent radiation therapy (Radiation group), while 725 patients either did not receive radiation therapy or it was unknown if they had (No-Radiation group). The 5-year OS rate was 40% in the radiation group compared to 38% in the no-radiation group. After propensity score matching, radiation therapy was associated with a significant improvement in OS (P = 0.005, HR = 0.8, 95% CI 0.7-0.9). Subgroup analyses indicated that patients undergoing primary tumor resection benefited most from radiation therapy in terms of OS.

CONCLUSION

Radiation therapy is associated with improved overall survival in elderly patients with localized extremity STSs. These findings suggest that radiation therapy should be considered as a key component of the treatment strategy for this patient population, taking into account individual patient characteristics and comorbidities.

Definitive single fraction spine stereotactic radiosurgery for metastatic sarcoma: Simultaneous integrated boost is associated with high tumor control and low vertebral fracture risk

INTRODUCTION

Sarcoma spinal metastases (SSM) are particularly difficult to manage given their poor response rates to chemotherapy and inherent radioresistance. We evaluated outcomes in a cohort of patients with SSM uniformly treated using single-fraction simultaneous-integrated-boost (SIB) spine stereotactic radiosurgery (SSRS).

MATERIALS AND METHODS

A retrospective review was conducted at a single tertiary institution treated with SSRS for SSM between April 2007-April 2023. 16-24 Gy was delivered to the GTV and 16 Gy uniformly to the CTV. Kaplan-Meier analysis was conducted to assess time to progression of disease (PD) with proportionate hazards modelling used to determine hazard ratios (HR) and respective 95 % confidence intervals (CI).

RESULTS

70 patients with 100 lesions underwent SSRS for SSM. Median follow-up was 19.3 months (IQR 7.7-27.8). Median age was 55 years (IQR42-63). Median GTV and CTVs were 14.5 cm3 (IQR 5-32) and 52.7 cm3 (IQR 29.5-87.5) respectively. Median GTV prescription dose and biologically equivalent dose (BED) [α/β = 10] was 24 Gy and 81.6 Gy respectively. 85 lesions received 24 Gy to the GTV. 27 % of patients had Bilsky 1b or greater disease. 16 of 100 lesions recurred representing a crude local failure rate of 16 % with a median time to failure of 10.4 months (IQR 5.7-18) in cases which failed locally. 1-year actuarial local control (LC) was 89 %. Median overall survival (OS) was 15.3 months (IQR 7.7-25) from SSRS. Every 1 Gy increase in GTV absolute minimum dose (DMin) across the range (5.8-25 Gy) was associated with a reduced risk of local failure (HR = 0.871 [95 % CI 0.782-0.97], p = 0.009). 9 % of patients developed vertebral compression fractures at a median of 13 months post SSRS (IQR 7-25).

CONCLUSION

This study represents one of the most homogenously treated and the largest cohorts of patients with SSM treated with single-fraction SSRS. Despite inherent radioresistance, SSRS confers durable and high rates of local control in SSM without unexpected long-term toxicity rates.

The health-related quality of life of sarcoma patients treated with neoadjuvant versus adjuvant radiotherapy - Results of a multi-center observational study

AIM

The sequence of radiotherapy and resection in patients with soft tissue sarcomas is usually discussed on an individual basis. Better understanding of potential differences of health-related quality of life (QoL) between patients undergoing adjuvant (ART) versus neoadjuvant radiotherapy (NART) is therefore helpful for clinical decision making.

METHODS

Adult sarcoma patients from 39 hospitals completed the European Organisation for Research and Treatment of Cancer Quality of Life Core Questionnaire (EORTC QLQ-C30). Differences in global QoL, physical functioning, role functioning, fatigue, pain, and insomnia between ART versus NART were investigated with multivariate regression, adjusting for age, gender, chemotherapy, grading, stage, tumor location, recurrence/distant metastasis, sarcoma type, time since last treatment, and treatment status using validated thresholds.

RESULTS

A total of 1110 patients participated. Of them, 340 had received radiotherapy (NART: n = 95, 28%; ART: n = 245, 72%). Global QoL was 59.3 on average after NART and 60.5 after ART (Badj = 1.0, p = 0.74). Physical functioning was 65.9 compared to 70.5 (Badj = 4.2; p = 0.16), role function 48.8 vs. 56.7 (Badj = 7.0, p = 0.08), fatigue 47.5 vs. 45.4 (Badj = -1.2; p = 0.71), pain 40.2 vs. 34.1 (Badj = -6.8; p = 0.08), and insomnia 33.7 vs. 41.6 (Badj = 5.5, p = 0.16). Among patients with NART, clinically relevant QoL impairments were less frequent 2 years after treatment compared to < 2 years thereafter (n = 6 vs. n = 4 on average).

CONCLUSION

There is little evidence for QoL differences in most domains and overall QoL between the two irradiation groups. However, patients after NART might experience worse role functioning and pain but fewer problems with insomnia compared to patients after ART.

The role of radiotherapy in the management of malignant peripheral nerve sheath tumors: a single-center retrospective cohort study

PURPOSE

This study sought to investigate the role of radiotherapy (RT) in addition to surgery for oncological outcomes in patients with malignant peripheral nerve sheath tumors (MPNST).

METHODS

In this single-center, retrospective cohort study, histopathologically confirmed MPNST were analyzed. Local control (LC), overall survival (OS), and distant metastasis-free survival (DMFS) were assessed using the Kaplan-Meier estimator. Multivariable Cox regression analysis was performed to identify factors associated with LC, OS, and DMFS.

RESULTS

We included 57 patients with a median follow-up of 20.0 months. Most MPNSTs were located deeply (87.5%), were larger than 5 cm (55.8%), and had high-grade histology (78.7%). Seventeen patients received surgery only, and 25 patients received surgery and pre- or postoperative RT. Median LC, OS, and DMFS after surgery only were 8.7, 25.5, and 22.0 months; after surgery with RT, the median LC was not reached, while the median OS and DMFS were 111.5 and 69.9 months. Multivariable Cox regression of LC revealed a negative influence of patients presenting with local disease recurrence compared to patients presenting with an initial primary diagnosis of localized MPNST (hazard ratio: 8.86, p = 0.003).

CONCLUSIONS

The addition of RT to wide surgical excision appears to have a beneficial effect on LC. Local disease recurrence at presentation is an adverse prognostic factor for developing subsequent local recurrences. Future clinical and translational studies are warranted to identify molecular targets and find effective perioperative combination therapies with RT to improve patient outcomes.

Similar additive effects of doxorubicin in combination with photon or proton irradiation in soft tissue sarcoma models

High-precision radiotherapy with proton beams is frequently used in the management of aggressive soft tissue sarcoma (STS) and is often combined with doxorubicin (Dox), the first-line chemotherapy for STS. However, current treatment approaches continue to result in high local recurrence rates often occurring within the treatment field. This strongly indicates the need of optimized treatment protocols taking the vast heterogeneity of STS into account, thereby fostering personalized treatment approaches. Here, we used preclinical STS models to investigate the radiation response following photon (X) or proton (H) irradiation alone and in combination with different treatment schedules of Dox. As preclinical models, fibrosarcoma (HT-1080), undifferentiated pleiomorphic sarcoma (GCT), and embryonal rhabdomyosarcoma (RD) cell lines were used; the latter two are mutated for TP53. The cellular response regarding clonogenic survival, apoptosis, cell-cycle distribution, proliferation, viability, morphology, and motility was investigated. The different STS cell types revealed a dose-dependent radiation response with reduced survival, proliferation, viability, and motility whereas G2/M phase arrest as well as apoptosis were induced. RD cells showed the most radiosensitive phenotype; the linear quadratic model fit could not be applied. In combined treatment schedules, Dox showed the highest efficiency when applied after or before and after radiation; Dox treatment only before radiation was less efficient. GCT cells were the most chemoresistant cell line in this study most probably due to their TP53 mutation status. Interestingly, similar additive effects could be observed for X or H irradiation in combination with Dox treatment. However, the additive effects were determined more frequently for X than for H irradiation. Thus, further investigations are needed to specify alternative drug therapies that display superior efficacy when combined with H therapy.

Brachytherapy for Organ and Function Preservation in Soft-Tissue Sarcomas in Adult and Paediatric Patients

Adjuvant radiotherapy is an integral component in the management of soft-tissue sarcomas. Brachytherapy is a very convenient and conformal way of delivering adjuvant radiotherapy in such tumours, which spares the surrounding normal tissue. Randomised studies have established the efficacy of brachytherapy in the adjuvant setting, with a 5-year local control of 80-85%. High dose rate, low dose rate and pulsed dose rate have shown equivalent local control, but high dose rate has gained popularity owing to patient convenience, radiation safety and flexibility in dose optimisation. Freehand insertion perioperative brachytherapy (intraoperative placement and postoperative treatment) is the most commonly used technique in soft-tissue sarcomas, with intraoperative radiotherapy and radioactive seed placement being the less commonly used techniques. Brachytherapy can be used as monotherapy or in combination with external beam radiotherapy, such as in cases of close/positive margins for safe dose escalation. Although the quantum of side-effects with external beam radiotherapy has considerably reduced with the evolution of technology and the introduction of intensity modulation (intensity-modulated radiotherapy), brachytherapy still scores better in terms of dose conformality, especially in recurrent tumours (previously irradiated) and when used to treat paediatric and geriatric patients.

Low-Cost, High-Pressure-Synthesized Oxygen-Entrapping Materials to Improve Treatment of Solid Tumors

Tumor hypoxia drives resistance to many cancer therapies, including radiotherapy and chemotherapy. Methods that increase tumor oxygen pressures, such as hyperbaric oxygen therapy and microbubble infusion, are utilized to improve the responses to current standard-of-care therapies. However, key obstacles remain, in particular delivery of oxygen at the appropriate dose and with optimal pharmacokinetics. Toward overcoming these hurdles, gas-entrapping materials (GeMs) that are capable of tunable oxygen release are formulated. It is shown that injection or implantation of these materials into tumors can mitigate tumor hypoxia by delivering oxygen locally and that these GeMs enhance responsiveness to radiation and chemotherapy in multiple tumor types. This paper also demonstrates, by comparing an oxygen (O2 )-GeM to a sham GeM, that the former generates an antitumorigenic and immunogenic tumor microenvironment in malignant peripheral nerve sheath tumors. Collectively the results indicate that the use of O2 -GeMs is promising as an adjunctive strategy for the treatment of solid tumors.

Brachytherapy in the Treatment of Soft-Tissue Sarcomas of the Extremities-A Current Concept and Systematic Review of the Literature

INTRODUCTION

Evidence on the use of brachytherapy in soft-tissue sarcoma (STS) is sparse. Therapy regimens are determined more by local interdisciplinary tumor conferences than by standardized protocols. Patient-specific factors complicate the standardized application of therapy protocols. The individuality of the treatment makes it difficult to compare results.

MATERIALS AND METHODS

A comprehensive literature search was conducted, whereby the literature from a period of almost 44 years (1977-2021) was graded and included in this systematic review. For this purpose, PubMed was used as the primary database. Search string included "soft-tissue sarcoma", "brachytherapy", and "extremity." Four independent researchers reviewed the literature. Only full-text articles written in English or German were included.

RESULTS

Of the 175 identified studies, 70 were eligible for analysis based on the inclusion and exclusion criteria. The key points to compare were local complications, recurrence rate and correlation with margins of resection, and the use of brachytherapy regarding tumor grading.

CONCLUSION

Brachytherapy represents an important subset of radiotherapy techniques used in STSs, whose indications and applications are constantly evolving, and for which a local control rate of 50% to 96% has been reported as monotherapy, depending on risk factors. However, the best benefit is seen in the combination of further resection and brachytherapy, and most authors at many other centers agree with this treatment strategy.

Neoadjuvant Radiation Therapy and Surgery Improves Metastasis-Free Survival over Surgery Alone in a Primary Mouse Model of Soft Tissue Sarcoma

This study aims to investigate whether adding neoadjuvant radiotherapy (RT), anti-programmed cell death protein-1 (PD-1) antibody (anti-PD-1), or RT + anti-PD-1 to surgical resection improves disease-free survival for mice with soft tissue sarcomas (STS). We generated a high mutational load primary mouse model of STS by intramuscular injection of adenovirus expressing Cas9 and guide RNA targeting Trp53 and intramuscular injection of 3-methylcholanthrene (MCA) into the gastrocnemius muscle of wild-type mice (p53/MCA model). We randomized tumor-bearing mice to receive isotype control or anti-PD-1 antibody with or without radiotherapy (20 Gy), followed by hind limb amputation. We used micro-CT to detect lung metastases with high spatial resolution, which was confirmed by histology. We investigated whether sarcoma metastasis was regulated by immunosurveillance by lymphocytes or tumor cell-intrinsic mechanisms. Compared with surgery with isotype control antibody, the combination of anti-PD-1, radiotherapy, and surgery improved local recurrence-free survival (P = 0.035) and disease-free survival (P = 0.005), but not metastasis-free survival. Mice treated with radiotherapy, but not anti-PD-1, showed significantly improved local recurrence-free survival and metastasis-free survival over surgery alone (P = 0.043 and P = 0.007, respectively). The overall metastasis rate was low (∼12%) in the p53/MCA sarcoma model, which limited the power to detect further improvement in metastasis-free survival with addition of anti-PD-1 therapy. Tail vein injections of sarcoma cells into immunocompetent mice suggested that impaired metastasis was due to inability of sarcoma cells to grow in the lungs rather than a consequence of immunosurveillance. In conclusion, neoadjuvant radiotherapy improves metastasis-free survival after surgery in a primary model of STS.

Myxoid liposarcoma originating in the retroperitoneum with metastasis to the calcaneus: a rare case report and review of literature

Myxoid liposarcoma (MLPS) is known to have a variety of metastatic manifestations. We report a MLPS originating in the pelvis with metastasis to the calcaneus. The patient was a 72-year-old man who developed lumbar pain and right lower extremity pain 2 years ago. He visited a nearby clinic and underwent a radiographic examination. Computed tomography (CT) revealed a tumor in the right retroperitoneum. A CT-guided needle biopsy was performed, and pathological examination revealed myxoid liposarcoma. Wide surgical resection was not performed due to the patients' wishes, technical difficulties, and magnitude of the invasion, and the patient received heavy particle radiation therapy (HPRT) of 70.4 Gy. After HPRT, the tumor mass was slightly reduced. However, 11 months after HPRT, a recurrent lesion in the liver was observed. Although HPRT was performed again for the metastatic liver lesion (70.4 Gy), the tumor increased in size. Furthermore, 1 month later, the patient complained of pain in the left foot, and CT and magnetic resonance imaging revealed an osteolytic lesion in the calcaneus. A biopsy was performed, and pathological examination showed a metastatic lesion of myxoid-type liposarcoma. The patient wore a short lower limb orthosis and was able to walk but died 1 month later. Oncologists should note that MLPS can metastasize to the calcaneus.

Surgical management of primary undifferentiated pleomorphic sarcoma of the rectum: a case report and review of the literature

Background

Undifferentiated pleomorphic sarcoma (UPS) is a malignant soft tissue tumor that has been reclassified from malignant fibrous histiocytoma with the development of the pathological diagnosis. It principally occurs in the extremities but rarely occurs in the rectum. We herein report a rare case of UPS arising in the rectum.

Case presentation

A 85-year-old woman was referred to our hospital with a complaint of anal pain, which had persisted for several months. Computed tomography (CT) showed a 53 × 58 × 75 mm mass on the left side of the rectum. Colonoscopy revealed a submucosal elevation in the rectum without any exposure of the tumor to the surface. Contrast-enhanced CT and magnetic resonance imaging revealed an 80-mm mass that originated in the rectal muscular propria, and we suspected a gastrointestinal stromal tumor. No lymph node metastasis or distant metastasis was observed. We performed a laparoscopic Hartmann’s operation. Intraoperatively, severe adhesion around the tumor caused tumor injury and right ureteral dissection. Thus, laparoscopic right ureteral anastomosis and ureteral stenting were additionally performed. The operation time was 6 h and 3 min, and the estimated blood loss was small. The patient was discharged without complications 25 days after surgery. A pathological examination showed that the tumor was composed of highly heterogeneous cells with no specific differentiation traits, leading to a diagnosis of UPS. Contrast-enhanced CT performed 2 months after surgery showed bilateral pelvic lymph node enlargement, which indicated recurrence. Considering the patient’s age, we performed radiotherapy (50 Gy/25 Fr targeting the pelvic region). At present, 16 months have passed since the completion of radiotherapy. Contrast-enhanced CT shows that the recurrent lymph nodes have disappeared, and no new distant metastasis has been observed.

Conclusions

We reported a case of UPS arising in the rectum. The surgical procedure and indication of preoperative therapy should be carefully selected because complete removal of the tumor is desirable in UPS.

MR-guided stereotactic body radiation therapy for primary cardiac sarcomas

BACKGROUND

Primary cardiac tumors are an extremely rare disease with limited prognosis. The treatment of choice is surgery. Other treatment options include chemotherapy and radiation therapy, which historically represented a palliative approach in patients who were not eligible for surgery. The development of hybrid MR-guided radiation therapy makes it possible to better visualize cardiac lesions and to apply high doses per fraction in sensible organs such as the heart.

CASE PRESENTATION

Patients affected by inoperable primary cardiac sarcomas and treated at two different institutions were considered for this analysis and retrospectively analyzed. All patients were treated using a 0.35 T hybrid MR Linac system (MRIdian, ViewRay Inc., Mountain View, CA). In the present study we investigated the feasibility, early outcome and toxicity of MR-guided RT in primary cardiac sarcomas. Four consecutive non-metastasized patients who were treated between 05-09/2020 were analyzed. The cardiac sarcomas were mostly located in the right atrium (50%) and one patient presented with 3 epicardial lesions. All patients received MRgRT as a salvage treatment for recurrent cardiac sarcoma after initial surgery, after a mean interval of 12 months (range 1-29 months). Regarding the treatment characteristics, the mean GTV size was 22.9 cc (range 2.5-56.9 cc) and patients were treated with a mean GTV dose of 38.9 Gy (range 30.1-41.1 Gy) in 5 fractions. Regarding feasibility, all treatments were completed as planned and all patients tolerated the treatment very well and showed only mild grade 1 or 2 symptoms like fatigue, dyspnea or mild chest pain at early follow-up.

CONCLUSION

To the best of our knowledge, in this retrospective analysis we present the first and largest series of patients presenting with primary cardiac sarcomas treated with online adaptive MRgRT. However, further studies are needed to evaluate the impact of this new methodology on the outcome of this very rare disease.

Radiation treatment for adult rare cancers: Oldest and newest indication

AIM

Aim of this analysis is to review the role of RT in the management of several rare tumors for adult patients.

METHODS

Collection data regarding RT and rare tumors was made by Pubmed.

RESULTS

For mucosal melanomas, RT is prescribed, being associated with lower local recurrence rate. For trachea tumors, RT was used as adjuvant or salvage treatment for unresectable disease. For pNET, RT can be a suitable option for post-surgical or unresectable/borderline. For bronchopulmonary neuroendocrine tumors the role of adjuvant treatments is uncertain. For hepatobiliary and ovarian malignancy, stereotactic body RT (SBRT) is a promising approach. For soft tissue sarcoma, perioperative treatments are indicated, and a growing role of SBRT in oligometastatic disease is recognized. For endocrine tumors, adjuvant RT has demonstrated benefits through reducing recurrence risk.

CONCLUSION

The radiotherapy is a frequent indication in adult rare cancers; thus the role of Radiation Oncologist must not be neglected.