Wound healing morbidity in STS patients treated with preoperative radiotherapy in relation to in vitro skin fibroblast radiosensitivity, proliferative capacity and TGF-β activity

Pelvic Ewing sarcoma: Should all patients receive pre-operative radiotherapy, or should it be delivered selectively?

BACKGROUND

Locally recurrent disease following surgical resection of Ewing sarcoma (ES) confers a poor prognosis. Limited evidence is available evaluating non-selective use of pre-operative radiotherapy (RT) for patients with pelvic ES and its effect on local control and survival.

PATIENTS AND METHODS

49 consecutive patients with pelvic ES were identified retrospectively from a prospectively collated database. Patients either received non-selective pre-operative RT and surgery (n = 27), or selective post-operative RT (n = 22) (surgery alone (n = 11) or surgery and post-operative RT (n = 11)).

RESULTS

Patients who had non-selective pre-operative radiotherapy appeared to have a higher LRFS, 88.0% compared to 66.5% in the selective RT group (p = 0.096, Kaplan Meier; p = 0.028, Chi-squared). Administration of non-selective, pre-operative RT to all patients with pelvic ES elevates the LFRS to that of the good responder group (≥90% tumour necrosis and margins, p = 0.880). There was no difference in metastasis-free survival, 60.0% and 54.5% (p = 0.728) and overall survival (OS), 57.7% and 63.6% (p = 0.893). The majority of pre-operative RT patients had both good necrosis (≥90%) (p = 0.003) and widely excised tumours, 81.5% vs 59.1% (p = 0.080). Tumour volume ≥250 ml was associated with worse LRFS (p = 0.045) and post-operative complications (p = 0.017). There may be improved LRFS (p = 0.057) with pre-operative proton-beam RT compared to surgery and selective post-operative RT.

CONCLUSION

Pre-operative photon or proton-beam RT to all pelvic ES may improve LRFS compared to the selective delivery of post-operative RT. Radiotherapy delivered to all patients results in a greater percentage of highly necrotic tumours at surgical excision, enabling a greater proportion of patients with wide resection margins.

Efficacy and Incontinence Rates After Urethroplasty for Radiation-induced Urethral Stenosis: A Systematic Review and Meta-analysis

OBJECTIVE

To estimate the efficacy of urethroplasty and rates of de novo stress urinary incontinence (SUI) in the specific setting of radiation-induced urethral stenosis.

METHODS

A systematic search of databases (PubMed and EMBASE) was performed between 1980-2019 (CRD42020144845). Inclusion criteria were: (1) prior pelvic radiotherapy; (2) surgical urethroplasty; (3) rates of successful treatment and/or SUI development and (4) total case number provided. The pooled summary of stenosis resolution rate and SUI were calculated using the random-effects model weighted by the inverse variance. Accessory analyses were performed by reconstructive technique and type of RT.

RESULTS

Ninety-six studies were identified, of which 8 retrospective studies met inclusion criteria, comprising 256 patients. The proportion of cases treated with external beam RT (EBRT), brachytherapy (BT), or combination (EBRT+BT) were 52%, 33%, and 15%, respectively, of studies that specified modality. Most strictures involved the bulbomembranous region (n = 212; 83%). Sixty-one percent of cases (n = 157) entailed primary anastomosis, while the remainder underwent augmentation reconstruction (graft or flap). The mean follow-up time after urethroplasty varied from 10 to 50.5 months. The pooled stenosis resolution rate was 80% (95% CI: 74%-86%). There were no significant associations between stenosis resolution rate and reconstructive technique (rho=0.20, P = .74) or RT modality (rho=-0.31, P = .53). Fifty-three cases developed subsequent SUI, with a pooled complication rate of 19% (95% CI: 10%-31%).

CONCLUSIONS

Urethroplasty after radiation-induced urethral stenosis is effective for 80% of cases, independent of prior RT modality or urethroplasty technique; however, 1 out of every 5 patients develops SUI post-procedure.

Surgical outcomes and prognostic factors of non-metastatic radiation-induced sarcoma of bone

BACKGROUND

The survival and prognostic factors in non-metastatic, radiation-induced bone sarcomas of bone have not been described. Moreover, the quantitative data about surgical outcomes and complications after limb-salvage surgery versus amputation are quite limited.

METHODS

Twenty-five patients with non-metastatic, radiation-induced sarcoma of bone who underwent definitive surgery were analysed. Histological diagnosis was osteosarcoma in 19 and undifferentiated pleomorphic sarcoma in six. The definitive surgery was limb-salvage surgery in 15 patients and an amputation in 10.

RESULTS

The 5-year overall survival rate (OS) and the 5-year event-free survival rate (EFS) were 53% (95% CI 31%-70%) and 40% (21%-59%), respectively. Patients with wide or radical surgical margins (n = 13) showed significantly better OS compared with those with marginal (n = 8) or intralesional (n = 2) margins (5-year OS, radical or wide = 74%, marginal = 17%, intralesional = 0%, p = 0.044). The risk of local recurrence was significantly higher in the limb-salvage group compared to the amputation group (49% vs 0%, p = 0.011). OS and EFS were not significantly different between limb-salvage group and an amputation group (p = 0.188 and 0.912, respectively).

CONCLUSIONS

We believe non-metastatic, radiation-induced sarcoma of bone should be resected with the aim of achieving wide or radical margins. Although limb-salvage surgery was related to higher rates of local recurrence compared with those of the amputation group, OS and EFS were not different among two groups. Surgeons need to discuss the higher risk of local recurrence in limb-salvage surgery.

Laser-Driven Ultrashort Pulsed Electron Beam Radiation at Doses of 0.5 and 1.0 Gy Induces Apoptosis in Human Fibroblasts

Rapidly evolving laser technologies have led to the development of laser-generated particle accelerators as an alternative to conventional facilities. However, the radiobiological characteristics need to be determined to enhance their applications in biology and medicine. In this study, the radiobiological effects of ultrashort pulsed electron beam (UPEB) and X-ray radiation in human lung fibroblasts (MRC-5 cell line) exposed to doses of 0.1, 0.5, and 1 Gy are compared. The changes of γH2AX foci number as a marker of DNA double-strand breaks (DSBs) were analyzed. In addition, the micronuclei induction and cell death via apoptosis were studied. We found that the biological action of UPEB-radiation compared to X-rays was characterized by significantly slower γH2AX foci elimination (with a dose of 1 Gy) and strong apoptosis induction (with doses of 0.5 and 1.0 Gy), accompanied by a slight increase in micronuclei formation (dose of 1 Gy). Our data suggest that UPEB radiation produces more complex DNA damage than X-ray radiation, leading to cell death rather than cytogenetic disturbance.

Wound healing complications in oncological patients: perspectives for cellular therapy

Various types of cancer are nowadays a serious medical and social problem and a great challenge for modern medicine. The majority of anticancer therapy is based on traditional chemotherapy and radiotherapy. Both of these highly non-specific types of treatment have a number of serious side effects including wound healing complications. Radiotherapy and chemotherapy mostly affect rapidly dividing skin cells (e.g. keratinocytes), as well as fibroblasts, melanocytes, endothelial and immune cells. Currently, there are many strategies to improve wound healing in oncological patients, including various types of dressings, biomaterials, growth factors, and cell therapies.

Body composition predictors of therapy response in patients with primary extremity soft tissue sarcomas

Background Recent studies have suggested that the quantity and quality of adipose tissue and muscle, assessed on non-contrast computed tomography (CT), may serve as imaging biomarkers of survival in patients with and without neoplasms. Purpose To assess body composition measures that could serve as predictors of therapy response in patients with extremity soft tissue sarcomas treated with radiation therapy and surgery. Material and Methods The study was IRB-approved. Sixty patients had a history of extremity soft tissue sarcoma and underwent FDG-PET/CT prior to radiation therapy and surgical resection. Cross-sectional areas and CT attenuation (HU) of abdominal subcutaneous adipose tissue (SAT), visceral adipose tissue (VAT), and psoas muscle were assessed on non-contrast CT. Clinical information on predictors of tumor recurrence and post-surgical wound infections were recorded. Cox proportional hazard models were used to determine longitudinal associations between body composition and tumor recurrence/wound infections. Results Twenty-three tumor recurrences occurred over a follow-up period of 43 ± 35 months. Higher SAT and lower psoas attenuation were associated with tumor recurrence which remained significant after adjustment for covariates ( P ≤ 0.01). There were 13 post-surgical wound infections. Higher VAT and SAT attenuation were associated with post-surgical wound infections ( P < 0.04); however, VAT attenuation lost significance after adjustment for covariates. Conclusion Abdominal adipose tissue and psoas muscle attenuation assessed on non-contrast CT may predict tumor recurrence and post-surgical infections in patients with extremity soft tissue sarcomas.

MnTE-2-PyP Treatment, or NOX4 Inhibition, Protects against Radiation-Induced Damage in Mouse Primary Prostate Fibroblasts by Inhibiting the TGF-Beta 1 Signaling Pathway

Prostate cancer patients who undergo radiotherapy frequently suffer from side effects caused by radiation-induced damage to normal tissues adjacent to the tumor. Exposure of these normal cells during radiation treatment can result in tissue fibrosis and cellular senescence, which ultimately leads to postirradiation-related chronic complications including urinary urgency and frequency, erectile dysfunction, urethral stricture and incontinence. Radiation-induced reactive oxygen species (ROS) have been reported as the most potent causative factor for radiation damage to normal tissue. While MnTE-2-PyP, a ROS scavenger, protects normal cells from radiation-induced damage, it does not protect cancer cells during radiation treatment. However, the mechanism by which MnTE-2-PyP provides protection from radiation-induced fibrosis has been unclear. Our current study reveals the underlying molecular mechanism of radiation protection by MnTE-2-PyP in normal mouse prostate fibroblast cells. To investigate the role of MnTE-2-PyP in normal tissue protection after irradiation, primary prostate fibroblasts from C57BL/6 mice were cultured in the presence or absence of MnTE-2-PyP and exposed to 2 Gy of X rays. We found that MnTE-2-PyP could protect primary prostate fibroblasts from radiation-induced activation, as measured by the contraction of collagen discs, and senescence, detected by beta-galactosidase staining. We observed that MnTE-2-PyP inhibited the TGF-β-mediated fibroblast activation pathway by downregulating the expression of TGF-β receptor 2, which in turn reduced the activation and/or expression of SMAD2, SMAD3 and SMAD4. As a result, SMAD2/3-mediated transcription of profibrotic markers was reduced by MnTE-2-PyP. Due to the inhibition of the TGF-β pathway, fibroblasts treated with MnTE-2-PyP could resist radiation-induced activation and senescence. NADPH oxidase 4 (NOX4) expression is upregulated after irradiation and produces ROS. As was observed with MnTE-2-PyP treatment, NOX4^-/- fibroblasts were protected from radiation-induced fibroblast activation and senescence. However, NOX4^-/- fibroblasts had reduced levels of active TGF-β1, which resulted in decreased TGF-β signaling. Therefore, our data suggest that reduction of ROS levels, either by MnTE-2-PyP treatment or by eliminating NOX4 activity, significantly protects normal prostate tissues from radiation-induced tissue damage, but that these approaches work on different components of the TGF-β signaling pathway. This study proposes a crucial insight into the molecular mechanism executed by MnTE-2-PyP when utilized as a radioprotector. An understanding of how this molecule works as a radioprotector will lead to a better controlled mode of treatment for post therapy complications in prostate cancer patients.

Study of Preoperative Radiotherapy for Sarcomas of the Extremities with Intensity-Modulation, Image-Guidance and Small Safety-margins (PREMISS)

Background

The aim of the trial is to demonstrate that with the use of modern IMRT/IGRT and reduction of safety margins postoperative wound complications can be reduced.

Methods/ Design

The trial is designed as a prospective, monocentric clinical phase II trial. The treatment is performed with helical IMRT on the Tomotherapy HiArt System© or with RapidArc© IMRT as available. All treatments are performed with 6 MV photons and daily online CT-based IGRT.

A dose of 50 Gy in 2 Gy single fractions (5 fractions per week) is prescribed. Restaging including MRI of the primary tumor site as well as CT of the thorax/abdomen is planned 4 weeks after RT. PET-examinations or any other imaging can be performed as required clinically. In cases of R1 resection, brachytherapy is anticipated in the 2nd postoperative week. Brachytherapy catheters are implanted into the tumor bed depending on the size and location of the lesion. Surgery is planned 5–6 weeks after completion of neoadjuvant RT. All patients are seen for a first follow-up visit 2 weeks after wound healing is completed, thereafter every 3 months during the first 2 years. The endpoints of the study are evaluated in detail during the first (2 weeks) and second (3 months) follow-up. Functional outcome and QOL are documented prior to treatment and at year 1 and 2. Treatment response and efficacy will be scored according to the RECIST 1.1 criteria. A total patient number of 50 with an expected 20 % rate of wound complications were calculated for the study, which translates into a 95 % confidence interval of 10.0-33.7 % for wound complication rate in a binomial distribution.

Discussion

The present study protocol prospectively evaluates the use of IMRT/IGRT for neoadjuvant RT in patients with soft tissue sarcomas of the extremity with the primary endpoint wound complications, which is the major concern with this treatment sequence. Besides complications rates, local control rates and survival rates, as well as QOL, functional outcome and treatment response parameters (imaging and pathology) are part of the protocol. The data of the present PREMISS study will enhance the current literature and support the hypothesis that neoadjuvant RT with IMRT/IGRT offers an excellent risk-benefit ratio in this patient population.

Trial registration

NCT01552239

The influence of time interval between preoperative radiation and surgical resection on the development of wound healing complications in extremity soft tissue sarcoma

OBJECTIVE

The aim of this study was to determine the relationship of the time interval between completion of preoperative radiation therapy (RT) and surgical resection on wound complications (WCs) in extremity soft tissue sarcoma (STS).

METHODS

Overall, 798 extremity STS patients were managed with preoperative RT and surgery from 1989 to 2013. WCs were defined as requiring secondary operations/invasive procedures for wound care, use of vacuum-assisted closure, prolonged dressing changes, or infection within 120 days of surgery.

RESULTS

Mean tumor size was 8.8 cm. A total of 743 (93 %) tumors were primary presentations, 565 (71 %) patients had lower extremity tumors, and 238 patients (30 %) had a prior unplanned excision. Of 242 patients (30 %) who developed a WC, 206 (37 %) had lower extremity tumors and 36 (15 %) had upper extremity tumors. Mean time from RT completion to surgery was 41.3 (range 4-470) days; 42.0 (range 4-470) days for upper extremity cases, and 41.1 (range 4-109) days for lower extremity cases. Similarly, mean time interval for patients who developed a WC was 40.9 (range 4-100) days, and 41.5 (range 4-470) days for those who did not develop a WC (p = 0.69). Thirty-nine cases (5 %) had surgery within 3 weeks of RT; 15 (38 %) patients developed WCs versus 227 (30 %) patients who had their tumors excised after 3 weeks (p = 0.28). One hundred and twenty-nine (16 %) patients had surgery within 4 weeks, and 39 (30 %) patients developed WCs versus 203 (30 %) patients who had their tumors excised after 4 weeks (p = 1.0). A trend towards a higher rate of WCs was seen for those patients who had surgery after 6 weeks (28 % prior vs. 34 % after; p = 0.08). There was no difference in WCs with intensity-modulated RT (IMRT) versus non-IMRT cases (p = 0.6).

CONCLUSION

The time interval between preoperative RT and surgical excision in extremity STS had minimal influence on the development of WCs. Four- or 5-week intervals showed equivalent complication rates between the two groups, suggesting an optimal interval to reduce potential WCs.

In vitro radiosensitization by pentoxifylline does not depend on p53 status

PURPOSE

The mode by which the xanthine derivative, pentoxifylline, induces a radiosensitizing effect in cell cultures is a key and controversial radiobiological issue and requires further elucidation.

MATERIALS AND METHODS

Six human glioblastoma cell lines were tested for the effect of pentoxifylline treatment at maximum G2/M block on the basis of cell survival, mitotic activity, and micronucleus formation after exposure to gamma radiation. Cell survival was measured by the colony-forming assay. Micronucleus formation (an indicator of DNA damage) and the proportion of binucleated cells (a representation of mitotic activity) were determined using the cytokinesis-block assay.

RESULTS

Remarkably, exposure to a single dose of 4 Gy produced strong G2/M blocks in both p53 mutant and wild-type cells. Addition of pentoxifylline at the peak of radiation-induced G2/M blocks resulted in a p53-independent reduction in cell survival in all cell lines. This radiosensitization was strongly correlated with the magnitude of the radiation-induced G2/M block. The changes observed in mitotic activity and micronucleus yield were also p53-independent.

CONCLUSIONS

These results are at variance with the view that pentoxifylline preferentially sensitizes p53 mutant cells, and that sensitization occurs only when cells are irradiated in the presence of the drug. The data suggest that the effectiveness of pentoxifylline as radiosensitizer depends on the proportion of cells that are arrested in the G2/M phase transition following exposure to ionizing radiation. These findings can assist in the identification of cancers that may benefit from therapies using G2/M checkpoint abrogators.

Cerebral radiation necrosis: a review of the pathobiology, diagnosis and management considerations

Radiation therapy forms one of the building blocks of the multi-disciplinary management of patients with brain tumors. Improved survival following radiation therapy may come with a cost, including the potential complication of radiation necrosis. Radiation necrosis impacts the quality of life in cancer survivors, and it is essential to detect and effectively treat this entity as early as possible. Significant progress in neuro-radiology and molecular pathology facilitate more straightforward diagnosis and characterization of cerebral radiation necrosis. Several therapeutic interventions, both medical and surgical, may halt the progression of radiation necrosis and diminish or abrogate its clinical manifestations, but there are still no definitive guidelines to follow explicitly that guide treatment of radiation necrosis. We discuss the pathobiology, clinical features, diagnosis, available treatment modalities, and outcomes in the management of patients with intracranial radiation necrosis that follows radiation used to treat brain tumors.

Studies of the in vivo radiosensitivity of human skin fibroblasts

BACKGROUND AND PURPOSE

To examine the radiosensitivity of skin cells obtained directly from the irradiated skin of patients undergoing fractionated radiation treatment prior to surgery for treatment of soft tissue sarcoma (STS) and to determine if there was a relationship with the development of wound healing complications associated with the surgery post-radiotherapy.

METHODS

Micronucleus (MN) formation was measured in cells (primarily dermal fibroblasts) obtained from human skin at their first division after being removed from STS patients during post-radiotherapy surgery (2-9 weeks after the end of the radiotherapy). At the time of radiotherapy (planned tumor dose - 50Gy in 25 daily fractions) measurements were made of surface skin dose at predetermined marked sites. Skin from these sites was obtained at surgery and cell suspensions were prepared directly for the cytokinesis-blocked MN assay. Cultured strains of the fibroblasts were also established from skin nominally outside the edge of the radiation beam and DNA damage (MN formation) was examined following irradiation in vitro for comparison with the results from the in situ irradiations.

RESULTS

Extensive DNA damage (MN) was detectable in fibroblasts from human skin at extended periods after irradiation (2-9 weeks after the end of the 5-week fractionated radiotherapy). Analysis of skin receiving a range of doses demonstrated that the level of damage observed was dose dependent. There was no clear correlation between the level of damage observed after irradiation in situ and irradiation of cell strains in culture. Similarly, there was no correlation between the extent of MN formation following in situ irradiation and the propensity for the patient to develop wound healing complications post-surgery.

CONCLUSIONS

Despite the presence of DNA damage in dermal fibroblasts weeks after the end of the radiation treatment, there was no relationship between this damage and wound healing complications following surgery post-irradiation. These results suggest that factors other than the radiosensitivity of the skin fibroblasts likely also play a role in wound healing in deep wound sites associated with surgery for STS following radiation therapy.

Interrelation amongst differentiation, senescence and genetic instability in long-term cultures of fibroblasts exposed to different radiation qualities

BACKGROUND AND PURPOSE

The goal of the present study was to investigate aging and genetic instability in the progeny of human fibroblasts exposed to X-rays and carbon ions.

MATERIALS AND METHODS

Following irradiation, cells were regularly subcultured until senescence. At selected time-points BrdU-labelling index, expression of cell cycle related proteins, cell differentiation pattern and chromosome aberrations were assessed.

RESULTS

After exposure, an immediate cell cycle arrest occurred followed by a period of a few weeks where premature differentiation and senescence were observed. In all cultures cycling cells expressing low levels of cell cycle inhibiting proteins were present and finally dominated the populations. About 5months after exposure, the cellular and molecular changes attributed to differentiation and senescence reappeared and persisted. Concurrently, genetic instability was observed, but the aberration yields and types differed between repeated experiments. The descendants of cells exposed to carbon ions did not senesce earlier and displayed a similar rate of genetic instability as the X-ray progeny. For high doses an impaired cell cycle regulation and extended life span was observed, but finally cell proliferation ceased in all populations.

CONCLUSIONS

The descendants of irradiated fibroblasts undergo stepwise senescence and differentiation. Genetic instability is frequent and an extension of the life span may occur.

Opportunities for improving the therapeutic ratio for patients with sarcoma

Sarcomas are mesenchymal cancers, which, in many cases, have distinctive molecular features. Limb-sparing surgery delivered at specialised sarcoma centres as part of a multidisciplinary approach has become the standard treatment for most patients and usually provides excellent local control. Preoperative treatment with chemotherapy is most common for patients with bone sarcomas. The ideal sequence of surgery and radiation for local management of soft-tissue sarcoma remains controversial on the basis of early versus late treatment complications, although preoperative radiation can provide the best results for improved long-term function. New methods for radiation delivery and tumour sensitisation might provide further improvements. However, metastatic disease is common, and conventional chemotherapy provides for only a narrow therapeutic window outside of a few responsive pathological subtypes. Targeting underlying molecular events in specific sarcomas can provide for dramatic benefits, as has been seen with imatinib treatment for gastrointestinal stromal tumours and dermatofibrosarcoma protuberans. Trials of agents targeting the cell cycle and angiogenesis in soft-tissue sarcomas, and of those targeting osteoclasts in bone sarcomas, are currently underway. Biological data and preclinical studies support trials using inhibitors of hedgehog signalling in chondrosarcoma, inhibitors of wnt/beta-catenin in osteosarcoma and aggressive fibromatosis, and inhibitors of histone deacetylases in synovial sarcoma and Ewing sarcoma. Pharmacogenetic approaches will be needed to identify individual determinants of response and outcome in order to maximise the benefits of targeting specific molecular events and keep side-effects to a minimum. Research in stem-cell biology and nanotechnology holds promise for additional novel treatment options in the future.

Genetic predictors of adverse radiotherapy effects: the Gene-PARE project

PURPOSE

The development of adverse effects resulting from the radiotherapy of cancer limits the use of this treatment modality. The validation of a test capable of predicting which patients would be most likely to develop adverse responses to radiation treatment, based on the possession of specific genetic variants, would therefore be of value. The purpose of the Genetic Predictors of Adverse Radiotherapy Effects (Gene-PARE) project is to help achieve this goal.

METHODS AND MATERIALS

A continuously expanding biorepository has been created consisting of frozen lymphocytes and DNA isolated from patients treated with radiotherapy. In conjunction with this biorepository, a database is maintained with detailed clinical information pertaining to diagnosis, treatment, and outcome. The DNA samples are screened using denaturing high performance liquid chromatography (DHPLC) and the Surveyor nuclease assay for variants in ATM, TGFB1, XRCC1, XRCC3, SOD2, and hHR21. It is anticipated that additional genes that control the biologic response to radiation will be screened in future work.

RESULTS

Evidence has been obtained that possession of variants in genes, the products of which play a role in radiation response, is predictive for the development of adverse effects after radiotherapy.

CONCLUSIONS

It is anticipated that the Gene-PARE project will yield information that will allow radiation oncologists to use genetic data to optimize treatment on an individual basis.