Secondary radiation-induced bone tumours demonstrate a high degree of genomic instability predictive of a poor prognosis

Genomic Insights Into High-Grade Infarct-Associated Bone Sarcomas

Sarcomas rarely develop in bones previously compromised by infarcts. These infarct-associated sarcomas often present as undifferentiated pleomorphic sarcomas (UPS), and their genetic characteristics are poorly understood. High-grade UPS of bone are typically treated with a combination of surgery and chemotherapy, similar to osteosarcoma. We conducted a detailed clinicopathologic and genomic analysis of 6 cases of intraosseous sarcomas arising from histologically and radiographically confirmed bone infarcts. We analyzed 523 genes for sequence-level mutations using next-generation sequencing with the TruSight Oncology 500 panel and utilized whole-genome single nucleotide polymorphism Microarray (OncoScan CNV) to detect copy number alterations and loss of heterozygosity (LOH). Genomic instability was assessed through homologous recombination deficiency (HRD) metrics, incorporating LOH, telomeric allelic imbalance, and large-scale state transitions. Fluorescence in situ hybridization and immunohistochemistry validated the findings. The cohort included 3 men and 3 women, with a median age of 70 years, and tumors located in the femur and tibia. Five of the 6 patients developed distant metastases. Treatment involved surgery and chemotherapy or immune checkpoint inhibitors. Genomic analysis revealed significant complexity and high HRD scores, ranging from 32 to 57 (with a cutoff of 32). Chromosome 12 alterations, including segmental amplification or chromothripsis, were observed in 4 cases. Notably, MDM2 amplification, confirmed by fluorescence in situ hybridization, was detected in 2 cases. Homozygous deletion of CDKN2A/B was observed in all six cases. Tumor mutational burden levels ranged from 2.4 to 7.9 mutations per megabase. Notable pathogenic mutations included H3-3A mutations (p.G35R and p.G35W), and mutations in HRAS, DNMT3A, NF2, PIK3CA, POLE, and TP53, each in one case. These results suggest that high-grade infarct-associated sarcomas of bone, whereas sharing high levels of structural variations with osteosarcoma, may exhibit potentially less frequent TP53 mutations and more common CDKN2A/B deletions. This points to the possibility that the mutation spectrum and disrupted pathways could be distinct from conventional osteosarcoma.

Case report: Extended Isolated Stopflow Limb Infusion (EISLI) for highly malignant osteosarcoma - complete pathological tumor remission and implantation of a knee joint prosthesis

INTRODUCTION AND IMPORTANCE

An 18-year old osteosarcoma patient with a huge tumor mass at the distal femur and inguinal metastases was treated with the intention to preserve the leg and additionally treat the pelvic metastases locally. Therefore we modulated the technique of isolated limb perfusion.

CASE PRESENTATION

Isolated Limb Perfusion was performed as an Extended Isolated Limb Stop-Flow Infusion (EISLI) where the pelvis was included into the perfusion bed. Balloon catheters were placed in the arterial and venous bifurcation in the pelvis. For increasing the drug concentration at the tumor site, an angiographic catheter was placed arterially with the tip right in front of the tumor region. A Stop-Flow phase before the perfusion phase was applied.

CLINICAL DISCUSSION

After 4 cycles of EISLI the lesions in the pelvis disappeared and surgical resection of the tumor and implantation of an endoprosthesis was possible and successful. Histopathological findings showed no vital cells in the resected tumor region. Currently the patient is tumor free and does not show recurrence or pulmonal metastases for 18 months after the last induction treatment cycle.

CONCLUSION

With EISLI the inclusion of the pelvis is possible during isolated limb perfusion. In addition with low total dosages EISLI enabled drug concentrations many times higher at the tumor site than possible during systemic chemotherapy or standard isolated limb perfusion. It is a technique that allows limb preservation and treatment of positive lymphnodes in the groin. Quality of life is maintained during the Regional Chemotherapy (RCT).

Neoadjuvant chemotherapy for radiation-associated soft-tissue sarcoma: A case report

Radiation-associated sarcomas are rare and aggressive types of sarcomas that can occur after exposure to ionizing radiation. We examine a case of radiation-associated undifferentiated/unclassified soft-tissue sarcoma with primary disease in the chest wall. The optimal treatment of these patients is surgical resection if possible; however, the role of chemotherapy has not been well defined. The patient described herein had a central tumor in the chest wall. Since many of these patients have borderline resectable tumors, the use of neoadjuvant chemotherapy may be helpful to downstage the tumors for possible surgical resection. In this case, doxorubicin plus ifosfamide chemotherapy was employed with a favorable therapeutic effect prior to being resected. To our knowledge this is the first report of greater than 90% necrosis in a patient with radiation-associated undifferentiated/unclassified soft-tissue sarcoma treated with chemotherapy for a borderline resectable mass.

Biodosimetry of Persons Chronically Exposed to Low and Therapeutic Doses of Ionizing Radiation

Dynamic changes of the chromosomal aberrations and the DNA damage were analyzed in individuals exposed to low and therapeutic doses of radiation. The investigation included 37 persons living in areas where the radioactive sources were discovered 10–12 years ago. It was established by biodosimetry methods that the examined persons had absorbed dose of 0.2–0.7 Gy or had increased number of chromosomal aberrations, though insufficient to determine a dose. Clinical examination, chromosomal analysis, and assay of DNA damage by the comet (single-cell gel electrophoresis) assay were carried out. There was no correlation between the doses received 10 years ago and the cytogenetic changes with clinical outcome. The effect of the local fractionated gamma-irradiation with doses of 40–70 Gy was studied in cancer patients with localized head and neck tumors. The study of chromosomal abnormalities, the DNA damages by the comet assay, and the micronuclei detection of the buccal cells revealed a statistically significant correlation between the initial cytogenetic indices in cancer patients and their dynamic changes during and after the radiation exposure. In addition, the correlation was detected between the initial cytogenetic parameters and the functional stage of red blood system. Our results allow us to conclude that there is a need for further research to estimate the individual radiation risk to optimize and individualize the subsequent medical management of radiotherapy.

Frequent induction of chromosomal aberrations in in vivo skin fibroblasts after allogeneic stem cell transplantation: hints to chromosomal instability after irradiation

Background

Total body irradiation (TBI) has been part of standard conditioning regimens before allogeneic stem cell transplantation for many years. Its effect on normal tissue in these patients has not been studied extensively.

Method

We studied the in vivo cytogenetic effects of TBI and high-dose chemotherapy on skin fibroblasts from 35 allogeneic stem cell transplantation (SCT) patients. Biopsies were obtained prospectively (n = 18 patients) before, 3 and 12 months after allogeneic SCT and retrospectively (n = 17 patients) 23–65 months after SCT for G-banded chromosome analysis.

Results

Chromosomal aberrations were detected in 2/18 patients (11 %) before allogeneic SCT, in 12/13 patients (92 %) after 3 months, in all patients after 12 months and in all patients in the retrospective group after allogeneic SCT. The percentage of aberrant cells was significantly higher at all times after allogeneic SCT compared to baseline analysis. Reciprocal translocations were the most common aberrations, but all other types of stable, structural chromosomal aberrations were also observed. Clonal aberrations were observed, but only in three cases they were detected in independently cultured flasks. A tendency to non-random clustering throughout the genome was observed. The percentage of aberrant cells was not different between patients with and without secondary malignancies in this study group.

Conclusion

High-dose chemotherapy and TBI leads to severe chromosomal damage in skin fibroblasts of patients after SCT. Our long-term data suggest that this damage increases with time, possibly due to in vivo radiation-induced chromosomal instability.

Radiation-Induced Intraspinal Chondrosarcoma: A Case Report

Study Design Case report and review of the literature. Objective To report a unique case of an intraspinal chondrosarcoma that was diagnosed 18 years after radiotherapy for a cervical carcinoma and its remarkably unusual clinical presentation. Methods A retrospective case description of an intraspinal mass lesion that occurred 6 weeks after previous spinal surgery. Results Within ∼9 weeks, the tumor had infiltrated the peritoneal cavity and reached the lumbar subcutaneous tissue. Conclusion Radiation-induced sarcomas are rare, are highly aggressive, and may be difficult to diagnose. Furthermore, the only means of achieving long-term survival is through early and extensive surgery.

Mdm2 and p53 Expression in Radiation-Induced Sarcomas of the Head and Neck: Comparison with De Novo Sarcomas

Background

The pathogenesis of radiation-induced sarcomas (RISs) is not well known. In RIS, TP53 mutations are frequent, but little is known about Mdm2-p53 interaction, which is a recent therapeutic target of sarcomas.

Methods

We studied the immunohistochemical expression of Mdm2 and p53 of 8 RISs. The intervals between radiation therapy and diagnosis of secondary sarcomas ranged from 3 to 17 years.

Results

Mdm2 expression was more common in de novo sarcomas than RISs (75% vs 37.5%), and p53 expression was more common in RISs than in de novo cases (75% vs 37.5%). While half of the RISs were Mdm2(–)/p53(+), none of de novo cases showed such combination; while half of de novo sarcomas were Mdm2(+)/p53(–), which are a candidate group of Mdm2 inhibitors, only 1 RIS showed such a combination. Variable immunoprofiles observed in both groups did not correlate with tumor types, except that all of 2 myxofibrosarcomas were Mdm2(+)/p53(+).

Conclusions

In conclusion, we speculated that both radiation-induced and de novo sarcomagenesis are not due to a unique genetic mechanism. Mdm2-expression without p53 overexpression in 1 case of RIS decreases the future possibility of applying Mdm2 inhibitors on a subset of these difficult tumors.