Immunobiology of cancer-associated fibroblasts in the context of radiotherapy

Radiotherapy (RT) still represents a mainstay of treatment in clinical oncology. Traditionally, the effectiveness of radiotherapy has been attributed to the killing potential of ionizing radiation (IR) over malignant cells, however, it has become clear that therapeutic efficacy of RT also involves activation of innate and adaptive anti-tumor immune responses. Therapeutic irradiation of the tumor microenvironment (TME) provokes profound cellular and biological reconfigurations which ultimately may influence immune recognition. As one of the major constituents of the TME, cancer-associated fibroblasts (CAFs) play central roles in cancer development at all stages and are recognized contributors of tumor immune evasion. While some studies argue that RT affects CAFs negatively through growth arrest and impaired motility, others claim that exposure of fibroblasts to RT promotes their conversion into a more activated phenotype. Nevertheless, despite the well-described immunoregulatory functions assigned to CAFs, little is known about the interplay between CAFs and immune cells in the context of RT. In this review, we go over current literature on the effects of radiation on CAFs and the influence that CAFs have on radiotherapy outcomes, and we summarize present knowledge on the transformed cellular crosstalk between CAFs and immune cells after radiation.

P08 The missing links in the chain

Case report - Introduction Sciatica symptoms are common symptoms in the general population. Most frequently, patients and health professional tend to conservatively manage symptoms assuming that disc prolapses are the main cause. Herein we describe a case of 69-year-old who had delayed diagnosis of spindle cell carcinoma secondary to radiotherapy for previous cancer. We will outline lessons learnt across the whole system, including carer’s perspective. Case report - Case description We present a case of 69-year-old woman who was referred to rheumatology with a 3-year history of worsening back pain and sciatica symptoms. She has a longstanding history of achalasia and previous ovarian cancer for which she had curative TAH and BFO and subsequent radiotherapy in 1997. The patient had worsening right leg paraesthesia and neuropathic symptoms suggestive of sciatica which started in 2013. She was self-managing her symptoms and practised yoga and home-based exercise. She was subsequently seen by her GP, NHS community physiotherapy team, private physiotherapist, osteopath, the GP practice physiotherapist and orthopaedics. An MRI spine was performed which showed degenerative changes with no acute nerve root compression and she was re-assured that there was no indication for surgery to the spine. Despite analgesia, regular physiotherapy and TENS device, her symptoms worsened with night pain and sleep disturbance, hence her rheumatology referral in 2016. Clinical examination revealed right-sided buttock and sacral tenderness with right upper leg wasting, right knee flexion and ankle dorsiflexion weakness and reduced sensation over the right lateral thigh and in the first web-space. Hence, an MRI pelvis and NCS/EMG were arranged. EMG findings were highly suggestive of acute, severe, postganglionic, axonal lesion of the right lower lumbosacral plexus/right sciatic nerve affecting predominantly tibial division/S1 myotome. Subsequent MRI spine and pelvis revealed a right-sided sciatic nerve tumour and urgent biopsy confirmed grade 2 malignant peripheral nerve sheath tumour consistent with spindle cell carcinoma. Patient was referred to the specialist sarcoma service MDT and had right leg and hemipelvis amputation. She unfortunately had an eventful post-op recovery with a number of complications, including pneumonia, stroke and small bowel obstruction secondary to metastatic disease and was referred to end of life care. Case report - Discussion Back pain and sciatica are common symptoms, mostly secondary to disc prolapse or degenerative spine disease. The differential of causes is wide and it is vital to consider red flags. In this case previous history of cancer and radiotherapy should have alerted clinicians to do detailed examination and arrange relevant investigations accordingly. Differentiating sciatic neuropathy from L5 or S1 radiculopathies or lumbosacral plexopathy can be difficult. With L5 or S1 radiculopathies, patients commonly experience low back pain radiating into the lateral or posterior leg (L5/S1 distributions). The pain in radiculopathy tends to improve with standing and walking and worsen with sitting. Whereas sciatic neuropathy typically start at the buttock area or proximal thigh and pain radiates posteriorly and laterally into the leg. Depending on severity, patients with a sciatic neuropathy can experience extreme weakness of knee flexion and movements of the feet. Sensation can be lost in lateral knee, lateral calf, dorsum of the foot, web space of the great toe, posterior calf and lateral foot and sole of the foot radiating posteriorly and laterally into the leg. Detailed clinical examination along with neurophysiological study would help to identify the level of the lesion. Radiation-induced sarcoma (RIS) is a known long-term complication of radiotherapy, with an incidence ranging from 0.03% to 0.80% and latency of onset of 10 years or greater after treatment. The definition of RIS has never been well established. Cahan criteria modified by Arlen et al. are most commonly used to define RIS: treatment with therapeutic irradiation at least 3 years prior to development of sarcoma, a sarcoma arising within the field of previous therapeutic irradiation; and differing histology between the sarcoma and the primary tumor. Compared to other spontaneous cancers, spindle cell carcinoma is more aggressive and has poor prognosis with an overall of 5-year. Case report - Key learning points

Iron-Palladium Decorated Carbon Nanotubes Achieve Radiosensitization via Reactive Oxygen Species Burst

Radiotherapy is recommended as a modality for cancer treatment in clinic. However, cancerous cells were resistant to therapeutic irradiation due to its DNA repair. In this work, single-walled carbon nanotubes with unique physical properties of hollow structures and high specific surface area were introduced as carrier for iron-palladium (FePd) to obtain iron-palladium decorated carbon nanotubes (FePd@CNTs). On one hand, FePd nanoparticles possess significant ability in radiosensitization as previously reported. On the other hand, carbon nanotubes offer higher efficiency in crossing biological barriers, inducing the accumulation and retention of FePd nanoparticles within tumor tissue. In order to verify the radiosensitization effect of FePd@CNTs, both in vitro and in vivo experiments were conducted. These experiments showed that the FePd@CNTs exhibited remarkably better radiosensitization effect and more obvious accumulation than FePd NPs, suggesting a potential of FePd@CNTs in radiosensitization.

Irradiation of Nf1 mutant mouse models of spinal plexiform neurofibromas drives pathologic progression and decreases survival

Background Genetically susceptible individuals can develop malignancies after irradiation of normal tissues. In the context of therapeutic irradiation, it is not known whether irradiating benign neoplasms in susceptible individuals promotes neoplastic transformation and worse clinical outcomes. Individuals with Neurofibromatosis 1 (NF1) are susceptible to both radiation-induced second malignancies and spontaneous progression of plexiform neurofibromas (PNs) to malignant peripheral nerve sheath tumors (MPNSTs). The role of radiotherapy in the treatment of benign neoplasms such as PNs is unclear. Methods To test whether radiotherapy promotes neoplastic progression of PNs and reduces overall survival, we administered spinal irradiation (SI) to conditional knockout mouse models of NF1-associated PNs in two germline contexts: Nf1 fllfl; PostnCre + and Nf1 fl/-; PostnCre +. Both genotypes develop extensive Nf1 null spinal PNs, modeling PNs in NF1 patients. A total of 101 mice were randomized to 0 Gy, 15 Gy (3 Gy x 5), or 30 Gy (3 Gy x 10) of spine-focused, fractionated SI and aged until signs of illness. Results SI decreased survival in both Nf1 fllfl mice and Nf1 fl/- mice, with the worst overall survival occurring in Nf1 fl/- mice receiving 30 Gy. SI was also associated with increasing worrisome histologic features along the PN-MPNST continuum in PNs irradiated to higher radiation doses. Conclusions This pre-clinical study provides experimental evidence that irradiation of pre-existing PNs reduces survival and may shift PNs to higher grade neoplasms.

Angiosarcoma of the Urinary Bladder Following Radiotherapy: Report of a Case and Review of the Literature

Background and objectives: Angiosarcomas are uncommon and extremely aggressive malignancies derived from vascular endothelial cells. Although they can occur anywhere in the body and at any age, they are more frequently found in the skin of the head and neck regions and in the elderly. Few cases have been recorded in deep soft tissues and in parenchymal organs. Angiosarcomas of the urinary bladder are exceedingly rare. They usually arise in adult patients with a history of radiation therapy, cigarette smoking, or exposure to chemical agents (e.g., vinyl chloride). Despite multidisciplinary treatment approaches combining surgery, radiotherapy, and chemotherapy, prognosis is dismal. Materials and methods: We describe a case of a 78-year-old Caucasian man presenting with a vesical mass incidentally discovered with abdominal computerized tomography (CT). He underwent transurethral resection of the bladder (TURB), and histology was compatible with angiosarcoma. Results: The patient had been a heavy smoker and his medical history included therapeutic irradiation for prostate cancer eight years previously. Radical cystoprostatectomy was feasible, and pathologic examination of the surgical specimen confirmed angiosarcoma involving the urinary bladder, prostate, and seminal vesicles. Post-operative peritonitis resulted in progressive multi-organ failure and death. Conclusions: Angiosarcoma primary to the urinary bladder is seldom encountered, however, it should be considered in the differential diagnosis of vesical tumors, especially in elderly men with a history of pelvic radiotherapy.

Application of shearwave™ elastography to evaluate heat-induced changes in the young's modulus of fresh bovine muscle: A preliminary study

PurposeThe purpose of this study was to investigate the variation in the Young’s modulus (E) of bovine muscle samples as a function of temperature change generated by therapeutic ultrasound using Shearwave™ Elastography.MethodsInitially, the bovine muscle was heated via therapeutic ultrasound with a frequency of 3 MHz, nominal intensity of 2 W·cm-2, and application time of 2 min. Immediately following cessation of therapeutic irradiation, an E image was recorded and the stiffness was measured in circular area positioned at six depths (from 0.4 to 2.9 cm) in the center of the region of interest. Next, an E image was recorded every minute for the first 5 min. Over the next 30 min, an image was recorded every 5 min. Finally, an image was acquired 60 min after cessation of therapeutic irradiation. In the second test, the same experimental procedure was performed 60 min later with the physiotherapy equipment configured with a 10-min application time. Finally, during the ultrasonic irradiation of a new bovine muscle sample, the physiotherapeutic transducer was applied in a circular motion and with an angular velocity of 3.6 ± 0.3 rad·s-1.ResultsIn the first test, the bovine muscle E decreased from 212.2 ± 32.8 to 80.1 ± 13.8 kPa at 0.4 cm-depth, as the temperature increased from 18.2 to 44.9 °C. This effect was reversed when the temperature decreased. In the second test, denaturation and cell death occurred, so an artifact appeared in the elastographic image and the Shearwave™ Elastography did not capture the E from the depth of 1.9 cm.ConclusionWe confirmed that it is possible to use Shearwave™ Elastography to investigate heat-induced changes in the elastic modulus of biological tissue.

Chronic Inflammation and Radiation-Induced Cystitis: Molecular Background and Therapeutic Perspectives

Radiation cystitis is a potential complication following the therapeutic irradiation of pelvic cancers. Its clinical management remains unclear, and few preclinical data are available on its underlying pathophysiology. The therapeutic strategy is difficult to establish because few prospective and randomized trials are available. In this review, we report on the clinical presentation and pathophysiology of radiation cystitis. Then we discuss potential therapeutic approaches, with a focus on the immunopathological processes underlying the onset of radiation cystitis, including the fibrotic process. Potential therapeutic avenues for therapeutic modulation will be highlighted, with a focus on the interaction between mesenchymal stromal cells and macrophages for the prevention and treatment of radiation cystitis.

Prediction of the Acute or Late Radiation Toxicity Effects in Radiotherapy Patients Using Ex Vivo Induced Biodosimetric Markers: A Review

A search for effective methods for the assessment of patients’ individual response to radiation is one of the important tasks of clinical radiobiology. This review summarizes available data on the use of ex vivo cytogenetic markers, typically used for biodosimetry, for the prediction of individual clinical radiosensitivity (normal tissue toxicity, NTT) in cells of cancer patients undergoing therapeutic irradiation. In approximately 50% of the relevant reports, selected for the analysis in peer-reviewed international journals, the average ex vivo induced yield of these biodosimetric markers was higher in patients with severe reactions than in patients with a lower grade of NTT. Also, a significant correlation was sometimes found between the biodosimetric marker yield and the severity of acute or late NTT reactions at an individual level, but this observation was not unequivocally proven. A similar controversy of published results was found regarding the attempts to apply G2- and γH2AX foci assays for NTT prediction. A correlation between ex vivo cytogenetic biomarker yields and NTT occurred most frequently when chromosome aberrations (not micronuclei) were measured in lymphocytes (not fibroblasts) irradiated to relatively high doses (4–6 Gy, not 2 Gy) in patients with various grades of late (not early) radiotherapy (RT) morbidity. The limitations of existing approaches are discussed, and recommendations on the improvement of the ex vivo cytogenetic testing for NTT prediction are provided. However, the efficiency of these methods still needs to be validated in properly organized clinical trials involving large and verified patient cohorts.

Radiation therapy for the prevention of heterotopic ossification: Efficacy and toxicity of single fraction radiotherapy

Numerous nonmalignant diseases can be treated with radiation therapy (RT). Among them, Heterotopic Ossification (HO) is a benign condition resulting from several causes that can be successfully managed with ionizing radiation. More often seen in the hip area after major surgical procedures, HO is of major concern as it can lead to functional disorders, pain and even to joint ankylosis. We retrospectively analyzed the outcome of therapeutic irradiation for the prevention of HO in 14 patients treated in our hospital between 2005 and 2011. All patients were irradiated with a dose ranging from 7 to10 Gy in a single fraction for prevention of HO after surgery. After a median follow up of 126 months (range 96 – 156 months) none of our patients developed HO. Impaired wound healing or other post surgery complications like trochanteric nonunion were not observed. A single fraction of RT seems to be a sufficient, cost effective and safe treatment regimen. In our study we report excellent results as none of our patients developed HO.