Neck of femur fractures are a common trauma presentation and patients with a history of malignancy are sent for long leg femur views (LLF), to exclude a distal lesion which would alter the management plan (Intra-medullary nail/Long stem Hemiarthroplasty). The aim of this is to identify incidence of malignancy on LLF views, the length of time in between each xray (XR) and to identify demographics.

Data was retrospectively collected from 01/01/2021 to 31/01/2021 from a single centre. All patients admitted to the Queen Elizabeth University Hospital had their electronic records (Bluespier, PACS, Clinical Portal) accessed. These confirmed if patients had a past medical history of malignancy, if they had LLF view and the time differences between diagnostic pelvis XR and LLF XR.

A total of 784 patients were identified in the specified time period. Of these, 138 were identified with a malignancy and there were 85 LLF views completed. LLF views diagnosed 1 patient with known prostate cancer that had a new distal femoral metastasis (Incidence = 1.28 cases per 1000). This patient underwent further imaging (MRI Femur) and received a long stem hip hemiarthroplasty. The average length of wait between the images was 9 hours 27 minutes.

LLF views can alter management of patients with malignancy and are therefore useful to perform. There can be a long delay between each image. Therefore we recommend imaging tumour with common bony metastasis (Renal, Thyroid, Breast, Prostrate, Lung) and other remaining tumours with known secondary metastasis. Imaging primary low risk (eg basal cell carcinoma) can lead to long delays in a frail patient cohort and consideration should be given to rationalise appropriate use of resources.

Breast cancer is the most frequent malignancy in women with an estimation of 2.1 million new diagnoses in 2018. Even though primary tumours are usually efficiently removed by surgery, 20–40% of patients will develop metastases in distant organs. Bone is one of the most frequent site of metastases from advanced breast cancer, accounting from 55 to 58% of all metastases. Currently, none of the therapeutic strategies used to manage breast cancer bone metastasis are really curative. Tailoring a suitable model to study and evaluate the disease pathophysiology and novel advanced therapies is one of the major challenges that will predict more effectively and efficiently the clinical response. Preclinical traditional models have been largely used as they can provide standardization and simplicity, moreover, further advancements have been made with 3D cultures, by spheroids and artificial matrices, patient derived xenografts and microfluidics. Despite these models recapitulate numerous aspects of tumour complexity, they do not completely mimic the clinical native microenvironment. Thus, to fulfil this need, in our study we developed a new, advanced and alternative model of human breast cancer bone metastasis as potential biologic assay for cancer research. The study involved breast cancer bone metastasis samples obtained from three female patients undergoing wide spinal decompression and stabilization through a posterior approach. Samples were cultured in a TubeSpin Bioreactor on a rolling apparatus under hypoxic conditions at time 0 and for up to 40 days and evaluated for viability by the Alamar Blue test, gene expression profile, histology and immunohistochemistry. Results showed the maintenance and preservation, at time 0 and after 40 days of culture, of the tissue viability, biological activity, as well as molecular markers, i.e. several key genes involved in the complex interactions between the tumour cells and bone able to drive cancer progression, cancer aggressiveness and metastasis to bone. A good tis sue morphological and microarchitectural preservation with the presence of lacunar osteolysis, fragmented trabeculae locally surrounded by osteoclast cells and malignant cells and an intense infiltration by tumour cells in bone marrow compartment in all examined samples. Histomorphometrical data on the levels of bone resorption and bone apposition parameters remained constant between T0 and T40 for all analysed patients. Additionally, immunohistochemistry showed homogeneous expression and location of CDH1, CDH2, KRT8, KRT18, Ki67, CASP3, ESR1, CD8 and CD68 between T0 and T40, thus further confirming the invasive behaviour of breast cancer cells and indicating the maintaining of the metastatic microenvironment. The novel tissue culture, set-up in this study, has significant advantages in comparison to the pre-existent 3D models: the tumour environment is the same of the clinical scenario, including all cell types as well as the native extracellular matrix; it can be quickly set-up employing only small samples of breast cancer bone metastasis tissue in a simple, ethically correct and cost-effective manner; it bypasses and/or decreases the necessity to use more complex preclinical model, thus reducing the ethical burden following the guiding principles aimed at replacing/reducing/refining (3R) animal use and their suffering for scientific purposes; it can allow the study of the interactions within the breast cancer bone metastasis tissue over a relatively long period of up to 40 days, preserving the tumour morphology and architecture and allowing also the evaluation of different biological factors, parameters and activities. Therefore, the study provides for the first time the feasibility and rationale for the use of a human-derived advanced alternative model for cancer research and testing of drugs and innovative strategies, taking into account patient individual characteristics and specific tumour subtypes so predicting patient specific responses.

Summary

Neurological deficits resulting from spinal cord compression occur infrequently. When presented with neurological compromise, the most common management was radiotherapy, with surgery only being offered to patients who developed neurological deficit or pathological fracture resulting in unresolved severe pain post radiotherapy.

Photodynamic therapy (PDT) uses the strong cytotoxicity of singlet oxygen and hyperthermia produced by irradiating excitation light on a photosensitizer. The phototoxic effects of indocyanine green (ICG) and near-infrared light (NIR) have been studied in different types of cancer cells. Plasma proteins bind strongly to ICG, followed by rapid clearance by the liver, resulting in no tumor-selective accumulation after systemic administration. Kimura et al. have proposed using a novel nanoparticle labeled with ICG (ICG-lactosome) that has tumor selective accumulation owing to enhanced permeability and retention (EPR) effect. In this study, we investigated the efficacy of PDT using ICG-lactosome and NIR for a bone metastatic mouse model of breast cancer.

Cells from the human breast cancer cell line, MDA-MB-231 were injected into the right tibia of 26 anesthetized BALB/C nu/nu mice at a concentration. The mice were then randomly divided into three groups: the PDT group (n = 9), the laser (laser irradiation only) group (n = 9), and the control group (n = 8). PDT was performed thrice (7, 21, 35 days after cell inoculation) following ICG-lactosome administration via the tail vein 24 hours before irradiation. The mice were percutaneously irradiated with an 810-nm medical diode laser for 10 min. In the laser group, mice were irradiated following saline administration 24 hours before irradiation. Radiographic analysis was performed for 49 days after cell inoculation. The area of osteolytic lesion was quantified. The right hind legs of 3 mice were amputated 24 hours after the third treatment. Histological analysis was performed using hematoxylin-eosin staining and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining of sagittal sections. The data was analyzed using Tukey-Kramer post-hoc test. P-value of <0.05 was considered significant.

X-ray on day 49 of the three groups are considered. The area of osteolytic lesion in the PDT group (7.9 ± 1.2 mm²: mean ± SD) was significantly smaller than that of the control (11.4 ± 1.4 mm²) and laser (11.9 ± 1.2 mm²) groups. In histological findings, we observed many TUNEL-positive cells in the metastatic tissue 24 hours after PDT. In the control and laser groups, TUNEL-positive cells were occasionally observed.

We have previously reported the effect of ICG-lactosome-enhanced PDT on the cytotoxicity of human breast cancer cells in vitroand on the delay of paralysis in a rat spinal metastasis model. In this study, we demonstrated the inhibitory effect of ICG-lactosome-enhanced PDT on bone destruction caused by human breast cancer cells in vivo. This PDT induced apoptosis and necrosis in the tumor cells. Intralesional resection is often performed for spinal metastases in an emergency. The residual tumor may regrow and cause neurological deficits. We believe that ICG-lactosome-enhanced PDT can decrease the rate of local recurrence through reduction of the residual tumor. PDT with ICG-lactosome and NIR had an inhibitory effect on the growth of bone metastasis of a human breast cancer.