Radiotherapy Use in Muscle-Invasive Bladder Cancer: Review of the Guidelines and Impact of Increased Awareness in Patient Referral at a Tertiary Center in Belgium.

Purpose: Pronounced underuse of radiotherapy (RT) in muscle-invasive bladder cancer (MIBC) is reported. This study aims to assess the awareness about the role of RT in different MIBC settings and see whether this has increased since 2017. Materials and Methods: We reviewed the bladder cancer guidelines of the EAU, ESMO, NCCN, NICE, and AUA/ASCO/ASTRO/SUO, focusing on the role of RT in MIBC. In 2017, we evaluated the use of RT in MIBC in Belgium. This raised awareness about the indications of RT in different MIBC settings. Here, we present a retrospective pattern of care analysis of the RT use for MIBC patients at our center from January 2012 until December 2021. Frequency of RT use, patient, disease and treatment characteristics were compared between two 5-year periods (2012-2016 and 2017-2021). Results: Review of the guidelines suggested that RT can be used as a treatment option in most MIBC settings. However, differences between guideline recommendations existed and high-level evidence was often lacking. Overall, 221 unique MIBC patients received RT at our center. RT use for MIBC was 39% higher in the second 5-year period (Between the same periods, the number of new MIBC registrations increased with 26%). The most pronounced increase, ie, 529%, was observed in the primary setting and was in parallel with patient preference becoming the main indication for RT. Participation in clinical trials seems to have had an important impact on the frequency of RT use in the adjuvant and metastatic setting. Conclusion: We provide a critical overview of the RT indications in MIBC as recommended by the international guidelines. Increased awareness about RT as a treatment option in MIBC seems to have an impact on the treatment choice in clinical practice, as was observed in our tertiary center.

Array CGH analysis identifies two distinct subgroups of primary angiosarcoma of bone.

Molecular genetic studies on vascular tumors are rare. Recently, possible involvement of MYC and KDR has been documented in a subset of angiosarcomas of soft tissue. We performed a cytogenetic analysis of primary angiosarcomas of bone (n = 13) and soft tissue (n = 5) using high density array-comparative genomic hybridization (array-CGH). Regions of interest were validated by fluorescence in situ hybridization (FISH). Antibodies for candidate genes (SKI, MYC, KDR, and MAPK9) were selected and immunohistochemistry was performed. Six angiosarcomas of bone and four angiosarcomas of soft tissue showed chromosomal losses, gains, and high level amplifications. Cluster analysis identified two groups: a group with a complex genetic profile and a group with only few genetic aberrations. Five regions of interest were selected, which were located at chromosome bands 1p36.23, 2q32-34, 5q35, 8q24, and 17q21.32-24.2. Interphase FISH confirmed the high-level amplifications. Immunohistochemical analysis showed high expression of MYC (16/60), MAPK9 (63/69), and SKI (52/62). There were no differences between the two groups with regards to location, immunohistochemical expression nor survival. In summary, we identified two subgroups of angiosarcoma: those with few or no gross aberrations and those which show numerous genetic aberrations consisting of chromosomal losses, gains and high level amplifications or complex aberrations. The most common finding was amplification of 2q and 17q in both angiosarcoma of bone and soft tissue, suggesting overlap in tumorigenesis irrespective of their location. We show MYC amplification in primary angiosarcoma indicating this is not entirely specific for radiation-induced angiosarcoma.

Active TGF-ß signaling and decreased expression of PTEN separates angiosarcoma of bone from its soft tissue counterpart.

Angiosarcomas constitute a heterogeneous group of highly malignant vascular tumors. Angiosarcoma of bone is rare and poorly characterized. For angiosarcoma of soft tissue, some pathways seem to be involved in tumor development. Our aim was to evaluate the role of these pathways in angiosarcoma of bone. We collected 37 primary angiosarcomas of bone and used 20 angiosarcomas of soft tissue for comparison. Immunohistochemistry was performed on constructed tissue microarrays to evaluate expression of CDKN2A, TP53, PTEN, BCL2, CDK4, MDM2, cyclin D1, ß-catenin, transforming growth factor-ß (TGF-ß), CD105, phospho-Smad1, phospho-Smad2, hypoxia-inducible factor-1α, plasminogen activator inhibitor type 1 (PAI-1), VEGF, CD117 and glucose transporter--1. PIK3CA was screened for hotspot mutations in 19 angiosarcomas. In nearly 55% of the angiosarcoma of bone, the retinoblastoma (Rb) pathway was affected. Loss of CDKN2A expression was associated with a significantly worse prognosis. No overexpression of TP53 or MDM2 was found, suggesting that the TP53 pathway is not important in angiosarcoma of bone. Angiosarcoma of bone showed highly active TGF-ß signaling with immunoreactivity for phospho-Smad2 and PAI-1. Although the phosphatidylinositol 3-kinase (PI3K)/Akt pathway seems to be active in both tumor groups, different mechanisms were involved: 41% of angiosarcoma of bone showed a decrease in expression of PTEN, whereas in angiosarcoma of soft tissue overexpression of KIT was found (90%). PIK3CA hotspot mutations were absent. In conclusion, the Rb pathway is involved in tumorigenesis of angiosarcoma of bone. The PI3K/Akt pathway is activated in both angiosarcoma of bone and soft tissue, however, with a different cause; PTEN expression is decreased in angiosarcoma of bone, whereas angiosarcomas of soft tissue show overexpression of KIT. Our findings support that angiosarcomas are a heterogeneous group of vascular malignancies. Both angiosarcoma of bone and soft tissue may benefit from therapeutic strategies targeting the PI3K/Akt pathway. However, interference with TGF-ß signaling may be specifically relevant in angiosarcoma of bone.

R132C IDH1 mutations are found in spindle cell hemangiomas and not in other vascular tumors or malformations.

Spindle cell hemangioma (SCH) is a rare, benign vascular tumor of the dermis and subcutis. The lesions can be multifocal and are overrepresented in Maffucci syndrome, in which patients also have multiple enchondromas. Somatic mosaic R132C IDH1 hotspot mutations were recently identified in Maffucci syndrome. We evaluated the presence of mutations in solitary and multiple SCHs in patients without multiple enchondromas and tested a range of other vascular lesions that enter into the differential diagnosis. The R132C IDH1 mutation was identified by hydrolysis probes assay and confirmed by Sanger sequencing in 18 of 28 (64%) SCHs; of the 10 negative cases, 2 harbored a mutation in IDH2 (R172T and R172M) by Sanger sequencing. None of 154 other vascular malformations and tumors harbored an IDH1 R132C mutation, and R132H IDH1 mutations were absent in all 182 cases. All 16 SCHs examined by immunohistochemistry were negative for expression of HIF-1α. In conclusion, 20 of 28 (71%) SCHs harbored mutations in exon 4 of IDH1 or IDH2. Given that mutations were absent in 154 other vascular lesions, the mutation seems to be highly specific for SCH. The mutation does not induce expression of HIF-1α in SCH, and therefore the exact mechanism by which mutations in IDH1 or IDH2 lead to vascular tumorigenesis remains to be established.

Somatic mosaic IDH1 and IDH2 mutations are associated with enchondroma and spindle cell hemangioma in Ollier disease and Maffucci syndrome.

Ollier disease and Maffucci syndrome are non-hereditary skeletal disorders characterized by multiple enchondromas (Ollier disease) combined with spindle cell hemangiomas (Maffucci syndrome). We report somatic heterozygous mutations in IDH1 (c.394C>T encoding an R132C substitution and c.395G>A encoding an R132H substitution) or IDH2 (c.516G>C encoding R172S) in 87% of enchondromas (benign cartilage tumors) and in 70% of spindle cell hemangiomas (benign vascular lesions). In total, 35 of 43 (81%) subjects with Ollier disease and 10 of 13 (77%) with Maffucci syndrome carried IDH1 (98%) or IDH2 (2%) mutations in their tumors. Fourteen of 16 subjects had identical mutations in separate lesions. Immunohistochemistry to detect mutant IDH1 R132H protein suggested intraneoplastic and somatic mosaicism. IDH1 mutations in cartilage tumors were associated with hypermethylation and downregulated expression of several genes. Mutations were also found in 40% of solitary central cartilaginous tumors and in four chondrosarcoma cell lines, which will enable functional studies to assess the role of IDH1 and IDH2 mutations in tumor formation.

Primary vascular tumors of bone: a spectrum of entities?

Vascular tumors of bone are a heterogeneous group. Numerous terms have been introduced as well as different classification systems. None of the classification schemes have been accepted due to lack of consistent terminology, accepted histologic criteria, and limited correlation with clinical outcome. It is acknowledged that vascular tumors of bone originate from endothelial cells, resulting in variable expression of endothelial markers. None of these markers are useful to discriminate between benign and malignant lesions. Although radiologic appearance is not specific, radiologic multifocality should trigger to include a vascular neoplasm in the differential diagnosis. This review gives an overview of current literature by describing all different histologic subtypes in correspondence with clinical, radiologic and genetic data. We propose the classification of vascular tumors of bone according to the three-tiered World Health Organization classification scheme for soft tissue tumors dividing entities into a benign, intermediate and malignant category. Hemangioma is the most often and commonly recognized benign lesion. Epithelioid hemangioma has been better defined over the past few years. Based on its locally aggressive behavior and occurrence of lymph node metastases, classification within the intermediate category could be considered. Angiosarcoma is the only accepted term for high-grade malignant vascular tumor of bone and so far, epithelioid hemangioendothelioma is the only accepted low-grade malignant vascular tumor of bone. It is still unclear whether other low-grade malignant vascular tumors of bone (e.g. hemangioendothelioma) truly exist. Unfortunately, molecular / genetic studies of vascular tumors of bone which might support the proposed classification are very sparse.

Distinct histological features characterize primary angiosarcoma of bone.

AIMS: To define the histological criteria of primary angiosarcoma of bone. METHODS AND RESULTS: Forty-two angiosarcomas of bone in 23 males and 15 females were studied. Histological criteria were related to patients' outcome. Eleven patients had multifocal lesions. Lesions were located in the long and short tubular bones followed by the pelvis, spine and trunk. Tumour cells were positive for CD31 in 38 of 40, von Willebrand Factor in 21 of 35, CD34 in 15 of 38, smooth muscle actin in 22 of 36, D2-40 in 11 of 35 and keratin AE1AE3 in 27 of 39. Thirty-nine tumours showed an epithelioid phenotype. One- and 5-year survival rates were 55% and 33%, respectively. Survival analysis showed that a macronucleolus, three or more mitoses per 10 high-power field (HPF) and fewer than five eosinophilic granulocytes per 10 HPF within a tumour was associated with an even worse survival compared to the overall group. CONCLUSIONS: Because keratin positivity is seen in the majority of cases, pathologists should avoid misinterpretation as metastatic carcinoma. A macronucleolus, three or more mitoses per 10 HPF and fewer than five eosinophilic granulocytes per 10 HPF can be used to further define angiosarcoma of bone.

Vascular tumors of bone: imaging findings.

PURPOSE: To identify radiological features of malignant vascular tumors of bone, which can be used to avoid erroneously diagnosing metastases based on radiological multifocality, and histological epitheloid phenotype. MATERIALS AND METHODS: From the databases of the Bologna & Netherlands Committee on Bone Tumors, 63 patients with a histological diagnosis of malignant vascular tumor of bone were retrieved. Epidemiological and imaging characteristics were recorded on a case record form. RESULTS: In 63 patients, 185 lesions were detected by radiographs (61 patients) and/or CT (30 patients) and/or MRI (19 patients). Multifocality was observed in 25 patients (40%), in these patients most lesions were located in the femur. Typically lesions were well-defined, osteolytic, had a geographically pattern of destruction and were also located in the femur. Most lesions showed cortical destruction (118 lesions). No periosteal reaction was seen in most cases (121 lesions). In 13 of 39 patients (33%) tumor extension was more advanced and/or (additional) lesions (29 lesions; 17%) were visible on MRI and CT. In 20 cases (51%) cortex destruction was better shown on CT or MRI. In six patients (15%) periosteal reaction was only seen on MRI or CT and not on radiographs. In 16 (41%) cases soft tissue extension was only seen on MRI or CT, and not on radiographs. Extensive reactive changes on T2-weighted images were seen in 11 patients (58%). CONCLUSION: When single, or regional multifocal osteolytic, well-marginated lesions with cortical destruction are seen, in the femur, and with marked reactive soft tissue changes on MRI, a diagnosis of malignant vascular tumor should trigger the use of additional immunohistochemistry to confirm the vascular nature of the tumor. CLINICAL RELEVANCE STATEMENT: Because of epithelioid phenotype at histology, radiological signs are key in entertaining a diagnosis of malignant vascular tumor of bone which should trigger the use of appropriate immunohistochemical stainings.

A reappraisal of hemangiopericytoma of bone; analysis of cases reclassified as synovial sarcoma and solitary fibrous tumor of bone.

Hemangiopericytoma (HPC) was first described as a neoplasm with distinct morphologic features, presumably composed of pericytes. In soft tissue, it is accepted that most such lesions are solitary fibrous tumors (SFTs), monophasic synovial sarcomas (SSs), or myofibromatoses. It is unclear whether HPC of bone exists. We reviewed 9 primary "HPC" of bone from 4 institutions diagnosed between 1952 and 2002. Immunohistochemistry was performed for CD31, CD34, von Willebrand factor, smooth muscle actin, keratin AE1/AE3, and epithelial membrane antigen. There were 4 male and 5 female patients between 21 and 73 years. All tumors were located within bone, either sited within spine or extremities. All tumors showed thin-walled branching vessels surrounded by undifferentiated spindle or round cells. These cells showed variation in their morphologic pattern: 6 tumors showed a pattern-less architecture and varying cellularity, consistent with SFT; 3 of 5 cases examined were CD34-positive. Three tumors showed more densely packed sheets and fascicles of poorly differentiated cells, resembling SS, of which 2 showed focal staining for keratin AE1/AE3 or epithelial membrane antigen. Fluorescent in-situ hybridization confirmed the presence of SS18 rearrangement in 1 of 2 tumors examined. In conclusion, similar to their soft-tissue counterpart, HPC-like features in bone are a nonspecific growth pattern rather than a true diagnosis. We confirm the existence of 2 entities: SFT and SS of bone. Both are characterized by distinct morphology and immunohistochemical profile. SFT of bone is located within spine and has a better prognosis, whereas SS of bone is located within long bones having a poor prognosis.