Comparison of radiography, computed tomography, and magnetic resonance imaging for evaluation of appendicular osteosarcoma in dogs

Vertebral Osteosarcoma in Two Cats-Diagnosis, Treatment, and Outcome

In this case report, we describe the diagnosis, treatment, and outcome of two feline cases of vertebral osteosarcoma. Case 1: A 6-year-old female neutered domestic longhaired cat was presented with progressive paraparesis, ataxia, and spinal hyperesthesia. MRI of the thoracolumbar spinal cord and vertebral column revealed a strongly contrast-enhancing mass lesion originating from the dorsal lamina and spinous process of T13. The lesion caused extradural compression of the spinal cord. Surgical debulking was performed, and the histopathological evaluation of surgical biopsies was consistent with vertebral osteosarcoma. The cat was paraplegic with intact nociception post-surgery. Subsequently, the cat recovered ambulation while remaining mildly ataxic and paraparetic at long-term follow-up. Post-operative chemotherapy was started with doxorubicin. CT scans at 2, 4, 9, 13, and 20 months post-surgery showed no signs of local recurrence or metastasis. Case 2: A 15.5-year-old male neutered domestic shorthaired cat was presented with progressive paraparesis, tail paresis, and spinal hyperesthesia. Radiographs and CT scan of the lumbar vertebral column showed a large mass originating from the dorsal lamina and spinous process of L6, suggestive of neoplasia, with severe compression of the spinal cord. Surgical debulking was performed, and the histopathological evaluation was consistent with vertebral osteosarcoma. Post-operative chemotherapy was started with doxorubicin. Seven months post-surgery, the patient was neurologically normal with no signs of metastatic disease. This case report highlights the possibility of good outcomes after the surgical treatment of feline vertebral osteosarcoma supplemented with post-surgical chemotherapy.

Novel radical pelvectomy technique to treat chondrosarcoma in a large-breed dog

Surgical management of chondrosarcoma with hemipelvectomy is well described, but there have been no reports on extensive excision involving bilateral pubis and unilateral ischium. This report describes a novel pelvectomy technique for the treatment of chondrosarcoma in a large-breed dog. A 12-year-old Labrador Retriever presented for tenesmus due to a large, intra-pelvic mass which was confirmed on computed tomography (CT). Surgery involved removal of the entire left ischium and both pubic bones with preservation of both hind limbs. Histopathology confirmed the diagnosis of a high-grade chondrosarcoma with tumour-free margins of less than 3 mm. The dog recovered well following surgery and regained ambulation within 9 days. Four months postoperatively, the dog had no ongoing pain or tenesmus and only a mild gait abnormality in the left hind limb. Pelvectomy involving the entire pubis and unilateral ischium was well tolerated in a large-breed dog. This technique may offer a novel surgical option to treat neoplasia previously considered too extensive for complete excision.

Ultrasensitive 3D Aerosol-Jet-Printed Perovskite X-ray Photodetector

X-ray photon detection is important for a wide range of applications. The highest demand, however, comes from medical imaging, which requires cost-effective, high-resolution detectors operating at low-photon flux, therefore stimulating the search for novel materials and new approaches. Recently, hybrid halide perovskite CH₃NH₃PbI₃ (MAPbI₃) has attracted considerable attention due to its advantageous optoelectronic properties and low fabrication costs. The presence of heavy atoms, providing a high scattering cross-section for photons, makes this material a perfect candidate for X-ray detection. Despite the already-successful demonstrations of efficiency in detection, its integration into standard microelectronics fabrication processes is still pending. Here, we demonstrate a promising method for building X-ray detector units by 3D aerosol jet printing with a record sensitivity of 2.2 × 10⁸ μC Gy_air^-1 cm^-2 when detecting 8 keV photons at dose rates below 1 μGy/s (detection limit 0.12 μGy/s), a 4-fold improvement on the best-in-class devices. An introduction of MAPbI₃-based detection into medical imaging would significantly reduce health hazards related to the strongly ionizing X-rays' photons.

CT angiography and MRI imaging features do not predict the tumor type and grade of feline injection site sarcoma

Computed tomographic angiography (CTA) and magnetic resonance imaging (MRI) have been described as methods for preoperative surgical planning in cats with feline injection site sarcomas (FISS), however, few published studies have compared these modalities. The objective of this retrospective, secondary analysis study was to determine if imaging features of FISS on CTA and MRI are predictive of neoplastic peritumoral projections. Archived data from a previous prospective study were retrieved for 10 cats with FISS. All cats had been evaluated in a single anesthetic episode with MRI and dual phase CT (CTA) imaging followed by surgical removal. Histopathological grading and targeted histopathology of imaging-identified peritumoral projections were performed. Two observers evaluated the CTA and MRI studies for FISS shape, margination, size, enhancement pattern, postcontrast uniformity, pre- and postcontrast margination, the number of muscles involved, mass mineralization, and bone lysis. Metal was present in the imaging field of three of 10 cats, resulting in one nondiagnostic MRI. Peritumoral projections were detected in all cats with both imaging modalities, and most were benign. At least one neoplastic peritumoral projection was detected in six cats using MRI, five cats using CTA, and three cats with both modalities. Higher grade FISS were larger than low grade using MRI, and FISS were larger using MRI. Other FISS imaging features using MRI and CTA were similar. Findings supported use of either MRI or CTA for detecting neoplastic peritumoral projections in cats with FISS. Authors recommend CTA for cats with known metallic objects in the scan field.

Imaging in Non-neurologic Oncologic Treatment Planning of the Head and Neck

Imaging is critical for the diagnosis and staging of veterinary oncology patients. Although cytology or biopsy is generally required for diagnosis, imaging characteristics inform the likelihood of a cancer diagnosis, can result in a prioritized list of differentials that guide further staging tests, and assist in the planning of surgery, radiation, and chemotherapy options. Advanced imaging, such as CT and MRI, can better define the extent of disease for surgical and radiation planning for head and neck cancer cases in particular. Additionally, new imaging technologies are continually being translated into veterinary fields, and they may provide more options for cancer patients as they become more widely available.

Retrospective Evaluation of Whole Body Computed Tomography for Tumor Staging in Dogs with Primary Appendicular Osteosarcoma

OBJECTIVE

To evaluate whole body computed tomography (CT) for staging canine appendicular osteosarcoma.

STUDY DESIGN

Retrospective case series.

ANIMALS

Client-owned dogs diagnosed with appendicular osteosarcoma (n=39).

METHODS

Medical records for client-owned dogs diagnosed with appendicular osteosarcoma from August 2008 to July 2014 were reviewed. Dogs were included if they had a confirmed diagnosis of appendicular osteosarcoma and were staged using whole body CT. Data collected included signalment, body weight, primary tumor location, serum alkaline phosphatase (ALP) activity, findings on 3-view thoracic radiographs, cytologic or histologic results, and findings on CT.

RESULTS

Thirty-nine dogs (median age 8.5 years; median body weight 37 kg) had osteosarcoma of the distal radius (n=17), proximal humerus (11) and other sites. Serum ALP activity was elevated in 14 dogs. Bone metastasis was not detected in any dog on whole body CT. Pulmonary metastasis was considered definitive on CT based on board certified radiologist assessment in 2/39 dogs (5%). Two additional dogs (2/39, 5%) had soft tissue masses diagnosed on CT, consistent with concurrent, non-metastatic malignancies.

CONCLUSION

Bone metastases were not identified in any dog with whole body CT. Thoracic and abdominal CT detected lung lesions and concurrent neoplasia in dogs with primary appendicular osteosarcoma. Whole body CT may be a useful adjunct to other screening tests for disseminated malignancy.

Outcomes of Limb-Sparing Surgery Using Two Generations of Metal Endoprosthesis in 45 Dogs With Distal Radial Osteosarcoma. A Veterinary Society of Surgical Oncology Retrospective Study

OBJECTIVE

To report outcomes in dogs with distal radial osteosarcoma (OSA) treated with metal endoprosthesis limb-sparing surgery and compare outcomes between 2 generations of endoprosthesis.

STUDY DESIGN

Multi-institutional retrospective case series.

ANIMALS

Forty-five dogs with distal radial OSA treated with endoprosthesis and chemotherapy.

METHODS

Data of dogs treated with either first-generation endoprosthesis (GEN1) or second-generation endoprosthesis (GEN2) were sourced from medical records and radiographs. Surgical outcomes included postoperative lameness assessment and the presence, severity, and time to onset of complications. Oncologic outcomes included presence of local recurrence or metastasis, time to onset of local recurrence, metastasis-free interval (MFI), and survival time. Results for surgical and oncologic outcomes were compared between GEN1 and GEN2.

RESULTS

Twenty-eight dogs received GEN1 and 17 dogs received GEN2. There were 39 complications (96%, 14 minor, 29 major) including infection (78%), implant-related complication (36%), and local recurrence (24%). Metastatic frequency was 67% and median MFI was 188 days (95% confidence interval [CI]: 126-250 days). Survival time ranged from 34 days to 6.1 years with a median of 289 days (95% CI: 207-371 days). There was no significant difference in complication severity, frequency, time to complication, MFI, or survival time between dogs receiving GEN1 and GEN2.

CONCLUSION

There was no significant difference in outcomes between dogs receiving GEN1 and GEN2 for limb-sparing surgery of the radius. Metastatic frequency and survival time for metal endoprosthesis were similar to that of amputation with curative intent chemotherapy.

Musculoskeletal MRI

MRI has the unique ability to detect abnormal fluid content, and is therefore unparalleled in its role of detection, diagnosis, prognosis, treatment planning and follow-up evaluation of musculoskeletal disease. MRI in companion animals should be considered in the following circumstances: a definitive diagnosis cannot be made on radiographs; a patient is nonresponsive to medical or surgical therapy; prognostic information is desired; assessing surgical margins and traumatic and/or infectious joint and bone disease; ruling out subtle developmental or early aggressive bone lesions. The MRI features of common disorders affecting the shoulder, elbow, stifle, carpal, and tarsal joints are included in this chapter.

ASSOCIATION BETWEEN COMPUTED TOMOGRAPHIC CHARACTERISTICS AND FRACTURES FOLLOWING STEREOTACTIC RADIOSURGERY IN DOGS WITH APPENDICULAR OSTEOSARCOMA

The objective of this observational, descriptive, retrospective study was to report CT characteristics associated with fractures following stereotactic radiosurgery in canine patients with appendicular osteosarcoma. Medical records (1999 and 2012) of dogs that had a diagnosis of appendicular osteosarcoma and undergone stereotactic radiosurgery were reviewed. Dogs were included in the study if they had undergone stereotactic radiosurgery for an aggressive bone lesion with follow-up information regarding fracture status, toxicity, and date and cause of death. Computed tomography details, staging, chemotherapy, toxicity, fracture status and survival data were recorded. Overall median survival time (MST) and fracture rates of treated dogs were calculated. CT characteristics were evaluated for association with time to fracture. Forty-six dogs met inclusion criteria. The median overall survival time was 9.7 months (95% CI: 6.9-14.3 months). The fracture-free rates at 3, 6, and 9 months were 73%, 44%, and 38% (95% CI: 60-86%, 29-60%, and 22-54%), respectively. The region of bone affected was significantly associated with time to fracture. The median time to fracture was 4.2 months in dogs with subchondral bone involvement and 16.3 months in dogs without subchondral bone involvement (P-value = 0.027, log-rank test). Acute and late skin effects were present in 58% and 16% of patients, respectively. Findings demonstrated a need for improved patient selection for this procedure, which can be aided by CT-based prognostic factors to predict the likelihood of fracture.

Association between absolute tumor burden and serum bone-specific alkaline phosphatase in canine appendicular osteosarcoma

BACKGROUND

In dogs with appendicular osteosarcoma (OSA), increased pretreatment serum bone-specific alkaline phosphatase (BALP) activity is a negative prognostic factor, associated with shorter disease-free intervals and survival times, but a biologic basis for observed differential serum BALP activities in canine OSA patients remains incompletely defined.

OBJECTIVE

Serum BALP activity will correlate with absolute tumor burden in dogs with OSA.

ANIMALS

This study included 96 client-owned dogs with appendicular OSA.

METHODS

In canine OSA cell lines, the expression and membranous release of BALP was evaluated in vitro. The correlation between serum BALP activity and radiographic primary tumor size was evaluated in OSA-bearing dogs. In dogs developing visceral OSA metastases, serial changes in serum BALP activities were evaluated in relation to progression of macroscopic metastases, and visceral metastatic OSA cells were evaluated for BALP expression.

RESULTS

In vitro, BALP expression was not associated with either tumorigenic or metastatic phenotype, rather the quantity of membranous BALP released was proportional with cell density. In dogs devoid of macroscopic metastases, there was a positive correlation between serum BALP activity and absolute primary tumor size. In dogs with progressive OSA metastases, serum BALP activity increased and coincided with the development of macroscopic metastases. OSA cells derived from visceral metastatic lesions retained BALP expression.

CONCLUSIONS AND CLINICAL IMPORTANCE

Tumor burden is a determinant of serum BALP activity in dogs with appendicular OSA. The association between increased pretreatment BALP activity and negative clinical prognosis may simply be attributed to greater initial tumor burden, and consequently more advanced tumor stage.

Accuracy of computed tomography in determining lesion size in canine appendicular osteosarcoma

Multidetector contrast enhanced computed tomography with acquisition of 0.625-mm thick transverse images was used to measure the extent of appendicular osteosarcoma in 10 dogs. The measured length of tumor based on CT was compared to the true length of tumor using histopathology. There was a statistically significant association with good correlation between the true length of osteosarcoma compared to the length of intramedullary/endosteal abnormalities on CT with a mean overestimation of 1.8% (SD = 15%). There was not a statistically significant association between the true tumor length and the length of periosteal proliferation on CT with a mean overestimation of 9.7% (SD = 30.3%). There was a statistically significant association, but with poor correlation, between the true tumor length compared to the length of abnormal contrast enhancement with a mean overestimation of 9.6% (SD = 34.8%). The extent of intramedullary/endosteal CT abnormalities assessed from submillimeter transverse images may be of value in assessing patient candidacy and surgical margins for limb-sparing surgery.

Radiography, 99mTc–HDP, and 111In Labeled Vitamin B12 SPECT of Canine Osteosarcoma: A Comparative Study

The objective of this article was to compare radiography, planar bone scintigraphy, and single-photon emission computed tomography (SPECT) to determine the size of osteosarcomas in long bones of dogs. Ten dogs with osteosarcoma in six radii, two humeri, one tibia, and one ulna were evaluated. Macroslides, mediolateral radiographs, planar scintigrams, and sagittal images from SPECT scans were used to obtain measurements. On the scintigraphic images, the edges of the tumor were established using the activity profile imaging tool. The radiographic magnification was factored. The mean percentage of tumor size overestimation was 9.29% on mediolateral radiographs, 5.35% on planar scintigrams, and 33.25% on SPECT images. The correlation coefficient adjusted for sample size was significantly higher (P<0.01) for technetium 99m (99mTc) hydroxyethylene diphosphonate (HDP) (75.5%) and radiography (61.3%) compared with indium 111–vitamin B12 (28.3%). The correlation coefficient for 99mTc–HDP was higher than that obtained for radiographs; however, statistical difference between the two variables was not demonstrated (P>0.05). 99mTc bone scan is a good estimator of intramedullary size of osteosarcoma in long bones when the activity profile tool to determine the margin of the tumor is used.

Vascularized Ulnar Bone Grafts for Limb-Sparing Surgery for the Treatment of Distal Radial OsteosarcomaS

The objective of this retrospective study was to compare vascularized free or roll-in ulnar bone grafts for limb-sparing surgery in dogs with radial osteosarcoma with the cortical allograft, metal endoprosthesis, or distraction osteogenesis techniques. Overall, the ulnar graft techniques used in this study demonstrated excellent healing properties. Complications included recurrence of the tumor in 25% (2/8) of the dogs, metastasis in 50% (4/8) of the dogs, implant loosening in 37.5% (3/8) of the dogs, implant failure in 12.5% (1/8) of the dogs, and infection in 62.5% (5/8) of the dogs. Mean survival time was 29.3 mo (range, 9 to 61 mo). The mean metastasis-free interval was 33.67 mo (range, 8 to 54 mo). Tumors recurred locally in two dogs at 10 mo and 20 mo postoperatively. This study yielded similar long-term complications as other limb-sparing options (such as cortical allografts and metal endoprostheses) and allowed dogs to bear weight on the operated limb with acceptable limb function. More research is needed regarding specific healing times for ulnar vascularized grafts, time until implant removal, and the extent of radial bone that could ultimately be replaced by the ulna.

Diagnostic imaging of the canine stifle: a review

The stifle joint, a common location for lameness in dogs, is a complex arrangement of osseous, articular, fibrocartilaginous, and ligamentous structures. The small size of its component structures, restricted joint space, and its intricate composition make successful diagnostic imaging a challenge. Different tissue types and their superimposition limit successful diagnostic imaging with a single modality. Most modalities exploit the complexity of tissue types found in the canine stifle joint. Improved understanding of the principles of each imaging modality and the properties of the tissues being examined will enhance successful diagnostic imaging.

Advanced imaging for veterinary cancer patients

This article presents an update on the recent advances made in veterinary advanced imaging specifically with regard to cross-sectional modalities (CT and MRI) and nuclear medicine (positron emission tomography [PET] and PET/CT). A brief summary of technical improvements and a review of recent literature are included to provide an overview of the progress made in this important element of the practicing veterinary oncologist's repertoire. An in-depth summary of PET is also included to introduce the technical aspects and potential clinical and research applications of this novel imaging modality in veterinary medicine.

Diagnosing appendicular osteosarcoma with ultrasound-guided fine-needle aspiration: 36 cases

OBJECTIVES

To determine the ability to obtain diagnostic cytology samples from appendicular bone lesions using ultrasound-guided needle aspirations. Secondary objectives were to compare cytological evaluations with histopathological results and to determine the utility of staining malignant mesenchymal cells for the presence of alkaline phosphatase.

METHODS

Aspirations from 36 aggressive appendicular bone lesions with histological diagnoses were included in the study. Ultrasound was used to guide the needle to the medullary cavity or the adjacent soft tissue mass. The smears stained with Wright-Giemsa and nitroblue tetrazolium chloride/5-bromo-4-chloro-3-indoyl phosphate toluidine salt (NBT/BCIP) were examined.

RESULTS

A diagnostic sample was obtained in 32 of the 36 cases. Of the 32 diagnostic samples, cytology indicated sarcoma, with a sensitivity of 97 per cent (confidence interval: 83 to 100 per cent) and a specificity of 100 per cent (confidence interval: 16 to 100 per cent). When a diagnosis of sarcoma was made on cytology, alkaline phosphatase staining indicated osteosarcoma, with a sensitivity of 100 per cent (confidence interval: 87 to 100 per cent).

CLINICAL SIGNIFICANCE

The results of this study indicate that ultrasound-guided needle aspiration of aggressive bone lesions is a viable technique for identifying malignant mesenchymal cells and for diagnosing sarcomas. It is cost-effective and minimally invasive. Furthermore, identifying alkaline-phosphatase-negative malignant mesenchymal cells from a bone aspiration may rule out osteosarcoma, whereas alkaline-phosphatase-positive malignant mesenchymal cells are suggestive of osteosarcoma.

Limb-Sparing Surgery in a Dog with Osteosarcoma of the Proximal Femur

OBJECTIVE

To report successful limb-sparing surgery in a dog with a proximal femoral osteosarcoma (OSA) using a composite allograft-prosthetic technique.

STUDY DESIGN

Case report.

ANIMAL

Client-owned dog.

METHODS

A stage IIB OSA of the proximal aspect of the femur was resected in accordance with oncologic and limb-sparing principles. The osseous defect was reconstructed with a proximal femoral allograft and cemented, long-stemmed femoral prosthesis. Soft tissue reconstruction was achieved by suturing host tendons to their respective allogeneic tendons on the allograft. Coxofemoral joint function was preserved using standard total hip arthroplasty techniques.

RESULTS

Limb-sparing surgery of the proximal aspect of the femur using a composite allograft-prosthetic technique resulted in excellent limb function. Postoperative complications included aseptic loosening of the femoral composite graft and allograft nonunion, which required revision, traumatic implant luxation, and local tumor recurrence. Limb function was excellent after surgical stabilization of the allograft nonunion but deteriorated after implant luxation 270 days postlimb-sparing surgery. Pulmonary and skeletal metastases were diagnosed and local tumor recurrence suspected 596 and 650 days postoperatively, respectively. The dog was euthanatized 688 days after limb-sparing surgery as a result of progressive local and metastatic disease.

CONCLUSIONS AND CLINICAL RELEVANCE

Limb-sparing surgery for dogs with primary bone tumors of the proximal aspect of the femur is feasible with good functional results.

Longitudinal Bone Transport for Treatment of Primary Bone Tumors in Dogs: Technique Description and Outcome in 9 Dogs

OBJECTIVE

To describe a surgical technique for bone transport osteogenesis (BTO) limb salvage and report outcome in 9 dogs with primary bone tumors.

ANIMALS

Nine dogs with spontaneously occurring primary bone tumors.

RESULTS

BTO surgery was performed as a primary means of limb salvage in 7 dogs and as a salvage procedure after catastrophic allograft infection and failure in 2 dogs. Mean defect size was 9.5 cm with a mean of 123 days distraction until docking. Mean time from surgery to fixator removal was 205 days. Minimum follow-up was 9 months. There were 2 histologically confirmed local recurrences where although limb function was excellent, eventually resulted in limb amputation. Limb function was good to excellent in all but 2 dogs; 1 was chronically non-weight bearing before BTO surgery because of complications associated with an allograft limb salvage that had been performed previously on the same limb. The cause of lameness in the other dog was undetermined.

CONCLUSIONS

BTO limb salvage can be successful in dogs with primary bone tumors. Whereas allograft limb salvage may be simpler from an initial management perspective, BTO has some unique advantages when compared with the allograft technique.

CLINICAL RELEVANCE

BTO has an emerging role in limb salvage surgery for dogs with primary bone tumors. BTO provides excellent long-term outcomes in some dogs with primary bone tumors and will likely become increasingly more attractive as technique modifications allow the duration of the treatment to be shortened.

Intercalary Bone Grafts for Joint and Limb Preservation in 17 Dogs with High-Grade Malignant Tumors of the Diaphysis

OBJECTIVE

To evaluate postoperative complications, limb function, and tumor control after intercalary resection and reconstruction for preservation of limb and joint function in dogs with high-grade malignant tumors of diaphyseal bone.

STUDY DESIGN

Retrospective study.

ANIMALS

Seventeen client-owned dogs.

METHODS

The bone tumor database and medical records were reviewed (1986-2002) for dogs with diaphyseal tumors treated with intercalary resection and reconstruction with either an allograft or irradiated autograft. Clinical presentation, diagnostic findings, surgical management, and outcome were determined from medical records and telephone interviews with veterinarians and owners. Statistical analyses included chi2 to test associations between intra- and postoperative variables with complications, and Kaplan-Meier survival analysis for disease-free interval, metastasis-free interval (MFI), and median survival time.

RESULTS

Intercalary limb-sparing surgery was performed in 17 dogs with diaphyseal tumors: osteosarcoma (OSA) (15), histiocytic sarcoma (1), and solitary metastasis from a pulmonary adenocarcinoma (1). One dog was excluded from further analysis when the spared limb was amputated 4 days postoperatively because of incomplete tumor resection. In 16 dogs, limb function was good to excellent. Complications occurred in 5 dogs (31.3%) and included superficial infection in 2 dogs (12.5%) and implant failure in 4 dogs (25%). All implant failures occurred in the ulna and there was a significant association between implant failure and non-cemented allografts (P=.042). Non-union of 1 or both osteotomies was diagnosed in 10 dogs (83.3%) and, despite lack of clinical signs in all cases, was significantly associated with the use of intracavitary locally released cisplatin (P=.046) and cemented intercalary grafts (P=.046). Local tumor recurrence was diagnosed in 1 dog (6.3%) and metastatic disease in 12 dogs (75.0%), including 10 dogs with OSA. The median MFI was 137 days. The local disease-free and overall limb-salvage rate was 94% and 100%, respectively. Overall median survival time was 393 days and the median survival time for dogs with OSA was 449 days.

CONCLUSION

Intercalary limb-sparing surgery results in better postoperative limb function with fewer and less severe complications than historical reports of dogs treated with non-intercalary limb-sparing surgery.

CLINICAL RELEVANCE

In dogs with diaphyseal tumors, intercalary limb-sparing surgery preserves normal joint function and results in good to excellent limb use with few complications and good local tumor control.

Intraoperative Extracorporeal Irradiation for Limb Sparing in 13 Dogs

OBJECTIVE

To evaluate extracorporeal intraoperative radiation therapy (IORT) as a treatment method for limb and joint sparing in dogs with appendicular sarcomas in sites other than the distal aspect of the radius.

STUDY DESIGN

Retrospective study.

ANIMALS

Thirteen client-owned dogs.

METHODS

The bone tumor database and medical records (1998-2002) were reviewed for dogs with primary appendicular bone tumors treated with IORT limb-sparing surgery and adjuvant chemotherapy. The segment of bone containing the tumor was isolated from adjacent soft tissue and an osteotomy performed distant to the tumor. The bone segment was exteriorized, irradiated (70 Gy single fraction), and then stabilized with internal fixation. Adjuvant chemotherapy was administered. Lameness was graded and local and distant tumor control was determined. Associations between intra- and postoperative variables with complications and Kaplan-Meier survival analysis for median disease-free interval and survival time were calculated.

RESULTS

Limb function was good or excellent in 10 dogs (77%). Postoperative complications (9 dogs, 69%) included deep infection, fracture of the irradiated bone, and implant failure. Surgical failure was more likely if a single implant was used to stabilize the osteotomized bone and if deep infection developed postoperatively. In 3 dogs, tumors recurred locally within bone in the radiation field. The disease-free and overall success rates of extracorporeal IORT for limb and joint preservation were 46% and 54%, respectively.

CONCLUSIONS

Extracorporeal IORT provides a novel alternative to traditional techniques for preservation of joint and limb function in dogs with primary appendicular sarcomas. A minimum of 2 implants and intramedullary bone cement should be used to stabilize the osteotomized bone to minimize postoperative complications. Extracorporeal IORT should be used with caution in dogs with tumors of the distal tibia because of a high complication rate. Dogs with tumors in areas of good soft-tissue coverage, such as the humerus and femur, may be good candidates for limb and joint-sparing surgery using extracorporeal IORT.

CLINICAL RELEVANCE

Extracorporeal IORT is a surgical technique that can be used for limb and joint salvage in dogs with primary appendicular sarcomas in sites usually not amenable to traditional limb-sparing techniques.

Pasteurized tumoral autograft and adjuvant chemotherapy for the treatment of canine distal radial osteosarcoma: 13 cases

OBJECTIVE

To report outcome in 13 dogs with distal radial osteosarcoma, without evidence of metastasis, treated by a combination of adjuvant chemotherapy and a pasteurized autograft limb-sparing procedure.

STUDY DESIGN

Prospective clinical study.

ANIMALS

Thirteen dogs with distal radial osteosarcoma.

METHODS

Limb-sparing procedure was performed using an autograft from the excised tumoral segment, pasteurized at 65 degrees C for 40 minutes. Adjuvant chemotherapy (cisplatin or cisplatin and doxorubicin) was administered in all dogs.

RESULTS

Mean and median survival times were 531 and 324 days, respectively (range, 180 to 1,868 days). Overall survival was 100% at 6 months, 50% at 12 months, 44% at 18 months, and 22% at 24 months. Lung metastasis occurred in 5 (38%) dogs. Observed complications were local recurrence (2 dogs, 15%), allograft infection (4 dogs, 31%), and implant failure (3 dogs, 23%). Limb function was good in 12 dogs (92%) and fair in 1 dog.

CONCLUSIONS

Pasteurized bone autograft derived from the tumoral bone segment was an effective alternative to cortical bone allograft for limb sparing in canine distal radial osteosarcoma, in terms of feasibility, pattern of healing, complications, and survival.

CLINICAL RELEVANCE

Use of a pasteurized bone autograft eliminates the need for a canine bone allograft bank and has the added advantage of good fit to the recipient site.

Differential enhancement of collagen crosslink excretion in cases of osteosarcoma and chondrosarcoma

Hydroxylysylpyridinoline (HP) and lysylpyridinoline (LP) are markers of collagen absorption and LP is specific for collagen type I in bone. In the present study we evaluated the concentration of HP and LP in urine of patients with osteosarcoma ( n=20; age range 16-49 years) and chondrosarcoma ( n=15; age range 18-70 years). The values were compared with those obtained from 74 healthy controls (age range 16-83 years). The range and upper limit of normal values (HP(max) and LP(max)) were measured in our control group. High performance liquid chromatography (HPLC) was used to determine concentrations of HP and LP (nmol/mmol creatinine). The average urinary HP concentrations were significantly increased in patients with osteosarcoma ( p=0.001) and chondrosarcoma ( p<0.001), whereas HP remained within the normal range in approximately half of the patients. The average urinary LP concentrations were not increased in osteosarcoma and chondrosarcoma patients as compared with the control group. Further studies in a large group of patients are necessary to evaluate whether HP might be a valuable marker of prognosis, and if its urinary concentration can be correlated to tumour burden.

Update on the biology and management of canine osteosarcoma

Osteosarcoma (OSA) is the most common primary bone tumor diagnosed in dogs. Our understanding of the risk factors and genetic changes in canine OSA patients is growing, but specific, innovative therapeutic strategies are slow in coming. Appendicular skeletal osteosarcoma, the most frequent form of this disease, is typically seen in large to giant breeds, with males being overrepresented in most reports. Axial skeletal OSA is less common than appendicular OSA, but the biologic behavior of the disease is equally aggressive in all skeletal sites except for the mandible. Though the current standard of care for dogs with osteosarcoma remains surgical resection of the affected site, followed by chemotherapy with either a platinum- (cisplatin or carboplatin) or doxorubicin-based protocol, novel therapies are being actively investigated.