SAFETY AND TOXICITY OF AN ACCELERATED COARSELY FRACTIONATED RADIATION PROTOCOL FOR TREATMENT OF APPENDICULAR OSTEOSARCOMA IN 14 DOGS: 10 GY × 2 FRACTIONS

Pamidronate-induced irreversible symptomatic hypocalcemia in a dog with hypercalcemia after glucocorticoid withdrawal: a case report

BACKGROUND

Pamidronate is used for the treatment of hypercalcemia. However, a rare but potential adverse event of pamidronate treatment is hypocalcemia. This report describes an unusual case of severe, irreversible hypocalcemia after a single injection of pamidronate for the treatment of hypercalcemia due to glucocorticoid withdrawal in a dog.

CASE PRESENTATION

An 11-year-old castrated male Maltese dog presented with anorexia, vomiting, and diarrhea (day 0). The patient had calcinosis cutis throughout the body, calcification of intraabdominal organs, mild azotemia, and severe hypercalcemia. The severe calcification was attributed to long-term glucocorticoid administration, which was discontinued 1 month before presentation. Fluid therapy, diuretics, calcitonin, and a single intravenous injection of pamidronate were used for the treatment of hypercalcemia. On day 14, normocalcemia was achieved, but renal failure occurred. On day 20, severe and irreversible hypocalcemia occurred, and on day 42, the patient was euthanized at the owner's request because of worsened hypocalcemia and renal failure.

CONCLUSIONS

Although hypocalcemia is an extremely rare adverse event of bisphosphonate treatment, bisphosphonates like pamidronate can result in potentially life-threatening conditions according to the patient's underlying conditions. Therefore, the patient's condition should be closely monitored and any underlying conditions should be carefully evaluated before initiating the treatment for hypercalcemia using pamidronate.

Description and efficacy of a response-based "QUAD" cyclical hypofractionated palliative-intent radiation protocol in dogs with macroscopic solid tumours: 108 cases

Palliative-intent radiation therapy can alleviate pain and clinical signs in dogs with cancer, but optimal fractionation scheme is unknown. The objective of this retrospective case series is to evaluate clinical benefit, objective response, adverse effects, and outcomes in 108 dogs with macroscopic solid tumours treated with a cyclical "QUAD" hypofractionated palliative-intent radiation therapy protocol. Median QUAD dose was 14 Gy (14-16 Gy). Median total dose was 28 Gy (14-48 Gy). Clinical benefit rate was 93%, with median onset of subjective palliation 21 days after the first QUAD, lasting a median of 134 days. Tumour volumetric objective response was assessed with CT prior to the third QUAD in 36 dogs, with stable disease in 24 dogs (67%) and partial response in 9 dogs (25%). Sinonasal and oral were the most common tumour locations in 32 and 30 dogs, respectively. Median progression-free survival was 153 days (95% CI 114-200). Median overall survival was 212 days (95% CI 152-259). Number of QUAD cycles completed, clinical benefit achieved, anti-inflammatory received, total radiation dose, time to maximum clinical benefit, and response duration were positively associated with progression-free and overall survival. Acute toxicities were observed in 15 dogs (14%) with 3 high-grade (grade 3) toxicities (3%). Low-grade (grade 1 and 2) late skin and ocular toxicities were observed in 31 dogs (29%), predominantly leukotrichia, alopecia, keratoconjunctivitis sicca, and cataracts. This report demonstrates that QUAD radiation is an alternative protocol to be considered for palliation of dogs with inoperable or advanced stage solid tumours.

Phase I evaluation of CycloSam® (Sm-153-DOTMP) bone seeking radiopharmaceutical in dogs with spontaneous appendicular osteosarcoma

153 Sm-DOTMP (CycloSam® ) is a newly-patented radiopharmaceutical for bone tumor treatment. DOTMP (1,4,7,10-tetraazacyclododecane-1,4,7,10-tetramethylene-phosphonate) is a macrocyclic chelating agent with superior binding properties to 153 Sm when compared with EDTMP (Quadramet™, used for palliative treatment of bone cancer). CycloSam® was administered at 1 mCi/kg (37 MBq/kg) in a prospective pilot study to seven dogs with bone cancer resulting in no myelosuppression. Then, 13 dogs were enrolled in a prospective clinical trial study using traditional 3+3 dose escalation and starting at 1.5 mCi/kg. Baseline evaluation included hematologic and biochemical testing, diagnosis confirmation, thoracic and limb radiographs, technetium-99 m-HDP bone scintigraphy, and 18 F-FDG PET scan (SUVmax). Toxicity (primary endpoint) was assessed through weekly blood counts and adverse events. Dogs received 1.5 mCi/kg (n = 4), 1.75 mCi/kg (n = 6), and 2 mCi/kg (n = 3) of 153 Sm-DOTMP. Dose-limiting neutropenia and thrombocytopenia were seen at 2 mCi/kg. No dose-limiting nonhematologic toxicities occurred. Efficacy (secondary endpoint) was assessed by objective lameness measurement (body-mounted inertial sensors), owner quality-of-life (QoL) questionnaire, and repeat PET scan. Objective lameness measurement improved in four dogs (53%-60% decrease) was equivocal in three dogs, and worsened in four dogs (66%-115% increase); two dogs were not evaluable. Repeat 18 F-FDG PET scan results varied and change in lameness did not consistently correlate with SUVmax changes. QoL score worsened (n = 5) or was improved/stable (n = 7). Carboplatin chemotherapy (300 mg/m2 IV every 3 weeks ×4) started 4 weeks after 153 Sm-DOTMP injection. No dog died of chemotherapy-related complications. All dogs completed study monitoring. The recommended dose for CycloSam® in dogs is 1.75 mCi/kg, which resulted in some pain control with minimal toxicity and was safely combined with chemotherapy.

Retrospective Evaluation of Outcome in Dogs With Appendicular Osteosarcoma Following Hypofractionated Palliative Radiation Therapy With or Without Bisphosphonates: 165 Cases (2010-2019)

Objective

To report the survival times in dogs that received a standardized palliative-intent radiation therapy (RT) protocol for the treatment of canine appendicular osteosarcoma (OSA), alone or in combination with bisphosphonates (BPs), and to determine whether the addition of BPs affects survival. A secondary objective was to identify prognostic features that may influence outcome in dogs undergoing treatment.

Design

Retrospective case series.

Materials and Methods

Dogs with presumed or confirmed OSA of the appendicular limb treated with daily hypofractionated RT (8 Gy x 2) at the Flint Animal Cancer Center between 2010 and 2019 were evaluated retrospectively. Clinical data were abstracted from the medical records, and adjuvant therapies were noted. Outcome was assessed using medical records and electronic follow up.

Results

One hundred and sixty-five dogs were included. Sixty-eight dogs received BPs as a part of their palliative-intent treatment. The median survival time from first RT treatment to death was not significantly different between groups (119 vs. 109 days for BP and non-BP groups, respectively, p = 0.758). Only age (>9 years) was found to be prognostic in this population (p = 0.031). Factors that were not found to be associated with survival time included BP drug type, timing of BP administration, tumor location, weight, breed, sex, time to treatment, concurrent administration of chemotherapy, and salvage amputation.

Conclusions

This study suggests no difference in outcome for dogs treated with and without BPs in addition to hypofractionated RT. Prospective studies are needed to determine if the addition of BPs to hypofractionated RT leads to an improved quality of life in dogs undergoing palliative-intent treatment for OSA.

Fracture rate and time to fracture in dogs with appendicular osteosarcoma receiving finely fractionated compared to coarsely fractionated radiation therapy: A single institution study

BACKGROUND

Radiation therapy (RT) is used for local pain alleviation in dogs with appendicular osteosarcoma (OS), especially among dogs that are poor surgical candidates for amputation. However, many historical reports of fractionated protocols lack time to fracture and fracture rates.

OBJECTIVES

The primary objectives of this retrospective study were to determine fracture rate and time to fracture of dogs receiving RT (coarse or fine fractionated) for appendicular OS. Secondary objectives were to evaluate tolerability and disease outcome measures.

METHODS

Fifty-one dogs that received RT as part of treatment for appendicular OS were available for evaluation. Forty-five received coarse fractionation (C-RT, 8 or 6 Gy per fraction protocols [C-RT8 or C-RT6]) while the remaining six received fine fractionation (F-RT).

RESULTS

The overall pathologic fracture rate was 37%. Pathologic fracture rate was significantly higher for dogs that received F-RT (5/6, 83%) compared to dogs that received C-RT (12/40, 30%, p = 0.021). In the 17 dogs that fractured, the overall median time to fracture was 57 days. For all dogs, the median progression free interval (PFI) and median overall survival time (OST) were 90 and 140 days, respectively. In a very small cohort of dogs (n = 7) treated with zoledronate and RT, fracture rate was 0% and extended survival times were noted.

CONCLUSIONS

In conclusion, C-RT is recommended over F-RT due to lower risk of pathologic fracture and similar PFI. Prospective evaluation of combined C-RT and zoledronate, especially for dogs with poor surgical candidacy, is warranted for the treatment of canine appendicular osteosarcoma.

CT characteristics and proposed scoring scheme are predictive of pathologic fracture in dogs with appendicular osteosarcoma treated with stereotactic body radiation therapy

Stereotactic body radiation therapy (SBRT) is an established limb-sparing treatment for dogs with appendicular osteosarcoma (OSA) and pathologic fractures are a common sequela. The objectives of this retrospective, observational, and descriptive study were to develop and evaluate objective CT criteria for predicting pathologic fractures and assess impacts on survival time. Included dogs had confirmed or suspected appendicular OSA, available CT scans, available outcome data, and were treated with SBRT. For each study, the number of quartiles affected by lysis on the most severely affected transverse slice, longest measurable length of contiguous full cortical lysis, presence of subchondral bone lysis, and ratio of the length of the affected bone to normal bone were recorded. A scoring system was developed for assigning grades (summed score 1-4 = grade 1, 5-7 = grade 2, and 8 or greater = grade 3.) A total of 127 CT datasets were sampled (123 patients). The median summed score was 7. The grade was correlated with pathologic fracture development (23% of grade 1, 35% of grade 2, and 57% of grade 3 resulting in fracture, P = 0.028). Subchondral bone lysis was correlated with fracture (odds ratio, 2.2, P = 0.02). Percent affected bone ≥40% was associated with decreased survival (P = 0.002). Dogs with <40% of affected bone had a median survival of 256 days versus 178 days for dogs with ≥40% affected bone. Findings from the current study can be used to assist in determining prognosis and planning radiation therapy for future dogs affected by appendicular OSA.

Imaging Method for Osteosarcoma Diagnosis and Clinical Staging Information Optimization

In order to better assist clinicians in the diagnosis and treatment of osteosarcoma, and our understanding of the advantages and disadvantages of different examination techniques of DR, CT and MRI, this article collects the pathological diagnosis of the PACS Medical system of Liaocheng People’s Hospital 2015 to 2018. 130 patients with osteosarcoma and imaging examination data, retrospectively analyzed the diagnostic and clinical staging information contained in DR, CT and MRI examination data of osteosarcoma patients, and detected the diagnosis and clinical staging information of osteosarcoma by comparing various examination methods ability to obtain the optimal imaging examination method that can provide complete diagnosis and clinical staging information of osteosarcoma, and is recommended as a routine clinical examination program. Finally, we conclude that: DR, CT, and MRI examinations have no significant differences in the detection capacity of osteosarcoma bone destruction, periosteal response, and periosteal triangle; MRI has less ability to detect tumor bone than DR and CT; DR has soft tissue. The ability to detect masses is inferior to CT and MRI. Among the single DR, CT or MRI examinations, CT examinations have the best comprehensive detection ability for all imaging diagnostic signs of osteosarcoma. MR examination has the best comprehensive display of clinical staging information such as infiltration range and infiltration boundary of osteosarcoma. Combined DR, CT, and MRI examinations are optimized imaging procedures that provide complete osteosarcoma diagnosis and clinical staging information.

Outcome and prognosis for canine appendicular osteosarcoma treated with stereotactic body radiation therapy in 123 dogs

Canine appendicular osteosarcoma is commonly treated with limb amputation; however, limb-sparing options are frequently desired or necessary for a subset of patients. We evaluated 123 patients and 130 sites treated with stereotactic body radiation therapy (SBRT). Eighty-two out of 98 dogs (84%) had maximum lameness improvement at a median of 3 weeks for a median of 6 months duration. Histopathologic evaluation of available samples from amputation or necropsy revealed >80% tumor necrosis in 50% of limbs consistent with local disease control. Of evaluable patients, 41% fractured and 21% pursued an amputation after treatment. Fine needle aspirate (n = 52) and needle core biopsy (n = 28) did not result in increased fracture risk compared to those without tumor sampling (n = 50). Median survival time (MST) was 233 days and time to first event was 143 days. Gross tumor volume and planned target volume were significantly inversely associated with survival and tumor location was significantly associated with survival. Dogs with salvage amputation had a significantly longer MST compared to those without (346 vs 202 days; P = .04). The presence of metastatic disease at the time of treatment in 15 dogs did not significantly impact survival time (200 vs 237 days without metastasis; P = .58). Skin side effects correlated significantly with dose with 33% of patients with acute grade 3 effects developing consequential late grade 3 effects. While SBRT improves lameness in most patients, further investigation is needed to identify candidates with minimal early fracture risk prior to initiating therapy.

Impact of radiation dose and pre-treatment pain levels on survival in dogs undergoing radiotherapy with or without chemotherapy for presumed extremity osteosarcoma

The purpose of this bi-institutional retrospective study was to determine whether survival for dogs with extremity osteosarcoma (OS) is improved through the use of stereotactic radiotherapy (SRT; a single fraction of 25 Gy, or 36 Gy total given in three consecutive daily fractions) plus chemotherapy, vs lower dose conventionally planned and delivered hypofractionated radiotherapy (CHRT; 14-20 Gy total in 1-2 consecutive daily fractions) plus chemotherapy. We also sought to determine whether baseline pain severity influences oncologic outcomes following radiotherapy for canine extremity OS. The medical records of 82 dogs undergoing radiotherapy for confirmed or presumed OS were reviewed. In dogs receiving combinations of both chemotherapy and radiotherapy, survival was significantly longer with SRT vs CHRT (median overall survival time: 350 vs 147 days; P = .031). In a univariate analysis, dogs with pulmonary metastases and high pain at the time of irradiation had short overall survival times; use of high radiation doses and chemotherapy were associated with improved survival. Separate multivariable models were built to assess the predictive nature of various factors that might influence event-free or overall survival in dogs treated with radiotherapy, with or without chemotherapy; for dogs treated with both chemotherapy and radiotherapy, overall survival times were significantly longer when baseline pain scores were 'low' (vs 'high'; hazard ratio: 0.258; P = .030), radiation doses were high (hazard ratio: 0.943; P = .034). Neither pain nor radiation dose were associated with survival in dogs treated with radiotherapy, without chemotherapy.

Limb-sparing in dogs using patient-specific, three-dimensional-printed endoprosthesis for distal radial osteosarcoma: A pilot study

Limb-sparing for distal radial osteosarcoma has a high rate of complications. Using personalized three-dimensional (3D)-printed implants might improve outcome. The goals of this study were to optimize use of patient-specific, 3D-printed endoprostheses for limb-sparing in dogs in the clinical environment and to report the outcome. This was a pilot study where five client-owned dogs were enrolled. Computed tomography (CT) of the thoracic limbs was performed, which was used to create patient-specific endoprostheses and cutting guides, and repeated on the day of surgery. Intra-arterial (IA) carboplatin was introduced in the clinical management. Limb-sparing was performed. Outcome measures were time required to produce the endoprosthesis and cutting guide, fit between cutting guide and endoprosthesis with host bones, gait analysis, size of the tumour, percent tumour necrosis, complications, disease-free interval (DFI) and survival time (ST). Four dogs received IA carboplatin. Excessive tumour growth between planning CT and surgery did not occur in any dog. The interval between the CT and surgery ranged from 14 to 70 days. Fit between the cutting-guide and endoprosthesis with the host bones was good to excellent. At least one complication occurred in all dogs. Two dogs were euthanized with STs of 192 and 531 days. The other dogs were alive with a follow up of 534 to 575 days. IA chemotherapy is a promising strategy to minimize the risk of excessive tumour growth while waiting for the endoprosthesis and cutting-guide to be made. The design of the cutting-guide was critical for best fit of the endoprosthesis with host bones.

Outcome and complications in dogs with appendicular primary bone tumors treated with stereotactic radiotherapy and concurrent surgical stabilization

OBJECTIVE

To document the outcome of dogs with appendicular primary bone tumors treated with stereotactic radiotherapy (SRT) and concurrent stabilization.

STUDY DESIGN

Multi-institutional retrospective case series.

ANIMALS

Eighteen dogs with presumptive or definitive diagnosis of appendicular osteosarcoma.

METHODS

Medical records of dogs with appendicular primary bone tumors treated with SRT and stabilization were reviewed for signalment, preoperative staging and diagnostics, radiation dose, stabilization method, and outcome.

RESULTS

The distal radius was affected in 13/18 cases. Osteosarcoma or sarcoma was confirmed cytologically or histologically in 15/18 cases. Seven dogs were diagnosed with a pathological fracture at the time of treatment, and 11 were considered at high risk for pathological fracture. Dogs received a single dose (n = 5) or 3 doses (n = 13) of SRT. Surgical stabilization was performed under the same anesthetic event as the final dose of SRT in 10 dogs. Stabilization was achieved with a bone plate (n = 15) or interlocking nail (n = 3). Seventeen dogs received adjuvant chemotherapy. Complications occurred in 16/17 dogs, 15/17 of those being considered major complications. Four dogs experienced more than one complication. Infection was the most common complication, diagnosed in 15/17 cases, and considered as a major complication in 13/15 cases. Postoperative fracture was recorded as a major complication in 3 cases. Nine dogs were amputated at a median of 152 days. The median survival time was 344 days.

CONCLUSION

Treatment of bone tumors with SRT and concurrent stabilization was associated with a prohibitively high complication rate in dogs. Alternative methods for limb salvage should be considered for dogs at risk for pathologic fracture.