Stereotactic radiation therapy for the treatment of functional pituitary adenomas associated with feline acromegaly

Wormhoudt, Tiffany L.; Boss, Mary Keara; Lunn, Katharine F.; Griffin, Lynn; Leary, Del; Dowers, Kristy L.; Rao, Sangeeta; LaRue, Susan M.

doi:10.1111/jvim.15212

Cited by 29 publications

(49 citation statements)

References 34 publications

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“…Conformity, gradient, and heterogeneity indices are commonly used to describe stereotactic radiotherapy treatment plans. The conformity index describes how the volume of a stereotactic radiotherapy plan conforms to the size and shape of the planning target volume, with values <2 being recommended, and values closer to 1 being ideal . Gradient index describes how steep the dose gradient is outside of the planning target volume, with smaller values having steeper gradients .…”

Section: Resultsmentioning

confidence: 99%

Long‐term survival with stereotactic radiotherapy for imaging‐diagnosed pituitary tumors in dogs

Hansen

Zwingenberger

Théon

et al. 2018

Vet Radiology Ultrasound

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Published studies on the use of stereotactic radiotherapy for dogs with pituitary tumors are limited. This retrospective observational study describes results of stereotactic radiotherapy for 45 dogs with imaging-diagnosed pituitary tumors. All dogs were treated at a single hospital during the period of December 2009-2015. The stereotactic radiotherapy was delivered in one 15 Gray (Gy) fraction or in three 8 Gy fractions. At the time of analysis, 41 dogs were deceased.Four were alive and censored from all survival analyses; one dog received 8 Gy every other day and was removed from protocol analyses. The median overall survival from first treatment was 311 days (95% confidence interval 226-410 days [range 1-2134 days]). Thirty-two dogs received 15 Gy (median overall survival 311 days; 95% confidence interval [range 221-427 days]), and 12 received 24 Gy on three consecutive days (median overall survival 245 days, 95% confidence interval [range 2-626 days]). Twenty-nine dogs had hyperadrenocorticism (median overall survival 245 days), while 16 had nonfunctional masses (median overall survival 626 days). Clinical improvement was reported in 37/45 cases. Presumptive signs of acute adverse effects within 4 months of stereotactic radiotherapy were noted in 10/45, and most had improvement spontaneously or with steroids. Late effects versus tumor progression were not discernable, but posttreatment blindness (2), hypernatremia (2), and progressive neurological signs (31) were reported.There was no statistical difference in median overall survival for different protocols. Patients with nonfunctional masses had longer median overall survival than those with hyperadrenocorticism (P = 0.0003). Survival outcomes with stereotactic radiotherapy were shorter than those previously reported with definitive radiation, especially for dogs with hyperadrenocorticism. K E Y W O R D SCushing's disease, hyperadrenocorticism, photon therapy, SRS, stereotaxis three-dimensional-conformal fields, or with a cone-based system for beam collimation. 17,18,25 There is one study of 51 dogs with

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Section: Resultsmentioning

confidence: 99%

Long‐term survival with stereotactic radiotherapy for imaging‐diagnosed pituitary tumors in dogs

Hansen

Zwingenberger

Théon

et al. 2018

Vet Radiology Ultrasound

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“…The high percentage of diabetic remission and definitive cure exceeds outcomes of previously reported medical treatment and radiation therapy. 2,13,14,[16][17][18] The most consistent effect of radiotherapy is the improvement or resolution of signs of neurological disease because of tumor size reduction; however, remission of hypersomatotropism and DM is often not achieved. In a recent publication on radiotherapy as treatment of hypersomatotropism in cats, stereotactic radiation therapy resulted in diabetic remission in 32% of the cats and in more than one third of these cats remission was only temporarily.…”

Section: Discussionmentioning

confidence: 99%

Evaluation of hypophysectomy for treatment of hypersomatotropism in 25 cats

Bokhorst

Galac

Kooistra

et al. 2021

Veterinary Internal Medicne

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Background: Successful treatment of cats with hypersomatotropism by transsphenoidal hypophysectomy is described in small numbers of cats. Objectives: To describe the endocrine profile, survival, and remission rates of hypersomatotropism and diabetes mellitus in a cohort of cats with hypersomatotropism that underwent hypophysectomy between 2008 and 2020. Animals: Twenty-five client-owned cats with spontaneous hypersomatotropism. Methods: Retrospective study. Diagnosis of hypersomatotropism was based on clinical signs, plasma insulin-like growth factor-1 (IGF-1) concentration, and imaging of the pituitary gland. Growth hormone (GH) and IGF-1 concentrations were measured repeatedly after surgery. Survival times were calculated based on follow-up information from owners and referring veterinarians. Results: Median postoperative hospital stay was 7 days (range, 3-18 days). One cat died within 4 weeks of surgery. Median plasma GH concentration decreased significantly from 51.0 ng/mL (range, 5.0-101.0 ng/mL) before surgery to 3.8 ng/mL (range, 0.6-13.0 ng/mL) at 5 hours after surgery. Remission of hypersomatotropism, defined as normalization of plasma IGF-1 concentration, occurred in 23/24 cats (median, 34 ng/mL; range, 14-240 ng/mL) and 22/24 cats entered diabetic remission. Median survival time was 1347 days (95% confidence interval, 900-1794 days; range, 11-3180 days) and the overall 1-, 2-, and 3-year all-cause survival rates were 76%, 76%, and 52%, respectively. Conclusions and Clinical Importance: This study shows the beneficial outcome of hypophysectomy in cats with hypersomatotropism, marked by low death rate and a high percentage of diabetic remission and definitive cure.

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“…Heterogeneity index (HI) describes PTV dose variation, and can be calculated with the simpler Radiation Therapy Oncology Group (RTOG) calculation where <2 is ideal, or with a more strict calculation using D98 and D2 (this calculation reveals more heterogeneity; values will vary widely by plan although the ideal value is 0) 28 . Table 6 shows that all CI were reasonably close to unity (median CI = 0.81 and 1.10, based on two different equations, respectively 26,28 ), GI was similar to the Paddick study for stereotactic wherein GI values were 2.4 to 3.3 27 (median GI = 3.35 in the current study), all cases had acceptable RTOG HI (median HI = 1.12), and 7/8 cases had alternate HI values ≤15 suggesting some heterogeneity in the approved plans 29 . Values for CI, GI and HI were only evaluated retrospectively and were not used in plan approval.…”

Section: Resultsmentioning

confidence: 76%

“…Conformity index (CI) describes how dose conforms to the PTV, with values <2 recommended, values closer to 1 ideal and two different common equations utilized. CI does not account for whether the dose is in the same location at the target 26‐28 . Gradient index (GI) describes how quickly the dose drops outside the PTV, with smaller values representing steeper gradients 29 .…”

Section: Resultsmentioning

confidence: 99%

Long‐term outcomes with conventional fractionated and stereotactic radiotherapy for suspected heart‐base tumours in dogs

Hansen

Théon

Willcox

et al. 2020

Vet Comparative Oncology

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Published radiotherapy results for suspected heart‐based tumours in dogs are limited. In this retrospective longitudinal study (3/2014‐2019), eight dogs with either clinical signs attributable to a heart‐base mass (6), or asymptomatic with a progressively larger mass on echocardiogram (2), received conventional fractionated radiotherapy (CFRT) or stereotactic body radiotherapy (SBRT). Clinical findings in symptomatic cases included one or more of the following: retching/coughing (4), exercise intolerance (2), collapse (1), pericardial effusion (2), rare ventricular premature contractions (2), abdominal effusion (1), or respiratory distress due to chylothorax (1). CFRT cases received 50 Gray (Gy) in 20 fractions and SBRT cases received 30 Gy in 5 or 24 Gy in three fractions. Two dogs received chemotherapy post‐radiation. At analysis, 7/8 dogs were deceased and one was alive 684 days post‐treatment. The estimated median overall survival (MOS) from first treatment was 785 days (95% CI 114‐868 days, [range 114‐1492 days]). Five dogs received CFRT (MOS 817 days; (95% CI 155 days‐not reached [range 155‐1492 days])). Three dogs received SBRT with one alive at analysis (MOS 414 days, (95% CI, 114 days‐not reached [range 114‐414 days])). No statistically significant difference was found between survival for CFRT and SBRT. Of the symptomatic patients, 5/6 showed improvement. Mass size reduced in 4/5 cases receiving follow‐up ultrasounds. Possible complications included asymptomatic radiation pneumonitis (4), atrial tachycardia/premature beats (4) and pericardial effusion with heart failure coincident with tumour progression (1). This study provides preliminary evidence that radiotherapy may impact clinically relevant or progressively enlarging heart‐base masses.

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Stereotactic radiation therapy for the treatment of functional pituitary adenomas associated with feline acromegaly

Cited by 29 publications

References 34 publications

Long‐term survival with stereotactic radiotherapy for imaging‐diagnosed pituitary tumors in dogs

Long‐term survival with stereotactic radiotherapy for imaging‐diagnosed pituitary tumors in dogs

Evaluation of hypophysectomy for treatment of hypersomatotropism in 25 cats

Long‐term outcomes with conventional fractionated and stereotactic radiotherapy for suspected heart‐base tumours in dogs

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