Clinical presentation, diagnostic findings and outcome of dogs undergoing surgical resection for intracranial meningioma: 101 dogs

Abstract

Background Meningioma is the most common primary brain neoplasm in dogs. Further information is required regarding the expected long-term prognosis of dogs following the surgical resection of an intracranial meningioma together with the influence of adjunctive therapies. Whilst there have been several studies reporting the long-term outcome of intracranial meningioma resection following surgery alone, surgery with the use of an ultrasonic aspirator, surgery combined with radiotherapy and surgery combined with the addition of hydroxyurea, it is currently unclear which type of adjunctive therapy is associated with the most favourable outcomes. The objective of this study is to describe the presentation and outcome of dogs undergoing surgery for the resection of an intracranial meningioma and the effect of clinical factors, adjunctive therapies and meningioma histopathological subtype on the long-term outcome. Results A hundred and one dogs that had intracranial surgery for meningioma resection were investigated from four referral centres. 94% of dogs survived to hospital discharge with a median survival time of 386 days. Approximately 50% of dogs survived for less than a year, 25% survived between 1 and 2 years, 15% survived between 2 and 3 years and 10% survived for greater than 3 years following discharge from hospital. One or more adjunctive therapies were used in 75 dogs and the analysis of the data did not reveal a clear benefit of a specific type of adjunctive therapy. Those dogs that had a transfrontal approach had a significantly reduced survival time (MST 184 days) compared to those dogs that had a rostrotentorial approach (MST 646 days; p < 0.05). There was no association between meningioma subtype and survival time. Conclusions This study did not identify a clear benefit of a specific type of adjunctive therapy on the survival time. Dogs that had a transfrontal approach had a significantly reduced survival time. Intracranial surgery for meningioma resection offers an excellent prognosis for survival to discharge from hospital with a median long term survival time of 386 days.

A novel meningioma with tyrosine‐rich crystals in a 6‐year‐old Great Dane

“…monitored with recheck examinations and repeat MRIs as clinically indicated. This dog was younger than the median age for dogs with meningiomas and in a breed that has not been commonly reported, [5][6][7][8][9] and it is possible that this tumor has a different biological pattern than other canine meningiomas. It is also important to note that despite the high mitotic index observed on histopathology, there are no neurological signs or MRI evidence of regrowth in the follow-up period to date.…”

“…Canine and human meningiomas share many histologic and imaging similarities, and previous studies have attempted to apply WHO classification of meningiomas to dogs 2‐4,9 . No correlation between histologic grade and prognosis has been identified 4 .…”

“…Treatment of intracranial meningiomas can consist of surgical resection, radiation, and less commonly administration of chemotherapies such as hydroxyurea 7‐15,20 . There are conflicting reports regarding survival time with some studies stating no significant difference in outcome between dogs with surgical resection alone compared with surgery with chemotherapy, radiation, or a combination of these therapies and another showing prolonged survival time with postoperative radiation 9,11‐15 .…”

“…19 Treatment of intracranial meningiomas can consist of surgical resection, radiation, and less commonly administration of chemotherapies such as hydroxyurea. [7][8][9][10][11][12][13][14][15]20 There are conflicting reports regarding survival time with some studies stating no significant difference in outcome between dogs with surgical resection alone compared with surgery with chemotherapy, radiation, or a combination of these therapies and another showing prolonged survival time with postoperative radiation. 9,[11][12][13][14][15] One study examined the influence of tumor cell proliferation receptors on effectiveness of radiation therapy and found that meningiomas with reduced tumor proliferation index were 9 times more likely to be controlled by radiation, which might explain improved survival times with radiation for some meningiomas.…”

“…Intracranial neoplasia occurs in 2.8% to 4% of dogs, and meningiomas comprise ~50% of brain tumors in dogs 1‐7 . The most common clinical signs associated with intracranial neoplasia in dogs include seizures, behavior changes, visual deficits and motor deficits depending on the location of the tumor 1,2,6‐9 . The majority of meningiomas in dogs occur in the forebrain, and 70% of forebrain tumors originate in the olfactory bulbs or frontal lobes 3,5‐9 .…”