Neutering is associated with developing hemangiosarcoma in dogs in the Veterinary Medical Database: An age and time-period matched case-control study (1964-2003).

The hypothesis that neutered dogs in the Veterinary Medical Database (VMDB) are at increased risk for developing hemangiosarcoma (HSA) was tested. Dogs (n = 5736) were diagnosed with HSA from a population of 2 106 324 dogs in the VMDB from 1964 to 2003. A case-control design matched on age and time period was created for general, cardiac, and splenic HSAs. A logistic regression analysis was performed including breed. Spayed females had an odds ratio (OR) of 1.59 for splenic, 1.47 for cardiac, and 1.72 for HSA in general. Castrated males had an OR of 1.26 for splenic and 1.14 for HSA in general compared to intact males. Controlled for historical time period and patient age, VMDB data support that neutering is associated with development of splenic HSA and HSA in general in both male and female dogs, but not cardiac HSA with an apparently lower than previously described magnitude of association. Key clinical message: This case-control design confirms an association between neutering and development of HSA and splenic HSA, but not cardiac HSA, in both male and female dogs. By controlling for time period at diagnosis, the bias of recent early neuter practices is eliminated, suggesting early neuter is not a principal driver of this effect.

La stérilisation est associée avec le développement d'hémangiosarcome chez les chiens dans le Veterinary Medical Database : une étude cas-témoin jumelant l'âge et la période de temps (1964­2003). L'hypothèse dans le Veterinary Medical Database (VNDB) selon laquelle les chiens stérilisés sont plus à risque de développer un hémangiosarcome (HSA) a été testée. Des chiens (n = 5736) ont été diagnostiqués avec un HSA à partir d'une population de 2 106 324 chiens dans le VMDB de 1964 à 2003. Un design cas-témoin apparié sur l'âge et la période de temps fut créé pour des HSAs en général, cardiaques et spléniques. Une analyse de régression logistique fut effectuée incluant la race. Les femelles stérilisées avaient un ratio de cotes (OR) de 1,59 pour un HSA splénique, de 1,47 pour HSA cardiaque et de 1,72 pour un HSA en général. Les mâles castrés avaient un OR de 1,26 pour les HSA splénique et de 1,14 pour les HSA généraux comparativement aux mâles entiers. En contrôlant pour la période de temps et l'âge du patient, les données du VMDB soutiennent le fait que la stérilisation est associée avec le développement de HSA splénique et d'HSA en général autant chez les chiens que chez les chiennes, mais pas les HSA cardiaques avec un degré d'association moindre que décrit antérieurement.Message clinique clé :Cette étude cas-témoin confirme une association entre la stérilisation et le développement d'HSA et d'HSA splénique, mais pas d'HSA cardiaque, autant chez le mâle que chez la femelle. En contrôlant pour la période de temps au moment du diagnostic, le biais pour la pratique récente de stérilisation tôt dans la vie de l'animal est éliminé, ce qui suggère que la stérilisation hâtive n'est pas un déterminant principal de cet effet.(Traduit par Dr Serge Messier).

Risk of Osteosarcoma in Dogs After Open Fracture Fixation.

OBJECTIVE: To critically evaluate whether open fracture fixation is a significant risk factor for latent osteosarcoma development. STUDY DESIGN: Case-control study. SAMPLE POPULATION: Dogs undergoing open fracture repair and dogs diagnosed with osteosarcoma. METHODS: Records were retrieved from the Veterinary Medical Database VMDB (1970-2000) for dogs undergoing surgical repair of a fracture and dogs diagnosed with osteosarcoma. Dogs with open reduction of joint luxation, dogs diagnosed with bacterial cystitis, and dogs diagnosed with urinary bladder transitional cell carcinoma (UBTCC) were queried as comparison populations. Relative risk for osteosarcoma development was determined. RESULTS: From a population of 19,041 fractures treated surgically, 15 of those dogs subsequently appeared in the VMDB with osteosarcoma affecting the same bone. The relative risk of a fracture repair and associated orthopedic implants and osteosarcoma occurrence was equivalent to the relative risk of open joint reduction and osteosarcoma occurrence (95% confidence interval; 0.998-1.00). The relative risk of having bacterial cystitis and appearing again in the VMDB with UBTCC was higher than the risk of open fracture repair and a subsequent diagnosis of osteosarcoma (P < .02). CONCLUSION: The incidence of fracture-related osteosarcoma may be significantly less than previously estimated based on cases queried from the VMDB. Although possible cases of implant-associated osteosarcoma were identified, their occurrence was rare. Elective implant removal for the purpose of reducing the risk of osteosarcoma after fracture repair may not be warranted and merits further investigation.

A population study of neutering status as a risk factor for canine prostate cancer.

BACKGROUND: Prostate cancer has been reported to occur more commonly in neutered than intact male dogs in several case series. This study was undertaken to evaluate risk of prostate cancer in a large population database. The hypothesis was that castration is a risk factor for prostate cancer in male companion dogs. METHODS: Data were derived from recorded visits to North American veterinary teaching hospitals. The Veterinary Medical Databases (VMDB) were queried to yield male dogs with urinary bladder transitional cell carcinoma (TCC), prostate adenocarcinoma (ACA), prostate TCC, prostate carcinoma (CA), and prostate tumors. A second query yielded all male dogs over the age of 4 years without a diagnosis of urinary tract cancer. These populations were compared to determine relative risks for developing each disease, singly and collectively, associated with neutering status. Odds ratios were calculated for breed as a risk factor. RESULTS: Neutered males had a significantly increased risk for each form of cancer. Neutered males had an odds ratio of 3.56 (3.02-4.21) for urinary bladder TCC, 8.00 (5.60-11.42) for prostate TCC, 2.12 (1.80-2.49) for prostate adenocarcinoma, 3.86 (3.13-4.16) for prostate carcinoma, and 2.84 (2.57-3.14) for all prostate cancers. Relative risks were highly similar when cases were limited to those with a histologically confirmed diagnosis. CONCLUSIONS: Breed predisposition suggests that genetic factors play a role in the development of prostate cancer. The risk associated with being neutered is highest for TCC, supporting previous work identifying the urothelium and ductular rather than acinar epithelium as the source of these tumors.