[gemy]

The association between gonadectomy and various
neoplasms in dogs has been examined in several
studies.15–20 Mammary gland cancer is an important

condition in female dogs, with approximately 20% to

50% of the tumors being histologically malignant.33,34




It is commonly believed that gonadectomized female

dogs have a reduced risk of mammary gland cancer and

that the earlier a dog is gonadectomized, the lower the


risk.28,29,34,35 However, authors of a recent systematic review36



of all reports in peer-reviewed journals on the

associations among neutering, age at neutering, and

mammary gland tumors concluded that the evidence

that neutering reduces the risk of mammary gland neoplasia

is weak and not a sound basis for firm recommendations

on neutering because of limited evidence

and bias in published results.

The present study included 1,360 female dogs, 535

of which were sexually intact. Only 11 dogs had mammary

gland neoplasia; all but one of these were spayed


at > 5 years of age. Given that mammary gland cancer is



seen more commonly in female dogs and 54.3% of the

dogs in the survey were female, this would still have

been equivalent to only 20 dogs in the study having

mammary gland cancer, had the cancer affected both

sexes equally. In comparison, 267 dogs in the study

had diagnoses of mast cell cancer (n = 148), hemangiosarcoma

(73), or lymphoma or lymphosarcoma (46).

There is a breed predilection for development of mammary


gland neoplasia,37 and analysis of results of the



present study suggested that mammary gland cancer is

not a major concern in Vizslas, regardless of gonadectomy

status.

The association between gonadectomy and various

neoplasms in dogs has been examined in several


studies.15–20 Mammary gland cancer is an important



condition in female dogs, with approximately 20% to


50% of the tumors being histologically malignant.33,34



It is commonly believed that gonadectomized female

dogs have a reduced risk of mammary gland cancer and

that the earlier a dog is gonadectomized, the lower the


risk.28,29,34,35 However, authors of a recent systematic review36



of all reports in peer-reviewed journals on the

associations among neutering, age at neutering, and

mammary gland tumors concluded that the evidence

that neutering reduces the risk of mammary gland neoplasia

is weak and not a sound basis for firm recommendations

on neutering because of limited evidence

and bias in published results.

The present study included 1,360 female dogs, 535

of which were sexually intact. Only 11 dogs had mammary

gland neoplasia; all but one of these were spayed


at > 5 years of age. Given that mammary gland cancer is



seen more commonly in female dogs and 54.3% of the

dogs in the survey were female, this would still have

been equivalent to only 20 dogs in the study having

mammary gland cancer, had the cancer affected both

sexes equally. In comparison, 267 dogs in the study

had diagnoses of mast cell cancer (n = 148), hemangiosarcoma

(73), or lymphoma or lymphosarcoma (46).

There is a breed predilection for development of mammary


gland neoplasia,37 and analysis of results of the



present study suggested that mammary gland cancer is

not a major concern in Vizslas, regardless of gonadectomy

status.

http://mercola.fileburst.com/PDF/Hea...izslaStudy.pdf

From the Viszla study.