Waters D J, Kengeri S S, Maras A H, Suckow C L, Chiang E C
The Center for Exceptional Longevity Studies, Gerald P. Murphy Cancer Foundation, 3000 Kent Avenue, Suite E2-400, West Lafayette, IN 47906, USA.
The Center for Exceptional Longevity Studies, Gerald P. Murphy Cancer Foundation, 3000 Kent Avenue, Suite E2-400, West Lafayette, IN 47906, USA.
Vet J. 2017 Jun;224:25-37. doi: 10.1016/j.tvjl.2017.05.006. Epub 2017 May 30.
Mammary cancer and pyometra are important health hazards associated with ovary conservation in pet dogs. Early ovariohysterectomy may reduce the incidence of these two diseases, but an estimate of the extent to which the development of mammary cancer or pyometra adversely influences overall longevity is missing. As a first step toward addressing this knowledge gap, the results of a historical cohort study of Rottweilers that lived in North America are reported. Questionnaires completed by owners and veterinarians were used to obtain lifetime health and medical information on 242 female Rottweilers, including years of lifetime ovary exposure, age at death, and cause of death. To determine the extent to which longevity was shortened in females that developed these ovary-associated diseases, age-anchored life expectancy-defined as the median number of remaining years until death for females alive at specified ages during the life course-and years of life lost, a measure of premature mortality, were estimated. Mammary carcinoma was diagnosed in 19 (7.9%) females; median age at diagnosis was 8.5 years; case fatality was 37%. Pyometra was diagnosed in 16 (6.6%) females; median age at diagnosis was 5.4 years; case fatality was 7%. Median lifetime ovary exposure for the study population was 4.3 years. Although risk for developing both diseases increased with longer ovary exposure, longer ovary exposure (≥4.3 years) was also associated with an overall longevity advantage-a 33% decrease in mortality, living 17 months longer than females with shorter ovary exposure (P=0.002). Analysis of age-anchored life expectancy showed that at no time points during the life course was the current or future diagnosis of mammary carcinoma or pyometra associated with shortened survival compared to females who never developed these conditions. This lack of longevity disadvantage is an expected result for diseases with late-onset, moderate (<50%) case fatality (mammary carcinoma) or low (<10%) case fatality (pyometra). These findings fail to support the notion that a strategy, such as elective ovariohysterectomy, implemented to reduce the incidence of mammary carcinoma and pyometra will beneficially impact overall longevity. It follows that future efforts to find and implement effective longevity-promoting interventions should look beyond reducing the incidence of a particular disease to considering trade-offs.
乳腺癌和子宫蓄脓是宠物狗保留卵巢所带来的重要健康隐患。早期卵巢子宫切除术可能会降低这两种疾病的发病率，但目前尚缺乏对乳腺癌或子宫蓄脓的发展对总体寿命产生不利影响程度的评估。作为填补这一知识空白的第一步，本文报告了一项对生活在北美的罗威纳犬进行的历史性队列研究结果。通过主人和兽医填写的问卷，获取了242只雌性罗威纳犬的终生健康和医疗信息，包括终生卵巢暴露年限、死亡年龄和死亡原因。为了确定患这些与卵巢相关疾病的雌性犬的寿命缩短程度，估算了年龄锚定预期寿命（定义为在生命过程中特定年龄存活的雌性犬直至死亡的剩余年数中位数）和寿命损失年数（一种衡量过早死亡的指标）。19只（7.9%）雌性犬被诊断出患有乳腺癌；诊断时的中位年龄为8.5岁；病死率为37%。16只（6.6%）雌性犬被诊断出患有子宫蓄脓；诊断时的中位年龄为5.4岁；病死率为7%。研究群体的终生卵巢暴露中位年限为4.3年。虽然患这两种疾病的风险都随着卵巢暴露时间的延长而增加，但较长的卵巢暴露时间（≥4.3年）也与总体寿命优势相关——死亡率降低33%，比卵巢暴露时间较短的雌性犬多活17个月（P = 0.002）。对年龄锚定预期寿命分析表明，在生命过程中的任何时间点，与从未患这些疾病的雌性犬相比，当前或未来诊断出乳腺癌或子宫蓄脓都与生存时间缩短无关。对于发病较晚、病死率中等（<50%）（乳腺癌）或较低（<10%）（子宫蓄脓）的疾病，这种寿命无劣势是预期结果。这些发现不支持这样一种观点，即像选择性卵巢子宫切除术这样旨在降低乳腺癌和子宫蓄脓发病率的策略会对总体寿命产生有益影响。由此可见，未来寻找并实施有效促进寿命延长干预措施的努力应超越降低特定疾病的发病率，转而考虑权衡取舍。
