接受观察的小肾脏肿瘤患者生存率更高

根据一项大规模回顾性研究结果，与接受手术治疗患者相比，采取观察等待策略的老年小肾脏肿瘤患者的全因死亡风险降低70%。

纽约大学医学中心的William C. Huang博士在美国临床肿瘤学会(ASCO)、美国放射肿瘤学会(ASTRO)以及泌尿肿瘤学会(SUO)主办的泌尿生殖肿瘤研讨会上称，对于这些小病变患者而言，5年肾癌死亡率仅为3%，观察等待似乎是一种安全的处置方法。此外，观察等待还有益于心血管系统，可使心脏死亡风险降低49%。

研究者称，肾脏手术与心脏疾病的关联可能是由于肾脏功能受损所致。目前认为，如果手术切除额外的正常肾脏组织，可加速肾脏衰竭进程，导致心血管疾病发生。

随着偶发性无症状肾脏肿瘤的发生率越来越高，上述结果的价值也将日益凸显。仅去年就有约65,000例新发病例，其中大部分是在检查其他腹部疾病时发现的。

研究者指出，虽然对于这类患者越来越倾向于采取观察等待，但仍有半数以上的患者接受手术治疗。他们研究发现，大部分手术治疗为根治性肾脏切除术，肾脏切除约占半数。大部分的小病变可通过腹腔镜切除，但仍会切除原本不希望切除的正常肾脏组织。现在医生可轻松地告诉老年患者，特别是哪些健康状况不足以耐受全身麻醉和手术的患者，肾癌死亡率很低，肾脏手术延长生命的几率也并不大。但由于目前难以确认究竟哪些肿瘤可能致命，因此对于身体完全健康且生命预期有望延长的老年患者，仍可选择手术治疗。

该项研究分析了监测、流行病与最终结局(SEER)数据库中2002~2007年确诊的8,317例小肾脏肿瘤患者的死亡率数据，患者年龄≥66岁，肿瘤小于1.5 cm。中位随访时间59个月，78%的患者接受手术治疗，其余接受观察等待。接受观察等待的患者比例在研究期间呈增加趋势，由2002年的约25%增加至2007年的近40%。

结果显示，在研究期间，共计2,078 例(25%)患者死亡，其中277 例(3%)死于肾癌。24%的患者至少发生1次心血管事件。两组患者肾癌死亡率未见差异，但手术治疗组患者全因死亡风险显著增加。与手术治疗组患者相比，观察等待组患者在7~36个月期间死亡风险降低30% [危险比(HR)， 0.70]，36个月时死亡风险降低63%(HR，0.37)。

研究还表明，观察等待组患者心血管方面受益明显。截止研究结束，25%的死亡患者死于心血管事件，但观察等待组患者心血管事件风险相对手术组患者下降49%。

Huang博士声称无相关利益冲突。

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By: MICHELE G. SULLIVAN, Internal Medicine News Digital Network

Older patients with small kidney tumors are up to 70% less likely to die from any cause when managed by watchful waiting rather than by surgery, based on findings from a large retrospective study.

Surveillance appears to be safe for these small lesions, with a kidney cancer mortality of just 3% over a 5-year period. In addition, watchful waiting seems to confer a cardiovascular benefit; these patients had a 49% lower cardiac mortality risk compared with that for patients who had kidney surgery, said lead author Dr. William C. Huang of New York University Medical Center.

The link between kidney surgery and heart problems is probably mediated by compromised kidney function, Dr. Huang said. "It’s believed that when surgery takes excess normal kidney tissue, it hastens the acceleration of kidney failure," leading to cardiovascular problems, he said.

The study findings are going to be increasingly valuable as imaging turns up more and more incidental asymptomatic kidney tumors. Last year alone, about 65,000 of these lesions were diagnosed, most of them during a work-up for other abdominal complaints.

While the trend toward surveillance of small asymptomatic lesions is growing, Dr. Huang said surgery is still the treatment mode for more than half of cases. Most procedures in the retrospective study were radical nephrectomies, with kidney removal in about half of those. "The majority of these small lesions could be removed laparoscopically, but even then you’re taking out normal kidney tissue that you might really want back someday," he said at a press briefing at the Genitourinary Cancers Symposium, sponsored by the American Society for Clinical Oncology, the American Society for Radiation Oncology, and the Society of Urologic Oncology.

"Physicians can comfortably tell an elderly patient, especially a patient who is not healthy enough to tolerate general anesthesia and surgery, that the likelihood of dying of kidney cancer is low and that kidney surgery is unlikely to extend their lives," he said. "However, since it is difficult to identify which tumors will become lethal, elderly patients who are completely healthy and have an extended life expectancy, may opt for surgery."

The study examined mortality data in the Surveillance, Epidemiology, and End Results database for 8,317 patients, aged 66 years or older, who were diagnosed from 2002 to 2007 with kidney tumors smaller than 1.5 cm. The patients were followed for a median of 59 months; 78% were managed with surgery and 22%, with surveillance. The use of surveillance increased over the course of the study, from about 25% in 2002 to almost 40% in 2007.

Over the study period, 2,078 (25%) of the patients died, including 277 (3%) who died of kidney cancer. At least one cardiovascular event occurred in 24% of the patients.

Kidney cancer mortality rates did not vary between the treatment groups. However, surgical patients had a significantly increased risk of death from any cause. At 7-36 months, those who had surveillance were 30% less likely to have died than those managed by surgery (hazard ratio, 0.70). After 36 months, patients were 63% less likely to have died if their tumors were managed by surveillance instead of surgery (HR, 0.37).

Dr. Huang also demonstrated that those in the surveillance group experienced a significant cardiovascular benefit as well. By the end of the study, 25% of the deaths were due to a cardiovascular event. Patients in the surveillance group had a 49% reduction in the chance of an event.

Dr. Huang said he had no relevant financial disclosures.