淋巴结数量未必是结肠癌生存率最佳预测指标

对COST(手术治疗临床结局)试验数据的最新分析显示，被广泛认为是结肠癌切除手术质量关键指标的淋巴结(LN)数量≥12对患者5年生存率并无显著影响(Ann. Surg. 2012;257:102-7 [doi:10.1097/SLA.0b013e318260a8e6])。

LN数量是确认手术切除程度的措施之一，也是判断结肠癌患者较好生存率结局的干净手术切缘指标。但这项分析结果提示，应对NL数量≥12和切缘等手术替代指标进行重新评价。


Kellie L. Mathis博士

COST 试验是一项大规模多中心随机试验，旨在比较腹腔镜和开放手术治疗结肠腺癌的结局。该试验收集了包括肿瘤位置和LN数量在内的多项手术变量数据。纳入该项研究的787例患者包括267例Ⅰ期患者、284例Ⅱ期患者和236例Ⅲ期患者，中位年龄70岁，半数为男性。

梅奥医院的Kellie L. Mathis博士及其同事对该试验数据再次分析后发现，5年总生存率和无病生存率均不受LN数量是否高于或低于12个的影响。校正年龄和癌症分期后，LN数量并不能预测总生存率和无病生存率(P=0.60)。

总肠长度、切缘或肠系膜长度等其他手术替代指标对生存率也无显著影响(P值均大于0.05)，肿瘤位置(右、左或乙状结肠)、手术方式(腹腔镜或开放手术)以及性别亦是如此。只有患者年龄和癌症分期可预测生存率。

作者认为，基于大量文献和全国质量论坛(NQF)认同的LN数量≥12个可作为手术质量替代指标，大多数人认为LN数量≥12或其他手术变量可预测生存率。但作者推测，手术标准化、监测和资格认证或许是质量控制的更佳策略。

作者指出，COST试验5年总生存率为77.2%，高于同期可比患者的全国生存率。所有参与试验的外科医生均在试验前经过资格认证，且至少完成20例腹腔镜结肠切除手术，并提交手术和病理学报告。所有腹腔镜切除手术均被录像，这些录像已经外部审评委员会随机审查。作者认为，如果上述结果得到其他试验证实，就应重新制定直接评估和监测外科手术质量的方案。

Mathis及其同事声称无相关利益冲突。

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By: JENNIE SMITH, Oncology Practice

Lymph node counts of 12 or higher, widely considered a key marker of surgical quality in colon cancer resection, had no significant effect on 5-year survival rates in settings where surgeons are audited and credentialed and where surgical techniques are standardized.

Lymph node (LN) count is one of several measures used to determine the extent of surgical resection and an indicator of clear surgical margins, which have been assumed to result in better survival outcomes for colon cancer patients. A new data analysis, however, of the COST (Clinical Outcomes of Surgical Therapy) trial suggests reevaluating the use of surgical surrogates such as 12 LNs and margins.

The COST trial, a large, multicenter randomized trial of colon cancer procedures, compared outcomes for laparoscopic and open techniques in treating colon adenocarcinoma. The trial collected data on a number of surgical variables, including tumor location and LN count. A total of 787 patients were included: 267 with stage I disease, 284 with stage II, and 236 with stage III. Their median age was 70 years, and 50% were male.

In the current study, Dr. Kellie L. Mathis of the Mayo Clinic in Rochester, Minn., and her colleagues found that 5-year overall and disease-free survival were not influenced by LN count of above or below 12 (Ann. Surg. 2012;257:102-7 [doi:10.1097/SLA.0b013e318260a8e6]). When they adjusted for age and cancer stage, LN count was seen as not predictive of overall or disease-free survival (P = .60).

Other surgical surrogates, including total bowel length, margins, or mesenteric length, likewise did not have a significant effect on survival (P greater than .05 for all), nor did tumor location (right, left, or sigmoid), surgical technique (laparoscopic or open), and sex. Only patient age and cancer stage were found to be predictive of survival.

"On the basis of abundant literature and the acceptance of the 12 LN count as a surgical quality surrogate by National Quality Forum, most would expect the 12 LN count or other surgical variables to be predictive of survival," Dr. Mathis and her associates wrote. However, they hypothesized that procedural standardization, monitoring, and credentialing may provide a better strategy for quality control.

Overall 5-year survival results from the COST trial, they noted, were 77.2% – better than national rates for comparable patient groups in the same time period. All enrolling surgeons underwent pretrial credentialing and had performed a minimum of 20 laparoscopic colon resections, for which they had submitted operative and pathology reports. All laparoscopic resections were video recorded, and videos were randomly audited by an external review committee.

If the observations in the current study can be validated by others, Dr. Mathis and her colleagues said, "we submit that now is the time to invest in the development of technical quality control programs that directly measure and monitor surgical procedures."

Dr. Mathis and her colleagues stated that they had no conflicts of interest related to their findings.