Higher cut-offs for the number of lymph nodes harvested do not predict better prognosis in patients with colon cancer / Pontos de corte mais altos para o número de linfonodos coletados não predizem melhor prognóstico em pacientes com câncer de cólon

ABSTRACT Background Current threshold for minimum lymph node harvest may not be adequate for appropriate staging in colon cancer and newer surgical techniques may allow more lymph nodes to be harvested. The aim of this study was to examine the prognostic role of harvesting and examining lymph nodes higher in number than the recommended threshold (≥12), in patients with colon cancer. Methods This retrospective study included 179 patients that underwent open colon resection for adenocarcinoma of the colon. A D3 resection with high vascular ligation was made so that large number of lymph nodes was removed in most patients. Differences in overall survival between below and above three cutoff points (≥18, ≥24, ≥40) were estimated. Results During median 33 months of follow-up, 45 patients died and mean overall survival was 108.7 ± 5.6 months (95% CI, 97.7-119.7). The mean number of lymph nodes harvested and examined was 44.0 ± 25.7 (median 38; range, 7-150). No significant effect was found for three different cut-off values (≥18, ≥24, or ≥40 nodes) on mean overall survival (p > 0.05 for all comparisons). The same was true for the whole study population as well as for N0 (N negative) and N1-2 (N positive) patient subgroups, when they are analyzed separately. Conclusions Our findings do not support the survival benefit of substantially higher number of lymph nodes harvested in colon cancer.

RESUMO Fundamento: O limite atual para a coleta mínima de linfonodos pode não ser adequado para o estadiamento adequado no câncer de cólon e novas técnicas cirúrgicas podem permitir que um número maior de linfonodos seja coletado. O objetivo deste estudo foi examinar o papel prognóstico da coleta e exame de linfonodos em número maior do que o limite recomendado (≥ 12), em pacientes com câncer de cólon. Método: Este estudo retrospectivo incluiu 179 pacientes submetidos à ressecção aberta de cólon para adenocarcinoma de cólon. A ressecção D3 com ligadura vascular alta foi realizada para que um grande número de linfonodos fosse removido na maioria dos pacientes. As diferenças na sobrevida global entre abaixo e acima de três pontos de corte (≥ 18, ≥ 24, ≥ 40) foram estimadas. Resultados: Durante a mediana de 33 meses de seguimento, 45 pacientes morreram e a sobrevida global média foi de 108,7 ± 5,6 meses (IC 95%: 97,7-119,7). O número médio de linfonodos coletados e examinados foi de 44,0 ± 25,7 (mediana = 38; variação: 7-150). Nenhum efeito significativo foi encontrado para três valores de corte diferentes (≥ 18, ≥ 24 ou ≥ 40 linfonodos) na sobrevida global média (p >0,05 para todas as comparações). O mesmo foi verdadeiro para toda a população do estudo, bem como para os subgrupos de pacientes N0 (N negativos) e N1-2 (N positivos), quando analisados separadamente. Conclusões: Nossos achados não apoiam o benefício na sobrevida de um número substancialmente maior de linfonodos coletados no câncer de cólon.

Effect of body mass index on the number of lymph nodes harvested in patients who underwent colorectal cancer resection / 中国肿瘤临床

Objective: To analyze the effect of body mass index (BMI) on the number of lymph nodes (LNs) harvested in patients who underwent colorectal cancer resection. Methods: A retrospective analysis of 328 patients with colorectal cancer who were treated at Fujian Provincial Hospital between December 2014 and January 2017 was conducted. All patients underwent colorectal cancer resec-tion and were assigned into 2 groups:<12-LN group and≥12-LN group. Potential clinicopathological variables that might influence the number of LNs harvested were statistically analyzed. Results: Univariate analyses demonstrated that BMI (χ2=7.697, P=0.006), tumor location (χ2=7.900, P=0.048), and TNM stage (χ2=34.795, P<0.01) affected the number of LNs harvested. Logistic regression analysis re-vealed that BMI of≥25 kg/m2 and rectosigmoid location were associated with 2.557-and 1.731-fold increases in the number of LNs harvested, compared with BMI<25 kg/m2 group and other tumor locations, respectively. Conclusions: Higher BMI may decrease the number of LNs harvested in patients who underwent colorectal cancer resection and could affect the postoperative pathological stage. K

Impact of the Number of Lymph Nodes Retrieved on Reliability of Nodal Staging of Stage II Colorectal Carcinomas

PURPOSE: The variety of outcomes in patients with stage II colorectal carcinomas might be due to understaging caused by an inadequate number of lymph nodes (LNs) being examined. The aim of this study was to determine if any number of examined LNs reflects a reliable node-negative staging for colorectal carcinomas (CRCs). METHODS: Data on 241 patients (132 males) who underwent potentially curative resections for pT3 and pT4 CRC were reviewed. The patients ranged in age from 21 to 87 (mean: 58.2) years with a median follow-up of 43 (range: 7~96) months. The relationship between the number of LNs harvested and both the 5-year disease-free survival (DFS) and the overall survival (OS) rates were assessed for stage II CRCs. RESULTS: A median of 15 LNs (range: 3~104) was harvested per tumor specimen, and lymph-node metastases were present in 107 cases (44.4%). The proportion of lymph-node metastases increased as a function of the number of LNs harvested (P=0.0002; 95% confidence interval, 0.3333~0.8138). The number of LNs revealed to be the best number for dividing stage II patients into subgroups with different DFS and OS rates was ten. The 5-year DFS and OS rates of the 48 patients (35.8%) with nine or fewer LNs harvested were 68.6% and 76.8%, respectively, whereas those of the 86 patients (64.2%) with ten or more LNs harvested were 87.2% and 91.9%, respectively (DFS, P=0.0082; OS, P=0.0303). Moreover, there were no statistical differences between the node-negative patients with nine or fewer LNs harvested and the 67 stage III patients with N1 in respect to the DFS (68.6% vs. 56.7%; P= 0.2031) and the OS (76.8% vs. 68.3%; P=0.2772) rates. CONCLUSIONS: This study suggests that examining a greater number of lymph nodes increases the likelihood of accurate nodal staging and that a minimum of ten LNs per surgical specimen should be harvested and examined to label a pT3 or pT4 CRC as node-negative.