Influência da terapia neoadjuvante na razão de linfonodos / Influence of neoadjuvant therapy on the ratio of lymph nodes

ABSTRACT

ABSTRACT Background: To evaluate the relationship between the ratio of affected lymph nodes (LNR) and clinical and anatomopathological variables in patients with rectal adenocarcinoma submitted or not to neoadjuvant chemoradiotherapy. Methods: The LNR was determined by dividing the number of compromised LNR by the total number of LNR dissected in the surgical specimen. Patients were divided into two groups: with QRT and without QRT. In each group, the relationship between LNR and the following variables was evaluated: degree of cell differentiation, depth of invasion in the rectal wall, angiolymphatic /perineural invasion, degree of tumor regression and occurrence of metastases. The LNR was evaluated in patients with more than 1, LNR (LNR >12) or less (LNR<12) in the surgical specimen with overall survival (OS) and disease-free survival (DFS). The results were expressed as the mean with the respective standard deviation. Qualitative variables were analyzed using Fisher's exact test, while quantitative variables were analyzed using the Kruskal -Wallis and Mann-Whitney tests. The significance level was 5%. Results: We evaluated 282 patients with QRT and 114 without QRT, between 1995-2011. In the QRT Group, LNR showed a significant association with mucinous tumors (P=0.007) and degree of tumor regression (P=0.003). In both groups, LNR was associated with poorly differentiated tumors (P=0.001, P=0.02), presence of angiolymphatic invasion (P<0.0001 and P=0.01), perineural (P=0.0007, P=0.02), degree of rectal wall invasion (T3>T2; P<0.0001, P=0.02); Compromised LNR (P<0.0001, P<0.01), metastases (P<0.0001, P<0.01). In patients with QRT, LNR<12 was associated with DFS (5.889; 95%CI1.935-19.687; P=0.018) and LNR>12 with DFS and OS (17.984; 95%CI5.931-54.351; P<0.001 and 10.286; 95%CI 2.654-39.854; P=0.007, respectively). Conclusion: LNR was associated with histological aspects of poor prognosis, regardless of the use of QRT. In the occurrence of less than 12 evaluated LNR, the LNR was associated only with the DFS.

RESUMO

RESUMO Contexto: Avaliar a relação entre a razão de linfonodos (RLA) acometidos e variáveis clínicas e anatomopatológicas em portadores de adenocarcinoma de reto submetidos ou não à quimiorradioterapia neoadjuvante. Métodos: A RLA foi determinada dividindo-se o número total de linfonodos (LFNs) dissecados no espécime cirúrgico pelo número de comprometidos. Os doentes foram divididos em dois grupos: com QRT e sem QRT. Em cada grupo foi avaliada a relação entre a RLA e as seguintes variáveis: grau de diferenciação celular, profundidade de invasão na parede retal, invasão angiolinfática/perineural, grau de regressão tumoral e ocorrência de metástases. Avaliou-se a RLA em pacientes com mais do que 12 LFNs (RLA>12) ou menos (RLA<12) na peça cirúrgica com a sobrevida global (SG) e sobrevida livre de doença (SLD). Os resultados foram expressos pela média com o respectivo desvio padrão. As variáveis qualitativas foram analisadas utilizando-se o teste exato de Fisher, enquanto as quantitativas pelos testes de Kruskal-Wallis e Mann-Whitney. O nível de significância foi de 5%. Resultados: Foram avaliados 282 pacientes com QRT e 114 sem QRT, entre 1995-2011. No Grupo QRT, RLA mostrou associação significativa com os tumores mucinosos (P=0,007) e grau de regressão tumoral (P=0,003). Nos dois grupos, a RLA associou-se com tumores pouco diferenciados (P=0,001 e P=0,02), presença de invasão angiolinfática (P<0,0001 e P=0,01), perineural (P=0,0007 e P=0,02), grau de invasão da parede retal (T3>T2; P<0,0001 e P=0,02); LFNs comprometidos (P<0,0001 e P<0,01), metástases (P<0,0001 e P<0,01). Nos pacientes com QRT, a RLA <12 associou-se com a SLD (5,889; IC95%1,935-19,687; P=0,018) e a RLA >12 com SLD e SG (17,984; IC95%5,931-54,351; P<0,001 e 10,286; IC95%2,654-39,854; P=0,007, respectivamente). Conclusão: A RLA associou-se a aspectos histológicos de mau prognóstico, independentemente do emprego de QRT. Na ocorrência de menos de 12 LFNs avaliados, a RLA associou-se apenas com a SLD.