Is Sentinel Lymph Node Mapping in Colorectal Cancer a Future Prognostic Factor? A Meta‐analysis

Abstract

The diagnostic value of sentinel lymph node mapping (SLNM) in patients with colorectal cancer (CRC) is controversial. Prognostic factors for CRC must be detected to improve its treatment. A PubMed query (key words: colorectal cancer, sentinel node) provided 182 studies on the sentinel lymph node (SLN) for CRC, the abstracts of which were reviewed. Altogether, 48 studies dealing with the diagnostic value of SLNM were selected from PubMed, and 6 other studies were retrieved from reviews. We compared the diagnostic value of SLNM with that of conventional histopathologic examination. We used the diagnostic accuracy odds ratio (DAOR) method. Because of significant heterogeneity, we chose the random effect model (Der Simonian and Laird). Statistics were performed on 33 studies, including 1794 patients (1201 colon and 332 rectum cancers). The mean SLNM failure rate was 10%. The global sensitivity and specificity of the SLNM were, respectively, 70% and 81%. The pooled DAOR was 10.7 (95% confidence interval 7.0-16.5). That means that a patient whose SLN is invaded has 10.7 times more risk to be node-positive than an SLN-negative patient. Lymphatic mapping appears to be readily applicable to CRC. One of the main reasons for the heterogeneity is the performance of the SLNM by Saha et al., whose data had better sensitivity (90%) than those in other studies. The SLNM technique should be better standardized in future studies. Understanding the cause of false-negative SLNs (9%) is a major issue to resolve before routinely using this technique in CRC management. The prognostic implication of micrometastases found in SLNs requires further evaluation.

Metastatic Lymphadenopathy in Colon Cancer

“…În nodulii limfatici cu diametrul mai mic de 5 mm s-au găsit metastaze, ce au reprezentat 17% [14]. Identificarea nodulului santinelă, bine documentată în melanom şi în cancerul de sân, are rezultate controversate în cancerul de colon datorită concordanţei scăzute între metastazele din nodulii limfatici şi nodulul santinelă [5,22]. Diferite metode folosite pentru identificarea nodulului santinelă sunt nesigure, deoarece au o sensibilitate redusă şi o rată înaltă a valorii predictive negative, ceea ce reduce acurateţea stadializării cancerului de colon.…”

“…Scăderea numărului de noduli limfatici fără metastaze examinaţi după rezecţia chirurgicală se asociază cu creşterea supravieţuirii. Creşterea supravieţuirii este corelată cu creşterea numărului (peste 12) nodulilor limfatici extirpaţi şi examinaţi şi cu creşterea numărului limfonodulilor negativi [3][4][5][6][20][21][22][23][24][25][26][27][28][29]. Rata supravieţuirii la 5 ani este de 80-90% în absenţa metastazelor în nodulii limfatici şi de 40% când acestea sunt prezente.…”

Pesquisa de linfonodo-sentinela em pacientes com adenocarcinoma de cólon

“…De acordo com os trabalhos de revisão, a taxa global média de falso-negativo é de 33%, variando de 0 a 63%. Quando observados somente os trabalhos que utilizaram o método combinado (corante e radiofármaco), como nesta avaliação, a taxa média foi de 28%, variando de 0 a 50% 19,27,29 . De acordo com o estudo de validade deste trabalho, a sensibilidade foi 66,7%, enquanto na literatura varia de 40 a 100% 17,26,28 .…”

“…Em recentes revisões de trabalhos relevantes, levando-se em consideração diferentes técnicas, a identificação de linfonodo-sentinela variou de 71 a 100% 18,19 .…”

Intraoperative sentinel lymph node mapping in patients with colon cancer: Study of 38 cases

“…At present, however, no consensus has yet been reached on the usefulness of SLN for colon cancer. Nevertheless, it is of interest to explore the use of new prognostic markers to evaluate the progression of this disease (9). Currently, the mainstay of treatment for non-metastatic colorectal cancer is complete surgical resection of the tumor-bearing colon, together with en bloc regional lymphadenectomy (10).…”