Lymph node metastasis is one of the most important prognostic factors in patients with gastric cancer. An inadequate number of dissected lymph nodes is an independent risk factor affecting recurrence, even in patients who are node negative. Oddly, certain early-stage patients still experience recurrence or metastasis within a short time, even if they have undergone standard radical mastectomy. Many researchers have attributed these adverse events to lymph node micrometastasis (LNM), which is defined as a microscopic deposit of malignant cells of less than 2 mm in diameter. With the development of diagnostic tools such as immunohistochemistry and reverse transcription-polymerase chain reaction, the rate of detection of LNM has been constantly increasing. Although there is no clear consensus about risk factors for or the definitive clinical significance of LNM, the clinical impact of LNM is remarkable in gastric cancer. For minimally invasive treatment in particular, such as endoscopic submucosal dissection and laparoscopic surgery, accurate diagnosis of LNM is regarded as the potential key to maintaining the balance between curability and safety. This review provides an overview of the definition, detection and significance of LNM in gastric cancer. We also summarize several attention-drawing controversies regarding the treatment of patients who may have LNM.

Laparoscopic colorectal surgery had been widely used for colorectal cancer patient and showed a favorable outcome on the postoperative morbidity rate. We attempted to evaluate physiological status of patients by mean of Estimation of physiologic ability and surgical stress (E-PASS) system and to analyze the difference variation of postoperative morbidity rate of open and laparoscopic colorectal cancer surgery in patients with different physiological status.In total 550 colorectal cancer patients who underwent surgery treatment were included. E-PASS and some conventional scoring systems were reviewed to examine their mortality prediction ability. The preoperative risk score (PRS) in the E-PASS system was used to evaluate the physiological status of patients. The difference of postoperative morbidity rate between open and laparoscopic colorectal cancer surgeries was analyzed respectively in patients with different physiological status.E-PASS had better prediction ability than other conventional scoring systems in colorectal cancer surgeries. Postoperative morbidities were developed in 143 patients. The parameters in the E-PASS system had positive correlations with postoperative morbidity. The overall postoperative morbidity rate of laparoscopic surgeries was lower than open surgeries (19.61% and 28.46%), but the postoperative morbidity rate of laparoscopic surgeries increased more significantly than in open surgery as PRS increased. When PRS was more than 0.7, the postoperative morbidity rate of laparoscopic surgeries would exceed the postoperative morbidity rate of open surgeries.The E-PASS system was capable to evaluate the physiological and surgical risk of colorectal cancer surgery. PRS could assist preoperative decision-making on the surgical method. Colorectal cancer patients who were assessed with a low physiological risk by PRS would be safe to undergo laparoscopic surgery. On the contrary, surgeons should make decisions prudently on the operation method for patient with a high physiological risk.