Regional lymph node metastasis is well established as the most important prognostic factor in patients with gastric cancer. Despite curative resection of their primary tumor, some patients with histologically node-negative gastric cancer will die as a result of local or distant tumor recurrence. Therefore, additional markers would be helpful for predicting patients at risk for recurrence
( 1 ).
Some studies examined the frequency of lymph node micrometastasis in histologically node-negative gastric cancer limited to the mucosa or submucosa. However, T1 tumors have a good prognosis, and the prognostic significance of lymph node micrometastasis from gastric
cancer remains unclear
To clarify the prognostic importance of lymph node micrometastasis in patients with gastric cancer, histologically node-negative gastric cancers invading the muscularis propria or deeper (T2 and T3) were selected for the Yasuda's study.
The results of this study indicate that lymph node micrometastasis is an independent prognostic indicator for patients with histologically node-negative gastric cancer invading the muscularis propria or deeper (T2 or T3).
Micrometastasis of four or more lymph nodes or micrometastasis of level 2 nodes was significantly associated with a poor outcome
( 1 ).
It is controversial whether lymph node micrometastasis detected by immunohistochemistry predicts the clinical outcome of patients with histologically node-negative gastric cancer.
Nakajo et al.reported that lymph node micrometastasis was correlated with a significantly
worse survival rate in patients with T1 or T2 tumors ( 4 ).
Cai et al.also found a significant relationship between lymph node micrometastasis and poor prognosis in patients with T3 gastric cancer ( 5 ).
However, Fukagawa et al. showed that the presence of lymph node micrometastasis did not affect the survival in large numbers of patients with T2 gastric cancer ( 6 ).
Siewert et al.15 observed that the presence of three of more tumor cells in more than 10% of the
dissected lymph nodes was the only significant prognostic factor ( 7 ).
In a similar finding from another study, the patient group with micrometastasis in level 2 nodes had
a significantly poorer survival rate than that of the group with micrometastasis limited to level 1 nodes ( 5 ).
Lymph node metastasis is linked to tumor progression.Lymph node micrometastasis in gastric cancer is also associated with deep invasion through the gastric wall, large tumor size, and positive lymphatic or venous invasion
( 2, 6, 5 ).
In the Yasuda's study, although no relationship was found between the presence of lymph node micrometastasis and clinico-pathologic characteristics, a weak association was found
between lymph node micrometastasis and depth of wall invasion
( 1 ).
In this series, the most common pattern of recurrence was peritoneal and lung metastasis. Similar to these results, previous studies reported that lymph node micrometastasis was strongly associated with subsequent development of hematogenous and peritoneal metastases, but not locoregional lymph node recurrence
( 1, 2,
1) Kazuhiro Yasuda, Yosuke Adachi, Norio Shiraishi, Masafumi Inomata,
Hiroaki Takeuchi, and Seigo Kitano. Prognostic Effect of Lymph Node Micrometastasis in Patients
With Histologically Node-Negative Gastric Cancer. Annals of Surgical Oncology, 9(8):771-774. Pub Med
2) Cai J, Ikeguchi M, Maeta M, Kaibara N. Micrometastasis in lymph nodes and microinvasion of the muscularis propria in primary lesions of submucosal gastric cancer. Surgery 2000;127:32-9. Pub Med
3) Cai J, Ikeguchi M, Tsujitani S, Maeta M, Kaibara N. Micrometastasis in lymph nodes of mucosal gastric cancer. Gastric Cancer 2000;3:91-6. Pub Med
4) Nakajo A, Natsugoe S, Ishigami S, et al. Detection and prediction of micrometastasis in the lymph nodes of patients with pN0 gastric cancer. Ann Surg Oncol 2001;8:158 -62. Pub Med
5) Cai J, Ikeguchi M, Maeta M, Kaibara N, Sakatani T. Clinicopathological value of immunohistochemical detection of occult involvement in pT3N0 gastric cancer. Gastric Cancer 1999;2:95-100. Pub Med
6) Fukagawa T, Sasako M, Mann GB, et al. Immunohistochemically detected micrometastases of the lymph nodes in patients with gastric carcinoma. Cancer 2001;92:753-60. Pub Med
7) Siewert JR, Kestlmeier R, Busch R, et al. Benefits of D2 lymph node dissection for patients with gastric cancer and pN0 and pN1 lymph node metastases. Br J Surg 1996;83:1144 -7. Pub Med
8) Maehara Y, Oshiro T, Endo K, et al. Clinical significance of occult micrometastasis in lymph nodes from patients with early gastric cancer who died of recurrence. Surgery 1996;119:397-402. Pub Med