Preoperative CT Scans and Node-Positive Gastric Cancer
June 1, 1999
Preoperative CT Scans and Node-Positive Gastric Cancer
abstract & commentary
Synopsis: The presence of lymph node metastases as determined histologically has proven to be an excellent indicator of prognosis in patients with gastric cancer. Seventy-eight patients were studied to evaluate the ability of preoperative CT scanning to predict surgical findings and prognosis. The level of lymph node metastases was graded as level I (perigastric nodes), level II (intermediate nodes along the left gastric, common hepatic and celiac arteries, or level III (distant nodes). Nodal status, as determined by CT was a good predictor of prognosis. Thus, the one-year survival for those with level I nodes was 55%, compared to 27% for those with level II and 7% for level III. CT-determined lymph node status offers important prognostic information in patients with gastric cancer.
Source: Adachi Y, et al. J Clin Gastroenterol 1999;28: 140-143.
The presence of lymph node metastases as determined by microscopic examination of surgical specimens has been recognized as an important prognostic indicator in gastric carcinoma. However, the value of determining lymph node metastases by computed tomography (CT) remains unknown. In the current report 78 patients were described. These were drawn from a population of patients who were seen at the First Department of Surgery, Oita Medical University in Japan. The level of lymph node metastases, as assessed by CT were graded as level-I, perigastric nodes; level-II, intermediate nodes along the left gastric, common hepatic, and celiac arteries; and, level-III, distant nodes along the hepatoduodenal ligament, pancreas, spleen, and abdominal aorta.
Sixty patients (79%) had stage IV tumors. For the whole group, one- and five-year survival rates were 29% and 6% respectively, and the one-year survival rate was significantly influenced by the level of lymph node metastases as demonstrated by CT scan (55% for level-I, 27% for level-II, and 7% for level-III; P < 0.01). In those patients who underwent gastrectomy, prognostic factors were tumor size ( < 10 cm vs. > 10 cm), gross type (localized vs infiltrative), and histologic type (well-differentiated vs poorly-differentiated).
Adachi and colleagues suggest that the prognosis of patients with CT-assessed node-positive gastric carcinoma is poor because of the high frequency of extensive tumor spread. However, patients having only positive level-I (perigastric) nodes on CT remain candidates for curative gastrectomy, which offers the possibility of long-term survival.
COMMENTARY
Perhaps the value of this study relates to the apparent correlation of CT scan noted lymphadenopathy and overall outcome. At surgery, lymph nodes that were found to be enlarged on CT scan were likely to harbor disease (more than 3/4 of the cases confirmed positive). Furthermore, the one-year survival rate was significantly influenced by the level of lymph node metastasis as determined by CT scan.
It is not unexpected that the presence or absence of lymph node metastases would have important predictive value with regard to survival in patients with gastric cancer.1 In fact, the number or level of lymph node metastases has proven to be significant in previous work. 2,3 However, those results were based upon data from operated patients and, thus, may represent a selected group. Furthermore, many of those patients had histologic assessment of lymph nodes but unresectable gastric tumors. Data from the current study may offer predictive value regarding those patients for whom laparotomy has the greatest chance to result in curative resection (i.e., those patients with no, or only level I adenopathy). In contrast, patients with advanced disease (e.g., level-III adenopathy) probably should not be treated by aggressive surgical intervention, for survival is extremely low. Consideration of quality-of-life issues in these patients would seem most appropriate and avoiding the morbidity of aggressive surgery would have clinical value.
This series highlights the potential importance of careful CT scanning in patients with gastric cancer. Patients with level I metastases remain good candidates for laparotomy. Those found preoperatively to have more extensive adenopathy may be better treated with palliative, limited surgery or with nonsurgical approaches. It remains to be seen whether preoperative chemotherapy and radiation therapy (neoadjuvant therapy) might convert some patients with level II or III adenopathy by CT scan to level I adenopathy with the attendant improvement in prognosis and in the chances of success from a more aggressive surgical approach.
References
1. Bozzetti F, et al. Surg Gynecol Obstet 1986;162: 229-234.
2. Gunven P, et al. Br J Surg 1994;78:352-354.
3. Adachi Y, et al. Br J Surg 1994;81:414-416.
Which of the following statements about lymph node metastases in gastric cancer is true?
a. Enlarged nodes by CT are commonly "reactive" and actually harbor metastatic cells in less than 25% of cases.
b. Neoadjuvant chemotherapy has been proven to cause level III adenopathy regress to level I adenopathy and permit a potentially curative resection.
c. Perigastric nodes (level I) may be present in patients for whom potentially curative resection is still a possibility.
d. Advanced nodal disease (level III), but without distant organ metastases, may be present in patients for whom potentially curative resection is still a possibility.
e. CT scans are not useful preoperatively in patients with gastric cancer, but can be of clinical benefit for follow-up postoperatively to determine local or metastatic disease.