Lymph Node Sampling Compromises Cancer Survival

September 2006 - A new study concludes that most patients who undergo gastric cancer staging by lymph node sampling have inadequate assessments that compromise survival. Research into other cancers has shown the importance of staging to prognosis. The authors suggest that with recent advances in the management of gastric cancers, assessment of new staging guidelines is timely.

Published in the 1 November, 2006 issue of CANCER, a peer-reviewed journal of the American Cancer Society, the study found that less than one third of gastric cancer patients had adequate lymph node assessments. This had a profound effect on patient survival. A change in the staging system guidelines in 1997 was intended to improve staging of gastric cancers, but only small improvements in the quality of lymph node assessments has resulted.

The authors stress that appropriate staging of gastric cancer is necessary in order to identify the most appropriate treatments. One of the most important factors in determining the stage of disease is metastasis to the lymph nodes. Lymph node assessment is quite complex, requiring collaboration between the surgeon who resects the lymph nodes and the pathologist who analyzes them. The work of either may be affected by patient characteristics such as obesity.

Evidence suggests that the pre-1997 system of staging recommended by the American Joint Committee on Cancer and Union Internationale Contre le Cancer was both improperly and variably used by physicians. To standardize staging methods, new guidelines changed the definition of adequate lymph node assessment from distance from primary tumour to the number of lymph nodes with cancer out of at least fifteen resected.

In the current study, Natalie Coburn, assistant professor at Sunnybrook Health Sciences Centre in Toronto and colleagues reviewed data from 10 807 patients with gastric cancers reported in the Surveillance, Epidemiology and End Results (SEER) database.

The authors found that compliance with new guidelines remains poor. Since 1997 the median number of lymph nodes resected has increased from nine to ten. Overall, only 29 per cent of patients had at least 15 lymph nodes resected. However, rates varied from 19 to 53 per cent in different SEER regions. Median survival was 33 months where the rate was highest but fell to 17 months where it was lowest. Adequate lymph node assessment improved survival at every stage, with the most significant benefit to patients with early stage disease.

The study found that poor use of the guidelines resulted in the possibility of inappropriately denying new adjuvant therapy in up to 11 per cent of cases. A few of the factors that predicted use of new guidelines included the SEER region, Asian ethnicity, advanced disease, type of resection and younger age. The authors conclude that inadequate staging of gastric cancer compromises patient care.

Natalie Coburn said:

"Education for pathologists, surgeons and medical oncologists should improve adequate lymph node assessment and by proxy, improve the care received by patients with gastric cancer, and their overall survival."

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