Cancer Survival Compromised By Poor Staging Methods
Staging of Gastric Cancer
Most patients who undergo gastric cancer staging by lymph node sampling have inadequate assessments that compromise survival, according to a new study. Published in the November 1, 2006 issue of CANCER, a peer-reviewed journal of the American Cancer Society, the study reveals that less than one third of gastric cancer patients had adequate lymph node assessments (ALNA). This had a profound effect on patient survival. Median survival in the region with the highest ALNA rate (53 percent) was 33 months compared to just 17 months in the worst rate (19 percent). A change in the staging system guidelines in 1997 was intended to improve staging of gastric cancers, but made only small improvements in the quality of lymph node assessments.
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 must analyze them. The work of either of these physicians may be impacted by patient characteristics, such as obesity.
Prior to 1997, evidence suggested that the system of staging as put forth by the American Joint Committee on Cancer (AJCC) and Union Internationale Contre le Cancer (UICC) was both improperly and variably used by physicians. To standardize staging methods, new guidelines in 1997 changed the definition of ALNA from distance from primary tumor to the number of lymph nodes with cancer out of at least 15 resected.
With evidence from other cancers showing the importance of staging to prognosis and recent advances in the management of gastric cancers, assessment of the new ALNA staging guidelines is timely. To identify compliance with the guidelines and its impact on survival, Natalie G. Coburn, M.D., M.P.H., an 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.
Compliance with new guidelines remains poor. After 1997 the median number of lymph nodes resected increased from 9 to only 10. Overall, only 29 percent of patients had at least 15 lymph nodes resected, indicating poor compliance by physicians. By SEER region, however, rates varied from 19 to 53 percent. Poor ALNA use in up to 11 percent of patients resulted in the possibility of inappropriately denying them new adjuvant therapy. A few of the factors that predicted use of new ALNA guidelines included the SEER region, Asian ethnicity, advanced disease, type of resection and younger age.
In the SEER region with the highest ALNA rate, median survival was 33 months. In the SEER region with the lowest ALNA rate, median survival fell to 17 months. ALNA improved survival at every stage, with the most significant benefit to patients with early stage disease.
This study, according to the authors, shows that inadequate staging of gastric cancer compromises patient care. "Education for pathologists, surgeons and medical oncologists should improve ALNA," according to Dr. Coburn, "and by proxy, improve the care received by patients with gastric cancer, and their overall survival."