ORLANDO — Two-thirds of gastric cancer patients still do not receive an adequate lymph node assessment for staging of their disease prior to surgery, Natalie G. Coburn, M.D., reported at the annual meeting of the American Society for Clinical Oncology. According to an analysis of 11,602 U.S. patients operated on from 1988 through 2001, only 27.6% had at least 15 nodes removed for examination, said Dr. Coburn of Princess Margaret Hospital and the University of Toronto.
The American Joint Commission on Cancer changed its guidelines in 1997 to make 15 nodes the standard for assessment. Though the Canadian investigators found some improvement subsequently, only 32.7% of cases from 1998 to 2001 were in compliance.
Dr. Coburn reported the median number of lymph nodes assessed was nine, with wide variation among the nine geographic regions included in the National Cancer Institute's Surveillance, Epidemiology, and End Results (SEER) database.
Hawaii had the best results. A median of 15 lymph nodes were examined, and 52.5% of patients received care that met the standard for adequate assessment. That state also had the best median survival (26 months) and the best 5-year actuarial overall survival (33.4%).
In contrast, Utah had the worst record. The median number of lymph nodes examined was six, and only 17.5% of patients received an adequate assessment. Utah's median survival was the lowest (15 months), as was its 5-year actuarial overall survival (16.2%).
“Patients who had more adequate surgery and lymph node assessment had better outcomes,” Dr. Coburn said at a press briefing, noting that variations in the number of lymph nodes collected correlated with disparities in survival.
Dr. Coburn reported a variety of factors affected the chance of receiving an adequate lymph node assessment. Better odds ratios (ORs) were associated with the following:
▸ Year of diagnosis (1998–2001, OR 1.4).
▸ Female gender (OR 1.3).
▸ Asian (OR 1.4–1.8) or African American (OR 1.4) descent.
▸ Tumor stage more advanced than T1 (OR 1.3–1.7).
▸ Increase in grade from well differentiated to undifferentiated (OR 1.4–1.8).
Patients were more likely to have an adequate assessment if they had a major surgery such as total resection (OR 1.8) or en bloc resection (OR 1.9). Patients under the age of 74 also were more likely to have an adequate assessment.
Although only a small number of patients had neoadjuvant radiation, they had lower odds of an adequate lymph node assessment (OR 0.2). Other investigators have reported similar results, according to Dr. Coburn. “They feel it's due to radiation changes in the surgical bed,” she said.
Many hazard ratios (HRs) for death reflected the odds for adequate assessment. Older patients were more likely to die (HR 1.4). Japanese and other Asian Americans (HR 0.82) were less likely to die, as were women (HR 0.83). However, risk of death also increased with higher tumor stage (HR 1.4–3.4) and grade (HR 1.4), she said.
Patients with total resections had a better hazard ratio (0.88) than did those with distal resections, but the odds of dying were higher with gastrectomy (HR 1.2) and en bloc surgery (HR 1.12). Neoadjuvant radiation did not have an effect on hazard ratios, but adjuvant radiation reduced risk slightly (HR 0.9).
The investigators calculated that having an adequate number of lymph nodes removed for assessment reduced the risk of death by 14% (HR 0.86).