SEER is an authoritative source of information on cancer incidence and survival in the United States. SEER currently collects and publishes cancer incidence and survival data from population-based cancer registries covering approximately 28 percent of the U.S. population.
See Module 7. Lymph nodes (C770-C779) are the usual primary sites; however, involvement in others sites is possible. If you have confirmation that the only involved site is something other than the lymph nodes, then code to that primary site