An in situ tumor has not spread beyond the limiting membrane of the top level of the stomach lining (the mucosa).
Standard Treatment Experience in Japan, where this stage is diagnosed often, indicates that almost all patients who undergo a gastrectomy will survive beyond five years. An American series has recently confirmed these results.
Five-Year Survival Over 90 percent
Stage I
TNM T1, N0, M0 (Stage IA)
T1, N1, M0 or T2, N0, M0 (Stage IB)
The cancer is confined to the stomach wall and no lymph nodes are involved.
Standard Treatment Surgery is the treatment of choice, although how extensive the operation has to be depends on the tumor's location and how much of the stomach is involved.