OUTLINE: Patients receive sargramostim (GM-CSF) intradermally (ID) on days 1-10 beginning a maximum of 6 months after complete surgical resection. Patients receive mutant K-ras peptide vaccine (limited to the specific K-ras mutation in their tumors) ID on day 7. Treatment repeats every 4 weeks for 3 courses in the absence of disease progression or unacceptable toxicity.