RATIONALE: Diagnostic procedures, such as positron emission tomography (PET), (done before, during, and after chemotherapy) may help doctors predict a patient's response to treatment and help plan the best treatment. Drugs used in chemotherapy, such as pemetrexed disodium and cisplatin, work in different ways to stop the growth of tumor cells, either by killing the cells or by stopping them from dividing. Giving combination chemotherapy after surgery may kill any tumor cells that remain after surgery.