I. To determine whether substituting adjuvant concurrent high dose cisplatin (CDDP) and fluorouracil (5-FU) with gemcitabine (gemcitabine hydrochloride) and paclitaxel will result in superior progression-free survival. (Detectable Plasma Epstein Barr Virus [EBV] Deoxyribonucleic Acid [DNA] Cohort randomized Phase II) II. To determine whether omitting adjuvant CDDP and 5-FU (observation alone in the adjuvant setting) will result in non-inferior overall survival as compared with those patients receiving adjuvant CDDP and 5-FU chemotherapy. (Undetectable Plasma EBV DNA Cohort Phase III)