The conductor Seiji Ozawa, who has been undergoing treatment for esophageal cancer, has canceled a weeklong tour in Europe with the Saito Kinen Orchestra to conserve his strength for performances at Carnegie Hall in December, a representative said on Friday. Mr. Ozawa, right, was to have performed in Prague, Vienna, Berlin and Paris from Dec. 3 to Dec. 10 before opening Carnegie’s Japan NYC festival with the orchestra on Dec. 14. “He said: ‘Cancel Europe, I’ve got to go to Carnegie,’ ” said Ronald Wilford, his manager. “That’s a tough tour,” Mr. Wilford added. “That’s why he said no. Carnegie is absolutely right on.” Mr. Ozawa is artistic director of the Carnegie festival. He is also principal conductor of the Vienna State Opera.