DECLARE @cutoffDate datetime = CONVERT(DATETIME, DATEADD(YEAR,-1,GETDATE()), 112)

SELECT 'DROP TABLE "' + TABLE_NAME + '"' AS 'Command'
    FROM INFORMATION_SCHEMA.TABLES
    WHERE (TABLE_NAME LIKE 'tableA%' OR TABLE_NAME LIKE 'tableB%')
    AND (CONVERT(DATETIME, SUBSTRING(TABLE_NAME, 7, 8), 112) < @cutoffDate)
    ORDER BY Command DESC

SELECT CONVERT(DATETIME, SUBSTRING('tableA20110305', 7, 8), 112)