Pfizer Affirms 2004 Forecast  NEW YORK (Reuters) - Pfizer Inc. &lt;A HREF="http://www.investor.reuters.com/FullQuote.aspx?ticker=PFE.N target=/stocks/quickinfo/fullquote"&gt;PFE.N&lt;/A&gt; on Tuesday  reaffirmed it expects 2004 earnings to be more than 20 percent  above last year, but warned that results in 2005-2007 will be  hurt by patent expirations on over a half-dozen of its  best-selling medicines.