To the Editor: Contrary to Hermann and Cooperman's assertions (issue of August 30), scalpel biopsy of a pancreatic mass is absolutely contraindicated in any patient with a localized, potentially curable lesion. Despite any attempt at isolation of the area before biopsy, cutting into the tumor violates the integrity of tissue barriers, with inevitable spillage of cancer cells into the peritoneal cavity. Carefully performed, transduodenal needle biopsy or, possibly, skinny-needle biopsy are acceptable methods. The commonly used Kocher maneuver for evaluating a mass in the head of the pancreas may also cause problems. With this maneuver, the dissecting finger enters the. . .