SUMMARY OF PKER REVIKW COMMENTS (Continued) 



tables and representative photomicrographs of selected tumors were included in the Results section of 

 the Report, and the Discussion section was modified to reflect the additional findings 



Discussion among the Panel members and the staff centered around several issues: the size and rela- 

 tive numbers of lesions in the recut sections vs. the original histologic sections (it was noted that all of 

 the adenomas were quite small and that there were no concomitant increases in hyperplasia and car- 

 cinomas in the recut sections); which sets of numbers could be compared with, or added to, the his- 

 torical control data base (it was agreed that only the original incidences could be compared or added); 

 whether the Panel should move to affirm or change the level of evidence in male rats; and the generic 

 issue of when and why the NTP should return to a study and do additional sections (there was agree- 

 ment that this would not be done routinely). 



Dr. Hooper moved that the conclusion for male rats be changed to clear evidence of carcinogenic activ- 

 ity. Dr. Perera seconded the motion, which was defeated by five votes (Dr. Ashby, Dr. Capen, Dr. 

 Gallo, Dr. Popp, and Dr Sivak) to four ( Dr Chinchilli, Dr. Hooper, Dr. Lijinsky, and Dr. Perera), with 

 one abstention (Dr Hughes). Dr. Popp moved that the Panel concur with the staffs original recom- 

 mendation, some evidence of carcinogenic activity The motion was seconded and approved by five 

 votes (Dr. Ashby, Dr. Capen, Dr Gallo, Dr. Popp, and Dr Sivak) to four (Dr. Chinchilli, Dr. Hooper, 

 Dr. Lijinsky, and Dr Perera), with one abstention (Dr. Hughes). 



13 Nitrofurantoin, NTP TR 341 



