RT Journal Article SR Electronic T1 Ultrasonography as the Gold Standard for In Vivo Volumetric Determination of Chemically-induced Mammary Tumors JF In Vivo JO In Vivo FD International Institute of Anticancer Research SP 465 OP 472 VO 30 IS 4 A1 FAUSTINO-ROCHA, ANA I. A1 GAMA, ADELINA A1 OLIVEIRA, PAULA A. A1 ALVARADO, ANTONIETA A1 FIDALGO-GONÇALVES, LIO A1 FERREIRA, RITA A1 GINJA, MÁRIO YR 2016 UL http://iv.iiarjournals.org/content/30/4/465.abstract AB Background/Aim: In this study, we evaluated the dimensions and volume of rat mammary tumors and the association of these variables with tumor invasiveness. Materials and Methods: Tumors were measured by caliper and ultrasonography. Volume was determined by water displacement and by application of four formulas using tumor length (L), width (W) and depth (D) or tumor weight. Results: Results confirmed the data obtained in our previous work, where we verified that mammary tumors grow as oblate spheroids. Conclusion: The determination of mammary tumor volume by applying the formula V=(4/3)×π×(L/2)×(L/2)×(D/2) is the best way to evaluate tumor volume in vivo. Beyond volume evaluation by water displacement, the determination on the basis of tumor weight is the most accurate way to evaluate tumor volume after animal sacrifice or tumor excision. According to our results, it is not possible to predict if a tumor is invasive or non-invasive by its dimensions, volume or weight. Future work in chemically-induced mammary cancer should use ultrasonography and water displacement or tumor weight to determine tumor volume in vivo and after animal sacrifice or tumor excision, respectively.