Location

Unilateral study of the most symptomatic side, expanding to the contralateral side if initial biopsy result is negative but strong clinical suspicion remains

Sizing

Biopsy should be greater than 1 cm, targeting a 2-cm segment because of concern for missed histologic findings secondary to skip lesions

Timing

Should be performed as soon as possible after initiation of therapy, ideally within the first week, but can be extended to within two weeks of starting treatment based on resource availability