We read with interest the comments by MacLennan and colleagues regarding our recent paper [1] outlining a standard set of outcomes we recommend collecting for all men treated with curative intent for prostate cancer. A stated goal of our project was to define a minimum set of outcomes for widespread prospective collection outside of clinical trials, with a focus on what matters to patients. All project members were identified on the basis of their expertise, and the two patient representatives were identified from separate prostate cancer survivorship and advocacy communities. Both had broad experience in representing communities of patients. We are unaware of established data supporting a specific proportion of patients in such a process and whether two were sufficient could be argued. However, both patients were treated equally in the group and provided clear and unique direction, particularly in the prioritization of outcome domains important to patients. For each element of the standard set, a proposal based on a review of the literature was presented to the group to provide evidence for inclusion or exclusion of an outcome, case-mix domain, or their corresponding definition. For patient-reported outcomes, we required tools that could be used across treatment options. Then, according to prioritization by working group members for assessing urinary incontinence, bowel irritation, sexual function, urinary obstruction, and urinary irritation, a range of tools were assessed, including the EORTC PR 25, FACT-P, EPIC, and a tool developed internally at MSKCC. Available information on psychometric properties could not identify one with clear advantages over another. The EPIC was chosen because of its preferred subscale scoring that matched the desired outcome domains of the working group. For clinical outcomes, we attempted to describe with specificity how each should be collected to allow for reliability across centers. As MacLennan and colleagues comment regarding prostate-specific antigen (PSA) for example, we agree that not only is there heterogeneity in testing methodologies, but we also anticipate that definitions of biochemical recurrence will continue to evolve. We suggest the two most common definitions in use today for surgery and radiation, but recommend that ‘‘PSA is measured at least annually and providers record all PSA values and dates’’ to allow for future flexibility. Additional details are provided in the extended data dictionary (www. ichom.org/medical-conditions/localized-prostate-cancer). All such points of discussion were reviewed during the six teleconferences, with feedback elicited from every participating member, including patients. Each outcome, case-mix factor, and domain definition was voted on independently via an anonymous electronic survey, with all members having equal weight. The authors’ work on core outcome sets for clinical trials appears well aligned with work by the National Cancer Institute [2] and we agree is complementary to our effort to collect these data outside the structure of clinical trials. We share the authors’ view that the patient’s voice is crucial. Importantly, implementation of any outcome set is key for testing and improvement. Today, with support from the Movember Foundation, the standard set is being implemented across multiple national registries and institutions. Their combined experience will contribute to continued refinement of the recommendations.