<qa>  What is the most common marker in men receiving ADT?One of the challenges in the overall management of men with high risk prostate cancer is the lack of a reliable test allowing clinicians to monitor tumor response both during and after radiation therapy. The commonly used marker, prostate specific antigen PSA, is less useful in men receiving ADT. In these men, the PSA is level is strongly suppressed by the ADT and is a less reliable surrogate for detecting active tumor. Importantly, ADT is given both during and for up to 3 years following radiation therapy, limiting the utility of PSA testing for an extended period of time during which the window for curative therapies may close. The development of an accurate, noninvasive monitoring test is needed, to guide early implementation of salvage strategies aimed at increasing the proportion of patients cured of their disease. 