Several groups have developed recommendations for cancer surveillance on the basis of therapeutic exposures, recognizing that these cancers are a leading cause of non-relapse late mortality [92] and serious morbidity [93]. The underlying premise for these surveillance recommendations is that almost half of the SMNs can be detected at an early stage by periodic surveillance [1, 3, 94, 95]. In general, because survival rates are strongly associated with the stage of disease at diagnosis, early initiation of SMN surveillance is recommended. This early surveillance is even more necessary because options become limited for the treatment of SMNs because of prior therapeutic exposures. The COG LTFU Guidelines [96] recommend monitoring for t-MDS/AML with annual complete blood count for 10 years after exposure to alkylating agents or topoisomerase II inhibitors. Most other SMNs are associated with radiation exposure, present as solid tumors and are site-specific. Screening recommendations include careful annual physical examination of the skin and underlying tissues in the radiation field. For example, young women treated for a childhood cancer with a moderate-to-high dose of chest radiation have a greatly increased risk of breast cancer, similar in magnitude to that of carriers of the BRCA mutation [97]. Mammography, the most widely accepted screening tool for breast cancer in the general population, may not be the ideal screening tool by itself, for radiation-related breast cancers occurring in relatively young women with dense breasts, hence the American Cancer Society recommends adjunct screening with MRI. Thus, the COG LTFU recommendations for females who received radiation with potential impact to the breast (i.e., radiation doses of 20 Gy or higher to the mantle, mediastinal, whole lung, and axillary fields) include monthly breast self-examination beginning at puberty; annual clinical breast examinations beginning at puberty until age 25 years; and a clinical breast examination every 6 months, with annual mammograms and MRIs beginning 8 years after radiation or at age 25 (whichever occurs later). Screening of those at risk for early-onset colorectal cancer (i.e., radiation doses of 30 Gy or higher to the abdomen, pelvis, or spine) should include colonoscopy every 5 years beginning at age 35 years or 10 years following radiation (whichever occurs last).