A total of 13,784 records were identified through database searches, and 14 articles were added from reference lists review. After removal of duplicates (n = 8,989), title/abstract screening was completed for 4,991 records, yielding 122 records for full text review. After the full-text review, 24 manuscripts were included in this review (Fig. 1). Among the 24 included articles, 16 were observational [14, 30,31,32,33,34,35,36,37,38,39,40,41,42,43,44] and 8 interventional [45,46,47,48,49,50,51,52].

Although the National Cancer Institute defines AYAs as individuals 15–39 years of age [53], nearly all included studies used age 18 years to distinguish between childhood/adolescent and adult populations. Many studies focused on populations either on or off treatment; some included both. Thus, consistent with our populations of interest, this review encompasses four patient groups: (1) child/adolescent patients on treatment (age at diagnosis and enrollment < 18 years; on therapy); (2) child/adolescent survivors of childhood/adolescent cancer (age at diagnosis and enrollment < 18 years; off therapy); (3) young adult (YA) cancer patients on treatment (age at diagnosis and enrollment 18–39 years; on therapy); and (4) YA/adult survivors of childhood/adolescent or YA cancer (age at diagnosis ≤ 39 years, age at enrollment ≥ 18 years). The population of survivors enrolled at > 39 years of age was very small (estimated < 50 survivors).

Included observational studies are summarized in Table 1. Fourteen of the 16 observational studies (87.5%) were cross-sectional [14, 31,32,33,34,35,36, 38,39,40,41,42,43,44], one was a case–control study [37], and one was a prospective study with median follow-up of 5.2 years [30]. Publication dates ranged from 2009 to 2024, with most (n = 10) studies published since 2015 [14, 30, 31, 33,34,35, 38, 41, 42, 44]. The studies were conducted in the United States (U.S.) (n = 5) [30, 32, 36, 40, 43], Spain (n = 4) [34, 38, 41, 42], Poland (n = 2) [31, 44], and 1 each for Australia [33], the Netherlands [14], Norway [37], and Turkey [39]; one included 6 international sites [35].

Sample sizes ranged from 21 to 330 participants, totaling 1,690 cancer patients and survivors across all studies. Mean/median age of study participants overall ranged from 10 to 33.7 years. The number of included participants in each age/treatment category were: (1) child/adolescent cancer patients on therapy (n = 95) [14, 31, 36, 40]; (2) child/adolescent survivors of childhood/adolescent cancer (n = 937) [14, 33, 34, 38,39,40,41,42,43,44]; (3) YA cancer patients on therapy (n = 24) [35]; (4) YA/adult survivors of childhood/adolescent or YA cancer (n = 464) [30, 35, 37]. Additionally, one study enrolled 170 survivors of either childhood or YA cancer which included participants from 6–40 years old at time of study (mean age 19.4 years) [32].

Six studies measured SB via accelerometry, with wrist-worn wGT3x-BT accelerometers (ActiGraph LLC, Pensacola, FL, USA) being the most common device (n = 3) [30, 38, 41]; other devices utilized included activPAL (thigh-worn; PAL Technologies Ltd., Glasgow, UK; n = 1) [37], Actical (hip-worn; Philips Respironics, Bend, OR, USA; n = 1) [14], and Actiwatch 2 (wrist-worn; Philips Respironics, Bend, OR, USA; n = 1) [36]. The most common metric reported for device-measured SB was total sedentary time in minutes per day (n = 4) [14, 30, 37, 38]. Other reported device-measured metrics were sedentary bouts per day (n = 1) [14], percentage of the day spent sedentary (n = 1) [30], immobile time (n = 1) [36], and the geometric mean of sedentary time per day (n = 1) [41].

Ten studies measured SB via self-report alone using various surveys [31,32,33,34,35, 39, 40, 42,43,44]; only two studies used the same validated questionnaire [Health Behavior in School-Aged Children (HBSC)] [44, 48]. Screen time was the most commonly-studied self-report SB domain, including watching television (TV) and using a computer (n = 11) [30,31,32,