The modes of eHealth intervention delivery included telephone (n=14) [26, 28, 30, 34, 36,37,38,39,40,41, 43, 44, 50, 51], websites (n=6) [26, 35, 37, 47,48,49], smartphone applications (n=9) [29, 31,32,33, 37, 41, 42, 45, 46], short message service (SMS; n=3) [37, 44, 46] or video consultations (n=1) [27] (see Table 4). Several studies combined different modes of delivery. One study supplemented remote follow-up with three home visits during chemotherapy [26]. Of the 26 included studies, the majority involved a delivery mode of direct and analogue contact with a health professional, that is, a nurse [26, 28, 30,31,32,33, 37,38,39,40, 50, 51], a surgeon/physician/general practitioner [41, 49], a therapist [34] or unspecified research staff [27, 29, 36, 43, 44, 47, 48]. In three studies, the intervention deliverance was purely digital [35, 42, 45, 46].

Patient education and information were included as intervention content in 13 of the eHealth programs, six of which provided education and information on PA behaviour change [29, 35, 36, 42, 43, 46]. In four studies, CRC patients received a digital educational program aiming to strengthen patients’ self-management skills [34, 47,48,49], while Soh et al. included health education in their mobile care system to support CRC patients’ QOL [45]. Avci et al. provided patients with education and counselling to lower anxiety levels and chemotherapy-based symptoms [26], while Young et al. delivered educational material to meet the emotional needs of CRC patients following surgery [51].

All the intervention studies comprised an element of monitoring of health condition and symptoms. Eight studies monitored the patient’s health condition and treatment side effects by using checklists that the patients responded to electronically [26, 29,30,31, 35, 39, 41, 44,45,46,47,48,49]. A pedometer or accelerometer was used to monitor daily PA (e.g. number of steps, walking distance, intensity) in six studies [29, 35, 36, 42, 43, 46], while Cheong et al. applied an activity tracker, like a Fitbit, to monitor the patient’s PA and heart rate [29]. One study used home telemonitoring to follow up with post-operative patients by monitoring vital signs (using an oximeter, thermometer, sphygmomanometer and echocardiogram) and changes in the surgical wound [49]. In one study, CRC patients’ health condition was monitored through a video consultation clinic by the surgeon in charge [27].

Eleven studies used a telephone to provide intervention content comprising counselling, therapy or psychosocial support. Four of those studies offered counselling on managing treatment symptoms and late effects [26, 39], healthy eating [36] or enhancing self-management [37]. Three studies provided supportive calls delivered by nurses focusing on psychosocial support to meet the CRC patients’ emotional and informational needs [27, 38, 50]. Two interventions comprised telephone-delivered reminiscence therapy [