Eilis McCaughan, Kader Parahoo, Irene Hueter, Laurel Northouse, Ian Bradbury

Survival rates for women with a diagnosis of breast cancer continue to improve. However, some women may experience physical, psychological and emotional effects post diagnosis, throughout treatment and beyond. Support groups can provide opportunities for people to share their experiences and learn from others. As the number of online support groups increases, more and more women with breast cancer will likely access them. To assess effects of online support groups on the emotional distress, uncertainty, anxiety, depression and quality of life (QoL) of women with breast cancer. We searched for trials in the Cochrane Breast Cancer Specialised Register, the Cochrane Central Register of Controlled Trials (CENTRAL; 2016, Issue 4), MEDLINE, Embase and PsycINFO on 2 May 2016, and we handsearched journals and reference lists. We also searched the World Health Organization's International Clinical Trials Registry Platform (WHO ICTRP) search portal and clinicaltrials.gov on 2 May 2016. We included randomised controlled trials (RCTs) assessing effects of online support groups on women with a diagnosis of breast cancer and women who have completed breast cancer treatment. We included studies comparing online support groups with a usual care group, and studies comparing two or more types of online support groups (without a usual care group). Two review authors independently extracted data and assessed risk of bias. We presented outcome data using mean differences (MDs) and standardised mean differences (SMDs) along with 95% confidence intervals (CIs), and we used the fixed-effect model when appropriate. We assessed the quality of the body of evidence using the GRADE approach. We included six studies (492 women) that assessed online support groups for women with breast cancer. Online support groups in these six trials lasted from six to 30 weeks. Women participated in these groups between 1.5 and 2.5 hours per week, and investigators conducted all studies in the USA. Participants were predominantly white and well educated and were moderate to high earners. Four studies compared an online support group versus a control group, and the other two compared a 'moderated' versus a 'peer-led' online support group, and a 'standard' versus an 'enhanced' online support group, respectively.None of the included studies measured 'emotional distress' or uncertainty. One study (78 women) for which data for analysis were missing reported no positive effects of online support on 'distress' and 'cancer-specific distress' versus support provided by a control group. Two studies measured anxiety: One study (72 women) found no difference in anxiety at the end of the intervention between the online support group and the control group (MD -0.40, 95% CI -6.42 to 5.62; low-quality evidence), and the second study (184 women) reported a reduction in anxiety levels at the end of the intervention when comparing the 'standard' support group (run by participants without prompting from health professionals) versus an 'enhanced' online support group (in which participants were specifically asked by the researcher to respond to one another's need for support).Five studies (414 women) measured depression. Three studies compared depression in the online support group with depression in the control group. Pooled data from two studies (120 women) showed a small to moderate reduction in depression in the online support group compared with control groups at the end of the intervention (SMD -0.37, 95% CI -0.75 to 0.00; very low-quality evidence). The third study, a pilot study (30 women), provided no data for analysis but reported no difference in depression between participants in support and control groups at the end of the intervention. Of the remaining two studies that measured depression, one study (60 women) provided no extractable data for comparison but reported no difference in depressive symptoms between a 'moderated' and a 'peer-led' support group; the other study (184 women) reported greater reduction in depression in the 'standard' support group than in the 'enhanced' online support group.Three studies measured quality of life. One pilot study (30 women) provided limited data for analysis but reported no change in quality of life at the end of the intervention. Only two studies (140 women) provided data for pooling and showed no positive effects on quality of life at four months post intervention compared with controls (SMD -0.11, 95% CI -0.47 to 0.24; very low-quality evidence). At 12 months post intervention, one study (78 women) reported that the intervention group did not attain better quality of life scores than the control group (MD -10.89, 95% CI -20.41 to -1.37; low-quality evidence).We found no data for subgroup analyses on stage of disease, treatment modality and types and doses of interventions. No studies measured adverse effects. This review did not find the evidence required to show whether participation in online support groups was beneficial for women with breast cancer, because identified trials were small and of low or very low quality. Large, rigorous trials with ethnically and economically diverse participants are needed to provide robust evidence regarding the psychosocial outcomes selected for this review.