Factors included in the multivariable analyses to identify covariates associated with increased distress six months after RT completion (FU3) were tumour subtype (invasive tumour types, i.e., luminal, HER2 +, triple-negative vs. Ductal Carcinoma In Situ, DCIS), RT combined with another treatment (neoadjuvant/adjuvant chemotherapy and/or endocrine therapy vs. RT alone), low FHL, low self-efficacy, and eHLQ domains 2 (poor understanding of health concepts), 4 (feeling less safe and in control), and 6 (limited access to effective digital services). The gene discussed is ERBB2; the disease is ductal breast carcinoma in situ.