Participants in the eConquerFear intervention group will receive six online modules with each containing educational text, illustrative graphics, interactive exercises, and brief videos. Every module will teach a specific topic, such as self-examination and medical surveillance, values-based goal setting, attention training, detached mindfulness, worry management and treatment summary and relapse prevention.

Participants in the eHealthMaintenance group will receive six videos, which were designed to provide comprehensive lifestyle guidance (e.g., relaxation techniques, diet and physical activity advices) to help with survivors' maintenance of health in long-term.

ConquerFear-HK is a culturally adapted, manualized intervention consisting of 6 individual face-to-face sessions over 10 weeks.

The augmented eConquerFear + eHealthMaintenance intervention is a combined unsupervised, self-guided web-based intervention that consists of 10 weekly online modules covering the content of eConquerFear and eHealthMaintenance interventions.

The key goals of this e-intervention are to: (i) teach strategies for controlling worry and excessive threat monitoring; (ii) modify underlying unhelpful MCQ beliefs about worry; (iii) develop appropriate monitoring and screening behaviours, (iv) encourage acceptance of the uncertainty brought about by a cancer diagnosis, and (v) clarify values and encourage engagement in values-based goal setting.

The primary outcome is the change in the total score of FCR assessed using the 42-item Fear of Cancer Recurrence Inventory (FCRI). The FCRI measures seven dimensions of FCR: (1) triggers, (2) severity, (3) psychological distress, (4) functional impairment, (5) reassurance, (6) insights, and (7) coping strategies. All items are rated on 5-point Likert scales ranging from 0 (not at all or never) to 4 (a great deal or all the time). Higher scores indicate higher levels of FCR.

Metacognition assessed by the 30-item Metacognitions Questionnaire (MCQ). The MCQ assesses individual differences in metacognitive beliefs, judgements, and monitoring tendencies across five domains: (1) positive beliefs about worry, (2) negative beliefs about thoughts concerning uncontrollability and danger, (3) cognitive confidence, (4) cognitive self-consciousness, and (5) the need to control thoughts. All items are rated on a 4-point Likert scale ranging from 1 (do not agree) to 4 (agree very much). Higher scores indicate higher levels of maladaptive metacognition.