BackgroundAndrogen deprivation therapy (ADT) is prescribed to almost half of all men diagnosed with prostate cancer. Although ADT is effective treatment, with virtually all men with advanced disease showing initial clinical response, it is associated with troublesome side effects including hot flushes and night sweats (HFNS). HFNS can be both frequent and severe and can have a significant impact on quality of life (QoL). They can occasionally be so debilitating that patients stop ADT altogether, despite the increased risk of disease relapse or death. Previous research has found that guided self-help cognitive behavioural therapy (CBT) can be effective in reducing HFNS due to ADT when delivered by a clinical psychologist. MANCAN2 aims test whether we can train the existing NHS Prostate Cancer Nurse Specialist (CNS) team to deliver guided self-help CBT and whether it is effective in reducing the impact of HFNS in men undergoing ADT.MethodsMANCAN2 is a phase III multicentre randomised controlled trial and process evaluation. Between 144 and 196 men with prostate cancer who are currently receiving ADT and are experiencing problematic HFNS will be individually randomised in a 1:1 ratio in groups of 6–8 participants to either treatment as usual (TAU) or participation in the guided self-help CBT intervention plus TAU. A process evaluation using the normalisation process theory (NPT) framework will be conducted, to understand the CNS team’s experiences of delivering the intervention and to establish the key influencers to its implementation as a routine practice service. Fidelity of implementation of the intervention will be conducted by expert assessment. The cost-effectiveness of the intervention and participant adherence to the trial intervention will also be assessed.DiscussionMANCAN2 will advance the program of work already conducted in development of management strategies for HFNS. This research will determine whether the severity of ADT-induced HFNS in men with prostate cancer can be reduced by a guided self-help CBT intervention, delivered by the existing NHS prostate cancer CNS team, within a multicentre study. The emphasis on this existing team, if successful, should facilitate translation through to implementation in routine practice.Trial registrationISRCTN reference58720120. Registered 13 December 2022Supplementary InformationThe online version contains supplementary material available at 10.1186/s13063-023-07325-w.