Table 3.

Context–mechanism–outcome (CMO) configurations, illustrative quotes and summary of our interpretations

CMO configuration	Quote	Related theme
CMO 1 The diagnosis of cancer (context) changed the perception of control (mechanism) in young adults to cause distress, frustration and anger (outcomes).	‘… like the feeling that I’ve got control over it, like complete control. For me that’s extremely important. As soon as I lose that, I think I’d really struggle. And I need to, yes, feel as though I’m in the driving seat more or less.’ (Cohort 1— participant 1)	From the Loss of Control theme: The unexpected diagnosis of cancer disrupted everyday life and young adults often had to relinquish control and permit others to manage aspects of their life. The feeling of ‘loss of control’ was experienced throughout the diagnostic and treatment phases and seemed to increase when cure was not likely as participants experienced a loss of their anticipated future.
CMO 2 In the context of disease progression (context), young adults continued with normal activities as a coping strategy that offered distraction (mechanism) leading to a feeling of some kind of ‘normality’ (outcome). A poor prognosis and physical decline compromised the maintenance of a ‘normal life’.	‘Yes but we’re not going to do that’ he [son] said, ‘We’re just going to carry on as normal.’ And I thought actually he’s right because carrying on normal makes it, it does make it more real. And more memorable … yes we do some lovely things, but it’s just trying to keep everything as normal as possible really and just make the most of that time. (Cohort 2—family member—son did not participate)	From the Maintenance of Normal Life theme: Young adults wanted to live as normal a life for as long as possible. Young adults and their families adjusted to a new normality, to accommodate the changes their disease progression created.
CMO 3 When there was trust between HCPs and a young adult (context), it was easier to introduce change or a new service (outcome) because a sense of abandonment (mechanism) or apprehension (mechanism) was less likely to occur. In contexts where continuity was provided (ie, seeing the same HCP) trust developed (outcome) because of a sense of being known (mechanism).	‘I think continuity is one thing that I’d put on a pedestal as being the most important, as a patient. It’s horrible seeing different people and having to tell your story over and over and over again. Yet when you see somebody you know, and they know your story, they know whether you’re well or you’re not well. They know how your psychology works a little bit. So they know how to present things to you. That makes a huge difference to how you trust them, what your relationship is like and how you respond to them [HCP’s].’ (Cohort 2—participant 7)	From the Continuity of Care theme: Young adults reported a high expectation and preference for continuity of care within and between services, which for them meant seeing the same HCPs whenever possible.
CMO 4 When a young person is dying because of cancer (context), HCPs find it challenging to talk about a poor prognosis or a shift in goal of treatment (outcome) because of their personal emotional discomfort of such discussions (mechanism).	‘I find some of the younger patients it feels very unfair and I do reflect a lot on my own mortality and how I would cope.’ (Cohort 2—participant 1 HCP) ‘And it’s a very stark contrast that [support] seems to be important for nurses but it’s not seen to be important for doctors … as an individual, you don’t talk because nobody wants you to talk about it, because you’re the strong leader … Some doctors will just completely divorce themselves from it and will not engage in any shape or way with their patients … But I think you just sort of, you potentially just end up with, you know, increasingly tired and burnt out and disengaged doctors.’ (Consultant oncologist, HCP workshop 1)	From the Professionals Need Support theme: The loss of a ‘life partially lived’ can be difficult for professionals, who feel a greater burden of sadness when young adults die. HCP workshop participants felt support for them was often reactive rather than proactive with nurses more likely to receive support than doctors. A further distinction was recognised between junior and senior doctors.
CMO 5 When the way services are delivered for young adults does not fully recognise the additional needs of the family or care-givers (context), this leads to them feeling marginalised (mechanism) resulting in feelings such as abandonment and distress (outcomes).	‘It is quite upsetting because, we actually felt abandoned, I felt abandoned.’ [Facilitator: By?] ‘By just the whole system really. It was just, if you didn’t ask, you wouldn’t know.’ (Family workshop 2— bereaved husband) ‘And she [24 year. old daughter] sort of became more and more sleepy and distant from us. But nobody would say to me, “This is what to look for. When she dies, this is what’s going to happen.’” (Family workshop 3—bereaved mother)	From the Families Need Support theme: Families often provided informal care for young adults within the home. While they wanted to support their child or partner, caring created a further burden. Families felt insufficiently supported in this role.
CMO 6 When emotive language is used in palliative and end-of-life care (context), misunderstandings (mechanisms) can easily occur, leading to a range of different outcomes from encouraging hope through to despair (outcomes).	‘So when my breast care nurses referred me to a hospice, I was like “Oh my god, that’s horrendous, I don’t want to do it”. But, you know, it’s been one of the best ever things. And I kept putting it off and saying, “I’m not ready for it, I’m not ready for it.” And she [CNS] went, “Look, if you just make contact, then when you do need them, you can tap into them and they’re quite good at financial advice.” So I said, “Okay right let’s do it.” And actually they’ve been fantastic. Actually from just the level of sorting things out.’ (Cohort 2—participant 19)	From the Language theme: One example was the use of the term ‘hospice’. When this was first raised with young adults, their initial reaction was one of rejection as hospices were where older people went to die and young adults did not believe that they were at this stage.
CMO 7 Few young adults have thoughts about long-term financial planning as they did not anticipate serious illness (context). This can lead to individuals and families facing financial precariousness (mechanism). Access to tailored advice, while it may not solve financial concerns, may provide individuals and their families a range of ‘tools’ to better cope with their financial situation (outcome).	‘You haven’t asked to be in that position. So I shouldn’t have to go to work and think, Well I’ll do a monotonous job just to pay the bills to only live another few months.’ If I’ve only got a few more months to live, I’d rather spend it with my family, you know, having the time with them. (Cohort 2— patient 6) ‘But, yes, I think that’s the crappest thing, it’s not having—if you are single and I don’t have a rich family, you know, yes it’s just the whole worry of like affording things and knowing what kind of life you’re going to end up with if you give up work, especially when you’ve been used to a different kind of life.’ (Cohort 2—patient 19)	From Financial Concerns theme: Financial concerns and insecurity are almost always expressed by young adults with cancer.

HCP, healthcare professionals.