Limited age-specific services
The treatment of AYAs with cancer in Australia has, until recently, been managed by paediatric or adult cancer centres.16 Internationally, some institutions have developed stand-alone AYA cancer facilities and others have developed AYA multidisciplinary care teams working alongside existing paediatric and adult treatment centres.17-20 For most patients (except those between 16 and 18 years of age, who can be treated in either location), the place of treatment is based on the patient’s age without considerations of their developmental stage, psychosocial needs or tumour-specific needs.16,21 Not all young people at the same age are at the same stage in the key areas of physical, cognitive and socioemotional development. Ideally, clinical teams should be able to consider the most developmentally appropriate location for treatment.19
It is important for patients to have access to expertise specific to their cancer, which may not necessarily be found in the cancer centre they attend. It is also important for patients to have access to expertise specific to their age – for example, a paediatric patient with a tumour usually occurring in adults, or an adult patient with a tumour usually occurring in paediatric patients may benefit from the medical expertise of cancer specialists who routinely look after these tumours. These patients are also less likely to be enrolled and treated in a relevant clinical trial, which, as discussed below, has an impact on survival.
The physical environments of paediatric and adult cancer centres are usually more suitable for younger and older patients, respectively, and contact with other AYAs who could provide peer support may be limited.18 Cancer centres may not have access to staff with expertise in treating AYAs or who can recognise, understand and support the individual needs of AYA patients.22
Treating an AYA in a paediatric or adult cancer centre when it is not age-appropriate may have an effect on the patient’s understanding of their diagnosis, treatment, decision-making and treatment compliance, which may ultimately affect their outcomes. Age-appropriate communication and consultations are essential for optimal care. Sometimes, clinicians may discuss care with the parents of an AYA patient when the AYA may wish to be more involved in the discussions.22 Other AYAs may be overwhelmed by their diagnosis, hospitalisation and the medical information they receive, and may struggle to take responsibility for their treatment decisions.22 This may be expected by clinicians working in an adult patient setting.
The effect of treatment location on AYA care and survival highlights the importance of having cancer services specific to this age group.
Different disease features
There is increasing evidence that cancers in the AYA age group have unique genetic and biological features compared with the same cancers in younger and older age groups, and that these biological differences may have an impact on survival.23 It has been shown that increasing age is associated with unfavourable biological subgroups in acute lymphoid leukaemia, and is also associated with poorer survival in many cancer types.24 The biology of sarcoma is not fully understood, but when compared with children, AYAs have been shown to have increased rates of less favourable tumour locations (36.8% vs 12.9%), lymph node involvement (35.5% vs 21.7%) and metastatic disease at diagnosis (30.3% vs 17.8%).25 Other studies have shown poorer outcomes for AYA patients with adult tumours such as breast cancer and colorectal cancer, and with paediatric tumours such as Wilms tumour and rhabdomyosarcoma, when outcome is adjusted for staging.23,24 A better understanding of the biology of cancers in AYA patients will help scientists and clinicians identify better targeted therapy.
Different treatment approaches
Traditionally, there have been different protocols for paediatric and adult patients for the same cancer types, leading to AYA patients being treated in different trials, depending on the treatment centre. There are multiple studies showing that AYA patients with acute lymphoblastic leukaemia have superior survival rates when treated in a paediatric trial, despite an increase in some side effects with these paediatric protocols.26 Researchers in cancer of AYAs are currently looking at differences in outcomes in several tumour groups, based on differences in treatment protocols, which will allow standardisation of treatment for this age group.
Different treatment side effects
AYA patients have been shown to experience more toxicity than paediatric patients when treated in the same trials. For example, for AYA patients treated for leukaemia, increases in peripheral neuropathy, glucose intolerance, pancreatitis and osteonecrosis have been seen, and increased toxicity has been seen in AYAs being treated for Ewing sarcoma.27-29 However, other trials have shown a reduced side-effect profile or different complications for AYA patients, or have shown that side effects are related to sex, not age.30 Studies are needed to examine age-related and sex-related differences in pharmacology, pharmacogenetic distribution, delivery and metabolism of drugs.
Different participation rates in clinical trials and research
Participation rates for AYA patients with cancer in clinical trials are lower compared with paediatric patients, and there continues to be a higher rate of clinical trial participation for AYA patients treated in paediatric centres compared with those treated in adult cancer centres.31-34
Barriers to the establishment of clinical trials for this age group include the cost of, and the time taken, to open a clinical trial, and the lack of centralised care for this age group. This results in a smaller number of AYA patients in each adult cancer centre and low accrual rates, unless multiple centres are open.35-37 Patients participating in clinical trials show improved survival,38,39 so it is important that AYA patients have access to trials.
Differences in psychosocial needs
Compared with their healthy peers, AYAs with cancer are at higher risk of experiencing poor psychological wellbeing and distress that can last many years after treatment.40 They may experience temporary loss of autonomy, increased dependence on others, and physical and emotional rifts between peers and parents. These psychosocial effects on wellbeing can result in poorer adherence to cancer treatment or delays in disclosure of important symptoms, resulting in an increased frequency of side effects. Psychosocial screening of AYAs with cancer is essential for clinicians to be able to offer appropriate psychological support during and after treatment, and to prevent negative effects on cancer outcomes.40 COSA developed guidelines on the Psychosocial Management of AYA Diagnosed with Cancer: Guidance for Health Professionals which is a useful resource for GPs providing psychosocial during or after cancer treatment.41