After assessing how its gender identity development service (GIDS) operates, Dr Cass found the treatment of young people identifying as transgender was below normal quality controls.
Her report found that its hormone treatment and assessment processes along with data collection and service model must be reviewed.
The interim report also concluded that the facility, which is England’s only specialist service for children and young people who identify as transgender, is overwhelmed by the number of referrals it has to deal with.
It said: “It has become increasingly clear that a single specialist provider model is not a safe or viable long-term option in view of concerns about lack of peer review and the ability to respond to the increasing demand.
“It is essential that these children and young people can access the same level of psychological and social support as any other child or young person in distress, from their first encounter with the NHS and at every level within the service.
“A fundamentally different service model is needed which is more in line with other paediatric provision, to provide timely and appropriate care for children and young people needing support around their gender identity.
“This must include support for any other clinical presentations that they may have.”
In 2009, the clinic received 50 referrals but by 2020, there were 2,500 with a further 4,600 young people on the waiting list.
When it started the service was typically used by males who had suffered gender dysphoria from an early age but this has changed and now the service has been flooded with young girls who are distressed about their gender.
There is also an overrepresentation of ‘looked after’ young people who have grown up in care and youngsters on the autism spectrum.
With referrals increasing, Dr Cass said the NHS should move to create regional hubs across the country instead of one specialised centre.
She also called for a review of data collection and for a new standardised collection system to be created.
In terms of hormone treatment, it added: “It is essential that principles of the General Medical Council’s Good Practice in Prescribing and Managing Medicines and Devices are closely followed, particularly given the gaps in the evidence base regarding hormone treatment.
“Standards for decision making regarding endocrine treatment should also be consistent with international best practice.”
The report concluded: “Because the specialist service has evolved rapidly and organically in response to demand, the clinical approach and overall service design has not been subjected to some of the normal quality controls that are typically applied when new or innovative treatments are introduced.”
The centre is run by the Tavistock and Portman NHS Foundation Trust, and specialises in experimental hormone treatment.
In a letter which prefaces the report, Dr Cass insists that she is not calling for services to stopped or reduce.
“I have heard that young service users are particularly worried that I will suggest that services should be reduced or stopped,” she said.
“I want to assure you that this is absolutely not the case – the reverse is true.
“I am advising that more services are made available to support you.”
The review is expected to submit formal recommendations at a later date. The Standard has approached the foundation trust for comment.
A Tavistock spokesperson said: “The Tavistock and Portman NHS Foundation Trust welcomes the focus of Dr Cass and her team on increasing and broadening the care and support available for this group of patients who are currently waiting far too long and on developing the evidence base. We will work with her and NHS England to support her recommendations.”