Updated PHTS surveillance guidance includes colorectal cancer, but evidence remains limited

This ERN GENTURIS expert guideline updates cancer surveillance advice for people with PTEN hamartoma tumour syndrome, including colorectal cancer surveillance. It is based on a literature review and multidisciplinary consensus, rather than a trial showing that any screening schedule improves outcomes.

The study at a glance

Study design	Review article and expert consensus guideline, based on a comprehensive literature review.
Who took part	People with PTEN hamartoma tumour syndrome (PHTS); no new participant cohort was reported.
What was tested	Revised surveillance recommendations for cancers associated with PHTS, including colorectal cancer.
What was measured	Updated recommendations for cancer surveillance; the article calls for prospective evaluation of their effectiveness.

This is guidance, not a study of a new screening test

This paper updates the European Reference Network on Genetic Tumour Risk Syndromes, or ERN GENTURIS, surveillance guidance for people with PTEN hamartoma tumour syndrome, usually shortened to PHTS. PHTS is an inherited condition associated with changes in the PTEN gene, which normally helps regulate cell growth. The syndrome can affect several body systems and can include both cancer risks and non-cancer features.

For colorectal cancer readers, the central point is clear: the guideline group includes colorectal cancer among the malignancies for which surveillance should be considered in PHTS. The abstract describes colorectal cancer risk as moderate, alongside higher hereditary risks of breast, thyroid and endometrial cancers, and a moderate risk of renal cancer and skin melanoma.

This is a review article and clinical guideline, not a randomised trial or a prospective study that followed a defined group of patients through a screening programme. The authors reviewed available research and revised prior guidance with clinicians from relevant specialties, people with PHTS and patient representatives. That process can produce practical, coordinated advice where evidence is sparse. It cannot establish that a particular surveillance schedule prevents colorectal cancer, detects it earlier, or improves survival.

The abstract does not give the detailed colorectal surveillance schedule, such as an age to begin, an interval between examinations or the circumstances that might alter that plan. Those details need to be read in the full guideline and interpreted by a team familiar with the individual patient, their genetic result, personal history and family history.

Why colorectal surveillance sits within a wider PHTS plan

PHTS is not a colorectal-only syndrome. The guideline addresses surveillance for breast, thyroid, endometrial, renal and colorectal cancers, as well as skin melanoma. It also recognises non-cancer manifestations, including skin and connective-tissue tumours, vascular malformations and neurodevelopmental differences.

That breadth has practical consequences. A person may see a gastroenterologist for colon surveillance, while also needing input from genetics, endocrinology, dermatology, breast care, gynaecology or other services. The authors describe the need for a coordinated multidisciplinary approach, meaning clinicians from different fields work from a shared plan rather than treating each surveillance question in isolation.

For someone who already has colorectal cancer, a hereditary cancer assessment can matter for more than routine screening. It may clarify whether relatives could benefit from genetic counselling and whether the person has cancer risks outside the colon and rectum that deserve separate attention. It does not mean that every person with colorectal cancer has PHTS, or that PHTS explains every colorectal cancer occurring in a carrier.

The distinction is important because PHTS is uncommon and clinically diverse. A guideline for a syndrome-level risk group cannot replace decisions based on an individual tumour, treatment history, prior colonoscopy findings or symptoms. In particular, surveillance aims to look for disease before symptoms arise; it is separate from the investigations needed for new symptoms or from follow-up after an established cancer diagnosis.

What changed from the 2020 guidance

The authors state that evidence on cancer risks and on the effectiveness of surveillance has accumulated since the previous ERN GENTURIS guideline, published in 2020. Their 2026 update incorporates that newer literature and revises recommendations across the cancers linked with PHTS.

That is useful progress, but the paper does not report a new effect size for colorectal surveillance. There is no hazard ratio, screening-detection rate, mortality reduction or percentage risk reduction in the abstract. Readers should be cautious with any account that turns this update into a claim that colon surveillance has been proven to save lives specifically in PHTS. The guideline does not make that claim in the supplied abstract.

In hereditary cancer care, recommendations often combine direct evidence, evidence borrowed cautiously from related settings, estimates of risk, clinical experience and the potential burdens of testing. Colonoscopy, for example, can identify and remove polyps, which are growths that can sometimes develop into cancer. But the benefit, optimal timing and optimal interval of colonoscopy may differ across inherited syndromes. Evidence from one syndrome cannot automatically settle those questions for another.

The update therefore has a measured role. It gives specialist teams a current framework for discussing surveillance in PHTS. It should not be read as proof that every component has the same strength of evidence, or that one fixed plan suits every carrier.

The evidence gap is part of the finding

The authors explicitly say that the proposed recommendations need prospective evaluation in people with PHTS. A prospective study defines a group and follows participants forward in time, allowing researchers to measure outcomes under a planned surveillance approach. Such studies could help answer questions this guideline cannot settle: how often surveillance detects significant findings, how many procedures lead to false alarms or complications, and whether the programme changes cancer stage or survival.

This gap is unsurprising in a rare, multisystem condition, but it remains consequential. Surveillance asks patients to commit time, preparation, procedures and repeated appointments. The authors acknowledge that this requires substantial patient commitment as well as well-organised multidisciplinary care. Those burdens belong in an informed discussion alongside possible benefits.

As a patient, I find the most useful reading of this paper is neither dismissal nor certainty. It is a current expert framework for a condition where the evidence base remains incomplete. If PHTS is relevant to your care, the worthwhile next conversation is about how the full guideline applies to your own history, rather than assuming that a general statement about PHTS determines your colorectal plan.