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High reported severity Media Coverage

Irish father says ChatGPT told him cancer was highly unlikely, delaying care before a stage-four oesophageal cancer diagnosis

Warren Tierney, 37, a former psychologist from County Kerry, Ireland, told the Daily Mail that in 2025 he put a worsening sore throat and difficulty swallowing to ChatGPT over several weeks instead of seeing a doctor. Screenshots he disclosed show the chatbot calling an improvement he reported a 'very encouraging sign' and ending a 'Final Scorecard Prediction' with 'Cancer? Highly unlikely'. In August 2025 he was diagnosed with stage-four adenocarcinoma of the oesophagus after attending A&E. He said ChatGPT 'probably delayed me getting serious attention' and that this probably cost him a couple of months, and he said he takes full ownership of relying on it. He also named his own reluctance to see a doctor and a private GP visit that ended with reflux tablets. No source establishes that the delay changed his prognosis. OpenAI said ChatGPT is not intended for use in the treatment of any health condition.

AI system
ChatGPT
OpenAI
Occurred
2025
Reported
27 August 2025
Event location
Unknown
What the AI did
Communicated with the person
Reported harm
Treatment Disruption
Whose AI use
Their own AI use
Setting
Health
Evidence
AI involvement reported · Causal attribution alleged · 4 sources, 1 underlying account
10 claims: 10 reported. 6 open questions
People reported harmed
1 person

Reported harm

He says ChatGPT's reassurance that cancer was highly unlikely probably delayed his seeking serious medical attention by a couple of months before he was diagnosed with stage-four oesophageal cancer in August 2025.

Outcome

Unknown
  • August 2025: diagnosed with stage-four adenocarcinoma of the oesophagus, which the Daily Mail of 27 August said happened the previous week, after he attended A&E.
  • 27 August 2025: the Daily Mail published an interview with him, with screenshots of ChatGPT prompts and replies he disclosed, and a statement from OpenAI.
  • 30 August to 6 September 2025: The Logical Indian, Storyboard18 and Futurism relayed the Daily Mail account. Futurism also reported him in a hospital bed in Germany, with more than $120,000 raised towards treatment.
  • OpenAI told the Daily Mail that ChatGPT is not intended for use in the treatment of any health condition and is not a substitute for professional advice.
  • No inspected source reports a complaint, lawsuit or regulatory action. No source later than September 2025 was found in this review, so his current condition is not recorded.

What remains unknown

  • Where he held the ChatGPT conversations and where the GP visit and the A&E attendance took place; his residence in Ireland is not used as the event location.
  • When the conversations began and how long they lasted; the Daily Mail says only that the sore throat began earlier in 2025 and that the conversations spanned weeks at a time.
  • The length of the delay: he told the Daily Mail it probably cost him a couple of months; Futurism renders this as a few months, and The Logical Indian's at least two months names no source.
  • Whether the delay changed the stage of the cancer or his prognosis; no clinical statement on this is reported.
  • The full conversation is not public; the quoted replies are those the Daily Mail chose from screenshots he disclosed.
  • His condition after September 2025; no later report was found in this review.

What the evidence supports

AI involvement: reported. Screenshots of prompts he disclosed to the Daily Mail show ChatGPT answering his symptom updates over weeks, calling an improvement he reported a 'very encouraging sign' and concluding 'Cancer? Highly unlikely — no red-flag symptoms, stable, improving.' He told the Daily Mail that ChatGPT 'probably delayed me getting serious attention' and that this probably cost him a couple of months. The link between the replies and the delay is his own account. He also names his reluctance to see a doctor and a GP visit that ended with reflux tablets, and no source establishes that the delay changed his prognosis.

10 claims: 10 reported. What the statuses mean

Reported Tierney says that in 2025, after he began suffering from a sore throat that eventually left him unable to swallow fluids, he used ChatGPT to discuss his symptoms in conversations spanning weeks instead of seeing a doctor.

Causal attribution. His account to the Daily Mail; Futurism relays the same interview.

  • dailymail.co.uk(opens in new tab) supports · English
    'used OpenAI's ChatGPT to seek medical advice after he began suffering from a sore throat earlier this year that eventually left him unable to swallow fluids.'; 'quickly fell into the trap of having a conversation with the AI chatbot which spanned weeks at a time.'
  • futurism.com(opens in new tab) supports · English
    'Tierney said he began asking the chatbot earlier this year if he should be worried about his persistent sore throat'
Reported Screenshots of prompts he disclosed to the Daily Mail show ChatGPT calling his report that he could swallow a cookie after taking blood-thinning medication a 'very encouraging sign', and ending a 'Final Scorecard Prediction' with 'Cancer? Highly unlikely — no red-flag symptoms, stable, improving.'

Causal attribution. The Daily Mail's description of screenshots he disclosed; the screenshots themselves were not inspected.

  • dailymail.co.uk(opens in new tab) supports · English
    'In a series of prompts disclosed to the Daily Mail, Mr Tierney can be seen asking ChatGPT whether his oesophagus pain was improving because he was able to swallow a cookie after taking blood thinning medication.'; 'Cancer? Highly unlikely — no red-flag symptoms, stable, improving.'
  • thelogicalindian.com(opens in new tab) supports · English
    'Cancer? Highly unlikely, no red-flag symptoms, stable, improving.'
  • futurism.com(opens in new tab) supports · English
    'which ChatGPT said was a "very encouraging sign."'
Reported When he wrote that he would sue if it was cancer, ChatGPT replied that if it was cancer it would write his court affidavit and buy him a Guinness, and added that nothing he had described strongly pointed to cancer.

Causal attribution. Quoted from the exchanges he disclosed to the Daily Mail; Futurism relays the quotation.

  • dailymail.co.uk(opens in new tab) supports · English
    'Fair play — if it's cancer, you won't need to sue me — I'll write your court affidavit and buy you a Guinness.'; 'nothing you've described strongly points to cancer.'
  • futurism.com(opens in new tab) supports · English
    'Fair play — if it's cancer, you won't need to sue me — I'll write your court affidavit and buy you a Guinness," it wrote at one point.'
Reported He was diagnosed with stage-four adenocarcinoma of the oesophagus in August 2025, in the week before the Daily Mail published its interview on 27 August, after attending A&E.

Causal attribution. His and his wife's account to the Daily Mail; no medical record is cited.

  • dailymail.co.uk(opens in new tab) supports · English
    'He was diagnosed with adenocarcinoma of the oesophagus last week'; 'Then came the devastating news: stage four adenocarcinoma of the oesophagus.'; 'he may never have gone to A&E where his cancer was ultimately uncovered.'
  • storyboard18.com(opens in new tab) supports · English
    'Doctors diagnosed him with stage-four esophageal adenocarcinoma'
Reported Tierney told the Daily Mail that ChatGPT probably delayed his getting serious attention and that this probably cost him a couple of months, and also said he takes full ownership of having relied on it.

Causal attribution. His own attribution of the delay to the chatbot; Futurism and Storyboard18 relay the same interview. No clinical assessment of the delay is reported.

Reported By his own account other factors contributed: he says he fell into a 'systemic male belief' that he did not need to see a doctor, that his cynicism of the Irish healthcare system drove him to AI, and that a doctor at a private GP visit after months of throat pain sent him home with reflux tablets.

Causal attribution. His account; the GP visit is his claim and is not otherwise documented.

  • dailymail.co.uk(opens in new tab) supports · English
    'Admitting he fell into the 'systemic male belief' that he didn't need to see a doctor'; 'said his cynicism of the Irish healthcare system also drove him into the hands of artificial intelligence.'; 'where he claims a doctor sent him home with a packet of reflux tablets.'
  • futurism.com(opens in new tab) supports · English
    'the young dad went along with the chatbot, and even returned to ask it for more advice once the pain got bad again'
Reported After he told ChatGPT that he had delayed treatment because he followed its view that the pains were muscular, it replied that he had trusted it early on when the symptoms could have pointed to muscular strain, and that it was not guessing recklessly.

Causal attribution. Quoted from the exchanges he disclosed to the Daily Mail; one source.

  • dailymail.co.uk(opens in new tab) supports · English
    'The 37-year-old then told the chatbot he was 'f****d' after he said he delayed medical treatment because he was following its belief that his oesophageal pains were 'muscular'.'; 'I wasn't guessing recklessly — I was following your own body signals, as you described them.'
Reported OpenAI told the Daily Mail that ChatGPT is not intended for use in the treatment of any health condition and is not a substitute for professional advice.

Causal attribution. OpenAI's general statement; it does not address his conversations.

  • dailymail.co.uk(opens in new tab) supports · English
    'not intended for use in the treatment of any health condition, and is not a substitute for professional advice'
  • futurism.com(opens in new tab) supports · English
    'not intended for use in the treatment of any health condition, and is not a substitute for professional advice.'
Reported His family raised money for treatment abroad: his wife's fundraiser said only palliative care is offered in Ireland, and Futurism reported him in a hospital bed in Germany with more than $120,000 raised.

Causal attribution. The family's fundraiser and Futurism's account citing the Irish Independent; kept as context on the aftermath.

Reported Tierney told the Daily Mail that the AI model tries to appeal to what the user wants it to say in order to keep them engaged, and that to some extent the statistical likelihood of what it said was wrong with him was right, though not in his case.

Causal attribution. His own explanation and qualification in the Daily Mail interview; one source.

  • dailymail.co.uk(opens in new tab) supports · English
    'The AI model is trying to appeal to what you want it to say in order to keep you engaged.'; 'To some extent, the statistical likelihood of what it said was wrong with me was actually very right.'; 'But unfortunately in this particular case, it wasn't.'

Sources

4 sources inspected, from 1 underlying account. Sources that repeat one account do not corroborate each other.

How the sources were read, and where the events happened

Read in English on 2026-10-21 (live page, HTTP 200; bodies/lr-tierney-dm-15030049.html/.txt). Daily Mail, Ciaran Foreman, published 27 Aug 2025 at 20:33 BST; an exclusive interview with Tierney, built on ChatGPT prompts and replies he disclosed, with OpenAI's statement and his wife's fundraiser text. Applies to s1.

Read in English on 2026-10-21 (live page, HTTP 200; bodies/lr-tierney-futurism.html/.txt). Futurism, Noor Al-Sibai, 6 Sep 2025; attributes its account to the Daily Mail interview and adds a hospital in Germany and a fundraising total, citing the Irish Independent, which was not read. Applies to s2.

Read in English on 2026-10-21 (live page, HTTP 200; bodies/lr-tierney-logicalindian.html/.txt). The Logical Indian, 30 Aug 2025; names no interview of its own, and its ChatGPT quotations match the Daily Mail's. Applies to s3.

Read in English on 2026-10-21 (live page, HTTP 200; bodies/lr-tierney-storyboard18.html/.txt). Storyboard18, 2 Sep 2025; names no interview of its own, and its quotations match the Daily Mail's. It calls him Dublin-based, which conflicts with the Daily Mail. Applies to s4.

Event countries: Unknown. Affected-person countries: Ireland. Court countries: Unknown.

The Daily Mail describes him as from Killarney, County Kerry, Ireland, and quotes his wife's fundraiser saying 'Here in Ireland, only palliative care is offered', which supports IE as his residence. No inspected source says where he held the ChatGPT conversations or where the GP visit and the A&E attendance took place, and a residence is not used as the event location, so the event country stays unknown. Germany appears only as a place of treatment after the diagnosis. Storyboard18 calls him Dublin-based, also in Ireland. No inspected source reports a court proceeding. Carried forward from the 2026-10-05 metadata review.

Reviewed for publication 2026-10-21: Published as a core case (communicated_with). Screenshots he disclosed to the Daily Mail show ChatGPT telling him over weeks that cancer was highly unlikely, and he says this probably delayed his seeking serious attention by a couple of months before a stage-four oesophageal cancer diagnosis. The causal link is his own account, given under his name.

People described

Warren Tierney, 37 at the time of the August 2025 reports, a former psychologist and father of two from Killarney, County Kerry, Ireland, who gave a named interview to the Daily Mail.

People reported harmed in this case

1 person

1 AI participant · 0 other people harmed

The reports describe one person, Tierney. His wife and children are not counted because no source records a separate harm for them that follows from the chatbot's replies.

Counted once within this case. The same person may appear in other cases. This count does not establish AI causation.

Tags

#chatgpt#openai#health-guidance#cancer#adult#ireland

Cite this case

Compiled per our published methodology: verification statuses, sourcing standards, and corrections process.

APA

NOPE. (2026). Irish father says ChatGPT told him cancer was highly unlikely, delaying care before a stage-four oesophageal cancer diagnosis. AI incidents. https://nope.net/incidents/2025-tierney-chatgpt-cancer-delay

BibTeX

@misc{2025_tierney_chatgpt_cancer_delay,
  title = {Irish father says ChatGPT told him cancer was highly unlikely, delaying care before a stage-four oesophageal cancer diagnosis},
  author = {NOPE},
  year = {2026},
  howpublished = {AI incidents},
  url = {https://nope.net/incidents/2025-tierney-chatgpt-cancer-delay}
}

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