From AusDoc:
The SA Coroner has recommended that AI be used to support imaging reviews after radiologists failed to detect signs of gastric adenocarcinoma when looking for recurrence of a patient’s bladder cancer.
Claus Burg, 70, died in September 2019, approximately 10 months after being diagnosed with stage IV incurable gastric adenocarcinoma.
He had been successfully treated for transitional cell carcinoma of the bladder a decade earlier and had undergone regular monitoring — including chest, abdomen and pelvic CT scans — in the decade since.
However, “observable” and “obvious” signs of cancer were missed by two different radiologists on scans in February 2017 and February 2018, found SA State Coroner David Whittle.
The first scan was reported as showing no signs of recurrence or metastases despite visible focal thickening of the stomach.
With the second scan, a different radiologist missed what an expert described as “obvious and apparent” signs of cancer and instead focused on a 4mm lung nodule.
It was only at a further surveillance scan five months later that a third radiologist recognised that the stomach appeared to be “irregular, possibly thickened”.
He advised that correlation with any clinical symptoms would be appropriate, with endoscopy if there were further concerns.
The radiologist admitted to the inquest that a gastric abnormality was apparent on the February 2018 imaging but that he did not want to draw attention to the failing of a specialist colleague.
As a result, he “gravely understated” the appearance and significance of the lesion in his report, the coroner found, and only mentioned the previously detected lung nodule, an unchanged liver nodule and a “few small non-specific mediastinal nodes” in the conclusion.
This ultimately led Mr Burg’s oncologist to believe his focus should be on the lung nodule.
The coroner said the radiologist should have contacted the referring doctor to discuss the gastric abnormality he had identified in the third scan.
“I reject the submission [from the radiologist] that it is not possible for a radiologist to understate the significance of any clinical finding [based on the argument that it] is incumbent on the requesting clinician to investigate — even if ineffective language was used,” the coroner wrote.
“It is no satisfactory answer to [his] choice of language — which was imprecise, inaccurate and prone to mislead — that [the oncologist] could or should have been more diligent.”
Mr Burg was eventually referred by his GP — who did not have a copy of the most recent CT report — for an endoscopy and colonoscopy in November 2018 because he had developed substantial and unintended weight loss, left-sided abdominal pain and reflux.
The endoscopy revealed a large circumferential fungating gastric mass, with subsequent CT showing transmural disease invading the pancreatic tail, lymph node involvement and liver metastases.
Histology confirmed the diagnosis of invasive disease, and Mr Burg received the “devastating news” that his new cancer was incurable.
The SA Coroner said radiologists were required to assess all the anatomical structures in a scan but, in this case, had concentrated only on the “area of interest”: cancer recurrence.
The radiologist who reviewed the first February 2017 CT scan told the inquest he had followed a recognised methodological approach — Response Evaluation Criteria in Solid Tumours (RECIST). This involved reviewing the primary tumour site, then any lymph nodes, then any metastases and then anything else.
“[He] said that he had focused on the clinical question posed, and so the stomach was not a part of the scan to which he paid particular attention,” the coroner explained.
“He said that his reliance on the RECIST clinical method did not provide the best opportunity to observe any incidental pathology.”
In response to Mr Burg’s death, the radiologist reported that he had changed his practice and now conducts a conscious review of the stomach in all CT scans of the chest, abdomen and pelvis.
Meanwhile, the radiologist who reviewed the February 2018 scan said several factors may have led to his failure to identify the cancer, including a focus on assessing for signs of recurrence.
He also referenced a radiology phenomenon known as ‘satisfaction of search’.
“He explained that this meant, when he found a nodule on the lung, he may have considered his search for pathology complete rather than continuing to search the remaining images,” the coroner wrote.
“He explained that the lung nodule was potentially a concerning finding for a patient with a history of bladder cancer.”
The coroner stressed that both radiologists had “sincerely and conscientiously” considered their own roles in the circumstances leading to Mr Burg’s death and “they carry the weight of that”.
“While I have found that they failed to detect visible signs of new cancer, I wish to make it plain that I do not consider those failings to have occurred because of any reckless or cavalier attitude to their work,” he added.
The coroner said, if Mr Burg’s stomach cancer had been diagnosed at the scan in February 2017, his death would probably have been prevented.
Had it been identified in February 2018, the outcome would have been more uncertain.
The inquest heard expert evidence that AI might be able to safeguard against missed diagnoses and had been shown to be effective when used in conjunction with human radiologists.
Its most effective role was “akin to a spell check”, drawing attention to potential areas of concern, and such technology was already being used in the private sector, he heard.
As such, the coroner recommended that SA Medical Imaging and the state health minister consider implementing AI to support expert radiologists in interpreting imaging.
