Mammography misdiagnosis: Patient diagnosed with cancer!
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Loss of chance is a jurisprudential notion that refers to the prejudice a person may suffer after losing the opportunity to obtain a favorable result in a given situation. In this case, losing the chance to avoid an operation due to a faulty diagnosis.

Patient victim of misdiagnosis takes case to court
• September 2010: during a follow-up mammogram, the radiologist writes a report reassuring the patient, mentioning the absence of any detectable progressive lesion.
• 4 months later, the patient discovered the nodule by autopalpation, and a serological work-up confirmed the presence of a cancerous tumour. She began chemotherapy, which was suspended due to intolerance.
• 6 months later, the patient underwent a mastectomy.
The patient appealed to the Commission de Conciliation et d'Indemnisation (CCI), which drew up an expert report acknowledging the radiologist's faulty diagnosis. The CCI found that the radiologist had failed to provide medical care and was therefore liable. The radiologist's insurer and the Office National d'Indemnisation des Accidents Médicaux (ONIAM) refused to pay.
The patient appealed to the civil courts, and the Court of Appeal rejected her claim for compensation.
According to the judges, radiotherapy, mastectomy and hormone therapy would have been essential, and chemotherapy probably indicated, if the diagnosis of carcinoma had been made as early as September 2010.
The patient decided to appeal to the French Supreme Court.
Ruling of March 29, 2023 (no. 22-13.630): “A loss of chance is direct and certain whenever the disappearance of a favorable eventuality is observed. Consequently, there is no loss of chance when it is considered certain that the fault had no consequences on the patient's state of health”.

Radiologist's liability ruled out
The French Supreme Court confirmed that the radiologist had made an erroneous diagnosis, causing a delay in the diagnosis of the patient's breast cancer.
However, it agrees with the Court of Appeal that, in September 2010, the patient already had a lesion and a carcinoma.
It considered that the disease was at a sufficiently advanced stage to consider that a mastectomy would have been indispensable as early as September 2010.
The radiologist's liability was ruled out, as there was no causal link between the failure to diagnose and the bodily injury suffered.