Second opinions often differ from the first, though the numbers vary widely with the condition, the setting and how a difference is measured. In a French study of 1,552 adults who requested a second opinion through an online network, the opinions diverged in 32.3% of cases, with higher rates for some conditions such as endometriosis (60.4%) and prostate adenoma (50%). The authors caution that participants volunteered for second opinions, so the figure cannot be applied to the wider population.[1] A systematic review of oncology second opinions that patients requested themselves reported a change in diagnosis, treatment or prognosis in between 2% and 51% of cases across studies.[2] A 2017 Mayo Clinic study of 286 referred patients found that final diagnoses were distinctly different from the referral diagnosis in 21% of cases and better defined or refined in a further 66%.[3] A 2018 study at a single cancer centre in the United States, involving 70 patients with breast cancer, found that review by a multidisciplinary tumour board changed the diagnosis for 43% of them.[4] Across many specialties and countries, studies have reported new diagnoses in 2% to 60% and changes of treatment in 20% to 60% of second opinions, although a clinic study in the Netherlands found a new diagnosis in 13% of patients.[5]
How a difference between opinions is handled matters. A qualitative study of 23 men with prostate cancer found that second opinions had variable effects on patients’ uncertainty, depending on how that uncertainty was addressed in the consultation.[6] Research on recorded oncology second opinion consultations similarly notes that a second opinion may in turn affect how uncertain patients feel, and found that oncologists vary in how they communicate uncertainty.[7] A different opinion is not a flaw in the process. It is information you did not have before.
A difference between two qualified specialists does not necessarily mean one of them is wrong. Medicine involves real judgement calls, not just fixed answers. Two experienced doctors can look at the same case and reasonably weigh the evidence differently. That is not confusion. It is you learning there is more than one reasonable path before you commit to just one of them.
A simple way to hold two different opinions at once:
- Ask each doctor the same specific question, in the same words if you can. For example: “What is the biggest risk of this approach, and what is the biggest risk of doing nothing?” Comparing answers to the same question makes the difference between the two opinions much clearer than comparing two open conversations.
- Ask what would change their mind. “Is there anything that would make you recommend the other approach instead?” This often shows that the difference comes down to one or two specific facts or values, not a wholesale difference in judgement.
- Weigh the difference against what matters most to you, clinically and personally. Think about recovery time, risk tolerance and your own priorities. Two good answers can both be right, and the one that is right for you is still your decision.
- A third opinion is sometimes worth it, particularly for complex decisions or decisions with high stakes. It is not a sign you are being indecisive. It is a sign you are taking the decision seriously.
A difference between doctors is not the system failing you. It is a sign there was a real decision to make.
One thing to be aware of. A study reported by UCLA Health in 2022 found that doctors giving second opinions can be influenced by knowing the first diagnosis, sometimes towards misdiagnosis. If a second opinion service asks whether the reviewing specialist should see the original diagnosis before forming their own view, it is worth knowing that this can shape the result.[8]
This guide is general information, not medical advice. Please discuss decisions about your care with your treating doctor.