As patients, we have little option but to trust our doctors and believe that their advice or diagnosis is correct. However, even though doctors are extremely well trained, human error at some point is inevitable.
Although it is inevitable, it is not acceptable for a doctor to make errors when we put our lives in their hands. A small error could lead to a huge amount of suffering or even death. These human errors may have been caused by negligence, and if this can be proven, then it is likely that it is grounds for a claim.
When it comes to misdiagnosing cancer, it is very often that medical professionals can be liable. If there is a failure to diagnose or a misdiagnosis, precious time could have been lost, and the disease may have progressed rapidly.
Doctors are also trained to develop a spectrum of "differential diagnoses", whereby they list out the possible options according to probability. If cancer as a diagnosis was not considered as a possibility or was not taken seriously enough as a probable diagnosis, then it is likely that a claim can be pursued.
However, it can be challenging to make a convincing case. A case would be judged by aligning the actions of the doctor in question with an archetypal competent doctor, and asking what they would have done in the given case. If a competent doctor could have made the correct diagnosis, liability can be proven.
If you or a loved on has been affected by a misdiagnosis or a delay in diagnosis of cancer, it's important to know that in taking action you may be preventing the unnecessary suffering of other patients.
Source: Findlaw, "failed diagnosis," accessed Sep. 15, 2017