If cancers have sufficient time to develop in the body, they can increase in severity. If enough time passes without a diagnosis, the cancer may even reach what's known as stage IV, or the most serious level of development possible. At stage IV, cancers have metastasized to one or more distant areas of the body, which typically leads to relatively poor prognoses for patients.

Cancers usually show symptoms before developing to late stages. Despite this, many cancers go undiagnosed for too long, and the consequences can be dire. Medical negligence is often one of the reasons for a cancer to go undetected for long periods of time and can include:

• A doctor, pathologist or radiologist misinterpreting diagnostic test results
  
• A doctor's misdiagnosis of cancer symptoms as being due to another medical condition
• Diagnostic tests being improperly administered
• A doctor failing to order diagnostic tests for a patient with classic symptoms

Occasionally, symptoms for some cancers may not begin to appear until the disease has advanced. However, medical negligence may still occur if the doctor knows a patient is at high risk of cancer and doesn't follow recommended screening guidelines for the patient's age group.