Simple Summary The COVID-19 pandemic impacted health care. We studied the impact of the COVID-19 outbreak on the referral and diagnosis of cancer patients, thereby aiming to help prevent the delay of cancer diagnosis in future pandemics. We found that during the COVID-19 outbreak, the time between presentation and referral in primary care for patients with colorectal and lung cancer was substantially increased. This was also seen for patients who presented with alarm symptoms. This shows that, in future pandemics, targeted GP support is needed to maintain effective cancer diagnosis. The Coronavirus disease 2019 (COVID-19) outbreak impacted health care. We investigated its impact on the time to referral and diagnosis for symptomatic cancer p...