A number of papers are presently appearing in journals on the impact to cancer patients in the UK of CV-19 and lockdown.
There seems to be no evidence that cancer patients on cytotoxic chemotherapy or other anticancer treatment are at an increased risk of mortality from COVID-19 disease compared with those not on active treatment. But there is evidence that urgent referrals have been down significantly (down 84% between Mar and May in one paper) and there has been a reduction in chemo treatment (by up to 66% in one paper).
We know from various communications that there is total commitment in the national cancer services to getting back to full speed without delay – and one estimate is that things are about 80% back to normal now.
Recent papers of interest (not all looking at the UK as a whole) include https://www.thelancet.com/pdfs/journals/lanonc/PIIS1470-2045(20)30392-2.pdf and https://www.researchgate.net/publication/340984562_Estimating_excess_mortality_in_people_with_cancer_and_multimorbidity_in_the_COVID-19_emergency and https://ukcoronaviruscancermonitoring.com/