A year ago, the ‘Big C’ was synonymous with cancer, but with the emergence of SARS-CoV2, COVID 19 became the most dominant ‘C’ in the context of health. Speculation on the fallout of the global pandemic on cancer health care and research has been extensive but as we live through this second wave what are the full implications for patients with cancer?
Initial concerns focussed on the vulnerability of patients with cancer; were they more clinically vulnerable to the disease? Should cancer treatments be withheld to reduce the risk? Initially, data to support clinical decision-making was sparse but international efforts developed at an astonishing pace and reports emerged to suggest that some patients with cancer are more likely to be infected by SARS-CoV-2, develop a severe COVID-19 infection and more likely to die as a result of COVID-19. However, there is considerable heterogeneity in this patient population, including the disease type, stage, nature of the (multi-modality) treatment, age and co-morbidities. Collectively, multiple prospective cohort studies have identified consistent patterns of patients at risk of more severe outcomes form COVID19 infection, including patient with lung cancer, haematological malignancies and advanced or active cancers. Factors associated with adverse outcome in the general population, including male sex, increasing age, comorbidities, poor performance status and smoking are also negative risk factors in the cancer patients. The impact of systemic cancer therapies per se did not increase the severity or mortality from COVID19. The major caveat is for patients with blood cancers where outcomes are particularly poor and may reflect the underlying immune state of people with blood cancer or the relatively intense treatments and the effect on immunity.
There SARS-CoV2 pandemic was also detrimental to elective cancer surgery. The risk of in-hospital SARS-CoV2 transmission, pulmonary complications and associated increased mortality, as well as decreased critical care capacity led to a substantial reduction on cancer operations worldwide. An important international study supports international, multi-centre cohort study of patients undergoing surgery for 10 different types of cancer who underwent elective surgery for 10 solid cancer types demonstrated the safety of elective cancer surgery in a COVID-19-free surgical pathway. This was defined as ‘complete segregation of the operating theatre, critical care, and inpatient ward areas’3. For the majority of cancer patients, all efforts should be made to ensure cancer treatments are delivered in accordance with our well-established best clinical practice and that dedicated COVID-19-free surgical pathways will allow safe elective cancer surgery during SARS-CoV-2 outbreaks. If the increasing pressures on healthcare services lead to deviations from planned cancer care the negative impact on cancer survival are inevitable. Pressures on cancer services as a result of workforce redeployment, disruption and changes to the treatment pathway including intermittent suspension of cancer screening services as well as delayed presentation have delayed diagnosis and treatment for cancer patients with many anecdotal tragic cases emerging. The full of the impact for long term cancer outcomes will take some time to emerge and quantify.
The advent of vaccines against SARS-CoV-2 is cause for optimism and patients with cancer are amongst the prioritised groups to receive the vaccines. The normal function of the immune system in patients with cancer can be impaired by the disease itself as well as the immune-suppressive cancer treatments, both of which could impact on the immune response to SARS-Cov2 vaccines. Further research is needed to understand the adequacy and durability of SARS-Cov2 vaccines when used in patients with cancer.
Over the last 12 months, research has helped us understand implications of the pandemic on patients already diagnosed with cancer and how to mitigate the impact. The unknown implications are on patients yet to be diagnosed and potential delays in that diagnostic pathway. There are multiple factors, including patient anxieties to seek medical services during the pandemic and delays in access to diagnostic services due to the reduced capacity in hospitals and further research is needed.