All over the news, the past couple of days:
‘Unusual’ cancers emerged after the pandemic. Doctors ask if covid is to blame. (msn.com)
Pretty much all the stories seem to focus on one specific doctor’s experiences. I’m skeptical.
As you should be. There are a number of plausible reasons why there may be an anomaly in the diagnosis statistics on cancer, chief among them was just that for a period of about two years there were fewer people receiving regular checkups and a backlog on testing labs, resulting in less early stage detection of nascent carcinomas. It is also the case that while the overall number of oncologists are increasing in rough correspondence to the overall population, family/general practitioners, internists, and other front line physicians who will refer a patient for a cancer diagnosis are leaving the profession in droves. (It is also the case that the greatest proportional increase in oncologists is in pediatric oncologists, and they tend to see a lot of ‘odd’ cancers because of how rare cancer is in children versus the more typical breast, prostate, melanomas which increase in propensity with age, and ‘lifestyle’ cancers such as lung, mouth, throat, gastrointestinal, and industrial exposure.) The linked article acknowledges this but then bypasses it without consideration for any statistical evaluation of cancer occurrence across demographics.
On the other hand, it is not beyond plausibility that SARS-CoV-2 could have an impact on fomenting cancers, either those that are incipient or even being the primary causative agent. There are numerous cancers that have been identified as being caused by or inhibiting immune suppression of viruses. SARS-CoV-2 has demonstrated to be able to host in a variety of mammalian cells (basically, any cell with an ACE2 receptor protein, and it can cause large scale inflammation, which is suspected to correlate with propensity forward developing cancer in some tissues. Even if SARS-CoV-2 is not a causative agent infection may suppress immune response to precancerous bodies which in essence could cause a lot of nascent carcinomas to develop ‘spontaneously’ instead of over a period of years or decades. (One of the significant concerns about taking immunosuppressive drugs, aside from infectious disease, is they may make a patient more prone to developing various cancers.)
Looking around on Pubmed/NIH I see a number of papers addressing the topic of SARS-CoV-2 and cancer but of course none have any definitive links or strong correlations, and if there were a correlation it would likely not be evident in data until there is a sufficient corpus of evidence to identify statistical trends above the fairly noisy baseline of diagnosis, notwithstanding confounding factors like changes in demographic mortality (due to both SARS-CoV-2 infection and various economic factors which have a surprisingly strong impact upon morbidity and mortality of many health issues), environmental contamination, nutritional factors, et cetera that are independent of any hypothesized increase in cancers due to SARS-CoV-2 infection.
I hope that makes everything as clear as the Handook of Infectious Disease Data Analysis which has been sitting in my “partially read” pile for the last four years.
Stranger