Drop in Cancer Reporting by Pathologists in North Rhine-Westphalia, Germany, During the COVID-19 Lockdown

The fight against the SARS-CoV-2 pandemic in Germany included the following radical steps:

• On March 10, 2020 large events with more than 1000 participants were banned.
• On March 13, 2020 the German Health Minister called on hospitals to postpone elective surgeries.
• On March 23, 2020 a lockdown was introduced, substantially reducing interpersonal contact and restricting people’s lives.
• By the end of March 2020 German hospitals had reserved almost 50% of their beds for coronavirus patients (1).

Analyses of the Belgian Cancer Registry showed a 44% relative reduction in newly diagnosed cancer cases in April 2020; the reported number of diagnoses recovered gradually from the middle of April onwards (2). Following the beginning of the nationwide lockdown in the Netherlands (March 15, 2020, 16th calendar week), Dinmohamed et al. observed a relative reduction in weekly cancer diagnoses (excluding skin cancer) reported by pathology departments of 9%, 19%, 25%, and 26% for the 16th through 19th calendar weeks, using as a baseline the 2nd through 8th calendar weeks, i.e. before the beginning of the SARS-CoV-2 outbreak in the Netherlands. There was a particularly large decrease in weekly numbers of skin cancer diagnoses (excluding basal cell carcinomas): 44%, 55%, 61%, and 60% in the 16th through 19th calendar weeks. The largest decrease was found in the oldest age group (≥80 years) (3).

In Germany this type of analysis using cancer registry data has not yet been performed, as the reporting delay means that the effect of lockdown on the incidence and treatment of cancer cannot be evaluated reliably until 12–18 months after diagnosis. However, because cancer is usually diagnosed by pathologists, a potential effect of the lockdown on cancer detection can be estimated at least provisionally, based on the number of cancer cases reported by pathologists.

Method

To this end, we first examined the data of the North Rhine-Westphalia State Cancer Registry (Landkrebsregister Nordrhein-Westfalen, www.landeskrebsregister.nrw) on all pathology departments in North Rhine-Westphalia that reported cancers, to see which of them consistently reported cases every month between July 2017 and August 2020 inclusive. The relevant date here is the date of detection, not the date of the report to the cancer registry. For the 12 pathology departments that met this inclusion criterion, we calculated the monthly mean (n = 3077 cases) and 95% confidence interval (2937 to 3217) for the monthly number of cases in 2019. The Figure shows the changes in the numbers of cases reported by these 12 departments between January 2019 and September 2020 inclusive. The North Rhine-Westphalia State Cancer Registry received a total of 63 956 reports from pathology departments during this period. In April 2020 there were substantially fewer cases (n = 2439) than in all the other months we investigated. There were 638 fewer cancer cases reported than the mean for 2019 (a 21% relative reduction). The number of cases reported recovered swiftly in May 2020. Up to September 2020 there was no evidence of a catch-up effect following April’s temporary decrease in reported cases.

Figure

Mean monthly number of cases detected by pathology departments and reported to the North Rhine-Westphalia State Cancer Registry between January 2019 and September 2020 inclusive

Discussion

Follow-up projects that cannot be implemented until after the reporting delay will investigate which cancers saw particularly large decreases and what potential effect decreases had on incidence, treatment, and stage distribution of cancers during and after lockdown. Our initial analyses are not sufficient to determine which factors explain this temporary decrease or to what extent. A decrease in detections in pathology departments can theoretically be attributed to the following factors:

• Physicians delaying confirmation of suspected cancer diagnoses during lockdown
• Less hospital screening during lockdown due to the major drop in hospitalization rates
• Patients delaying confirmation of suspected cancer out of fear of contracting SARS-CoV-2

It should be noted that our analyses are based on detected cases, not new cases alone. Because detections in pathology departments include reports on disease progression and detection of additional abnormalities (e.g. follow-up reporting of lymph node metastasis), it can be assumed that the temporary decrease in cancer incidence will be less than the 21% relative reduction stated above. A 21% decrease in reported detections of new cancers in one month would mean a decrease of approximately 2% for 2020 as a whole. However, because detections by pathology departments are almost always associated with oncology care, they are a suitable surrogate for assessing a temporary decrease in cancer care during lockdown.

Conflict of interest statement
The authors declare that no conflict of interest exists.

Manuscript received on 27 October 2020, revised version accepted on 11 November 2020.

Translated from the original German by Caroline Shimakawa-Devitt, M.A.

Cite this as:
Stang A, Kühling L, Khil L, Kajüter H, Schützendübel A, Mattauch V: A decline in cancer reporting by pathologists in North Rhine-Westphalia, Germany, during the COVID-19 lockdown.
Dtsch Arztebl Int 2020; 117: 886–7. DOI: 10.3238/arztebl.2020.0886

References

1. Bundesministerium für Gesundheit: Coronavirus SARS-CoV-2: Chronik der bisherigen Maßnahmen. www.bundesgesundheitsministerium.de/coronavirus/chronik-coronavirus.html (last accessed on 23 October 2020).

2. Belgisches Krebsregister: Krebsdiagnosen sinken während Corona-Lockdown um 44 Prozent. Pressemitteilung vom 15.7.2020. www.grenzecho.net/38988/artikel/2020–07–15/krebsdiagnosen-sinken-wahrend-corona-lockdown-um-44-prozent (last accessed on 18 August 2020).

3. Dinmohamed AG, Visser O, Verhoeven RHA, et al.: Fewer cancer diagnoses during the COVID-19 epidemic in the Netherlands. Lancet 2020; 21: 750–1