RESUMEN
The aim of this study was to investigate how breast cancer follow-up in the Netherlands changed during the COVID-19 pandemic, compared to 2018-2019, and to what extent follow-up during the pandemic corresponded to the patient risk of recurrence. During the early phase of the pandemic the Dutch Society for Surgical Oncology (NVCO) issued a report with recommendations on how follow-up could be postponed, as a guidance for the pandemic, based on a low, intermediate or high risk of recurrence. In this study we investigated to what extent this advice was followed. A dataset of 33160 women diagnosed with primary invasive breast cancer between January of 2017 and July of 2021 was selected from the Netherlands Cancer Registry (NCR) and Dutch Hospital Data (DHD). The pandemic, 2020 and weeks 1-32 of 2021, was divided into six periods (A to F), based on the number of hospitalized COVID patients in the Netherlands. The five-year risk of locoregional recurrence (LRR) was determined for each patient with the INFLUENCE nomogram. The LRR risk was compared to the risk groups from the NVCO report with a Kruskal-Wallis test. The percentage of patients who received a mammogram during period A to F was compared to the same periods of 2018-2019 with a chisquared test. Correlation between the LRR risk, and if patients had a mammogram, was investigated with logistic regression. This analysis was repeated separately for the risk groups. Correlation between the LRR risk, and time intervals between surgery and the first and second mammogram was analyzed using cox proportional hazard models, this was also repeated for the risk groups. There was a significant difference in LRR risk between the NVCO risk groups. In the low-risk group (n=7673), 86 patients (1.1%) had a risk >5%. In the intermediate risk group (n=19197), 18364 patients (95.7%) had a risk of < 5%, and 65 patients (0.34%) had a risk of >10%. In the high-risk group (n=2674), 2365 patients (88.4%) had a risk < 10%. The percentage of patients who received a mammogram was significantly lower in periods B to F of the pandemic. Logistic regression showed a negative correlation between the risk of LRR and if patients had a mammogram in 2020 (OR 0.93) and 2021 (OR 0.93). There was also a negative correlation between the risk groups and mammography in 2020 (OR 0.92 for intermediate and 0.80 for high), and for the risk groups and mammography in 2021 (OR 0.98 for intermediate and 0.95 for high). There was no significant impact of LRR risk, or risk group, on time intervals between mammograms. During the pandemic, patients with a higher LRR risk, or a higher risk according to NVCO advice, had lower odds of having a mammogram. If the advice would have been followed, in 0.5% of the patients scheduled for follow-up, the recommendation was to postpone in contrast to a high estimation of the individual risk. For 62.7%, a follow-up was recommended, despite a low estimated individuals risk. Because the number of high-risk patients is relatively low, individual risk prediction could be supportive, in case of future restrictions. This way the high-risk patients can be identified and prioritized for follow-up, and can also be encouraged to come to the hospital.
RESUMEN
Introduction: The COVID-19 pandemic led to a decrease in the incidence of breast cancer diagnoses in the Netherlands. This was due to the encouragement to stay at home, a lack of capacity at the general practitioner (GP) and an increased reluctance of patients to visit the GP. Moreover, from the 16th of March the Dutch breast cancer screening program was halted and gradually restarted from June onwards. Part of the follow-up visits for breast cancer survivors were also postponed or changed to an appointment by phone. However, it is not known how this affected the incidence of second primary breast cancer (SPBC) and pathologically confirmed breast cancer recurrences. Objective: To investigate the effect of the COVID-19 pandemic on the diagnosis of SPBC and breast cancer recurrences. Methods: Women diagnosed with a pathological confirmed SPBC or recurrence (locoregional recurrences (LRR) + distant metastasis (DM)) between January 1st 2017 and February 28th 2021 were selected from the Netherlands Cancer Registry, based on diagnoses of the Nationwide Histopathology and Cytopathology Data Network and Archive (PALGA). Patients with a SPBC or recurrence who had their primary breast tumor diagnosed more than five years ago were excluded. March 1st 2020 till February 28th 2021 was regarded as the S COVID-19 period. Incidence was expressed per 100, 000 women, who were diagnosed with breast cancer less than 5 years ago, and who were still alive. Incidence of SPBCs and recurrences was calculated for the total COVID-19 period and for four subperiods, and compared with the corresponding periods in 2017/2019 (averaged). Results: A total of 393 patients were diagnosed with a SPBCs in 2017, 340 in 2018, 299 in 2019, 342 in 2020 and 71 up to February 2021. A total of 447 patients were diagnosed with a recurrence in 2017, 520 in 2018, 516 in 2019, 529 in 2020 and 80 up to February 2021. During the COVID-19 period a total of 449 patients were diagnosed with a SPBCs per 100, 000 breast cancer survivors, this was comparable to the 445 patients diagnosed per year per 100, 000 breast cancer survivors in 2017/2019 (p=0.91) (Table 1). The incidence of SPBCs was significantly lower during March-May 2020 compared to the same period in 2017/2019 (86 vs. 121) (p=0.03), leading to 50 less SPBCs diagnoses. The incidence was higher during June-August 2020 (124 vs. 95), however this was not significant (p=0.09). The incidence of recurrences in the COVID-19 period, and within all four subperiods, was comparable to the incidence in 2017/2019. Conclusion: The COVID-19 pandemic led to a decrease in the detection of SPBCs at the beginning of the pandemic. However, this drop in incidence was caught up in the period thereafter. This might be related to the restart of the regular follow-up visits (partly in real-life consultations), the call to go to the GP in case of complaints and the improved accessibility of the GPs. The incidence of recurrences did not decrease since it includes also DM, which cause worrisome symptoms for which care is sought.