ABSTRACT
Introduction. The SARS-CoV-2 infection rate and the COVID-19 death rate were relatively high in the Netherlands during the first wave of the COVID-19 pandemic (2.7 and 7.2 times higher than in Norway, respectively). Moreover, social measures differed between the two countries. This study aimed to compare the effect of the pandemic on breast cancer incidence and stage between the Netherlands and Norway. Methods. Women diagnosed with DCIS or invasive breast cancer between January 2017 and December 2021 were selected from the Netherlands Cancer Registry and from the Cancer Registry of Norway. The COVID-19 period was divided in three approximately equal periods: March-September 2020 (first wave), October 2020-April 2021 (second wave), May-December 2021 (post-second wave). Breast cancer incidence during the COVID-19 periods was compared with averaged data of the corresponding reference period: March-September 2017, 2018, 2019 (first wave-ref), October-April 2017, 2018, 2019 (second wave-ref), May-December 2017, 2018, 2019 (post-second wave-ref). Incidences were compared by age group, clinical tumor stage, and method of detection. Results. The number of breast cancer diagnosis and the breast cancer incidence are shown in Table 1. Compared to the reference period, breast cancer incidence was lower during the first wave in the Netherlands and Norway (IRR: 0.72;95%CI: 0.70-0.75;IRR: 0.83, 95%CI 0.78-0.88, respectively), and was higher post-second wave in Norway (IRR: 1.10, 95%CI: 1.04-1.16) (Table 1). During the first wave, breast cancer incidence was lower in all age groups in the Netherlands (age < 50 IRR: 0.85, 95%CI: 0.79-0.91;50-69 IRR: 0.64, 95%CIL 0.61-0.67;70-74 IRR: 0.61, 95%CI: 0.56-0.67;>74 IRR: 0.86, 95%CI: 0.80-0.93, respectively). During the first wave, incidence was lower in women aged 50- 69 in Norway (i.e., women eligible for screening;IRR: 0.68, 95%CI: 0.62-0.74). Post-second wave incidence was higher in women aged 50-69 and >74 in Norway (IRR: 1.09, 95%CI: 1.01-1.17;IRR: 1.13, 95%CI: 1.00-1.28, respectively). In the first wave the incidence of DCIS, stage I tumors, and screen-detected tumors was lower in the Netherlands (IRR: 0.55, 95%CI: 0.50-0.61;IRR: 0.62, 95%CI: 0.59-0.65, IRR: 0.36, 95%CI: 0.33-0.38, respectively) as well as Norway (IRR: 0.66, 95%CI: 0.54-0.79;IRR: 0.73, 95%CI: 0.66-0.81, IRR: 0.46;95%CI: 0.40-0.52, respectively). Conclusion. The current study showed that the incidence of early-stage tumors mainly decreased. Moreover, during the first wave of the pandemic breast cancer incidence decreased in all age groups in the Netherlands but only in women aged 50-69 in Norway. The relatively high infection and death rate in the Netherlands might have increased the fear of patients to visit the general practitioner (GP) and/or to overburden the healthcare system at the start-up of the pandemic. In addition, it might have reduced the capacity at the GP. As a result, appointments with the GP might have been postponed, resulting in a decrease in the number of breast cancer diagnoses in all age groups. A catch-up in breast cancer diagnoses was seen post-second wave in Norway, but not in the Netherlands. Incidence rates should therefore be monitored in the coming period. (Table Presented).
ABSTRACT
Introduction: The burden of the COVID-19 pandemic forced the Dutch health care services to discontinue their national screening programs on 16 March 2020 (week 12). For breast cancer, the program invites women aged 50-74 years for biennial screening mammography. From mid-June 2020 (week 25) the breast cancer screening program was resumed, albeit with reduced capacity (max 60%). We aimed to investigate the impact of resuming the screening program on incidence, tumor-, and T-stage of screen- and non-screen-detected ductal carcinoma in situ (DCIS) and invasive breast cancer (IBC) in the Netherlands. Methods: Women, 50-74 years of age, diagnosed with DCIS or IBC in weeks 2-35 of 2018, 2019 and 2020 were selected from the Netherlands Cancer Registry. Weekly incidence of screen- and non-screen-detected tumors was calculated and expressed per 1 million women aged 50-74 years living in the Netherlands. Weeks 2-35 were divided in seven periods, representing separate phases of the pandemic. For each period, incidence of screen- and non-screen-detected tumors was stratified by clinical tumor stage (TNM) and clinical T-stage. Incidence in each period of 2020 was compared with the incidence in the same period of 2018/2019 (averaged). Results: In weeks 2-35, 7,250 patients were diagnosed in 2018, 7,299 in 2019, and 5,300 in 2020. During weeks 2-12 2020 the weekly average incidence of screen-detected tumors was 42/1 million women aged 50-74. In week 13 incidence dropped to 19, and was almost zero during weeks 14-25. Incidence increased to 4 in week 26, when the screening was gradually restarted, and increased to an weekly average of 24 tumors/1 million in weeks 30-35, when screening had restarted in most of the Netherlands. During weeks 14-16, 17-25, 26-29, and 30-35 2020 incidence of screen detected DCIS, stage I-II tumors and T0-2 tumors was lower than in the same period of 2018/2019. Distribution of tumor- and T-stage in newly diagnosed tumors did not differ between the periods (24% DCIS, 57% stage I, 18% stage II, 1% stage III, 1% stage IV;24% T0, 59% T1, 15% T2, 2% T3, 0% T4). During weeks 2-11 2020 the weekly average incidence of non-screen-detected tumors was 38/1 million women aged 50-74. Incidence dropped to 16 in week 14, and increased to an average of 37 tumors per week in weeks 17-35. During weeks 17-25, 26-29, and 30-35 the incidence and distribution of non-screen-detected DCIS, stage I-IV and T0-4 tumors was comparable with 2018/2019 (weekly incidence (distribution): 3 DCIS (9%), 15 stage I (40%), 13 stage II (36%), 3 stage III (7%), 3 stage IV (8%);3 T0 (9%), 17 T1 (45%), 12 T2 (34%), 3 T3 (8%), 2 T4 (5%)). Conclusion: The temporary suspension of the breast cancer screening program reduced the incidence of breast cancer. After resuming screening the incidence did not raise above the incidence in 2018/2019, therefore it is expected that the incidence will rise during the next months. The results to date did not show a shift towards a higher tumor stage or T-stage.
ABSTRACT
Introduction: The COVID-19 outbreak led to the suspension of the Dutch breast cancer screening program, increased the reluctance of patients to visit the general practitioner (GP), and led to a lack of capacity at the GP. As a consequence, the incidence of breast cancer diagnoses decreased. Objective: This study aimed to investigate the impact of the COVID-19 outbreak on the incidence of different stages of breast cancer, by screening status. Methods: Women diagnosed between January 1st 2017 and February 28th 2021 with primary breast cancer without a history of breast cancer were selected from the Netherlands Cancer Registry. March 1st 2020 till February 28th 2021 was regarded as the COVID-19 period. Breast cancer incidence within this COVID-19 period was calculated by tumor stage and compared with the incidence in 2017/2019 (reference). Incidence was expressed per 100, 000 women aged 18 year or older, living in the Netherlands at the start of the year. Thereafter, the COVID-19 period was divided into four subperiods, based on COVID-19 related events: March-April 2020, May-June 2020, July-August 2020, September 2020-February 2021. Incidence in each of those periods was calculated by tumor stage and compared with the incidence in 2017/2019. Analyses were further stratified by screening status. Incidence of screenS detected tumors was expressed per 100, 000 women aged 50-74 living in the Netherlands at the start of the year. Results: A total of 15, 916 women were diagnosed in 2017, 15, 574 in 2018, 15, 867 in 2019, 13, 497 in 2020 and 2, 532 up to February 2021. Compared to 2017/2019, the incidence of DCIS and stage I-III tumors was statistically significantly lower during the COVID-19 period (32%, 24%, 9% and 11% respectively) (Table 1), leading to 603, 1539, 520 and 160 missed diagnoses respectively. The incidence of stage IV tumors was 5% higher, however this was not significant. The incidence of DCIS remained significantly lower throughout the four subperiods, while the incidence of stage I-II tumors was comparable with 2017/2019 in September 2020-February 2021 and the incidence of stage III was comparable with 2017/2019 in both July-August 2020 and September 2020-February 2021. The incidence of DCIS and stage I-II non-screen-detected tumors was significantly lower during March-April 2020 and was comparable with 2017/2019 in the subperiods thereafter. The incidence of DCIS and stage I-IV screen-detected tumors was significantly lower during March 2020-February 2021, with the incidence of DCIS and stage I-III tumors being lower during each subperiod and the incidence of stage IV tumors being lower during May-June 2020. Conclusion: The COVID-19 outbreak led to a decrease in the incidence of DCIS and stage I-III tumor diagnoses, which still lags behind in February 2021. Until February 2021 no stage shift was seen.
ABSTRACT
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.
ABSTRACT
Introduction: The COVID-19 outbreak forced health care services to switch focus to COVID-19 patients, thereby generating pressure on all other health care services, most likely impacting breast cancer care as well. However, the impact of the COVID-19 outbreak on the breast cancer treatment strategy is unknown. Objective: To investigate the impact of the COVID-19 outbreak on the breast cancer treatment strategy. Methods: We selected women diagnosed with breast cancer between January 1st 2018 and June 30th 2020 from the Netherlands Cancer Registry. Women with previous breast cancer or with a synchronous tumor were excluded. The following periods based on COVID-19 related events were analyzed: 2018/2019 (reference), weeks 1-8, weeks 9-12, weeks 13-17, and weeks 18-26 in 2020. Patients were divided into periods based on their date of diagnosis. For patients with DCIS we used logistic regression to investigate the association between period of diagnosis and chance of being treated within six months following diagnosis. For patients with invasive tumors receiving surgery, we used logistic regression to investigate the association between period of diagnosis and chance of receiving a certain type of treatment, adjusting for tumor stage. Furthermore, time length between the following time points were calculated per tumor stage: S 1) diagnosis and first treatment (of any kind), 2) diagnosis and start of neo-adjuvant treatment, 3) diagnosis and operation (no neo-adjuvant treatment was given), 4) end of neo-adjuvant treatment and operation, 5) operation and start of adjuvant systemic treatment, and 6) operation and start of radiotherapy. Time lengths were calculated for each period of 2020 and compared with 2018/2019. Results: A total of 1, 795 DCIS and 11, 785 invasive tumors were diagnosed in 2018, 1, 826 DCIS and 11, 987 invasive tumors in 2019 and 597 DCIS and 4, 566 invasive tumors up to June 2020. Compared to 2018/2019, patients diagnosed with a DCIS were less likely to be treated within six months following diagnosis (ORwks1-8: 0.63, ORwks9-12: 0.50, ORwks18-26: 0.51) (Table). Patients diagnosed with an invasive tumor in weeks 9-12 2020 were less likely to receive neo-adjuvant chemotherapy (ORwks9-12: 0.63), while patients diagnosed thereafter were more likely to receive neo-adjuvant chemotherapy (ORwks13-17: 1.39, ORwks18-26: 1.41). Patients were more likely to receive neo-adjuvant endocrine therapy (ORwks1-8: 1.64, ORwks9-12: 3.14, ORwks13-17: 1.85, ORwks18-26: 1.28), mastectomy (ORwks18-26: 1.32), or adjuvant chemotherapy (ORwks9-12: 1.36), while they were less likely to receive radiotherapy (ORwks18-26: 0.74). Patients receiving a mastectomy for their invasive tumor were more likely to receive an immediate reconstruction (ORwks18-26: 1.57). Compared to 2018/2019, time between diagnosis and first treatment, diagnosis and operation, diagnosis and neo-adjuvant treatment, and operation and adjuvant systemic treatment decreased significantly for patients diagnosed with a stage I-III tumor in weeks 9-12, 13-17 or 18-26. Conclusion: The COVID-19 outbreak affected multiple aspects of the breast cancer treatment strategy and led to a shorter time to therapy, probably due to prioritizing of oncological care and a reduction in the number of patients.