Is there an association between breast cancer and incident adhesive capsulitis of the shoulder? A retrospective cohort study from Germany

No Significant Association Between Herpes Zoster and Breast Cancer: A German Outpatient Study with over 120,000 Participants

PURPOSE

The purpose of this study was to investigate a possible association between Herpes Zoster (HZ) and the subsequent diagnosis of breast cancer (BC).

METHODS

Utilizing the Disease Analyzer database, anonymized medical records from German office-based practices were accessed. Longitudinal data of female patients aged 18 years and above diagnosed with HZ between 2005 and 2021 were included. Individuals without HZ diagnoses were matched to HZ patients using a nearest neighbor propensity score matching (1:1) based on age, sex, index year, average yearly consultation frequency during the follow-up, and predefined co-diagnoses. The incidence of BC in the cohort with and without HZ was evaluated using Kaplan-Meier curves and compared using the log-rank test. Finally, a univariable Cox regression analysis was conducted to assess the association between HZ and BC.

RESULTS

This study included 64,255 women with HZ and an equal number without HZ, with comparable characteristics in terms of age, visit frequency, and comorbidities. Analysis revealed no significant association between HZ and subsequent BC incidence, with similar rates observed in both HZ and non-HZ cohorts across different age groups.

CONCLUSIONS

In this retrospective cohort study consisting of well-matched patients, the results indicate no significant association between an HZ infection and the development of BC over a 10-year follow-up period. This is the largest study of its kind to date.

Is there an association between mastitis and breast cancer? a retrospective cohort study from Germany

PURPOSE

The aim of the study was to explore the association between mastitis and subsequent breast cancer.

METHODS

This retrospective cohort study included women aged ≥ 18 years with an initial mastitis diagnosis from 315 office-based gynecologists in Germany between January 2005 and December 2021. Women without mastitis were matched to women with mastitis using propensity score matching based on age, index year, average yearly consultation frequency during the follow-up period, and coexisting diseases such as obesity, benign mammary dysplasia, hypertrophy of the breast, unspecified lump of breast, and other disorders of the breast. The 10-year cumulative incidence of breast cancer for the mastitis-cohort and non-mastitis-cohort was studied with Kaplan-Meier curves using the log-rank test. The association between mastitis and breast cancer was studied separately for four age groups with univariable Cox regression analyses.

RESULTS

In the follow-up period of 7 months to 10 years after the index date, 2.9% of mastitis patients and 2.4% of matched non-mastitis patients were diagnosed with breast cancer. A Cox regression analysis revealed a significant association between mastitis and subsequent breast cancer (HR: 1.37; 95% CI: 1.11-1.70). According to the age-stratified analyses, a strong and significant association was only observed in the age group > 50 years (HR: 1.73; 95% 1.25-2.40).

CONCLUSION

The findings of our retrospective cohort study support an association between mastitis and subsequent breast cancer diagnoses in women aged > 50 years. The pathophysiological basis and possibility of confounders however requires further investigation.

Is there an association between endometriosis and subsequent breast cancer? A retrospective cohort study from Germany

PURPOSE

Given the relatively high incidence of both endometriosis and breast cancer, investigating the potential connection between these gynecological diseases is of substantial clinical significance. However, there is no clear consensus in the literature on the extent to which the risk of breast cancer is increased in patients with endometriosis. Therefore, we conducted a large-scale observational study investigating the association between endometriosis and breast cancer risk.

METHODS

This study included women aged ≥ 18 years with an initial endometriosis diagnosis from one of 315 office-based gynecologists in Germany between January 2005 and December 2021. Non-endometriosis patients were matched 1:1 to patients with endometriosis based on age, index year, average yearly consultation frequency, and predefined co-diagnoses within 12 months before or on the index date, including obesity and benign breast disorders. The association between endometriosis and the 10-year incidence of breast cancer was studied using Kaplan-Meier curves and log-rank tests. Finally, a univariable Cox regression analysis was conducted to assess the association between endometriosis and breast cancer.

RESULTS

Over a follow-up period of up to 10 years, no significant difference was observed between the endometriosis (2.4%) and the matched non-endometriosis group (2.5%) with regard to breast cancer diagnoses. Furthermore, the regression analysis revealed no significant association between endometriosis and subsequent breast cancer.

CONCLUSION

In summary, our comprehensive 10-year study involving a substantial sample of women indicates that endometriosis is not significantly associated with an increased risk of subsequent breast cancer.

Association between iron deficiency anemia and subsequent stomach and colorectal cancer diagnosis in Germany

PURPOSE

Iron deficiency anemia (IDA) is the most common form of anemia worldwide, resulting in a high burden of disease. Accumulating evidence suggests that IDA is associated with the development of gastrointestinal (GI) cancers.

METHODS

Data from the IDA database (IQVIA) of primary care practices in Germany of adult patients first diagnosed with IDA between January 2005 and December 2021 were retrospectively analyzed and compared with a 1:1 propensity score-adjusted cohort without IDA. Study outcomes were first stomach cancer or colorectal cancer (CRC) diagnosis up to 10 years after the index date as a function of IDA.

RESULTS

A total of 122,502 individuals with IDA and 122,502 individuals without IDA were included. The 10-year cumulative incidence of CRC was 1.4% in the IDA patients compared to 0.8% in the cohort without IDA (p < 0.001). Regression analysis revealed a significant association between IDA and subsequent CRC (HR 2.05; 95% CI 1.83-2.30). Stomach cancer was diagnosed in 0.3% of IDA patients compared to 0.2% in the non-IDA cohort during the 10-year follow-up period (p = 0.002). However, this was significant only in the age group > 80 years (HR 2.73; 95% CI 1.60-4.67) and in men (HR 1.90; 95% CI 1.38-2.61).

CONCLUSION

These findings add to the literature and suggest an association between IDA and GI cancers. The extent to which this association is due to GI bleeding or other pathophysiological processes that may be caused by IDA requires further investigation, particularly experimental studies.

Herpes zoster is not associated with subsequent gastrointestinal cancer: data from over 200,000 outpatients in Germany

PURPOSE

Gastrointestinal (GI) cancers are an increasing global health challenge. Viral diseases play an important role in the development of GI cancers. For example, Epstein-Barr virus, which belongs to the human herpesvirus family, is a well-recognized risk factor for the development of gastric cancer. The purpose of this study was to investigate a possible association between varicella-zoster virus reactivation and subsequent diagnosis of GI cancer.

METHODS

In this retrospective cohort study, a total of 103,123 patients with a first diagnosis of herpes zoster (HZ) between 2005 and 2021 were propensity score matched to a cohort of 103,123 patients without HZ. Patient data was extracted from the Disease Analyzer database (IQVIA). The incidence of GI cancer was compared as a function of HZ. Cox regression analysis was used to examine the association between HZ and GI cancer.

RESULTS

Over a follow-up period of up to 10 years, the incidence of GI cancer did not differ between the two cohorts (HZ cohort 2.26 cases per 1000 patient-years vs. non-HZ cohort 2.37 cases per 1000 patient-years, p = 0.548). In regression analysis, HZ was not associated with an increased risk of developing GI cancer (HR: 0.97; 95% CI 0.89-1.05). Furthermore, no significant effect of the presence of HZ on the incidence of different GI cancer entities was found.

CONCLUSION

In this retrospective cohort study consisting of well-matched patients, we observed no significant association between a HZ infection and the development of GI cancer during a long-term follow-up.