Challenging the current norm: Does health related quality of life data from reference populations accurately reflect baseline values in breast cancer patients? An observational cohort study comparing EORTC QLQ-C30 scores between the general Swedish population and baseline scores in breast cancer patients.

BACKGROUND: Increased overall survival in breast cancer patients has led to a growing recognition of long-term effects of cancer treatment of patients' quality of life. Health related quality of life (HRQoL) data, as measured by patient reported outcome measures (PROMs), is increasingly incorporated into clinical practice and research. A commonly used method current available to interpret HRQoL PROMs data is by comparison to reference values, often obtained from sampling of the general population. The aim of this study was to assess whether HRQoL reference values derived from the general population are an accurate representation of the baseline values of an outpatient breast clinic population. METHODS: A prospective observational cohort study was conducted by obtaining EORTC QLQ-C30 values for all patients offered an appointment in the outpatient breast clinic. These results were then compared to published baseline values in the general Swedish population, matched by gender and age. RESULTS: 568 questionnaires were returned with a response rate of 81,1 %. The outpatient breast clinic cohort reported a higher grade of symptoms, lower function and lower quality of life compared to the equivalent reference population. CONCLUSION: This study challenges the assumption that the reference values accurately reflect those of the study population which clinicians and researchers need to account for in study design and clinical practice.

Association of postoperative infection and oncological outcome after breast cancer surgery.

BACKGROUND: Surgical-site infection (SSI) is a well known complication after breast cancer surgery and has been reported to be associated with cancer recurrence. The aim of this study was to investigate the association between SSI and breast cancer recurrence, adjusting for several known confounders. The secondary aim was to assess a possible association between any postoperative infection and breast cancer recurrence. METHOD: This retrospective cohort study included all patients who underwent breast cancer surgery from January 2009 to December 2010 in the Uppsala region of Sweden. Data collected included patient, treatment and tumour characteristics, infection rates and outcome. Association between postoperative infection and oncological outcome was examined using Kaplan-Meier curves and Cox regression analysis. RESULTS: Some 492 patients (439 with invasive breast cancer) with a median follow-up of 8.4 years were included. Mean(s.d.) age was 62(13) years. Sixty-two (14.1 per cent) of those with invasive breast cancer had an SSI and 43 (9.8 per cent) had another postoperative infection. Some 26 patients had local recurrence; 55 had systemic recurrence. Systemic recurrence was significantly increased after SSI with simple analysis (log rank test, P = 0.035) but this was not observed on adjusted analysis. However, tumour size and lymph node status remained significant predictors for breast cancer recurrence on multiple regression. Other postoperative infections were not associated with recurrence. CONCLUSION: Neither SSI nor other postoperative infections were associated with worse oncological outcome in this study. Rather, other factors that relate to both SSI and recurrence may be responsible for the association seen in previous studies.