Significant inter- and intra-laboratory variation in grading of ductal carcinoma in situ of the breast : a nationwide study of 4901 patients in the Netherlands

Purpose: A considerable part of ductal carcinoma in situ (DCIS) lesions may never progress into invasive breast cancer. However, standard treatment consists of surgical excision. Trials aim to identify a subgroup of low-risk DCIS patients that can safely forgo surgical treatment based on histologic grade, which highlights the importance of accurate grading. Using real-life nationwide data, we aimed to create insight and awareness in grading variation of DCIS in daily clinical practice. Methods: All synoptic pathology reports of pure DCIS resection specimens between 2013 and 2016 were retrieved from PALGA, the nationwide Dutch Pathology Registry. Absolute differences in proportions of grade I-III were visualized using funnel plots. Multivariable analysis was performed by logistic regression to correct for case-mix, providing odds ratios and 95% confidence intervals for high-grade (III) versus low-grade (I–II) DCIS. Results: 4952 DCIS reports from 36 laboratories were included, of which 12.5% were reported as grade I (range 6.1–24.4%), 39.5% as grade II (18.2–57.6%), and 48.0% as grade III (30.2–72.7%). After correction for case-mix, 14 laboratories (38.9%) reported a significantly lower (n = 4) or higher (n = 10) proportion of high-grade DCIS than the reference laboratory. Adjusted ORs (95%CI) ranged from 0.52 (0.31–0.87) to 3.83 (1.42–10.39). Significant grading differences were also observed among pathologists within laboratories. Conclusion: In this cohort of 4901 patients, we observed substantial inter- and intra-laboratory variation in DCIS grading, not explained by differences in case-mix. Therefore, there is an urgent need for nationwide standardization of grading practices, especially since the future management of DCIS may alter significantly depending on histologic grade

Landelijke variatie in moleculaire diagnostiek bij gemetastaseerde longkanker

OBJECTIVE: The objective of this study is to determine at a national level whether patients with metastatic non-small cell lung cancer (NSCLC) are adequately tested for EGFR mutations and ALK rearrangement, because targeted therapy is tailored to the results of molecular diagnostics. DESIGN: Retrospective cohort study. METHOD: Data from all patients with metastatic non-squamous NSCLC diagnosed in 2013 or 2015 were identified from the Netherlands Cancer Registry, and coupled with data from the Netherlands national pathology registry (PALGA). Using information extracted from PALGA we determined what percentage of the tumours were tested for EGFR or KRAS mutations and ALK rearrangement, identified the variables that were associated with the performance of molecular diagnostics and investigated the differences between 48 laboratories. RESULTS: A total of 6,619 patients were included (2013: n = 3,195; 2015: n = 3,424). In 2013, EGFR or KRAS testing was performed on 73.1% of the tumours (variation between laboratories 30.6-91.7%); in 2015 this was 78.9% (variation 40.0-91.0%). In 2013 49.5% of the tumours without EGFR or KRAS mutations underwent ALK testing (variation between laboratories 6.3-100%) and in 2015 ALK testing was performed on 77.4% (32.5-100%). In 2015, 6 and 7 laboratories tested significantly fewer EGFR and ALK tests, respectively, than the national average. CONCLUSION: In 2013, molecular testing for EGFR and KRAS mutations and, in particular, for ALK rearrangement was suboptimal. EGFR and ALK testing was performed significantly more often in 2015. Despite this increase, there is room for improvement in a number of laboratories and hospitals, considering that some patients were possibly wrongly not eligible for targeted therapy

Landelijke variatie in moleculaire diagnostiek bij gemetastaseerde longkanker

OBJECTIVE: The objective of this study is to determine at a national level whether patients with metastatic non-small cell lung cancer (NSCLC) are adequately tested for EGFR mutations and ALK rearrangement, because targeted therapy is tailored to the results of molecular diagnostics. DESIGN: Retrospective cohort study. METHOD: Data from all patients with metastatic non-squamous NSCLC diagnosed in 2013 or 2015 were identified from the Netherlands Cancer Registry, and coupled with data from the Netherlands national pathology registry (PALGA). Using information extracted from PALGA we determined what percentage of the tumours were tested for EGFR or KRAS mutations and ALK rearrangement, identified the variables that were associated with the performance of molecular diagnostics and investigated the differences between 48 laboratories. RESULTS: A total of 6,619 patients were included (2013: n = 3,195; 2015: n = 3,424). In 2013, EGFR or KRAS testing was performed on 73.1% of the tumours (variation between laboratories 30.6-91.7%); in 2015 this was 78.9% (variation 40.0-91.0%). In 2013 49.5% of the tumours without EGFR or KRAS mutations underwent ALK testing (variation between laboratories 6.3-100%) and in 2015 ALK testing was performed on 77.4% (32.5-100%). In 2015, 6 and 7 laboratories tested significantly fewer EGFR and ALK tests, respectively, than the national average. CONCLUSION: In 2013, molecular testing for EGFR and KRAS mutations and, in particular, for ALK rearrangement was suboptimal. EGFR and ALK testing was performed significantly more often in 2015. Despite this increase, there is room for improvement in a number of laboratories and hospitals, considering that some patients were possibly wrongly not eligible for targeted therapy