Tessa G Steenbruggen1, Erik van Werkhoven2, Mette S van Ramshorst3, Vincent O Dezentjé1, Marleen Kok4, Sabine C Linn5, Sabine Siesling6, Gabe S Sonke7. 1. Department of Medical Oncology, The Netherlands Cancer Institute, PO Box 90203, 1006 BE, Amsterdam, the Netherlands. 2. Department of Biometrics, The Netherlands Cancer Institute, PO Box 90203, 1006 BE, Amsterdam, the Netherlands. 3. Department of Medical Oncology, The Netherlands Cancer Institute, PO Box 90203, 1006 BE, Amsterdam, the Netherlands; Department of Internal Medicine, Onze Lieve Vrouwe Gasthuis, Postbus 95500, 1090 HM, Amsterdam, the Netherlands. 4. Department of Medical Oncology, The Netherlands Cancer Institute, PO Box 90203, 1006 BE, Amsterdam, the Netherlands; Department of Tumor Biology & Immunology, The Netherlands Cancer Institute, PO Box 90203, 1006 BE, Amsterdam, the Netherlands. 5. Department of Medical Oncology, The Netherlands Cancer Institute, PO Box 90203, 1006 BE, Amsterdam, the Netherlands; Department of Molecular Pathology, University Medical Center Utrecht, PO Box 85500, 3508 GA, Utrecht, the Netherlands. 6. Department of Research and Development, Netherlands Comprehensive Cancer Organisation, PO Box 19079, 3501 DB, Utrecht, the Netherlands; Department of Health Technology and Services Research, Technical Medical Centre, University of Twente, PO Box 217, 7500 AE, Enschede, the Netherlands. 7. Department of Medical Oncology, The Netherlands Cancer Institute, PO Box 90203, 1006 BE, Amsterdam, the Netherlands. Electronic address: g.sonke@nki.nl.
Abstract
BACKGROUND: Recommendations on adjuvant chemotherapy in pT1N0M0 triple-negative breast cancer (TNBC) differ among international guidelines owing to lack of randomized trial data. We evaluated associations of adjuvant chemotherapy with a long-term outcome in a population-based cohort of pT1N0M0 TNBC. METHODS: All patients diagnosed with pT1N0M0 TNBC in the Netherlands between 2005 and 2016 were identified from the Netherlands Cancer Registry. Patient, tumour and treatment characteristics were recorded. The date and cause of death were obtained from Statistics Netherlands. We used multivariable Cox regression models to evaluate associations of adjuvant chemotherapy with breast cancer-specific survival (BCSS) and overall survival (OS), adjusted for baseline characteristics and performed sensitivity analyses using propensity score (PS) weighting. RESULTS: We identified 4366 patients: 284 with pT1a, 923 with pT1b and 3159 with pT1c tumours. Adjuvant chemotherapy was administered in 53% of patients. Patients receiving chemotherapy had more unfavourable baseline characteristics including younger age, larger tumours and higher tumour grade. At 8.2 years median follow-up (interquartile range = 5.8-10.9), 671 patients had died, of whom 311 because of breast cancer. After adjustment for baseline characteristics, chemotherapy was associated with improved BCSS (adjusted hazard ratio [aHR] = 0.65; 95% confidence interval [CI] = 0.48-0.89). The effect of chemotherapy differed by tumour size (pT1a: aHR = 4.28, 95% CI = 1.12-16.44; pT1b: aHR = 1.12, 95% CI = 0.51-2.49; pT1c: aHR = 0.60, 95% CI = 0.43-0.82; pinteraction = 0.02). Findings for OS were in line with BCSS results. PS-weighting analysis confirmed the results of the primary analysis. CONCLUSIONS: Adjuvant chemotherapy is associated with better BCSS and OS in pT1N0M0 TNBC. Better outcome is most evident in pT1c tumours and may not outweigh harm in pT1a/pT1b tumours.
BACKGROUND: Recommendations on adjuvant chemotherapy in pT1N0M0 triple-negative breast cancer (TNBC) differ among international guidelines owing to lack of randomized trial data. We evaluated associations of adjuvant chemotherapy with a long-term outcome in a population-based cohort of pT1N0M0 TNBC. METHODS: All patients diagnosed with pT1N0M0 TNBC in the Netherlands between 2005 and 2016 were identified from the Netherlands Cancer Registry. Patient, tumour and treatment characteristics were recorded. The date and cause of death were obtained from Statistics Netherlands. We used multivariable Cox regression models to evaluate associations of adjuvant chemotherapy with breast cancer-specific survival (BCSS) and overall survival (OS), adjusted for baseline characteristics and performed sensitivity analyses using propensity score (PS) weighting. RESULTS: We identified 4366 patients: 284 with pT1a, 923 with pT1b and 3159 with pT1c tumours. Adjuvant chemotherapy was administered in 53% of patients. Patients receiving chemotherapy had more unfavourable baseline characteristics including younger age, larger tumours and higher tumour grade. At 8.2 years median follow-up (interquartile range = 5.8-10.9), 671 patients had died, of whom 311 because of breast cancer. After adjustment for baseline characteristics, chemotherapy was associated with improved BCSS (adjusted hazard ratio [aHR] = 0.65; 95% confidence interval [CI] = 0.48-0.89). The effect of chemotherapy differed by tumour size (pT1a: aHR = 4.28, 95% CI = 1.12-16.44; pT1b: aHR = 1.12, 95% CI = 0.51-2.49; pT1c: aHR = 0.60, 95% CI = 0.43-0.82; pinteraction = 0.02). Findings for OS were in line with BCSS results. PS-weighting analysis confirmed the results of the primary analysis. CONCLUSIONS: Adjuvant chemotherapy is associated with better BCSS and OS in pT1N0M0 TNBC. Better outcome is most evident in pT1c tumours and may not outweigh harm in pT1a/pT1b tumours.
Authors: Genevieve A Fasano; Solange Bayard; Yalei Chen; Leticia Varella; Tessa Cigler; Jessica Bensenhaver; Rache Simmons; Alexander Swistel; Jennifer Marti; Anne Moore; Eleni Andreopoulou; John Ng; Andrew Brandmaier; Silvia Formenti; Haythem Ali; Melissa Davis; Lisa Newman Journal: Breast Cancer Res Treat Date: 2022-01-13 Impact factor: 4.872