Takayuki Iwamoto1, Tomomi Fujisawa2, Tadahiko Shien3, Kazuhiro Araki4, Kentaro Sakamaki5, Takafumi Sangai6, Yuichiro Kikawa7, Shintaro Takao8, Reiki Nishimura9, Masato Takahashi10, Tomohiko Aihara11, Hirofumi Mukai12, Naruto Taira3. 1. Department of Breast and Endocrine Surgery, Okayama University Hospital, 2-5-1 Shikata-cho, Kita-ku, Okayama, 700-8558, Japan. tiwamoto@md.okayama-u.ac.jp. 2. Department of Breast Oncology, Gunma Prefectural Cancer Center, Gunma, Japan. 3. Department of Breast and Endocrine Surgery, Okayama University Hospital, 2-5-1 Shikata-cho, Kita-ku, Okayama, 700-8558, Japan. 4. Department of Medical Oncology, Gunma Prefectural Cancer Center, Gunma, Japan. 5. Department of Biostatistics and Bioinformatics, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan. 6. Department of Breast and Thyroid Surgery, Chiba University Hospital, Chiba, Japan. 7. Department of Breast Surgery, Kobe City Medical Center General Hospital, Kobe, Japan. 8. Department of Breast Surgery, Hyogo Cancer Center, Hyogo, Japan. 9. Department of Breast Oncology, Kumamoto Shinto General Hospital, Kumamoto, Japan. 10. Department of Breast Surgery, National Hospital Organization Hokkaido Cancer Center, Hokkaido, Japan. 11. Breast Center, Aihara Hospital, Osaka, Japan. 12. Division of Breast and Medical Oncology, National Cancer Center Hospital East, Kashiwa, Japan.
Abstract
PURPOSE: Second-line endocrine therapy (ET) for estrogen receptor (ER)-positive and human epidermal growth factor 2 (HER2)-negative metastatic breast cancer (MBC) is offered based on the response to first-line ET. However, no clinical trials have evaluated the efficacy and safety of secondary ETs in patients with poor responses to initial ET. This study evaluated the efficacy of second-line ET in ER-positive and HER2-negative postmenopausal MBC patients with low or very low sensitivity to initial ET. METHODS: This multicenter prospective observational cohort study evaluated the response of 49 patients to second-line ETs in postmenopausal MBC patients with low or very low sensitivity to initial ET. The primary endpoint was the clinical benefit rate (CBR) for 24 weeks. RESULTS: Of the 49 patients assessed, 40 (82%) received fulvestrant in the second line, 5 (10%) received selective estrogen receptor modulators, 3 (6%) received aromatase inhibitors (AIs) alone, and 1 received everolimus with a steroidal AI. The overall CBR was 44.9% [90% confidence interval (CI): 34.6-57.6, p = 0.009]; CBR demonstrated similar significance across the progesterone receptor-positive (n = 39, 51.3%, 90% CI: 39.6-65.2, p = 0.002), very low sensitivity (n = 17, 58.8%, 90% CI: 42.0-78.8, p = 0.003), and non-visceral metastases (n = 25, 48.0%, 90% CI: 34.1-65.9, p = 0.018) groups. The median progression-free survival was 7.1 months (95% CI: 5.6-10.6). CONCLUSION: Second-line ET might be a viable treatment option for postmenopausal patients with MBC with low and very low sensitivity to initial ET. Future studies based on larger and independent cohorts are needed to validate these findings.
PURPOSE: Second-line endocrine therapy (ET) for estrogen receptor (ER)-positive and human epidermal growth factor 2 (HER2)-negative metastatic breast cancer (MBC) is offered based on the response to first-line ET. However, no clinical trials have evaluated the efficacy and safety of secondary ETs in patients with poor responses to initial ET. This study evaluated the efficacy of second-line ET in ER-positive and HER2-negative postmenopausal MBCpatients with low or very low sensitivity to initial ET. METHODS: This multicenter prospective observational cohort study evaluated the response of 49 patients to second-line ETs in postmenopausal MBCpatients with low or very low sensitivity to initial ET. The primary endpoint was the clinical benefit rate (CBR) for 24 weeks. RESULTS: Of the 49 patients assessed, 40 (82%) received fulvestrant in the second line, 5 (10%) received selective estrogen receptor modulators, 3 (6%) received aromatase inhibitors (AIs) alone, and 1 received everolimus with a steroidal AI. The overall CBR was 44.9% [90% confidence interval (CI): 34.6-57.6, p = 0.009]; CBR demonstrated similar significance across the progesterone receptor-positive (n = 39, 51.3%, 90% CI: 39.6-65.2, p = 0.002), very low sensitivity (n = 17, 58.8%, 90% CI: 42.0-78.8, p = 0.003), and non-visceral metastases (n = 25, 48.0%, 90% CI: 34.1-65.9, p = 0.018) groups. The median progression-free survival was 7.1 months (95% CI: 5.6-10.6). CONCLUSION: Second-line ET might be a viable treatment option for postmenopausal patients with MBC with low and very low sensitivity to initial ET. Future studies based on larger and independent cohorts are needed to validate these findings.
Entities:
Keywords:
Endocrine therapies; Estrogen receptor-positive; HER2-negative; Metastatic breast cancer; Resistance
Authors: Laura Testa; Max Mano; Roberto Jun Arai; Renata Colombo Bonadio; Sergio V Serrano; Marina M Costa Zorzetto; Susanne Crocamo; Oren Smaletz; Ruffo Freitas-Junior; Paulo M Hoff Journal: Clinics (Sao Paulo) Date: 2021-10-11 Impact factor: 2.365