Tumor size and grade associated with long-term survival after tamoxifen treatment in ER + / ERBB2- breast cancer
According to the results of a 25-year survival assessment published in JAMA network open.
Researchers identified a statistically significant difference in Distant Recurrence Free Interval (DRFI) by tumor size, including T1a / b (88%), T1c (76%), and T2 (63%) tumors; log -rank P<.001 similar differences in drfi by tumor grade were noted for and log-rank>P = .02) tumors. Progesterone receptor (PR) status and Ki-67 expression were not found to be statistically significant with the DRFI results.
“This secondary analysis of data from the Stockholm Randomized Tamoxifen (STO-3) clinical trial, examined whether clinically [utilized]]Breast cancer markers were independently associated with long-term survival and the benefit of tamoxifen therapy. The results indicated that, among this selected subgroup, tumor size and grade were associated with long-term survival, and a significant benefit of tamoxifen treatment was observed in patients with larger tumors, lower tumor grades and PR-positive tumors, ”study investigators wrote.
The study included 565 postmenopausal women with a diagnosis of ER-positive / ERBB2-negative breast cancer. In this population, 520 (92.0%) patients had complete information on the characteristics of their tumor. Of 559 patients, 168 (30.0%) had tumors of size T1a / b, 292 (52.2%) had T1c and 99 (17.7%) had T2 at primary diagnosis. Of 557 patients, 128 (23.0%) had grade 1 tumors, 361 (64.8%) had grade 2 and 68 (12.2%) had grade 3.
Investigators used Cox proportional hazards survival analysis to predict long-term survival. A significant reduction in the long-term risk of distant recurrence was identified in patients with smaller tumors (T1a / b and T1c) compared to larger tumors (T2; T1a / b tumors: HR: 0.31 ; 95% CI: 0.17-0.55; T1c tumors: HR, 0.58; 95% CI: 0.38-0.88).
Patients with grade 1 tumors had a reduced risk of long-term recurrence compared to grade 3 tumors (RR: 0.48; 95% CI: 0.24-0.95). When comparing grade 2 and grade 3 tumors, there was no statistical difference in long-term DRFI.
Patients with T1c tumors who received tamoxifen had a statistically significant reduction in the long-term risk of distant recurrence (RR: 0.53; 95% CI, 0.32-0.89), as did those with T2 tumors (RR: 0.34; 95% CI, 0.16-0.73). However, this was not observed in patients with smaller tumors (T1a / b) compared to patients who did not receive adjuvant therapy. In addition, patients who received tamoxifen compared to those who did not experience a significant reduction in long-term risk of distant recurrence (RR: 0.24; 95% CI: 0.07-0, 82) for grade 1 tumors and (RR: 0.50; 95% CI, 0.31-0.80) for grade 2 tumors. There was no significant benefit for grade 3 tumors .
PR-positive patients who received tamoxifen had a reduced risk of long-term distant recurrence compared to those who did not receive adjuvant therapy (RR: 0.38; 95% CI: 0, 24-0.62). People with PR-negative disease have experienced no noticeable long-term therapeutic benefit. In addition, patients who took tamoxifen had moderate to high results. Ki-67 expression (HR, 0.39; 95% CI, 0.17-0.92) and a low Ki-67 (HR, 0.45; 95% CI: 0.29-0.71) had a reduced long-term risk compared to those in the untreated arm.
“The results of this analysis suggest that tumor size is associated with the long-term risk of distant recurrence, independent of other markers used clinically in patients with lymph node, ER-positive breast cancer. ERBB2-negative, ”the researchers concluded. .
Dar H, Johansson A, Nordenskjöld A, et al. Assessment of 25-year survival of women with estrogen receptor positive / ERBB2-negative breast cancer treated with and without tamoxifen treatment: a secondary analysis of data from the Stockholm Randomized Tamoxifen Trial . JAMA Netw Open. 2021; 4 (6): e2114904. doi: 10.1001 / jamanetworkopen.2021.14904