Azambuja, Evandro de

Abstract Background: Invasive lobular carcinoma (ILC) accounts for up to 15% of breast cancer (BC) cases and has distinct clinical and biological features compared to invasive carcinoma of no special type (IBC-NST). Prior studies, including PENELOPE-B, suggested greater benefit from adjuvant palbociclib (palbo) in ILC. We assessed the prognostic and predictive value of histology in patients (pts) treated with endocrine therapy (ET) ± palbo. Methods: PALLAS is a global, phase III trial in which pts with stage II-III, HR+/HER2− BC were randomized to 2 years (y) of adjuvant palbo + ET or ET alone. Pts with IBC-NST or pure ILC per local pathology assessment were included. Endpoints included invasive disease-free (IDFS; primary), distant recurrence-free (DRFS), locoregional recurrence-free (LRRFS), and overall survival (OS). Prognostic value was assessed using univariable and multivariate Cox models adjusted for age, T and N stage, grade, and progesterone receptor. Predictive value was assessed using histology-by-treatment interactions. Results: Among 5,748 pts in the ITT population, 4,982 (87%) were included (3,838 IBC-NST [67%], 1,144 ILC [20%]); median follow-up 6.9y. Compared with IBC-NST, ILC was associated with older age (median 54 vs 51 y), higher T stage (T3/T4: 41.7% vs 20.4%), fewer grade 3 tumors (12.7% vs 33.5%), higher mastectomy rates (74.5% vs 58.4%), less (neo)adjuvant chemotherapy (72.2% vs 86.2%), and less tamoxifen as initial ET (28.8% vs 34.5%) (all p<0.001). ILC prevalence varied by country: lower in Asia (Japan 10.5%, Korea 0%, Taiwan 2.8%) and higher in Europe (23.1%) and North America (24.0%). When evaluating the predictive value, palbo appeared to confer greater benefit in ILC for all endpoints (HRs ranging from 0.41 to 0.86) and not in IBC-NST (HRs ranging from 0.97 to 1.01), although the histology-by-treatment interaction was significant only for LRRFS (Table). In the overall population, 7-year IDFS was 79.3% for IBC-NST and 75.8% for ILC. While the difference was significant in univariable analysis (HR 1.17, 95% CI 1.01-1.35), it was not in multivariable analysis (HR 1.06, 0.91-1.24). Notably, the proportional hazards assumption was violated, and time-dependent modeling demonstrated that worse outcomes for ILC on IDFS, DRFS, and other endpoints emerged predominantly beyond 3 years. Conclusions: In this large, randomized dataset of pts with early HR+/HER2− breast cancer with long-term follow-up, ILC demonstrated distinct clinicopathologic features and geographic distribution. While ILC was not an independent prognostic factor over the entire follow-up, time-dependent modeling revealed worse long-term outcomes which only emerged after 3 years. Palbo appeared to be associated with more favorable outcomes in ILC than in IBC-NST across endpoints. These findings suggest a potential benefit of palbo in ILC that warrants further investigation in other adjuvant trials evaluating CDK4/6 inhibitors. Citation Format: G. Nader-Marta, C. Desmedt, D. Hlauschek, A. DeMichele, G. Zoppoli, E. Blondeaux, E. de Azambuja, M. Bellet-Ezquerra, O. Metzger-Filho, J. M. Suga, G. Pfeiler, M. P. Goetz, M. Ruiz-Borrego, S. Loibl, J. Meisel, A. Ring, K. Van Baelen, E. P. Mamounas, N. Zdenkowski, E. Agostinetto, M. Lambertini, E. Gauthier, L. Soelkner, A. C. Dueck, M. Gnant, E. L. Mayer. Long-term prognostic and predictive value of lobular histology in the PALLAS trial [abstract]. In: Proceedings of the San Antonio Breast Cancer Symposium 2025; 2025 Dec 9-12; San Antonio, TX. Philadelphia (PA): AACR; Clin Cancer Res 2026;32(4 Suppl):Abstract nr PS3-11-06.

ImportanceYoung women with breast cancer who have germline pathogenic variants in BRCA1 or BRCA2 face unique challenges regarding fertility. Previous studies demonstrating the feasibility and safety of pregnancy in breast cancer survivors included limited data regarding BRCA carriers.ObjectiveTo investigate cumulative incidence of pregnancy and disease-free survival in young women who are BRCA carriers.Design, Setting, and ParticipantsInternational, multicenter, hospital-based, retrospective cohort study conducted at 78 participating centers worldwide. The study included female participants diagnosed with invasive breast cancer at age 40 years or younger between January 2000 and December 2020 carrying germline pathogenic variants in BRCA1 and/or BRCA2. Last delivery was October 7, 2022; last follow-up was February 20, 2023.ExposurePregnancy after breast cancer.Main Outcomes and MeasuresPrimary end points were cumulative incidence of pregnancy after breast cancer and disease-free survival. Secondary end points were breast cancer–specific survival, overall survival, pregnancy, and fetal and obstetric outcomes.ResultsOf 4732 BRCA carriers included, 659 had at least 1 pregnancy after breast cancer and 4073 did not. Median age at diagnosis in the overall cohort was 35 years (IQR, 31-38 years). Cumulative incidence of pregnancy at 10 years was 22% (95% CI, 21%-24%), with a median time from breast cancer diagnosis to conception of 3.5 years (IQR, 2.2-5.3 years). Among the 659 patients who had a pregnancy, 45 (6.9%) and 63 (9.7%) had an induced abortion or a miscarriage, respectively. Of the 517 patients (79.7%) with a completed pregnancy, 406 (91.0%) delivered at term (≥37 weeks) and 54 (10.4%) had twins. Among the 470 infants born with known information on pregnancy complications, 4 (0.9%) had documented congenital anomalies. Median follow-up was 7.8 years (IQR, 4.5-12.6 years). No significant difference in disease-free survival was observed between patients with or without a pregnancy after breast cancer (adjusted hazard ratio, 0.99; 95% CI, 0.81-1.20). Patients who had a pregnancy had significantly better breast cancer–specific survival and overall survival.Conclusions and RelevanceIn this global study, 1 in 5 young BRCA carriers conceived within 10 years after breast cancer diagnosis. Pregnancy following breast cancer in BRCA carriers was not associated with decreased disease-free survival.Trial RegistrationClinicalTrials.gov Identifier: NCT03673306

Background: The potential gonadotoxicity of anti-HER2 agents remains largely unknown, and limited, conflicting evidence exists for taxanes. Antimüllerian hormone (AMH) is an established biomarker of ovarian reserve that may aid in quantifying anticancer treatment–induced gonadotoxicity. Patients and Methods: The present biomarker analysis of the randomized phase III neoadjuvant NeoALTTO trial included premenopausal women aged ≤45 years at diagnosis of HER2-positive early breast cancer with available frozen serum samples at baseline (ie, before anticancer treatments), at week 2 (ie, the “biological window” of anti-HER2 therapy alone), and/or at the time of surgery (ie, after completing paclitaxel + anti-HER2 therapy, before starting adjuvant chemotherapy). Results: The present analysis included 130 patients with a median age of 38 years (interquartile ratio [IQR], age 33–42 years). AMH values at the 3 time points differed significantly (P<.001). At baseline, median AMH levels were 1.29 ng/mL (IQR, 0.56–2.62 ng/mL). At week 2, a small but significant reduction in AMH levels was observed (median, 1.10 ng/mL; IQR, 0.45–2.09 ng/mL; P<.001). At surgery, a larger significant decline in AMH levels was observed (median, 0.01 ng/mL; IQR, 0.01–0.03 ng/mL; P<.001). Although the type of anti-HER2 treatment (trastuzumab and/or lapatinib) did not seem to impact the results, age and pretreatment ovarian reserve had a major influence on treatment-induced gonadotoxicity risk. Conclusions: This NeoALTTO biomarker analysis showed that anti-HER2 therapies alone had limited gonadotoxicity but that the addition of weekly paclitaxel resulted in marked AMH decline with possible negative implications for subsequent ovarian function and fertility.

522 Background: Our preclinical findings suggest a role for the mevalonate pathway (MVA) in treatment resistance in HER2+ BC by providing alternative growth and survival signaling to bypass potent HER2 blockade, which could be overcome by the MVA inhibitors statins and nitrogen-containing bisphosphonates (NBs). Here we explored the effect of MVA inhibitors’ use on pts’ outcomes in the ALTTO trial (BIG2-06; NCT00490139). Methods: In the ALTTO trial, 8381 pts with HER2+ BC were randomized to 1 year of adjuvant lapatinib (L), trastuzumab (T), L+T, or T→L. All pts with documented treatment start with statins or NBs < 1 year after randomization were considered as MVA inhibitors users. Survival curves, with a median follow-up of 6.9 years, for disease-free survival (DFS), distant relapse-free interval (DRFI), BC-specific survival (BCSS), and overall survival (OS) according to MVA inhibitors use were estimated by the Kaplan Meier method and Log-rank test. All multivariate survival analyses employed a Cox proportional hazards regression model, adjusting for tumor size, nodal status, hormonal receptor (HoR), menopausal status, BMI, timing of chemo, and randomization arm. We considered interactions terms in Cox’s model between MVA inhibitors use and randomization arm, hormonal status, and BMI group. Results: Among the 8381 pts included in this study, 493 and 299 were statins or NBs users, respectively. Table 1 summarizes the significant differences in pts’ characteristics according to MVA inhibitors use ( P <.005). In multivariate survival analyses, only NBs use was associated independently with better BCSS (HR, 0.44; 95% CI, 0.23 - 0.84; P = 0.014). Statin use was not independently associated with prognosis but only in interaction with pts characteristics: worse DFS, BCSS and OS in pts treated with L+T, worse DRFI and OS in pts treated with HoR+ BC (respective interaction P-values <0.05 in the Cox’s model). Conclusions: NBs independently predicted improved BC-specific outcome in pts with HER2+ BC treated with adjuvant anti-HER2 therapy. Statin use was associated with an inferior outcome in pts with HoR+ disease and/or those treated with L+T. Whether this inferior association in statin users may reflect the underlying predisposition factors that can weaken the efficacy of anti-HER2 treatments and whether this effect was observed only in the L+T arm due to the more potent inhibition of the HER2 signaling pathway remain open questions. Further clinical investigations on the impact of MVA inhibitors on the outcome of pts with HER2+ BC are warranted. [Table: see text]

Abstract Background: Knowledge regarding risk of treatment-induced premature ovarian insufficiency (POI) is crucial for appropriate oncofertility counseling. While the gonadotoxicity of anthracycline- and cyclophosphamide-based chemotherapy (CT) in young breast cancer (BC) patients (pts) is well established, the impact of anti-HER2 agents remains largely unknown and limited conflicting evidence exists for taxanes. Anti-Mullerian hormone (AMH) is an established biomarker of ovarian reserve; its measurements during systemic therapies may aid in diagnosis and prediction of POI. The NeoALTTO trial represented a unique setting to explore the acute gonadotoxicity of anti-HER2 therapy alone and in combination with weekly paclitaxel in pts not previously exposed to any other potentially gonadotoxic anticancer treatment. Methods: NeoALTTO (NCT00553358) is a multicenter, open-label, randomized phase III neoadjuvant trial in HER2-positive early BC pts randomized to receive lapatinib (L), trastuzumab (T), or their combination (L+T) alone for 6 weeks followed by the addition of paclitaxel for 12 weeks before surgery.The present analysis included only premenopausal women aged ≤45 years with available frozen serum samples at baseline (i.e. before administering any anticancer treatment), at week 2 (i.e. “biological window” of anti-HER2 therapy alone) and/or at surgery (i.e. after completion of paclitaxel plus anti-HER2 therapy). Central AMH testing was performed at Erasme Hospital (Brussels, Belgium) with the Roche Elecsys® AMH Plus assay (LoD=0.010 ng/ml). AMH levels during anti-HER2 therapy alone and then combined with paclitaxel were assessed as a measure of treatment impact on ovarian reserve. The impact of different anti-HER2 agents (T and/or L), pts’ age and baseline AMH levels on treatment gonadotoxicity were also investigated. Results: The present analysis included 130 pts with a median age of 38 years (IQR: 33-42 years), of whom 86 (66.2%) were ≤40 years. At baseline, median AMH levels were 1.29 ng/mL (IQR 0.56 - 2.62 ng/mL). At week 2, a small but significant reduction in AMH levels was observed (median value: 1.10 ng/mL, IQR 0.45 - 2.09 ng/mL, p&lt;0.001; median cumulative decrease: -12.5%, IQR -37.6% - 12.4%). At surgery, there was a large significant decline in AMH levels (median value: 0.01 ng/mL, IQR 0.01 - 0.03 ng/mL, p&lt;0.001; median cumulative decrease: -99.9%, IQR -100.0% - -98.7%). Type of anti-HER2 treatment (L vs. L vs. T+L) did not impact the results: there was no significant difference between treatment arms in degree of reduction in AMH levels at week 2 (p=0.763) or at surgery (p=0.700). Age and pre-treatment ovarian reserve had a major impact on treatment-induced gonadotoxicity risk, with a more profound decrease in AMH levels observed for older pts (p&lt;0.001) and those with lower baseline AMH levels (p&lt;0.001). Among pts aged &lt;35 years, there was no significant difference in AMH levels between those with (n=7) or without (n=35) a subsequent pregnancy at baseline (p=0.316), week 2 (p=0.463) or at surgery (p=0.610). Conclusions: This biomarker analysis of the NeoALTTO trial showed for the first time the potential acute gonadal damage induced by anti-HER2 therapies alone and with the addition of weekly paclitaxel. We observed a small but significant reduction in AMH levels during T and/or L alone and then a profound reduction to almost undetectable levels following the addition of weekly paclitaxel, without differences by specific anti-HER2 regimen. Age and pre-treatment AMH levels strongly impacted gonadotoxicity risk. While this analysis is limited by lack of AMH measurement in longer term follow-up, findings have important implications for future research and oncofertility counseling of premenopausal women with HER2-positive BC. Citation Format: Matteo Lambertini, Marcello Ceppi, Richard A. Anderson, David A. Cameron, Marco Bruzzone, Maria Alice Franzoi, Claudia Massarotti, Sarra El-Abed, Yingbo Wang, Christophe Lecocq, Paolo Nuciforo, Rebecca Rolyance, Lajos Pusztai, Joohyuk Sohn, Jacopo Ligato, Maria Maddalena Latocca, Luca Arecco, Barbara Pistilli, Kathryn J. Ruddy, Alberto Ballestrero, Lucia Del Mastro, Fedro A. Peccatori, Ann H. Partridge, Cristina Saura, Michael Untch, Martine Piccart, Serena Di Cosimo, Evandro de Azambuja, Isabelle Demeestere. Impact of anti-HER2 therapy alone and in association with weekly paclitaxel on the ovarian reserve of young women with HER2-positive early breast cancer: Biomarker analysis of the NeoALTTO trial [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr PD5-05.

Abstract Background: The erythropoietin (EPO) receptor activation can stimulate tumor proliferation and may be implicated in resistance to anti-HER2 therapies. EPO administration can be used for the management of chemotherapy-induced anemia. We aim to assess if EPO intake during the adjuvant anti-HER2 treatment impacts the outcomes of HER2-positive early breast cancer (EBC) patients. Methods: For this post hoc analysis of the ALTTO trial (NCT00490139), we categorized two cohorts according to the use of EPO during adjuvant anti-HER2 treatment: i) at least one EPO dose (EPO-cohort) vs ii) no EPO (non-EPO-cohort). We compared their baseline characteristics to identify potential confounders. The primary endpoint disease-free-survival (DFS), and the secondary endpoint overall survival (OS) were compared between these two cohorts, with subgroup analysis according to menopausal status, tumor characteristics, and anti-HER2 treatment. Kaplan Meier method, log-rank test, and Cox regression model adjusted for confounders were performed for DFS and OS (removal criterion p&lt;0.10). The frequency of cardiovascular and thromboembolic adverse events (AEs) of EPO interest was compared between both cohorts. Results: Out of the 8,381 patients recruited in the ALTTO trial, 123 (1.5%) received EPO concomitantly with adjuvant treatment, 59 in the single HER2 blockade (Lapatinib (L)-alone or Trastuzumab (T)-alone) and 64 in dual blockade (T→L or T+L) arms. The median age of EPO-cohort patients was 54 (range: 27-74) years, and 39% were premenopausal, while most had pathologic tumor size &gt;2 cm (56.9%), positive nodal status (58.5%), positive hormone receptor (HR) status (61.8%), and poorly differentiated or undifferentiated histologic grade (64.2%). Baseline characteristics were similar in both cohorts, except for the timing of chemotherapy, for which 93.5% of patients from the EPO-cohort were enrolled in the concurrent designs (2/2B) vs 44.2% in the non-EPO-cohort (p&lt;0.001). Median FU was 6.9 years, with 6,409 (76.5%) patients still on follow-up. For the entire ALTTO cohort, the estimated 3- and 7-year DFS were 88.3% (95% CI: 87.6% - 89.0%) and 80.1% (95% CI: 79.1% - 81.0%), respectively. No difference in DFS by EPO administration (Yes/No) was observed (log-rank p=0.70). The effect of EPO remained non-significant when controlled for the four stratification factors and all other characteristics (p=0.91). The effect of EPO administration on DFS was significant for the subgroup of premenopausal women (p=0.041), favoring the EPO-cohort, noting that this result is based on small event numbers. The interaction was found significant in Cox analysis (p=0.024), remaining significant after adjustment for important prognostic variables (p=0.032). For the entire ALTTO cohort, 758 (9.0%) deaths occurred, with 3-year OS estimate 95.7% (95% CI: 95.2% - 96.1%) and 7-year OS estimate 89.9% (89.2% - 90.6%). The OS results are consistent with those for DFS regarding the lack of a significant association with EPO and the significance (p&lt;0.10) of menopausal status and EPO interaction. In the EPO-cohort (n=123), eight (6.5%) AEs of EPO interest were recorded, while from the non-EPO-cohort (n=8,147), 417 (5.1%) reported similar AEs. Three fatal and 25 life-threatening AEs of EPO interest were recorded in the non-EPO-cohort, and none in the EPO-cohort. Conclusion: EPO administration to patients receiving adjuvant anti-HER2 treatment for HER2-positive EBC was safe and not associated with a harmful impact on survival outcomes, however the sample size of patients who received EPO is rather small. These findings contrast with data suggesting poorer outcomes with EPO, therefore further investigation of tumour microenvironment is needed to better understand these results, particularly in the premenopausal subgroup. Citation Format: Diogo Martins-Branco, Marie Kassapian, Véronique Debien, Rafael Caparica, Daniel Eiger, Urania Dafni, Charitini Andriakopoulou, Sarra El-Abed, Miguel Izquierdo, Malou Vicente, Saranya Chumsri, Martine Piccart-Gebhart, Alvaro Moreno-Aspitia, Ann Søegaard Knop, Janine Lombard, Evandro de Azambuja. The impact of erythropoietin administration concomitantly with adjuvant anti-HER2 treatment on the patients’ outcome: Sub-analysis of the ALTTO study [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P1-14-05.

PURPOSE Many patients and physicians remain concerned about the potential detrimental effects of pregnancy after breast cancer (BC) in terms of reproductive outcomes and maternal safety. This systematic review and meta-analysis aimed at providing updated evidence on these topics. METHODS A systematic literature review was conducted to identify studies including patients with a pregnancy after BC (PROSPERO number CRD42020158324). Likelihood of pregnancy after BC, their reproductive outcomes, and maternal safety were assessed. Pooled relative risks, odds ratios (ORs), and hazard ratios (HRs) with 95% CIs were calculated using random effects models. RESULTS Of 6,462 identified records, 39 were included involving 8,093,401 women from the general population and 112,840 patients with BC of whom 7,505 had a pregnancy after diagnosis. BC survivors were significantly less likely to have a subsequent pregnancy compared with the general population (relative risk, 0.40; 95% CI, 0.32 to 0.49). Risks of caesarean section (OR, 1.14; 95% CI, 1.04 to 1.25), low birth weight (OR, 1.50; 95% CI, 1.31 to 1.73), preterm birth (OR, 1.45; 95% CI, 1.11 to 1.88), and small for gestational age (OR, 1.16; 95% CI, 1.01 to 1.33) were significantly higher in BC survivors, particularly in those with previous chemotherapy exposure, compared with the general population. No significantly increased risk of congenital abnormalities or other reproductive complications were observed. Compared to patients with BC without subsequent pregnancy, those with a pregnancy had better disease-free survival (HR, 0.66; 95% CI, 0.49 to 0.89) and overall survival (HR, 0.56; 95% CI, 0.45 to 0.68). Similar results were observed after correcting for potential confounders and irrespective of patient, tumor, and treatment characteristics, pregnancy outcome, and timing of pregnancy. CONCLUSION These results provide reassuring evidence on the safety of conceiving in BC survivors. Patients' pregnancy desire should be considered a crucial component of their survivorship care plan.

524 Background: PREDICT+ is a widely used, free, online tool based on traditional clinico-pathological features, including HER2, developed to predict individual mortality of EBC pts and to aid clinical decision making for adjuvant therapy. However, its prognostic role in HER2+ EBC pts treated with chemotherapy (CT) and anti-HER2 therapies remains unclear. We aimed to investigate the prognostic performance of PREDICT+ in HER2+ EBC pts enrolled in the ALTTO trial. Methods: ALTTO is a phase III study evaluating adjuvant lapatinib (L) +/- trastuzumab (T) vs. T alone in pts with HER2+ EBC. Pts enrolled in the ALTTO trial and receiving T-based therapy started concurrently with CT were eligible for this analysis. We calculated PREDICT+ estimates using variables extracted from ALTTO database, blinded to pts outcomes. The prognostic performance of PREDICT+ was evaluated by assessing its calibration and discriminatory accuracy. For calibration, median predicted 5-year (5-yr) overall survival (OS) was compared to observed 5-yr OS. For discriminatory accuracy, the area under the receiver-operator characteristic (AUC under the ROC) curve and corresponding 95% confidence intervals (CI) for predicted 5-yr OS were calculated. Subgroup analyses were performed according to type of anti-HER2 therapy, type of CT, age, hormone receptor (HR) status, nodal status and tumor size. Results: This analysis included 2,794 pts. After a median follow-up of 6.0 years (IQR, 5.8-6.7), 182 deaths were observed. Overall, PREDICT+ underestimated 5-yr OS by 6.7% (95% CI, 5.8-7.6): observed 5-year OS was 94.7% vs. predicted 88.0%. The underestimation was consistent across all subgroups (Table). For discriminatory accuracy, AUC under the ROC curve was 73.7% (95%CI 69.7-77.8) in the overall population, ranging between 61.7% and 77.7% across the analysed subgroups. Conclusions: In HER2+ EBC pts enrolled in the ALTTO trial, the PREDICT+ score highly underestimated OS. The low performance of this prognostic tool was consistent across all pts subgroups. PREDICT+ should be used with caution to give prognostic estimation in HER2+ EBC pts treated in the modern era with effective chemotherapy and anti-HER2 targeted therapies.[Table: see text]

Abstract Background: In HER2-positive breast cancer patients, timing from the end of (neo)adjuvant trastuzumab (T)-based therapy to diagnosis of metastatic breast cancer is the key factor in determining the optimal first-line treatment. There is currently lack of clear evidence to support the possible prognostic role of this interval and 12 months has been mostly empirically used. The present analysis aimed to investigate patterns of relapse, first-line choice and survival outcomes of patients with HER2-positive early breast cancer who relapsed after adjuvant T-based therapy depending on T-free interval (TFI, i.e. timing from end of adjuvant T to diagnosis of distant metastases). Methods: In ALTTO, HER2-positive early breast cancer patients were randomized to 1 year of either T alone, lapatinib (L) alone, their sequence (T–&gt;L) or their combination (T+L). This exploratory analysis included only pts in the T or T+L arms who experienced a distant disease-free survival (DDFS) event. Two cohorts of patients were defined depending on TFI: group A (TFI of &lt;12 months) and group B (&gt;12 months). Baseline characteristics, patterns of relapse, first-line choice and overall survival (OS) were compared. OS was defined as time between date of DDFS event to death; age at diagnosis, tumor size and hormone receptor status were the variables included in the final multivariate models. Results: Out of 8,381 patients included in ALTTO, 404 patients in the T and T+L arms developed a DDFS event, of whom 201 occurred &lt;12 months (group A) and 203 &gt;12 months (group B) after the end of adjuvant T. Patients in group A were older (p=0.013), had larger tumors (p=0.004) and more frequently hormone receptor-negative disease (p&lt;0.001). No significant difference in patterns of first DDFS event was observed (p=0.073); however, a numerically higher number of patients in group A compared to group B developed brain metastasis (26% vs. 15%). First-line anti-HER2 therapy was received by 57% of the patients. Choice of first-line anti-HER2 therapy was different between the two groups (p=0.022): the majority of patients received T in both groups (61% vs. 65% in groups A and B, respectively), while more patients in group A received L (25% vs. 11%) and less received pertuzumab (8% vs. 17%). OS survival was significantly shorter in group A compared to group B: median OS was 18.4 and 29.3 months in groups A and B, respectively (adjusted HR 0.69; 95% CI 0.54-0.89; p=0.004). Similar results were observed after the exclusion of patients treated with first-line pertuzumab-based therapy (n=29): median OS was 18.2 and 26.8 months in groups A and B, respectively (adjusted HR 0.66; 95% CI 0.51-0.86; p=0.002). Better outcomes in terms of OS for patients in group B was observed across all analyzed subgroups with no interaction according to hormone receptor status (p=0.814) nor type of adjuvant anti-HER2 treatment (p=0.233): hormone receptor-positive (adjusted HR 0.69; 95% CI 0.48-0.99), hormone receptor-negative (adjusted HR 0.68; 95% CI 0.48-0.98), T+L arm (adjusted HR 0.55; 95% CI 0.38-0.80) and T arm (adjusted HR 0.80; 95% CI 0.55-1.17). Conclusions: In the ALTTO trial, HER2-positive early breast cancer patients who experienced shorter TFI (i.e. &lt;12 months vs. &gt;12 months) following adjuvant T-based therapy had inferior OS after the diagnosis of distant recurrence. Given its prognostic value, TFI can help to individualize clinical recommendations and to design future trials in the metastatic setting for patients relapsing after prior exposure to anti-HER2 therapy for early disease. Citation Format: Matteo Lambertini, Dominique Agbor-Tarh, Otto Metzger-Filho, Noam Ponde, Francesca Poggio, Florentine Hilbers, Larissa A Korde, Saranya Chumsri, Olena Werner, Lucia Del Mastro, Rafael Caparica, Volker Moebus, Alvaro Moreno-Aspitia, Martine Piccart, Evandro de Azambuja. Prognostic role of distant disease-free interval from completion of adjuvant trastuzumab in HER2-positive early breast cancer: Analysis from the ALTTO (BIG 2-06) trial [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PD3-04.

Abstract Background: Pregnancy-related issues are a priority for young breast cancer (BC) patients. Increasing evidence has shown that pregnancy after prior BC diagnosis is feasible. Nevertheless, few BC survivors conceive following anticancer treatment completion and many physicians remain concerned about the potentially detrimental effects of pregnancy after BC in terms of fetal/obstetrical outcomes and maternal prognosis. This systematic review and meta-analysis aims at providing updated and solid evidence on these important issues. Methods: A systematic literature review up to January 31, 2020 with no language restriction was conducted to identify studies including patients with a pregnancy after prior BC diagnosis. Chances of pregnancy after BC, fetal and obstetrical outcomes, disease-free survival (DFS) and overall survival (OS) were assessed. Pooled relative risks (RRs), hazard ratios (HRs) or odds ratio (ORs) with 95% confidence intervals (CI) were calculated using the random effects models. The study is registered with the PROSPERO registration number CRD42020158324. Results: Overall, 39 studies were included. Out of the 8,265,713 young women included in these studies, 8,093,401 were from the general population, 57,739 had cancers other than BC, 114,573 had BC. Among the 114,573 BC patients, 7,505 had a pregnancy after BC diagnosis and 107,068 did not. Compared to women from the general population, BC patients had 60% reduced chances of having a pregnancy following anticancer treatment completion (RR 0.40, 95% CI 0.32-0.49). Among other cancer patients, only women with prior cervical cancer had lower pregnancy rates (RR 0.33, 95% CI 0.31-0.35) than BC patients. Compared to the general population, BC survivors had significantly increased risks of low birth weight (OR 1.50, 95% CI 1.31-1.73), small for gestational age (OR 1.16, 95% CI 1.01-1.33), preterm delivery (OR 1.45, 95% CI 1.11-1.88) and caesarean section (OR 1.14, 95% CI 1.04-1.25). No significant increased risk of congenital abnormalities (OR 1.63, 95% CI 0.89-2.98) or other pregnancy or delivery complications (spontaneous or induced abortion, gestosis, antepartum or postpartum hemorrhage) was observed. Prior chemotherapy exposure or short pregnancy interval (defined as &lt;2 or &lt;5 years after BC diagnosis) were not associated with additional increased risk of complications. Pregnancy after BC was not associated with a negative impact on patients’ outcomes. Compared to BC patients without subsequent pregnancy, those with pregnancy after BC had better OS (HR 0.56, 95% CI 0.46-0.67) and DFS (HR 0.73, 95% CI 0.56-0.94). Similar results were observed in the studies correcting for the potential “healthy mother effect” (OS: HR 0.52, 95% CI 0.42-0.65; DFS: HR 0.74, 95% CI 0.58-0.96). No detrimental prognostic effect of pregnancy after BC was observed in patients with hormone-receptor positive disease (DFS: HR 1.10, 95% CI 0.73-1.66), while better outcomes were observed for those with hormone-receptor negative disease (DFS: HR 0.72, 95% CI 0.55-0.95). The safety of pregnancy after BC was observed irrespective of BRCA status, nodal status, previous chemotherapy exposure, pregnancy interval and pregnancy outcomes. Conclusions: This large meta-analysis provides solid evidence on the safety of pregnancy after prior BC diagnosis. The increased risk of fetal and obstetrical complications (but not of congenital abnormalities) calls for ensuring a closer monitoring of these pregnancies. The significantly reduced chances of conceiving as compared to the general population and other cancer patients should raise further awareness on the need to improve the oncofertility counseling of young BC patients wishing to complete their family planning following anticancer treatment completion. Citation Format: Eva Blondeaux, Marta Perachino, Marco Bruzzone, Richard A. Anderson, Evandro De Azambuja, Philip D. Poorvu, Hee Jeong Kim, Cynthia Villarreal-Garza, Barbara Pistilli, Ines Vaz-Luis, Cristina Saura, Kathryn J. Ruddy, Maria Alice Franzoi, Chiara Sertoli, Marcello Ceppi, Hatem A. Azim, Jr., Frederic Amant, Isabelle Demeestere, Lucia Del Mastro, Ann H. Partridge, Olivia Pagani, Fedro A. Peccatori, Matteo Lambertini. Chances of pregnancy after breast cancer, reproductive and disease outcomes: A systematic review and meta-analysis [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr GS3-09.