Systematic review and meta-analysis of post-progression outcomes in ER+/HER2- metastatic breast cancer after CDK4/6 inhibitors within randomized clinical trials.

BACKGROUND: Cyclin-dependent kinase 4/6 (CDK4/6) inhibitors and endocrine therapy (ET) deeply transformed the treatment landscape of hormone receptor-positive/human epidermal growth factor receptor 2-negative (HR+/HER2-) advanced breast cancer. Randomized clinical trials suggest that second progression-free survival (PFS2) was not compromised and time to subsequent chemotherapy (TTC) may be delayed. We carried out a meta-analysis to assess the benefit on PFS2 and on delaying the TTC. METHODS: We conducted a systematic literature search of randomized clinical trials with CDK4/6 inhibitors and ET reporting PFS2 or TTC of HR+/HER2- pre- or postmenopausal metastatic breast cancer. We also reviewed abstracts and presentations from all major conference proceedings. We calculated the pooled hazard ratios (HR) for PFS2 and TTC using random-effects models with 95% confidence intervals (CI). I2 was used to quantify heterogeneity between results of the studies. RESULTS: Eight studies (MONALEESA-2/3/7, MONARCH-2/3, PALOMA-1/2/3) were included in this analysis (N = 4580 patients). PFS2 benefit was observed in patients who received CDK4/6 inhibitors plus ET (pooled HR = 0.68, 95% CI = 0.62-0.74, I2 = 0%) and also a delay in subsequent TTC (pooled HR = 0.65, 95% CI = 0.60-0.71, I2 = 0%). A benefit in terms of PFS (pooled HR = 0.55, 95% CI = 0.51-0.59, I2 = 0%) and overall survival (pooled HR = 0.76, 95% CI = 0.69-0.84, I2 = 0%) was also observed. CONCLUSIONS: CDK4/6 inhibitors plus ET compared with ET alone improve PFS2 and TTC. The delay of chemotherapy may postpone the start of a more toxic treatment option, delaying related toxicities and potentially maintaining a better quality of life for patients, for a longer time. The benefit in PFS2 may postpone the onset of endocrine resistance and help further validate this treatment approach.

Evaluation of endocrine therapy and patients preferences in early breast cancer: results of Elena study.

PURPOSE: The development of the adjuvant therapy requires that clinicians and patients should discuss the magnitude of benefit of treatment for individual patient, estimating the pros and cons and the personal preferences. The aim of the present study was to determine the preferences of women treated with adjuvant hormonal therapy (HT) for breast cancer. METHODS: The analyses were conducted into three different groups of early breast cancer patients to evaluate the survival benefit needed to make treatment worthwhile before starting HT (A), after a few months from the beginning (B) and after several years of HT (C). The questionnaires, showing hypothetical scenarios based on potential survival times and rates without HT, were used to determine the lowest gains women judged necessary to make the treatment worthwhile. RESULTS: A total of 452 patients were included in the study: 149 in group A, 150 in group B and 153 in group C. In group C, 65% of patients were receiving HT with aromatase inhibitors (with or without a LHRH analogue). In the groups A, B, C 8%, 20% and 26%, respectively, received adjuvant chemotherapy. Overall, 355 women (79%) had children. The responses were quite similar between the three groups. A median gain of 10 years was judged necessary to make adjuvant HT worthwhile based on the hypothetical scenario of untreated mean survival time of 5 and 15 years. Median gain of 20% more women surviving was judged necessary to make adjuvant HT worthwhile based on an untreated 5-year survival rate expectation of 60%. Cognitive dysfunction was considered the side effect least compatible with the continuation of treatment in all three groups. CONCLUSIONS: This is a large study of patient preferences on HT. Compared with other studies with similar design, the patients included in the present study required larger benefits to make adjuvant therapy worthwhile.

Changes in PgR and Ki-67 in residual tumour and outcome of breast cancer patients treated with neoadjuvant chemotherapy.

BACKGROUND: Limited data are available on the prognostic value of changes in the biological features of residual tumours following neoadjuvant therapies in breast cancer patients. PATIENTS AND METHODS: We collected information through the institutional clinical database on all consecutive breast cancer patients treated with neoadjuvant chemotherapy at the European Institute of Oncology (IEO), Milan, Italy, between 1999 and 2011. We selected patients who did not achieve pathological complete response at final surgery. All patients had a pathological evaluation, including ER, PgR, HER2 protein and Ki-67 expression carried out at the IEO both at diagnostic core biopsy and at final surgery. RESULTS: We identified a total of 904 patients. The 5% of patients who were ER positive at diagnostic biopsy had ER-negative residual tumour at final surgery. For PgR expression, 67% of the patients, whose tumours had a PgR >20% at diagnostic biopsy had a PgR <20% at final surgery. The Ki-67 expression changed from >20% to <20% in 40% of the patients. At the multivariate analysis, the decrease of PgR-immunoreactive cells correlated with improved outcome in terms of disease-free survival (DFS) [hazard ratio (HR) 0.73; 95% confidence interval (CI) 0.54-1.00, P 0.046]. In addition, the decrease of Ki-67 expression to <20% of the cells at final surgery was found to be associated with better outcome both in terms of DFS (HR 0.52; 95% CI 0.40-0.68 P < 0.0001) and overall survival (HR 0.45; 95% CI 0.32-0.64, P < 0.0001). CONCLUSION: The decrease of PgR and Ki-67 expression after preoperative chemotherapy has a prognostic role in breast cancer patients with residual disease.

Progesterone receptor loss identifies Luminal B breast cancer subgroups at higher risk of relapse.

BACKGROUND: The immunohistochemical (IHC) evaluation of estrogen receptor (ER), progesterone receptor (PgR), Ki-67 and HER2 is considered a surrogate means for identifying the molecular subtypes of breast cancer with different prognosis. PATIENTS AND METHODS: We explored patterns of recurrence in 4837 women with breast cancer defined as Luminal B (ER-positive and/or PgR-positive, HER2 positive and/or Ki-67≥14%) by IHC classification. We evaluated four subgroups within the Luminal B subtype according to HER2 expression and PgR status. RESULTS: Patients within the ER+/PgR+/HER2- subgroup presented a 5-year breast cancer-related survival (BCS) of 97% (95% confidence interval (CI), 96-97) and overall survival (OS) of 95% [95% CI, 95-96], the best survivals of the Luminal B subgroups. In the multivariate analysis, the ER+/PgR-/HER2- subgroup was associated with a reduced BCS (HR 1.71; 95%CI, 1.25-2.35) and OS (HR 1.47; 95%CI, 1.10-1.96) when compared with the ER+/PgR+/HER2- subgroup. Also patients within the ER+/PgR-/HER2+ subgroup had a reduced BCS (HR 1.93; 95%CI, 1.32-2.83) and OS (HR 1.62; 95%CI, 1.14-2.30) when compared with ER+/PgR+/HER2- subgroup. On the other hand, no statistically significant differences were found with regard to BCS and OS among patients with ER+/PgR+/HER2+ and patients with ER+/PgR+/HER2- disease. CONCLUSIONS: PgR loss identifies Luminal B breast cancer subgroups at higher risk of relapse and death, both with HER-2-positive and HER-2-negative disease.

Breast cancer subtypes and outcome after local and regional relapse.

BACKGROUND: To evaluate the outcome of breast cancer patients after locoregional recurrence (LRR) according to tumor biological features evaluated at first diagnosis and at the time of recurrence. PATIENTS AND METHODS: We collected information on all consecutive breast cancer patients operated at the European Institute of Oncology between 1994 and 2005. The tumor characteristics and subsequent outcome of patients who experienced LRR were analyzed. RESULTS: Two hundred and seventy nine patients with LRR were identified, 197 and 82 patients with local and regional recurrence respectively. The overall discordance rate between primary cancer and LRR was 9% for estrogen receptor expression, 22% for progesterone receptor and 4% for human epidermal growth factor receptor 2. For patients with regional recurrence, the risk of distant metastasis was significantly higher compared with local relapse in case of late recurrence (hazard ratio [HR] = 2.76; 95% CI 1.31-5.85). Patients with triple-negative breast cancer at LRR experienced a higher risk of subsequent relapse (HR 2.87 [1.67-4.91]) and death (HR 2.00 [1.25-3.19]). CONCLUSION: LRR correlates with a high risk of subsequent events and death in particular in patients with triple-negative subtype.

Outcome of special types of luminal breast cancer.

BACKGROUND: The identification of special types of breast cancer might be of value in assessing prognosis and predicting response to therapy. METHODS: A total of 7372 consecutive patients with immunohistochemically defined luminal invasive breast cancer operated at the European Institute of Oncology between 1997 and 2005 were included. We then explored patterns of recurrence by histological type. Median follow-up was 5.8 years. RESULTS: Tumors from 5707 patients were classified as invasive ductal cancer (IDC) not otherwise specified (NOS), 851 lobular, 338 mixed ductal and lobular, 250 cribriform, 143 mucinous and 83 tubular carcinomas. Compared with IDC NOS disease-free survival (DFS) was significantly longer in patients with cribriform tumors [5-year DFS 97.9% versus 87.4%; hazard ratio (HR) = 0.48; P = 0.015) and in pooled cribriform plus tubular carcinomas (5-year DFS 98.7% versus 87.4%; HR = 0.45; P = 0.005). Mucinous tumors presented similar DFS if compared with IDC (5-year DFS 93 % versus 87.4%; HR = 1.03; P = 0.91). Conversely, DFS was poorer for patients with lobular carcinoma (5-year DFS 86.8% versus 87.4%; HR = 1.27; P = 0.01). CONCLUSIONS: The diagnosis of tubular, cribriform and lobular carcinomas carry distinct prognostic implications. The identification of these special types has a significant utility in luminal breast cancer and should be considered in therapeutic algorithms.

Prognosis in women with small (T1mic,T1a,T1b) node-negative operable breast cancer by immunohistochemically selected subtypes.

Knowledge is limited about prognostic significance of breast cancer subtypes among women with small invasive node-negative breast tumours. We explored patterns of recurrence in 1691 women with pT1mic/T1a/T1b, pN0 and M0 breast cancer according to four immunohistochemically defined tumour subtypes: (i) Luminal A (ER-positive, PgR-positive, HER2-negative and Ki-67 < 14%); (ii) Luminal B (ER-positive and/or PgR-positive, HER2-positive and/or Ki-67 ≥ 14%); (iii) HER2-positive, both endocrine receptors absent; and (iv) Triple Negative. At multivariate analysis, women with the Triple Negative breast cancer subtype had an increased risk of loco-regional relapse (LRR) (Hazards Ratio (HR) 3.58; 95%CI: 1.40-9.13) and breast cancer related events (HR 2.18; 95%CI: 1.04-4.57). Overall, Luminal B subtype was not associated with a statistically significant increased risk of recurrence compared with Luminal A, while patients with Luminal B subtype tumours overexpressing HER2 had a 2 fold risk of reduced breast cancer related survival (BCS), but not an increased risk of LRR and distant metastases. Women with HER2 breast cancer subtype had a statistically significant increased risk of LRR (HR 4.53; 95%CI: 1.56-13.1), distant metastases and reduced BCS (HR 3.22; 95%CI: 1.44-7.18) and overall survival (HR 2.87; 95%CI: 1.05-7.89) when compared with the Luminal A subtype, at multivariate analysis. In conclusion, women with small size, node-negative, breast cancer are at higher risk of relapse if with HER2-positive endocrine receptor absent or Triple Negative disease.

Prognosis and adjuvant treatment effects in selected breast cancer subtypes of very young women (<35 years) with operable breast cancer.

BACKGROUND: There is limited knowledge about prognosis of selected breast cancer subtypes among very young women. PATIENTS AND METHODS: We explored patterns of recurrence by age according to four immunohistochemically defined tumor subtypes: Luminal A and Luminal B (estrogen receptor positive and/or progesterone receptor positive and either human epidermal growth factor receptor 2 (HER2) positive and/or high Ki-67), HER2-positive (and) endocrine receptor absent and Triple Negative, in 2970 premenopausal patients with pT1-3, pN0-3 and M0 breast cancer. RESULTS: Patients <35 years of age (315, 11%) presented a significantly increased risk of recurrence and death [hazards ratio (HR) = 1.65, 95% confidence interval (CI) 1.30-2.10 and HR = 1.78, 95% CI 1.12-2.85, respectively] when compared with older patients (2655, 89%) with similar characteristics of disease. This was true considering patients with Luminal B [HR = 1.62, 95% CI 1.21-2.18 for disease-free survival (DFS) and HR = 2.09, 95% CI 0.96-4.53 for overall survival (OS)] and with Triple Negative (HR = 2.04, 95% CI 1.11-3.72 for DFS and HR = 2.20, 95% CI 1.10-4.41 for OS) breast cancer, observing the highest risk of recurrence in the younger patients with HER2-positive breast cancer (HR = 2.37, 95% CI 1.12-5.02) when compared with older patients. CONCLUSIONS: Very young patients with Triple Negative, Luminal B or HER2-positive breast cancer have a worse prognosis when compared with older patients with similar characteristics of disease.

Minimal axillary lymph node involvement in breast cancer has different prognostic implications according to the staging procedure.

It is still controversial whether the identification of micrometastases and isolated tumor cells in the axillary lymph nodes of patients with breast cancer has any prognostic value. We evaluated the prognostic role of isolated tumor cells and micrometastases in the axillary lymph nodes in 3,158 consecutive patients pT1-2 pN0-N1mi (with a single involved lymph node) and M0, referred to the Division of Medical Oncology after surgery performed at the European Institute of Oncology from April 1997 to December 2002. Median follow-up was 6.3 years (range 0.1-11 years). Sentinel lymph node biopsy (SLNB) and axillary lymph node dissection (ALND) were performed in 2,087 and 1,071 patients, respectively. A worse metastasis-free survival was observed for patients with micrometastatic disease compared to node-negative patients, if staged with ALND (log-rank P < .0001; HR: 3.17; 95% CI 1.72-5.83 at multivariate analysis), but not for patients who underwent SLNB (log-rank P = 0.36). The presence of a single micrometastatic lymph node is associated with a higher risk of distant recurrence as compared to node-negative disease only for patients undergoing ALND for staging purposes. Treatment recommendations for systemic therapy should not take into account the presence of a single micrometastatic lymph node identified during complete serial sectioning of sentinel node(s).

Central nervous system metastases in a cohort of metastatic breast cancer patients treated with trastuzumab.

BACKGROUND: Several analyses suggest an increase of brain metastases in HER2 over-expressing breast cancers treated with trastuzumab as compared to historical series of unselected patients. PATIENTS AND METHODS: We analyzed the incidence of central nervous system (CNS) metastases in 78 patients with HER2 over-expressing breast cancer treated with trastuzumab between July 2000 and June 2006 at the Oncology Department of University Federico II in Naples. We also characterized and compared patients with and without CNS involvement. RESULTS: The median follow-up was 35.3 months (95%CI 26.3-44); median overall survival was 56 months (95%CIs 46-nr); 5 patients showed CNS involvement before trastuzumab therapy while 31 developed CNS metastases during trastuzumab treatment. The median overall survival after CNS metastases was 25.4 months (95%CIs 15.2-nr); patients with CNS lesions showed worse overall survival than patients without CNS lesions (39.1 vs. 75 months, p = 0.005). CONCLUSION: CNS metastases are common events in patients with metastatic HER2 over-expressing breast cancer treated with trastuzumab; the impact on survival is detrimental even if survival after CNS metastases is longer than historical reports. Appropriate investigation of the role of CNS imaging screening and the prophylactic treatment strategies for CNS represents a priority research in this setting.

Biology, prognosis and response to therapy of breast carcinomas according to HER2 score.

BACKGROUND: The standardization of the HER2 score and recent changes in therapeutic modalities points to the need for a reevaluation of the role of HER2 in recently diagnosed breast carcinoma. PATIENTS AND METHODS: A multicenter, retrospective study of 1794 primary breast carcinomas diagnosed in Italy in 2000/2001 and scored in HER2 four categories according to immunohistochemistry was conducted. RESULTS: Ductal histotype, vascular invasion, grade, MIB1 positivity, estrogen and progesterone receptor expression differed significantly in HER2 3+ tumors compared with the other categories. HER2 2+ tumors almost showed values intermediate between those of the negative and the 3+ subgroups. The characteristics of HER2 1+ tumors were found to be in between those of HER2 0 and 2+ tumors. With a median follow-up of 54 months, HER2 3+ status was associated with higher relapse rates in node-positive and node-negative subgroups, while HER2 2+ only in node positive. Analysis of relapses according to type of therapy provided evidence of responsiveness of HER2-positive tumors to chemotherapy, especially taxanes. CONCLUSIONS: The present prognostic significance of HER2 is correlated to receptor expression level and points to the need to consider HER2 2+ and HER2 3+ tumors as distinct diseases with different outcomes and specific features.

Targeting HER2 as a therapeutic strategy for breast cancer: a paradigmatic shift of drug development in oncology.

Targeted therapies are causing a dramatic change in cancer drug development. Trastuzumab, a humanized recombinant monoclonal antibody that recognizes the extracellular domain of HER2 trans-membrane protein, is among the first target-specific drugs that have been licensed for clinical use and its development represents a model of integration of new agents with classical treatment strategies. In preclinical models, trastuzumab has demonstrated a marked antiproliferative effect and a synergistic action with several chemotherapeutic agents. Monotherapy trials indicate that trastuzumab is active as a single agent in HER2 positive patients, is well tolerated, and is associated with preservation of quality of life (QoL). Furthermore, as first line therapy for metastatic breast cancer overexpressing HER2 receptor, the addition of trastuzumab to taxane-based chemotherapy significantly increased rate of objective response, time to disease progression and survival when compared with chemotherapy alone. Trastuzumab has shown important activity when used with many chemotherapeutic agents such as platinum salts, gemcitabine, vinorelbine and capecitabine and liposomal anthracyclines. Various trials are now ongoing to optimize the use of trastuzumab and to investigate its role in the adjuvant and in the neo-adjuvant setting.