CDK4/6 Inhibitors as Upfront Treatment in a Patient with Breast Cancer Presenting with a Clinical Critic Situation: A Case Report and Review of the Literature

CDK4/6 inhibitors have revolutionized the treatment algorithm of luminal metastatic breast cancer, becoming the recommended first-line therapy in association with endocrine therapy. However, due to its theoretically greater and more rapid tumor shrinkage, the upfront use of chemotherapy is considered in some clinical situations like visceral crisis. At the state of the art level, a paucity of data is available about the use of CDK4/6 inhibitors in patients presenting with visceral crisis or with life-threatening conditions since this population was historically excluded from clinical trials. In addition, data regarding direct comparison between combinations of chemotherapy and CDK4/6 inhibitors in terms of efficacy, rapidity of responses and long-term outcomes are lacking. We report the case of a 68-year-old woman with luminal metastatic breast cancer presenting at diagnosis with a critical and potentially life-threatening condition. The patient was treated with first-line Abemaciclib plus letrozole and achieved a rapid partial response with sudden clinical stabilization. Although the patient did not technically present with a visceral crisis, this case presentation also endorsed the upfront use of CDK4/6 inhibitor combinations in critical clinical situations in the absence of severe organ dysfunction and after multidisciplinary discussion.

Modeling the Prognostic Impact of Circulating Tumor Cells Enumeration in Metastatic Breast Cancer for Clinical Trial Design Simulation

Despite the strong prognostic stratification of circulating tumor cells (CTCs) enumeration in metastatic breast cancer (MBC), current clinical trials usually do not include a baseline CTCs in their design. This study aimed to generate a classifier for CTCs prognostic simulation in existing datasets for hypothesis generation in patients with MBC. A K-nearest neighbor machine learning algorithm was trained on a pooled dataset comprising 2436 individual MBC patients from the European Pooled Analysis Consortium and the MD Anderson Cancer Center to identify patients likely to have CTCs ≥ 5/7 mL blood (StageIVaggressive vs StageIVindolent). The model had a 65.1% accuracy and its prognostic impact resulted in a hazard ratio (HR) of 1.89 (Simulatedaggressive vs SimulatedindolentP < .001), similar to patients with actual CTCs enumeration (HR 2.76; P < .001). The classifier's performance was then tested on an independent retrospective database comprising 446 consecutive hormone receptor (HR)-positive HER2-negative MBC patients. The model further stratified clinical subgroups usually considered prognostically homogeneous such as patients with bone-only or liver metastases. Bone-only disease classified as Simulatedaggressive had a significantly worse overall survival (OS; P < .0001), while patients with liver metastases classified as Simulatedindolent had a significantly better prognosis (P < .0001). Consistent results were observed for patients who had undergone CTCs enumeration in the pooled population. The differential prognostic impact of endocrine- (ET) and chemotherapy (CT) was explored across the simulated subgroups. No significant differences were observed between ET and CT in the overall population, both in terms of progression-free survival (PFS) and OS. In contrast, a statistically significant difference, favoring CT over ET was observed among Simulatedaggressive patients (HR: 0.62; P = .030 and HR: 0.60; P = .037, respectively, for PFS and OS).

Multidisciplinary Team Meeting Proposal and Final Therapeutic Choice in Early Breast Cancer: Is There an Agreement?

Background

A multidisciplinary team meeting (MDM) approach in breast cancer (BC) management is a standard of care. One of the roles of MDMs is to identify the best diagnostic and therapeutic strategies for patients (pts) with new diagnosis of early BC. The purpose of this study was to define whether there was an agreement between the planned program (i.e., MDMs-based decision) and that actually applied. In addition, the study explored factors associated with discordance.

Methods

We conducted a retrospective study of a consecutive series of 291 patients with new diagnosis of early BC, discussed at MDMs at the University Hospital of Udine (Italy), from January 2017 to June 2018. The association between clinico-biological factors and discordance between what was decided during the MDMs and what was consequently applied by the oncologist was explored through uni- and multivariate logistic regression analyses.

Results

The median age was 62 years (range 27–88 years). Among invasive early BC patients, the most frequent phenotype was luminal A (38%), followed by luminal B (33%), HER2-positive (12%), and triple-negative (5%). In situ carcinoma (DCIS) represented 12% of cases. The median time from MDM discussion to first oncologic examination was 2 weeks. The rate of discordance between MDM-based decision and final choice, during a face-to-face consultation with the oncologist, was 15.8% (46/291). The most frequent reason for changing the MDM-based program was clinical decision (87%). Follow-up was preferred to the chemotherapy (CT) proposed within the MDMs in 15% of cases, and to the endocrine therapy (ET) in 39% of cases (among these, 44.5% had a diagnosis of DCIS). Therapeutic change from sequential CT-ET to ET alone was chosen in 16/46 pts (35%): among these patients, seven had a luminal B disease and six had an HER2-positive disease. On univariate analysis, factors associated with discordance were values of Ki-67 14%–30% (OR 3.91; 95% CI 1.19–12.9), age >70 years (OR 2.44, 95% CI 1.28–4.63), housewife/retired status (OR 2.35, 95% CI 1.14–4.85), polypharmacy (OR 1.95; 95% CI 1.02–3.72), postmenopausal status (OR 4.15; 95% CI 1.58–10.9), and high Charlson Comorbidity Index (OR 1.31; 95% CI 1.09–1.57). The association with marital status, educational level, alcohol and smoke habits, presence of a caregiver, parity, grading, histotype and phenotype, and stage was not statistically significant. On multivariate analysis, only Ki-67 value maintained its statistical significance.

Conclusion

The results of our study could be useful for enhancing the role of MDMs in the clinical decision-making process in early BC.

Refining neutropenia risk assessment in patients treated with first-line endocrine therapy (ET) and cyclin-dependent kinase 4/6 inhibitors (CDK4/6i) for metastatic breast cancer (MBC) through a cell-free DNA workflow (cfDNA)

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Background: The combination of ET and CDK4/6i is the current standard of care for hormone receptor (HR)-positive/HER2-negative MBC (luminal MBC), with neutropenia being the main dose limiting toxicity. We previously observed the potential association between leucocyte count (WBC) and different fractions of cell free circulating DNA (cfDNA) (Bortot et al 2020). The present study aimed to evaluate the feasibility of a cfDNA-based workflow as a new tool to assess the risk of treatment induced neutropenia. Methods: The study analyzed a prospective cohort 83 luminal MBC patients (pts) treated with first line ET and CDK4/6i in the CRO-2018-56 multicenter study from 2018 to 2021. cfDNA was characterized through droplet digital PCR (ddPCR) based on different ACTB DNA fragments lengths: short (s), medium (m) and long (l). Blood samples were collected before treatment start (BL) and at the first clinical evaluation after 3 months (E1). Associations between clinical characteristics, neutropenia and cfDNA were explored through Kruskal Wallis, time to G3 neutropenia (NG3) (TTN) was analyzed through log-rank and Cox regression. Results: Neutropenia was G3 in 44 out of 83 pts (53%) and G4 in 2 pts (2%). Median TTN was 1.8 months, 60% of NG3 occurred within 3.7 months. Overall, 74 pts (89%) resolved toxicity within 7 days, 10 pts (12%) reduced CDK4/6i dose after NG3. BL neutrophils count (Neu) and WBC were significantly lower in pts that developed NG3 (P = 0.0013 and P = 0.0020 respectively). De novo metastatic pts had numerically higher Neu (median 4825 vs 3895), but only a numerically lower risk of NG3 was observed (HR 0.53 P = 0.064). Although bone involvement was not associated with risk of developing NG3, the total number of metastatic lesions was associated with higher NG3 (P = 0.0016). In particular, > 5 metastatic lesions were associated with higher NG3 risk (p = 0.013). E1 ACTB_m was significantly lower with respect to BL in pts that experienced NG3 (median 100% vs 16%, P = 0.0136 in NG3 no vs yes) with a consistent impact on the risk of NG3 (HR: 2.81, P = 0.025). No associations were observed for the other ACTB fragment length fractions. BL Neu and ACTB_m dichotomized at the median were then combined to describe 4 distinct TTN risk groups (P = 0.0006). Interestingly, pts with low BL Neu and low E1 ACTB_m had a median TTN of 0.9 months, while pts with high BL Neu and high E1 ACTB_m have not experienced NG3 after a median follow-up of 16.1 months. Conclusions: The present study proofed the concept of using cfDNA to provide clinically meaningful data not only about tumor biology, but also for a comprehensive patient assessment. Based on these results, a prospective study focused on a multiparametric neutropenia risk assessment will be started.

Uncovering the differential impact of ESR1 and PIK3CA codon variants on the clinical phenotype of metastatic breast cancer (MBC) through circulating tumor DNA (ctDNA) next-generation sequencing (NGS)

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Background: The exposure to endocrine therapy (ET) can induce the onset of ESR1 gene alterations that have an impact on not only treatment resistance but also clinical phenotype. We previously demonstrated the potential of liquid biopsy in describing the metastatic behavior of MBC. The aim of this study was to explore the different clinical phenotype across the main ESR1 and PIK3CA codon variants. Methods: The study retrospectively analyzed a cohort of 501 MBC patients (pts) characterized for ctDNA through NGS before treatment start at Northwestern University (Chicago, IL), Massachusetts General Hospital (Boston, MA), CRO National Cancer Institute (Aviano, IT) and ASUFC Hospital (Udine, IT) between 2014 and 2020. Associations between clinical characteristics and ESR1 and PIK3CA codon variants were explored through logistic regression corrected for sites and ESR1/ PIK3CA status. Survival was tested through Cox regression both for progression-free survival (PFS) and overall survival (OS). Results: Of the total 501 pts, 289 (58%) were diagnosed with hormone-receptor positive (HRpos) MBC, 114 (23%) with HER2-positive MBC, and 93 (19%) with triple-negative MBC. ESR1 mutations were detected in 71 pts (14%) and PIK3CA in 154 pts (31%). The most represented ESR1 gene mutations were found in codons 380 (9%), 536 (23%), 537 (34%), and 538 (34%), while alterations in codons 542 (19%), 545 (21%), and 1047 (60%) were the most common for PIK3CA. As expected, ESR1 mutations were found only in HRpos pts previously exposed to ET (P < 0.001). No significant differences were observed for PIK3CA. After multivariable analysis, ESR1mutations were confirmed as highly associated with liver and bone metastases (OR 3.31, P < 0.001 and OR 5.09, P < 0.001). Moreover, an association with lung (OR 2.07, P = 0.010) was observed in this cohort. After multivariable analysis, codon 537 mutations were associated with bone involvement (OR 12.97, P = 0.014), codon 538 with liver (OR 4.73, P = 0.010), and codon 536 with soft tissue (OR 5.84, P = 0.006) and liver (OR 4.06, P = 0.048). PIK3CA mutations were associated with bone (OR 2.61, P < 0.001) and lung metastases (OR 1.62, P = 0.044). Specifically, codon 1047 mutations were the primary driver (OR 3.14, P = 0.001 and OR 1.97, P = 0.019). In HRpos MBC, baseline mutations in ESR1 codon 537 and 538 had a negative impact on OS (HR 3.73, P < 0.010 and HR 2.99, P < 0.021), while 380 and 536 had a negative impact on PFS (HR 18.98, P < 0.001 and HR 2.60, P = 0.015). No impact was observed across PIK3CA gene variants. Conclusions: This study showed the different tumor biology across ESR1 and PIK3CA gene variants. As novel selective estrogen receptor degraders (SERDS) and PIK3CA inhibitors are gaining momentum as new ET options in MBC, these results highlight the future pivotal role of ctDNA NGS in refining tumor biology characterization.

Liquid biopsy for baseline evaluation of tumor burden in patients with hormone receptor-positive, HER2-negative metastatic breast cancer: A proof of principle study

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Background: Liquid biopsy-based biomarkers, including circulating tumor DNA (ctDNA), are increasingly important for the characterization of metastatic breast cancer (MBC). Currently, CA15.3 is the most commonly used serum marker for monitoring disease burden. To date, no liquid biopsy-based biomarkers have been proposed for this scope in clinical practice. Methods: The CRO-2018-56 multicenter study prospectively enrolled 83 patients (pts) with luminal-like MBC treated with first line endocrine therapy (ET) and CDK4/6 inhibitors. All pts were characterized for ctDNA through droplet digital PCR (ddPCR) in from 2018 to 2021. Clinicopathological and laboratory characteristics at baseline were tested for associations with tumor markers, ACTB fragments lengths, methylation status of ESR1 main promoters (expressed as promA and promB ratio, i.e., met_ratio) and ESR1/PIK3CA mutational status through Kruskal-Wallis test and Chi-square test. Prognosis was tested in terms of Progression Free Survival (PFS) and Overall Survival (OS) through log-rank test. Results: At baseline, in 26 (31%) pts disease was diagnosed as de novo metastatic, 66 (80%) pts had < 3 of metastatic sites, and 41 (49%) pts had < 5 of metastatic lesions. Bone metastases were detected in 53 (64%) pts, liver metastases in 21 (25%) pts, and lung lesions in 30 (36%) pts. A ctDNA-detected ESR1 mutation and a PIK3CA mutation were found in 15% of pts and in 34% pts, respectively. Met_ratio was > 1.5 in 35 (42%) of pts. Median CA15.3 was 48.2 U/mL and median CEA was 3.8 U/mL. Number of liver metastases and number of metastatic sites were significantly higher in pts with ESR1 mutation (respectively, P = 0.0055 and P = 0.0208). CA15.3 and ctDNA yield were significantly higher in pts with number of metastatic sites ≥ 3, (respectively, P = 0.0164, and P = 0.0239), while number of metastatic sites ≥ 3 and number of metastatic lesions ≥ 5 were significantly associated with CEA > 3.8 U/mL (respectively, P = 0.039, and P = 0.029). Presence of bone metastases was significantly associated with PIK3CA mutation (P = 0.040), while number of metastatic sites ≥ 3 was significantly associated with ESR1 mutation (P = 0.022). No association with tumor burden was observed for different ACTB DNA fragments lengths. Met_ratio > 1.5 was significantly associated with lower number of metastatic lesions (P = 0.031). Number of metastatic sites ≥ 3, high ctDNA yield and CEA were associated with worse OS (respectively P = 0.0465, P = 0.0250 and P = 0.0474), while only CEA impacted on PFS (P = 0.0097). Conclusions: In pts with luminal-like MBC, some liquid biopsy-based biomarkers (i.e., ctDNA-detected ESR1 and PIK3CA mutations, ctDNA yield) were significantly associated with the burden of disease. The potential clinical validity and utility of these results deserve to be tested in an expansion cohort.

T-DM1 versus pertuzumab, trastuzumab and a taxane as first-line therapy of early-relapsed HER2-positive metastatic breast cancer: an Italian multicenter observational study

Background

The current standard first-line treatment of human epidermal growth factor receptor 2 (HER2)-positive (+) metastatic breast cancer is the combination of pertuzumab, trastuzumab and a taxane (P + T + taxane), while standard second-line is ado-trastuzumab-emtansine (T-DM1). The registration trial of pertuzumab, however, did not include early-relapsing patients, defined as patients experiencing tumor relapse ≤12 months from the end of (neo)adjuvant anti-HER2 therapy. Conversely, the pivotal trial of T-DM1 included some patients relapsing ≤6 months after the end of (neo)adjuvant trastuzumab. Thus, a proportion of early-relapsing patients are currently eligible to receive T-DM1 as first-line treatment. Nevertheless, no direct comparison exists between the two regimens in this clinical setting.

Patients and methods

We retrospectively compared T-DM1 versus P + T + taxane as first-line treatment in two cohorts of early-relapsing patients in an Italian ‘real-world’ setting, involving 14 public health care institutions. The primary endpoint was progression-free survival. Secondary endpoints included patients' characterization, overall survival and post-progression survival. Univariate and multivariate analyses were carried out. All tests were two-sided and a P ≤ 0.05 was considered statistically significant.

Results

Among 1252 screened patients, 75 met the inclusion criteria. Forty-four (58.7%) received P + T + taxane and 31 (41.3%) received T-DM1. The two cohorts showed similar characteristics of aggressiveness and no significant differences in treatment history. T-DM1, compared with P + T + taxane was associated with worse progression-free survival (adjusted hazard ratio: 2.26, 95% confidence interval: 1.13-4.52, P = 0.021) and overall survival (adjusted hazard ratio: 3.95, 95% confidence interval: 1.38-11.32, P = 0.010), irrespective of previous (neo)adjuvant treatment, age, hormone receptors status, time-to-relapse (≤6 months or within 6-12 months) and presence of visceral/brain metastases. No differences were observed in post-progression survival (P = 0.095).

Conclusions

Our study suggests superiority for P + T + taxane over T-DM1 as up-front treatment of early-relapsing HER2+ metastatic breast cancer, which merits further assessment in larger and prospective trials.

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This is the first study comparing pertuzumab + trastuzumab + taxane (P + T + taxane) with T-DM1 in early-relapsing HER2+ MBC.

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The majority of early-relapsing HER2+ MBC have high-grade, node-positive, large primary tumors.

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First-line T-DM1 compared with P + T + taxane is associated with worse progression-free survival.

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First-line T-DM1 compared with P + T + taxane is associated with worse overall survival.

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Post-progression survival does not differ between the two treatments cohorts.

Overall Survival in Metastatic Breast Cancer Patients in the Third Millennium: Results of the COSMO Study

INTRODUCTION

Metastatic breast cancer (MBC) is a life-threatening disease, and although some data suggest a trend in survival improvement, it has not yet been unequivocally demonstrated. This study aimed to evaluate the overall survival (OS) of MBC patients, assessing its correlation with prognostic factors.

PATIENTS AND METHODS

COSMO (Checking Overall Survival in a MBC Observational study) is an Italian longitudinal retrospective multicenter study that enrolled patients with MBC diagnosed between 2000 and 2008. The primary objective was to detect a temporal difference in OS; the secondary objective was to identify prognostic factors as causal factors of the temporal variation in OS.

RESULTS

A total of 3721 of 3930 patients from 31 centers were distributed in 3 periods: 886 (23.8%), 1302 (35.0%), and 1533 (41.2%) in 2000-2002, 2003-2005, and 2006-2008, respectively. With a median follow-up of 9.3 years, median OS was 2.8 years (95% confidence interval, 2.6-2.9). No difference in OS was found in the 3 cohorts (P for trend = .563). The worst prognosis was observed for patients with triple-negative MBC (OS, 1.5 years) and for those with central nervous system metastases (1.7 years); the best prognosis was observed in those with bone metastases or nonvisceral disease (3.4 and 3.2 years, respectively) and in patients with a disease-free interval, defined as the time between resection of the primary malignancy and diagnosis of MBC, of > 2 years (3 years).

CONCLUSIONS

The COSMO study found improvement in OS between 2000 and 2008. Molecular subtype remained the strongest prognostic factor, and the role of other prognostic factors was confirmed, in particular disease-free interval, site of metastasis, and age.

Human epidermal growth factor receptor-2 (HER2) is a potential therapeutic target in extramammary Paget’s disease of the vulva

Background

Invasive vulvar Paget’s disease with over-expression of the human epidermal growth factor receptor 2 (HER2) protein is potentially suitable for targeted therapy, especially in a metastatic setting where no effective treatments are available.

Methods

Four consecutive patients with HER2 positive advanced vulvar Paget’s disease, treated with weekly trastuzumab (loading dose 4 mg/kg, then 2 mg/kg) and paclitaxel (80 mg/m2) followed by 3-weekly trastuzumab maintenance (6 mg/kg), are reported.

Results

Median age and follow-up of patients were 62.5 years (45–74) and 16 months (6-54), respectively. Complete or partial responses were observed in all patients. Median time to response was 3 months (range 2–4), while median duration of response was 10 months (range 2–34). Case 1 presented with pulmonary and lymph nodes involvement. She experienced a radiological complete response after 24 treatment administrations, and a progression-free survival of 36 months. At disease progression, treatment re-challenge achieved partial response. She is currently receiving treatment with trastuzumab–emtansine. Case 2 was a 74-year-old woman who developed pulmonary metastasis after first-line cisplatin treatment. She had a partial response and a progression-free survival of 10 months. Case 3 had inguinal and para-aortic lymphadenopathy in complete response after 18 treatment administrations. She developed brain metastasis while receiving trastuzumab maintenance. Case 4 was treated for locally advanced disease and experienced a subjective benefit with relief in perineal pain and itching. No unexpected treatment-related side effects were reported.

Conclusions

Advanced vulvar Paget’s disease is a rare disorder and no standard treatment is available. In the sub-group of HER2 positive disease, weekly paclitaxel–trastuzumab appears to be active and safe, and may be considered a therapeutic option in these patients.

Plasma-Based Longitudinal Evaluation of ESR1 Epigenetic Status in Hormone Receptor-Positive HER2-Negative Metastatic Breast Cancer

Background

Endocrine therapy (ET) is the mainstay of treatment for hormone receptor-positive human epidermal growth factor receptor 2 (HER2)-negative metastatic breast cancer; however, adaptive mechanisms emerge in about 25–30% of cases through alterations in the estrogen receptor ligand-binding domain, with a consequent ligand-independent estrogen receptor activity. Epigenetic-mediated events are less known and potentially involved in alternative mechanisms of resistance. The aim of this study was to test the feasibility of estrogen receptor 1 (ESR1) epigenetic characterization through liquid biopsy and to show its potential longitudinal application for an early ET sensitivity assessment.

Methods

A cohort of 49 women with hormone receptor-positive HER2-negative MBC was prospectively enrolled and characterized through circulating tumor DNA using methylation-specific droplet digital PCR (MS-ddPCR) before treatment start (BL) and after 3 months concomitantly with computed tomography (CT) scan restaging (EV1). ESR1 epigenetic status was defined by assessing the methylation of its main promoters (promA and promB). The most established cell-free tumor DNA (ctDNA) factors associated with ET resistance [ESR1 and phosphatidylinositol-4,5-bisphosphate 3-kinase, catalytic subunit alpha (PIK3CA) mutations] were assessed through next-generation sequencing. Associations were tested through Mann–Whitney U test, matched pairs variations through Wilcoxon signed rank test, and survival was analyzed by log-rank test.

Results

The ET backbone was mainly based on aromatase inhibitors (AIs) (70.83%) in association with CDK4/6 inhibitors (93.75%). Significantly lower promA levels at baseline were observed in patients with liver metastases (P = 0.0212) and in patients with ESR1 mutations (P = 0.0091). No significant impact on PFS was observed for promA (P = 0.3777) and promB (P = 0.7455) dichotomized at the median while a ≥2-fold increase in promB or in either promA or promB at EV1 resulted in a significantly worse prognosis (respectively P = 0.0189, P = 0.0294). A significant increase at EV1 was observed for promB among patients with PIK3CA mutation (P = 0.0173). A trend was observed for promB in ESR1 wild-type patients and for promA in the ESR1 mutant subgroup.

Conclusion

The study proofed the concept of an epigenetic characterization strategy based on ctDNA and is capable of being integrated in the current clinical workflow to give useful insights on treatment sensitivity.

Clinico-radiological monitoring strategies in patients with metastatic breast cancer: a real-world study

Aim: A monitoring strategy for metastatic breast cancer patients (M-MBC) has been little studied. Materials & methods: This retrospective study analyzed a consecutive cohort of 382 MBC patients to analyze different M-MBC strategies to identify factors influencing intensive M-MBC. Results: Elevated baseline serum tumor markers (STM) was the strongest factor associated with increased use of STM tests. Having more frequent oncology office visits was associated with more intensive chemotherapy/magnetic resonance imaging (MRI) using. Increased use of imaging tests was associated with participation to clinical trial. Single and elderly patients were less likely to have frequent testing. Having clinically measurable disease was less likely to have more intensive M-MBC. Conclusion: STM testing and scans were frequently ordered in M-MBC. In the present study, strategies are little influenced by clinico-pathological characteristics.

Determinants of choice in offering drug holidays during first-line therapy for metastatic colorectal cancer

Background: 'Drug holidays' (DH) for metastatic colorectal cancer (mCRC) were introduced to preserve quality of life. We studied factors associated to a DH offer in first line. Materials & methods: We retrospectively analyzed 754 consecutive patients treated with chemotherapy for mCRC in two Italian institutions between 2005 and 2017. Associations between baseline clinical-pathological factors and DH (56 or more days of treatment interruption) were investigated. Results: In 754 patients, previous metastasectomy, previous thermoablation and previous surgery of primary tumor were independently associated with DH. Excluding procedures or clinical trials: primary rectal cancer and resection of primary tumor were significantly associated to DH. Conclusions: DH was offered to patients with lower burden of disease, but further investigations are needed to safely guide a holiday strategy.

The SENECA study: Prognostic role of serum biomarkers in older patients with metastatic colorectal cancer

BACKGROUND

Aging induces meaningful changes in the immune system and inflammation response with increase in monocyte-lymphocyte ratio (MLR) and serum lactate dehydrogenase (LDH) levels. Aim of this study was to explore the prognostic role of MLR and LDH levels in older patients (pts) with metastatic colorectal cancer (mCRC).

METHODS

We conducted a retrospective analysis of a consecutive cohort of 168 older (>70 years) patients with mCRC. The prognostic impact of MLR and LDH levels on overall survival (OS) was investigated through uni-and multivariate Cox regression analyses. Moreover, we categorized patients into three groups according to MLR and LDH levels (group 1: MLR-low and LDH-low; group 2: MLR-high or LDH-high; group 3: MLR-high and LDH-high).

RESULTS

By univariate analysis, high LDH level (HR 1.74, 95% CI 1.05-2.90) and high MLR level (HR 2.19, 95% CI 1.48-3.44) were significantly associated with a worse OS. Conversely, primary tumor resection and left-sidedness were significantly associated with a longer OS. By multivariate analysis, high LDH level (HR 2.00, 95% CI 1.13-3.55) and high MLR level (HR 2.99, 95% CI 1.68-5.33) were independent prognostic factors of worse prognosis. Compared to group 1, a shorter survival was reported for patients included in group 2 (HR 1.97, 95% CI 1.21-3.23 in univariate; HR 2.54, 95% CI 1.43-4.51 in multivariate) or in group 3 (HR 2.42, 95% CI 24-4.74, p = .010 in univariate; HR 5.59, 95% CI 2.15-14.54 in multivariate) CONCLUSIONS: High baseline levels of LDH, MLR or both are independent unfavorable prognostic factors in older patients treated with first-line chemotherapy for mCRC.

Abstract P5-14-08: Predictors of relative dose intensity and early dose reduction in patients with metastatic breast cancer treated with palbociclib and endocrine therapy

Background: The combination of endocrine therapy with the cyclin-dependent kinases 4/6 inhibitor palbociclib was proven to be effective for the treatment of hormone receptor (HR)-positive/HER2-negative metastatic breast cancer (MBC). Although generally well tolerated, treatment delays and dose reductions are frequently observed with palbociclib, mainly due to severe neutropenia. Predictors of palbociclib-related toxicities are still unknown, as well as the clinical relevance of its relative dose intensity (RDI). Henceforth, this study aimed to identify baseline clinicopathological features associated with a RDI &lt;75% and early dose reduction (within the first 3 months of treatment). Secondarily, we explored the impact of RDI &lt;75% and early dose reduction on progression-free survival.

Methods: We reviewed data of 150 consecutive patients with HR-positive/HER2-negative MBC patients treated with palbociclib at two Italian cancer centers from 2017 to 2019. Eligible patients must have received at least 3 cycles of treatment. Those who experienced early suspension due to unacceptable toxicities were still eligible. RDI was calculated as the ratio of actual dose intensity (cumulative administered dose/treatment duration) and planned dose intensity (cumulative planned dose/planned treatment duration). The association of both RDI &lt;75% and early dose reduction with baseline clinicopathological features was assessed using multivariate logistic regression. The following variables were investigated as predictors of dose reduction: de novo vs. recurrent MBC, prior chemotherapy, treatment line, associated endocrine therapy, performance status (PS), weight, renal clearance, hemoglobin level, absolute white blood cell (WBC) count, absolute neutrophils count and absolute platelet count. A ROC analysis was performed to identify the best cut-off for baseline weight in predicting a RDI &lt;75%, while continuous laboratory variables were dichotomized according to clinically relevant cut-offs.

Results: Overall, 142 patients were deemed eligible. Of these patients, 98 (69.0%) were treated with palbociclib plus fulvestrant, 44 (31.0%) with palbociclib plus aromatase inhibitors, and 73 (51.4%) in the first-line setting. The median number of administered palbociclib cycles was 8 (range: 1-24) and 61 patients (43.0%) required at least a first-level dose reduction (29 within 3 months). Furthermore, the median time to first dose reduction was 3.22 months, with neutropenia being responsible for 85.24% of first-level dose reductions. In the whole cohort, median RDI was 90.5% (95.1% for patients without dose reduction and 80% for those who had received a dose reduction). Notably, 28 patients (19.7%) experienced a RDI &lt;75%. Through multivariate logistic regression, baseline weight ≤66 kg (OR 3.01, 95% CI: 1.08-8.35, p=0.03) and WBC ≤4.5 × 109/L (OR 3.15, 95% CI: 1.08-9.12, p=0.03) were independently associated with a RDI &lt;75%. Moreover, baseline weight ≤66 kg was also significantly correlated with early dose reduction (OR 2.77, 95% CI: 1.09-7.01, p=0.03). After a median follow-up of 11.76 months, median PFS was 13.99 months. When exploring potential prognostic factors, neither a RDI &lt;75% (HR 1.01, 95% CI: 0.52-1.95, p=0.97) nor a dose reduction within the first 3 months (HR 1.39, 95% CI: 0.67-2.91, p=0.31) did significantly impact PFS.

Conclusions: In our analysis, baseline weight and WBC were statistically associated with a RDI &lt;75% in patients with MBC treated with palbociclib. Furthermore, baseline weight was also able to predict an early dose reduction in the study population. Lastly, early dose reduction and RDI &lt;75% did not impact PFS. Although the small sample size and the limited follow-up, our results warrant further investigation in specifically designed trials.

Citation Format: Giacomo Pelizzari, Elisa Bertoli, Marco Giavarra, Carla Corvaja, Lorenzo Gerratana, Debora Basile, Michele Bartoletti, Camilla Lisanti, Lucia Bortot, Silvia Buriolla, Mattia Garutti, Debora Avoledo, Marta Bonotto, Lucia Da Ros, Silvia Bolzonello, Mauro Mansutti, Paola Di Nardo, Gianpiero Fasola, Simon Spazzapan, Alessandro M Minisini, Fabio Puglisi. Predictors of relative dose intensity and early dose reduction in patients with metastatic breast cancer treated with palbociclib and endocrine therapy [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P5-14-08.

Long-term toxicity profile of trastuzumab emtansine (T-DM1): A multicenter real-life study

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Background: T-DM1 is widely used in HER2 positive metastatic breast cancer (MBC) patients (pts), often for many cycles until progression. However, little is known about its long term toxicity. The aim of this study was to evaluate the safety profile of T-DM1 when delivered for ≥12 cycles. Methods: HER2 positive MBC pts who had received ≥12 cycles of T-DM1 across 18 Italian cancer centers were enrolled from January 2017 to September 2018. The 12 cycles cut-off was chosen based on the EMILIA trial median PFS (9.6 months), to identify a patient population treated with T-DM1 for longer time. Tumor and clinical characteristics were collected. Standard haematological tests, blood chemistries and side effects (nausea, vomiting, diarrhea, stomatitis, asthenia) were recorded cycle by cycle, according CTCAE criteria version 4. Haematological and laboratory toxicities were available for 86 patients, while other toxicities for all 115 patients. Results: Overall, 115 pts were enrolled. Median age was 54.5 (range 29.6–81.9); median time from diagnosis of metastatic disease to first T-DM1 cycle was 32.5 months. T-DM1 was administered as 2nd line and 3rd line of treatment in 45.2% and 27.8% of pts, respectively. Median number of cycles was 18 (range 12-59). Complete response, partial response and stable disease rates were 11.4%, 43% and 45.6%, respectively. Treatment related side effects are shown in table 1. Interestingly, no increased liver toxicity was observed in pts with liver metastases. Analysis of mean CTCAE grade by cycle showed that no relevant incremental toxicity was observed during long term T-DM1 therapy. Conclusions: T-DM1 is safe and well tolerated in these long responding pts. We found no relevant cumulative toxicity. Patients should be treated with T-DM1 as long as their tumor responds, as no safety issues are related to its long term use. [Table: see text]

The IMPACT study: early loss of skeletal muscle mass in advanced pancreatic cancer patients

BACKGROUND

Pancreatic cancer (PC) patients have multiple risk factors for sarcopenia and loss of skeletal muscle mass (LSMM), which may cause greater treatment toxicities, reduced response to cancer therapy, prolonged hospitalization, impaired quality of life, and worse prognosis.

METHODS

This is a retrospective study on advanced PC patients treated at the Department of Oncology of Udine, Italy, from January 2012 to November 2017. Among 162 patients who received chemotherapy, 94 consecutive patients with an available computed tomography (CT) scan were retrospectively analyzed. The primary objective of our study was to explore if an early LSMM ≥ 10% (measured at first radiological evaluation and compared with baseline) and/or baseline sarcopenia may impact prognosis. Baseline sarcopenia was defined according to Prado's criteria. Skeletal muscle area was measured as cross-sectional areas (cm² ) using CT scan data through the Picture archiving and communication system (PACS) image system.

RESULTS

In the whole cohort, 48% of patients were ≤70 years old, and 50% had metastatic disease. At baseline, 73% of patients had sarcopenia, and 16% presented a visceral fat area ≥ 44 cm² /m² . Overall, 21% experienced an early LSMM ≥ 10%. Approximately 33% of sarcopenic patients at baseline and ~35% of patients with early LSMM ≥ 10% had a body mass index > 25 kg/m² . Of note, 71% of patients were evaluated by a nutritionist, and 56% received a dietary supplementation (oral and/or parenteral). After a median follow-up of 30.44 months, median overall survival (OS) was 11.28 months, whereas median progression-free survival (PFS) was 5.72 months. By multivariate analysis, early LSMM ≥ 10% was significantly associated with worse OS [hazard ratio (HR): 2.16; 95% confidence interval (CI) 1.23-3.78; P = 0.007] and PFS (HR: 2.31; 95% CI 1.30-4.09; P = 0.004). Moreover, an exploratory analysis showed that inflammatory indexes, such as neutrophil-lymphocyte ratio variation, impact early LSMM ≥ 10% (odds ratio 1.31, 95% CI 1.06-1.61, P = 0.010).

CONCLUSIONS

Early LSMM ≥ 10% has a negative prognostic role in advanced PC patients. Further prospective investigations are needed to confirm these preliminary data.

Abstract P1-14-04: Overall survival in metastatic breast cancer patients in the third millennium: Results of an Italian study

BACKGROUND - Metastatic breast cancer (MBC) is a life-threatening disease. It is important to provide data about real-life MBC patients (pts) to understand the current prognostic factors. The aim of the present observational study, named COSMO (Checking Overall Survival in a MBC Observational study) is to describe the overall survival (OS) in a large cohort of MBC pts, assessing its correlation with specific prognostic factors (demographic, clinic, pathologic and biological).

PATIENTS AND METHODS - The COSMO study is a multicenter, retrospective, cohort study, developed throughout the collaboration of 31 Italian oncological centers. Data about pts diagnosed as metastatic from 01/01/2000 to 31/12/2008, were collected. The association between molecular subtypes, metastatic sites, disease free interval (DFI) and OS were assessed. Pts were classified in three subgroups, based on the biological characteristics of their tumor: luminal, HER2-positive (regardless of hormone receptor) and triple negative (TN). Metastatic sites were categorized as visceral versus non-visceral disease, only bone and central nervous system (CNS) metastases. DFI was calculated from diagnosis to first relapse only for M0 pts.

RESULTS - Of 3931 MBC pts enrolled in the study, 3720 were evaluable, with a median age of 61 years (interquartile range, IQR, 51-71). 1804 (62,1%) pts had a luminal disease, 691 (23,8%) HER2-positive, 410 (14.1%) TN. Median DFI was 3.2 years (IQR 1.7- 6.0). Regarding metastatic sites, pts with visceral disease were 2332 (63%); 826 (22,2%) pts had bone isolated metastases; in 306 (8,3%) pts, CNS metastases were reported. With a median follow up of 9 years (IQR 5.7-11.0) and 3098 (83.3%) recorded events, we founded a median OS of 2.8 years (95%CI: 2.7-2.9) years. OS was strictly depending from molecular subtypes with a better prognosis for HER2-positive versus luminal and TN MBC pts, median OS of 3.1 (95%CI 2.8-3.4), 3.0 (95%CI: 2.9-3.1) and 1.5 (95%CI: 1.3-1.7) years respectively (p-value&lt;0.001). 525 (14,1%) pts received trastuzumab. Metastatic sites affect prognosis, with a better OS for bone disease (3.4 years, 95%CI: 3.1-3.6) versus visceral disease (2.2 years 95%CI: 2.0- 2.3). Brain metastasis correlate with the worst prognosis: OS of 1.5 years (95% CI: 0.8 – 1.7). Even DFI shows a correlation with prognosis: pts with DFI&gt;2 years show a median OS of 3 years (95% CI: 2.9 – 3.2), while those with DFI&lt;2 years have a median OS of 2.4 years (95% CI: 2.3-2.6); HR was 0.69 (95%CI: 0,62-0,76) for every five years of increase in DFI (p-value&lt;0.001).

CONCLUSIONS - Molecular subtype is crucial for prognosis: HER2-positive subtype has the best prognosis, while TN subtype has the shorter OS. Having a longer DFI from diagnosis (&gt;2 years) correlate with a better prognosis. Our study confirm that sites of metastasis affects outcome: visceral involvement correlates with poor prognosis and, particularly, pts with brain metastasis represent the worst subgroup, while pts with solely bone disease have the best prognosis. The COSMO study provides a view on the Italian landscape of MBC between 2000 and 2008, adding new insights about pts prognosis.

Citation Format: La Verde N, Collovà E, Blasi L, Pinotti G, Bernardo A, Bonotto M, Garrone O, Brunello A, Cavazzini MG, Bareggi C, Prochilo T, Porcu L, Moretti A, Barni S, On Behalf of COSMO Study Group. Overall survival in metastatic breast cancer patients in the third millennium: Results of an Italian study [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P1-14-04.

Human epidermal growth factor receptor 2 dual blockade with trastuzumab and pertuzumab in real life: Italian clinical practice versus the CLEOPATRA trial results

OBJECTIVES

Given their inclusion and exclusion criteria, randomized clinical trials (RCT) might not include a population that truly mirrors real life (RL). This raises concerns about the applicability of RCT results in clinical practice. We evaluated the efficacy of anti-HER2 treatment with pertuzumab combined with trastuzumab and a taxane as first-line treatment for HER2-positive metastatic breast cancer in a RL setting, and compared the safety results obtained in our population versus the experimental cohort of the CLEOPATRA RCT, which led to the approval of this therapy.

MATERIALS AND METHODS

Patients treated with trastuzumab, pertuzumab and a taxane were enrolled in this retrospective study. We compared the tumor features and the patients' characteristics of the RL cohort to those of the CLEOPATRA cohort. We also compared the median progression-free survival (PFS) in the RL population versus specific patients' subgroups.

RESULTS

RL patients were more frequently HR-positive, less likely to have visceral metastases (P < .001 for both) and had more frequently received (neo)adjuvant hormone therapy or trastuzumab than CLEOPATRA patients (P = .004 and P < .001, respectively). The median number of anti-HER2 cycles was 8 vs 24 and the median number of cycles was 7 vs 8 for docetaxel in the RL versus CLEOPATRA population, respectively. Adverse reactions of all grades were less frequent in RL. Median PFS was 27.8 months in the RL population and the treatment was equally effective in all patients' subgroups.

CONCLUSION

This study provides compelling evidence that pertuzumab, trastuzumab and a taxane are effective and safe also in a clinical scenario.

Luminal-like HER2-negative stage IA breast cancer: a multicenter retrospective study on long-term outcome with propensity score analysis

The benefit of adding chemotherapy (CT) to adjuvant hormone therapy (HT) in stage IA luminal-like HER2-negative breast cancer (BC) is unclear. We retrospectively evaluated predictive factors and clinical outcome of 1,222 patients from 4 oncologic centers. Three hundred and eighty patients received CT and HT (CT-cohort) and 842 received HT alone (HT-cohort). Disease-free survival (DFS) and overall survival (OS) were evaluated with univariate and multivariate analyses. We also applied the propensity score methodology. Compared with the HT-cohort, patients in the CT-cohort were more likely to be younger, have larger tumors of a higher histological grade that were Ki67-positive, and lower estrogen and progesterone receptor expression. At univariate analysis, a higher histological grade and Ki67 were significantly associated to a lower DFS. At multivariable analysis, only histological grade was predictive of DFS. The CT-cohort had a worse outcome than the HT-cohort in terms of DFS and OS, but differences disappeared when matched according to propensity score. In summary, patients with stage IA luminal-like BC had an excellent prognosis, however relapse and mortality were higher in the CT-cohort than in the HT-cohort. Longer use of adjuvant HT or other therapeutic strategies may be needed to improve outcome.

Androgen receptor in estrogen receptor positive breast cancer: Beyond expression

In recent years, new therapeutic approaches have reshaped the overall strategy of breast cancer (BC) treatment and have markedly improved patient survival. This is, in part, due to novel therapies for estrogen receptor (ER)-positive BC. Unfortunately, many patients present de novo resistance to these therapies or develop an acquired resistance over time. Therefore, research is now focused on discovering new molecular targets to overcome these resistances. Interestingly, preclinical and clinical studies have shown a critical role for the cross-talk between androgen receptor (AR) and ER in luminal-like BC. AR is expressed in >60% of BC and in up to 90% of ERα-positive tumors. Multiple studies suggest that AR is associated with a favorable prognosis. However, AR overexpression and, in particular, the high AR:ER ratio, seem to be involved in resistance to hormonal treatment. In this setting, a group of BCs could benefit from AR-inhibitors; nevertheless, some ER-positive BC patients do not seem to benefit from this strategy. Therefore, it is crucial to identify biomarkers that would enable the selection of patients who might benefit from combination treatment with ER and AR inhibitors.