Clinical significance and prognostic value of receptor conversion in hormone receptor positive breast cancers after neoadjuvant chemotherapy

Background

Neoadjuvant chemotherapy (NAC) is widely used in advanced breast cancer patients. However, there is little known about conversion frequency of estrogen receptor (ER) and/or progesterone receptor (PR) status for hormone receptor positive-breast cancer patients after NAC and their correlation with prognosis.

Methods

In this study, 231 breast cancer patients with residual disease after NAC were enrolled and divided into receptor stable group (having no conversion in both ER and PR status pre- and post-NAC) and any receptor conversion group (having any conversion in either ER or PR status). Univariate and multivariate survival analyses were used to compare survival differences between the two groups.

Results

Fifty-five patients (23.8%) had ER and/or PR conversion after NAC. Younger patients (≤ 50 years) were more likely to have receptor conversion (P = 0.014). For 213 patients (92.2%) who received adjuvant endocrinotherapy after surgery, the 5-year disease free survival (DFS) estimates for patients in the any receptor conversion group (55.2%) was worse than patients in the receptor stable group (73.7%, Log-rank test, P = 0.015). While the 5-year overall survival estimates for patients with or without receptor conversion were not statistically different (86.0 vs. 82.4%, Log-rank test, P = 0.587). In multivariate Cox proportional hazard analyses, patients with any receptor conversion had worse DFS (hazard ratio, 1.995; 95% confidence interval, 1.130–3.521, P = 0.031).

Conclusions

It is necessary to recommend patients to test biomarkers in residual disease and pay more attention to patients who have any receptor conversion. These patients may need more individual therapy after surgery.

Evaluation of [89Zr]trastuzumab-PET/CT in differentiating HER2-positive from HER2-negative breast cancer

PURPOSE

To evaluate whether tumor uptake of [⁸⁹Zr]trastuzumab can distinguish HER2-positive from HER2-negative breast cancer.

METHODS

Women with HER2-positive (n = 34) and HER2-negative (n = 16) breast cancer underwent PET/CT 5 ± 2 days following [⁸⁹Zr]trastuzumab administration. HER2 status was determined based on immunohistochemistry and/or fluorescence in situ hybridization of primary or metastatic/recurrent tumor. Tumor [⁸⁹Zr]trastuzumab uptake was assessed qualitatively and semiquantitatively as maximum standardized uptake value (SUV_max), and correlated with HER2 status. Additionally, intrapatient heterogeneity of [⁸⁹Zr]trastuzumab uptake was evaluated.

RESULTS

On a per-patient basis, [⁸⁹Zr]trastuzumab-PET/CT was positive in 30/34 (88.2%) HER2-positive and negative in 15/16 (93.7%) HER2-negative patients. Considering all lesions, the SUV_max was not significantly different in patients with HER2-positive versus HER2-negative disease (p = 0.06). The same was true of when only hepatic lesions were evaluated (p = 0.42). However, after excluding hepatic lesions, tumor SUV_max was significantly higher in HER2-positive compared to HER2-negative patients (p = 0.003). A cutoff SUV_max of 3.2, determined by ROC analysis, demonstrated positive-predictive value of 83.3% (95% CI 65.3%, 94.4%), sensitivity of 75.8% (57.7%, 88.9%), negative-predictive value of 50% (24.7%, 75.3%), and specificity of 61.5% (95% 31.6%, 86.1%) for differentiating HER2-positive from HER2-negative lesions. There was intrapatient heterogeneity of [⁸⁹Zr]trastuzumab uptake in 20% of patients with multiple lesions.

CONCLUSIONS

[⁸⁹Zr]trastuzumab has the potential to characterize the HER2 status of the complete tumor burden in patients with breast cancer, thus obviating repeat or multiple tissue sampling to assess intrapatient heterogeneity of HER2 status.

Negative genic switch of HER-2 in the primary tumor instead of the synchronous metastatic nodal lesions after neoadjuvant chemotherapy in a patient with primary HER2-positive breast cancer

Background

A few retrospective studies have indicated that neoadjuvant chemotherapy (NAC) in breast cancer may change biomarker profiles of the primary tumor. Little is known about the status of HER-2 gene of the synchronous nodal metastases when that of the residual tumor undergoes negative conversion in a neoadjuvant setting.

Case presentation

We describe a female patient with left breast cancer (T2N2M0) who underwent negative conversion of HER-2 in the primary tumor instead of the synchronous nodal lesions after NAC. Core needle biopsy showed invasive ductal carcinoma with HER2 immunohistochemistry (IHC) (2+) and amplified HER-2 gene determined by fluorescence in situ hybridization (FISH). Then, the patient underwent 4 cycles of anthracycline- and taxane-based NAC and subsequent left modified radical mastectomy. Postoperative pathology showed invasive ductal carcinoma involving 4 of 12 surgically excised axillary lymph nodes with HER2 IHC (1+) and FISH negative (HER2 gene not amplified) in the residual tumor of the breast specimen. Due to the negative genic switch of HER2 after NAC, the patient rejected to accept trastuzumab. Under the patient’s consent, the synchronous nodal lesions were further investigated and showed HER2 IHC(−) but FISH positive (HER-2 gene amplified). Therefore, the patient agreed to accept adjuvant trastuzumab treatment every 3 weeks for 1 year.

Conclusions

We propose further assessment of HER2 gene in the synchronous nodal metastases, especially when negative genic switch of HER-2 occurs in the primary tumor after NAC in order to tailor the systemic regimens for breast cancer patients.

HER2-positive breast cancer

Anti-HER2 treatment for HER2-positive breast cancer has changed the natural biology of this disease. This Series article reviews the main achievements so far in the treatment of both metastatic and early HER2-positive breast cancer. The success of neoadjuvant therapy in HER2-positive early breast cancer is especially acknowledged, as pertuzumab has been approved on the basis of a higher proportion of patients achieving a pathological complete response with pertuzumab and trastuzumab than with trastuzumab alone in a neoadjuvant study. Event-free survival after the confirmatory adjuvant trial completed recruitment was numerically better with pertuzumab plus trastuzumab than with trastuzumab alone. With survival rates of almost 5 years in women with metastatic HER2-positive breast cancer and 75% of patients achieving a pathological complete response, new treatments in the past decade have clearly improved the prognosis of HER2-positive breast cancer. Despite these achievements, however, the persisting high toll of deaths resulting from HER2-positive breast cancer calls for continued, intensive clinical research of newer therapies and combinations.

Predicting and Overcoming Chemotherapeutic Resistance in Breast Cancer

Our understanding of breast cancer and its therapeutic approach has improved greatly due to the advancement of molecular biology in recent years. Clinically, breast cancers are characterized into three basic types based on their immunohistochemical properties. They are triple-negative breast cancer, estrogen receptor (ER) and progesterone receptor (PR)-positive-HR positive breast cancer, and human epidermal growth factor receptor 2 (HER2)-positive breast cancer. Even though these subtypes have been characterized, assessment of a breast cancer's receptor status is still widely used to determine whether or not a targeted therapy could be applied. Moreover, drug resistance is common in all breast cancer types despite the different treatment modalities applied. The development of resistance to different therapeutics is not mutually exclusive. It seems that tumor could be resistant to multiple treatment strategies, such as being both chemoresistant and monoclonal antibody resistant. However, the underlying mechanisms are complicated and need further investigation. In this chapter, we aim to provide a brief review of the different types of breast cancer and their respective treatment strategies. We also review the possible mechanisms of potential drug resistance associated with each treatment type. We believe that a better understanding of the drug resistance mechanisms can lead to a more effective and efficient therapeutic success.

Modern therapies and iatrogenic changes in breast pathology

Iatrogenic changes within the breast can provide challenges for the histopathologist in routine practice. Diagnostic procedures, such as core biopsies, result in reactive changes and can cause displacement of benign and malignant cells, the interpretation of which may cause difficulties in the resection specimen. Breast augmentation surgery with implants or injection of fillers, performed for cosmetic reasons or as part of a reconstructive process following removal of breast cancer, also produces reactive changes locally and at distant sites that may mimic cancer. The entity of implant-associated anaplastic large-cell lymphoma is now well recognized, with progress in our understanding of the underlying biological factors that drive its development. Chemotherapy and radiotherapy used in the treatment of breast cancer causes characteristic changes in normal breast tissue, and can alter the histological appearance and receptor status of the tumour. Radiotherapy to the breast, for breast cancer or childhood malignancies, increases the risk of developing a secondary malignancy in the breast long after treatment. In this review, we describe some of the iatrogenic changes that may be seen in histological specimens from the breast.

Weekly paclitaxel plus carboplatin with or without trastuzumab as neoadjuvant chemotherapy for HER2-positive breast cancer: loss of HER2 amplification and its impact on response and prognosis

PURPOSE

Neoadjuvant chemotherapy (NCT) plus anti-HER2 agents are the standard of care for locally advanced HER2-positive breast cancer. The aim of this study was to evaluate the prevalence and prognostic impact of HER2 loss in patients with HER2-positive disease treated with neoadjuvant therapy with or without trastuzumab.

METHODS

549 consecutive HER2-positive patients were included in this study. 379 patients were treated with paclitaxel, carboplatin, and trastuzumab (PCH cohort) and 170 were treated with paclitaxel and carboplatin only (PC cohort). Conversion of biomarkers before and after NCT was evaluated via immunohistochemistry (IHC) test. Cox regression model was used to investigate prognostic markers to relapse-free survival (RFS).

RESULTS

50.9% patients were considered as pCR responder in PCH cohort, whereas only 25.9% of patients experienced pCR in PC cohort (P < 0.001). HER2 loss were more frequently shown in PCH cohort with a proportion of 19.8%, compared to 9.4% in PC cohort (P = 0.009). In PCH cohort, patients with a loss of HER2 expression tended to have a higher risk of relapse compared to patients with maintained HER2 expression (HR = 2.639, 95% CI 1.103-6.311, P = 0.029). However, it did not correlate to patient outcome in the PC cohort (P = 0.296). Loss of HER2 was also correlated to ER conversion in PCH cohort.

CONCLUSION

Our study has provided new evidence that anti-HER2 treatment has a significant impact on HER2 loss. Far more importantly, the loss of HER2 amplification could identify non-pCR patients with high risk of disease relapse, which might help in tailoring following systemic treatment.

HER2 loss in HER2-positive gastric or gastroesophageal cancer after trastuzumab therapy: Implication for further clinical research

Mechanisms of acquired resistance to trastuzumab-based treatment in gastric cancer are largely unknown. In this study, we analyzed 22 pairs of tumor samples taken at baseline and post-progression in patients receiving chemotherapy and trastuzumab for advanced HER2-positive [immunohistochemistry (IHC) 3+ or 2+ with in-situ hybridization (ISH) amplification] gastric or gastroesophageal cancers. Strict clinical criteria for defining acquired trastuzumab resistance were adopted. Loss of HER2 positivity and loss of HER2 over-expression were defined as post-trastuzumab IHC score <3+ and absence of ISH amplification, and IHC "downscoring" from 2+/3+ to 0/1+, respectively. HER2 IHC was always performed, while ISH was missing in 3 post-progression samples. Patients with initial HER2 IHC score 3+ and 2+ were 14 (64%) and 8 (36%), respectively. Loss of HER2 positivity and HER2 over-expression was observed in 32 and 32% samples, respectively. The chance of HER2 loss was not associated with any of the baseline clinicopathological variables. The only exception was in patients with initial IHC score 2+ versus 3+, for both endpoints of HER2 positivity (80 vs. 14%; p = 0.008) and HER2 over-expression (63 vs. 14%; p = 0.025). As already shown in breast cancer, loss of HER2 may be observed also in gastric cancers patients treated with trastuzumab-based chemotherapy in the clinical practice. This phenomenon may be one of the biological reasons explaining the failure of anti-HER2 second-line strategies in initially HER2-positive disease.

The importance of tissue confirmation of metastatic disease in patients with breast cancer: lesson from a brain metastasis case

Background

The discrepancy of estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2) statuses in breast cancers has been reported. Available systemic therapy for patients with breast cancer is based on the molecular subtypes as identified by IHC and/or FISH. However, these biomarkers may change throughout tumor progression.

Case presentation

We report a relatively uncommon case of a 39-year-old Chinese woman with local advanced breast cancer (LABC) treated with 6 cycles of docetaxel, doxorubicin and cyclophosphamide (TAC) regimen neoadjuvant chemotherapy, and subsequently mastectomy, intensity-modulated radiation therapy (IMRT) and tamoxifen followed as regularly. Brain metastatic event appeared in 6 months after mastectomy. Treatment for brain metastasis was surgical resection and followed by whole brain radiotherapy (WBRT) approved by multidisciplinary team (MDT). Initial pathological diagnosis was IDC, cT4N1M0, luminal B (ER+ 90%, PR+90%, HER2 0, Ki67+ 70%) based on ultrasound-guided core needle biopsy. Surgical pathology revealed IDC, pT2N3M0 luminal B (ER+ 20%, PR+20%, HER2 0, Ki67+ 20%). Histological response to neoadjuvant chemotherapy is grade 3 according to the Miller/Payne grading system. Final pathology of brain metastasis showed a HER2 overexpression metastatic breast cancer luminal B (ER+ 70%, PR+ 70%, HER2 2+, Ki67+ 30%), FISH confirmed HER2 overexpression. Weekly paclitaxel plus trastuzumab was given for 12 weeks, then trastuzumab every 3 weeks for a whole year. Patient follow-up is still ongoing, no new events appear yet.

Conclusions

The determination of hormone receptors and HER2 status should be routinely performed in all involved tissues, if possible, and systemic therapy should be tailored following the latest finding.

Translating neoadjuvant therapy into survival benefits: one size does not fit all

Neoadjuvant therapy has been established as an effective therapeutic approach for patients with locally advanced breast cancer. Similar outcomes between neoadjuvant and adjuvant chemotherapy have been demonstrated in several trials. Nevertheless, neoadjuvant therapy has some advantages over adjuvant therapy, including tumour downstaging, in vivo assessment of therapeutic efficacy, reduced treatment durations, and the need to enrol fewer patients for clinical trials to reach their preplanned objectives. The number of neoadjuvant trials in patients with breast cancer has increased substantially in the past 5 years, particularly in the context of HER2-positive disease. Substantial improvements in the pathological complete response rate to anti-HER2 therapy, a proposed surrogate end point for long-term clinical benefit, have been observed with neoadjuvant dual-agent HER2 blockade. Thus, it was hypothesized that this approach would provide additional survival benefits over standard-of-care therapy with the anti-HER2 antibody trastuzumab in the adjuvant setting. Emerging data, however, are calling this notion into question. We discuss potential reasons why results of neoadjuvant trials of targeted therapies have not been mirrored in the adjuvant setting, and other than inherent differences in clinical-trial designs and statistical power, we consider how the biology of the disease, patient characteristics, and drug administration and schedule might influence the results.

Body mass index and survival after diagnosis of invasive breast cancer: a study based on the Japanese National Clinical Database-Breast Cancer Registry

Few studies have reported the association between body mass index (BMI) and outcome among Asian breast cancer patients. We analyzed data for 20,090 female invasive breast cancer patients who had been followed‐up for a median period of 6.7 years entered in the National Clinical Database–Breast Cancer Registry between 2004 and 2006. We used mainly the WHO criteria for BMI (kg/m²) categories; <18.5 (underweight), ≥18.5–<21.8 (reference), ≥21.8–<25, ≥25–<30 (overweight), and ≥30 (obese). We divided normal weight patients into two subgroups because this category includes many patients compared to others. The timing of BMI measurement was not specified. The Cox proportional hazards model and cubic spline regression were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs). Smoking, alcohol, and physical activity were not controlled. A total of 1418 all‐cause, 937 breast cancer–specific deaths, and 2433 recurrences were observed. Obesity was associated with an increased risk of all‐cause (HR: 1.46; 95% CI: 1.16–1.83) and breast cancer–specific death (HR: 1.47; 95% CI: 1.11–1.93) for all patients, and with all‐cause (HR: 1.47; 95% CI: 1.13–1.92) and breast cancer–specific death (HR: 1.58; 95% CI: 1.13–2.20) for postmenopausal patients. Being underweight was associated with an increased risk of all‐cause death for all (HR: 1.41; 95% CI: 1.16–1.71) and for postmenopausal patients (HR: 1.45; 95% CI: 1.15–1.84). With regard to subtype and menopausal status, obesity was associated with an increased risk of breast cancer–specific death for all cases of luminal B tumor (HR: 2.59; 95% CI: 1.51–4.43; P_{heterogeneity} of Luminal B vs. Triple negative = 0.016) and for postmenopausal patients with luminal B tumor (HR: 3.24; 95% CI: 1.71–6.17). Being obese or underweight is associated with a higher risk of death among female breast cancer patients in Japan.