Char-Hong Ng

Metformin synergizes 5-fluorouracil, epirubicin, and cyclophosphamide (FEC) combination therapy through impairing intracellular ATP production and DNA repair in breast cancer stem cells

Metformin, an AMPK activator, has been reported to improve pathological response to chemotherapy in diabetic breast cancer patients. To date, its mechanism of action in cancer, especially in cancer stem cells (CSCs) have not been fully elucidated. In this study, we demonstrated that metformin, but not other AMPK activators (e.g. AICAR and A-769662), synergizes 5-fluouracil, epirubicin, and cyclophosphamide (FEC) combination chemotherapy in non-stem breast cancer cells and breast cancer stem cells. We show that this occurs through an AMPK-dependent mechanism in parental breast cancer cell lines. In contrast, the synergistic effects of metformin and FEC occurred in an AMPK-independent mechanism in breast CSCs. Further analyses revealed that metformin accelerated glucose consumption and lactate production more severely in the breast CSCs but the production of intracellular ATP was severely hampered, leading to a severe energy crisis and impairs the ability of CSCs to repair FEC-induced DNA damage. Indeed, addition of extracellular ATP completely abrogated the synergistic effects of metformin on FEC sensitivity in breast CSCs. In conclusion, our results suggest that metformin synergizes FEC sensitivity through distinct mechanism in parental breast cancer cell lines and CSCs, thus providing further evidence for the clinical relevance of metformin for the treatment of cancers.

The Estrogen Receptor Negative-Progesterone Receptor Positive Breast Carcinoma is a Biological Entity and not a Technical Artifact

The ER-/PR+ breast tumor may be the result of a false ER negative result. The aim of this study was to investigate whether there is a difference in patient and tumor characteristics of the ER-/PR+ phenotype in an Asian setting. A total of 2629 breast cancer patients were categorized on the basis of their age, ethnicity, tumor hormonal receptor phenotype, grade and histological type. There were 1230 (46.8%) ER+/PR+, 306 (11.6%) ER+/PR-, 122 (4.6%) ER-/PR+ and 972 (37%) ER-/PR-. ER-/PR+ tumors were 2.5 times more likely to be younger than 50 years at diagnosis (OR: 2.52; 95% CI: 1.72-3.67). Compared to ER+/PR+ tumors, the ER-/ PR+ phenotype was twice more likely to be associated with grade 3 tumors (OR:2.02; 95%CI: 1.00-4.10). In contrast, compared to ER-/PR- tumors, the ER-/PR+ phenotype was 90% less likely to be associated with a grade 3 tumor (OR: 0.12; 95%CI:0.05-0.26), and more likely to have invasive lobular than invasive ductal histology (OR: 3.66; 95%CI: 1.47-9.11). These results show that the ER-/PR+ phenotype occurs in a younger age group and is associated with intermediate histopathological characteristics compared to ER+/PR+ and ER-/PR- tumors. This may imply that it is a distinct entity and not a technical artifact.

The predictive accuracy of PREDICT: a personalized decision-making tool for Southeast Asian women with breast cancer.

Abstract Web-based prognostication tools may provide a simple and economically feasible option to aid prognostication and selection of chemotherapy in early breast cancers. We validated PREDICT, a free online breast cancer prognostication and treatment benefit tool, in a resource-limited setting. All 1480 patients who underwent complete surgical treatment for stages I to III breast cancer from 1998 to 2006 were identified from the prospective breast cancer registry of University Malaya Medical Centre, Kuala Lumpur, Malaysia. Calibration was evaluated by comparing the model-predicted overall survival (OS) with patients’ actual OS. Model discrimination was tested using receiver-operating characteristic (ROC) analysis. Median age at diagnosis was 50 years. The median tumor size at presentation was 3 cm and 54% of patients had lymph node-negative disease. About 55% of women had estrogen receptor-positive breast cancer. Overall, the model-predicted 5 and 10-year OS was 86.3% and 77.5%, respectively, whereas the observed 5 and 10-year OS was 87.6% (difference: −1.3%) and 74.2% (difference: 3.3%), respectively; P values for goodness-of-fit test were 0.18 and 0.12, respectively. The program was accurate in most subgroups of patients, but significantly overestimated survival in patients aged <40 years, and in those receiving neoadjuvant chemotherapy. PREDICT performed well in terms of discrimination; areas under ROC curve were 0.78 (95% confidence interval [CI]: 0.74–0.81) and 0.73 (95% CI: 0.68–0.78) for 5 and 10-year OS, respectively. Based on its accurate performance in this study, PREDICT may be clinically useful in prognosticating women with breast cancer and personalizing breast cancer treatment in resource-limited settings.

Risk of Treatment Related Death and Febrile Neutropaenia with Taxane-Based Adjuvant Chemotherapy for Breast Cancer in a Middle Income Country Outside a Clinical Trial Setting

BACKGROUND The risk of treatment-related death (TRD) and febrile neutropaenia (FN) with adjuvant taxane- based chemotherapy for early breast cancer is unknown in Malaysia despite its widespread usage in recent years. This study aims to determine these rates in patients treated in University Malaya Medical Centre (UMMC). PATIENTS AND METHODS Patients who were treated with adjuvant taxane-based chemotherapy for early breast cancer stages I, II or III from 2007-2011 in UMMC were identified from our UMMC Breast Cancer Registry. The TRD and FN rates were then determined retrospectively from medical records. TRD was defined as death occurring during or within 30 days of completing chemotherapy as a consequence of the chemotherapy treatment. FN was defined as an oral temperature >38.5°C or two consecutive readings of >38.0°C for 2 hours and an absolute neutrophil count <0.5x109/L, or expected to fall below 0.5x109/L. RESULTS A total of 622 patients received adjuvant chemotherapy during this period. Of these patients 209 (33.6%) received taxane-based chemotherapy. 4 taxane-based regimens were used namely the FEC-D, TC, TAC and AC-PCX regimens. The commonest regimen employed was the FEC-D regimen accounting for 79.9% of the patients. The FN rate was 10% and there was no TRD. CONCLUSION Adjuvant taxane-based chemotherapy in UMMC for early breast cancer has a FN rate of 10%. Primary prophylactic G-CSF should be considered for patients with any additional risk factor for FN.

Do Clinical Features and Survival of Single Hormone Receptor Positive Breast Cancers Differ from Double Hormone Receptor Positive Breast Cancers

The significance of the single hormone receptor positive phenotype of breast cancer is still poorly understood. The use of hormone therapy has been found to be less effective for this type, which has a survival outcome midway between double positive and double negative phenotypes. The aim of this study was to investigate differences in patient and tumor characteristics and survival between double-receptor positive (ER+PR+), double receptor negative (ER-PR-) and single receptor positive (ER+PR- and ER-PR+) breast cancer in an Asian setting. A total of 1,992 patients with newly diagnosed stage I to IV breast cancer between 2003 and 2008, and where information on ER and PR were available, were included in this study. The majority of patients had ER+PR+ tumors (n=903: 45.3%), followed by 741 (37.2%) ER-PR-, 247 (12.4%) ER+PR-, and 101 (5.1%) ER-PR+ tumors. Using multivariate analysis, ER+PR- tumors were 2.4 times more likely to be grade 3 compared to ER+PR+ tumors. ER+PR- and ER-PR+ tumors were 82% and 86% respectively less likely to be grade 3 compared with ER-PR- tumors. ER-PR+ tumours were associated with younger age. There were no survival differences between patients with ER+PR+ and ER-PR+ tumors. However, ER+PR- tumors have poorer survival compared with ER+PR+ tumours. ER-PR- tumours had the worst survival. Adjuvant hormonal therapy with tamoxifen was found to have identical survival advantage in patients with ER+PR+ and ER-PR+ tumors whereas impact was slightly lower in patients with ER+PR- tumors. In conclusion, we found ER+PR- tumors to be more aggressive and have poorer survival when compared to ER+PR+ tumors, while patients with ER-PR+ tumours were younger, but had a similar survival to their counterparts with ER+PR+ tumours.

Determinants of choice of surgery in Asian patients with early breast cancer in a middle income country

BACKGROUND Breast-conserving surgery (BCS) plus radiotherapy is equivalent to modified radical mastectomy (MRM) in terms of outcome. However there is wide variation in mastectomy rates dependent both on tumour and patient characteristics. OBJECTIVE This study aimed to assess the determinants of surgery choice in Asian patients with early breast cancer in a middle-income country. MATERIALS AND METHODS 184 patients with early breast cancer treated between Jan 2008 and Dec 2010 were recruited to complete a questionnaire. Chi-square test was used to analyze the association between surgery choice and demographic and tumour factors, surgeon recommendation, family member and partner opinions, fear of recurrence, avoidance of second surgery, fear of disfigurement, interference with sex life, fear of radiation and loss of femininity. RESULTS 85 (46%) had BCS while 99 (54%) had mastectomy. Age >60, Chinese ethnicity, lower education level, and larger tumour size were significantly associated with mastectomy. Surgeon recommendation was important in surgery choice. Although both groups did not place much importance on interference with sex life, 14.1% of the BCS group felt it was very important compared to 5.1% in the mastectomy group and this was statistically significant. There was no statistical difference between the two groups in terms of the other factors. When analyzed by ethnicity, significantly more Malay and Indian women considered partner and family member opinions very important and were more concerned about loss of femininity compared to Chinese women. There were no statistical differences between the three ethnic groups in terms of the other factors. CONCLUSIONS When counseling on surgical options, the surgeon has to take into account the ethnicity, social background and education level, age and reliance on partner and family members. Decision-making is usually a collective effort rather than just between the patient and surgeon, and involving the whole family into the process early is important.

Risk of treatment related death (TRD) with adjuvant chemotherapy for breast cancer: A study in University Malaya Medical Centre (UMMC)

Background: The risk of TRD with adjuvant chemotherapy for early breast cancer is unknown in Malaysia despite its widespread usage. This study aims to determine this rate in a large cohort of patients treated in UMMC. Patients & Methods: Patients who were treated with neoadjuvant or adjuvant chemotherapy for early breast cancer stages I, II or III from 2000-2007 in UMMC were identified from our UMMC Breast Cancer Registry. The TRD rate and 5 years overall survival (OS) were determined. TRD is defined as death occurring during or within 30 days of completing chemotherapy as a consequence of the chemotherapy treatment. OS was defined as death from any cause from the date of diagnosis to the date of death. OS was determined using the Kaplan-Meier method and differences between AJCC stages were compared by log-rank test. Results: A total of 1317 were identified for analysis. The median age at diagnosis was 49 years with a range of 24 to 74 years. The rate of TRD was 0.1%. The 5 years OS rate was 77.3% with a median follow up of 62 months. The 5 years OS according to AJCC stage were 90.7% for stage I, 83.9% for stage II and 62.2% for stage III disease. The commonest chemotherapy regimen used was the FEC (5-Fluorouracil, Epirubicin, Cyclophosphamide) regimen accounting for approximately 90% of the cases. Conclusion: Adjuvant chemotherapy for early breast cancer with the FEC regimen is safe with a TRD rate of 0.1% in our centre. Background The role of chemotherapy in cancer treatment is highly misunderstood not just in the public domain but also amongst medical practitioners. The fact that chemotherapy only plays a minor role as a definitive modality of cancer treatment is not well understood and it is mainly limited to haematological malignancies and germ cell tumours. Chemotherapys role in the treatment of solid tumours is mainly confined to neoadjuvant, adjuvant and palliative settings. As such, it is of utmost importance to be cognizant to the rate of TRDs with chemotherapy other than being aware of its potential benefits when used in these settings. Informing patients that this risk is negligible or less than one percent which is the figure often quoted by clinicians may be inadequate as this gives the impression that it is extremely rare. Moreover less than 1% can mean anywhere between 1 in 1001, 1 in 10000, 1 in 100000, 1 in 1000000 and so forth. Patients deserve to fully understand the real risk of TRDs and equally important is the need for clinicians to realize that TRDs are much commoner than perceived. There are various definitions of TRD used in the literature. For the purpose of this study the TRD was defined as deaths that occurred less than or equal to 30 days after the last cycle of chemotherapy, death of which was due to the chemotherapy itself. This definition was chosen as it was commonly used in many reported phase 3 trials and it is the least ambiguous amongst all definitions encountered in the literature. One major drawback is the fact that it does not take into account deaths that may be related to the long term side effects of chemotherapy for example deaths due to cardiac events which is especially relevant for anthracycline drugs commonly used for breast cancer treatment. Having said that, it is very difficult to prove that these deaths are directly due to the effect of chemotherapy alone as there are frequently many other confounding factors. Breast cancer is the commonest cancer treated with adjuvant chemotherapy in Malaysia. A commonly used regimen is the FAC regime (5 Fluorouracil, Adriamycin, Cyclophosphamide). In a trial involving 1491 patients in node positive breast cancer patients post definitive surgery, 745 patients received adjuvant TAC (Docetaxel, Adriamycin, Cyclophosphamide) and 746 patients received FAC. The TRDs for the TAC group and FAC group was similar at 0.3%. (1). The commonest regime used in our center is the FEC regime (5 Fluorouracil, Epirubicin, Cyclophosphamide). A pivotal phase 3 study, PACS 01 trial compared the FEC regime for 6 cycles with the FEC-D regime (FEC3-Docetaxel3) involving 996 patients in the FEC arm and 1003 patients in the FEC-D arm. Although significant high rates of febrile neutropaenia at 8.4% and 11.2% were reported in the FEC and FEC-D arms respectively, there were no early TRDs. However, there was one delayed cardiac death in each

Abstract 5493: Metformin synergizes 5-fluorouracil, epirubicin, and cyclophosphamide (FEC) sensitivity in breast cancer stem cells and non-stem breast cancer cells

Proceedings: AACR Annual Meeting 2014; April 5-9, 2014; San Diego, CA Incorporating cancer stem cells (CSCs)-targeting therapies into current therapies could prevent cancer progression, recurrence and metastasis. An anti-diabetic, AMPK-activating drug, metformin has been shown to kill CSCs and reduces cancer incidence and cancer related death. This study aimed to evaluate the combination treatment of metformin or other AMPK/mTOR-acting drugs with chemotherapy on breast CSCs and non-CSCs in the pre-clinical and clinical settings. We investigated the combination effect of metformin, AICAR, A-769662, or rapamycin with doxorubicin, cisplatin, paclitaxel, or FEC on breast CSCs (mammospheres) and non-CSCs in vitro. The study was extended clinically in a pilot study of ten non-diabetic locally advanced breast cancer patients treated with metformin and neoadjuvant FEC chemotherapy. Nine patients treated with FEC only were identified as historical controls. ESA+/CD44+/CD24-/low (CSCs) population of the tumor samples and tumor response were evaluated. In contrast to other drugs, metformin exhibited higher sensitivity in CSCs compared to attached cell lines. Metformin combined with FEC demonstrated a synergistic effect on breast CSCs and non-CSCs. Patients receiving metformin/FEC neoadjuvant therapy showed a significant reduction in CSCs proportion (P=0.008). Proportion of CSCs after treatment with metformin/FEC was significantly lower compared with the FEC-only neoadjuvant group (P=0.008). Five out of nine patients (56%) receiving metformin/FEC therapy showed a clinical response versus one out of eight (13%) patients in the FEC-only group. In conclusion, metformin synergizes FEC sensitivity in both CSCs and non-CSCs in breast cancer cell lines. Combination treatment of metformin and FEC reduces CSCs in primary tumor from non-diabetic locally advanced breast cancer patients. These results indicate that neoadjuvant metformin/FEC may be a potential treatment option for breast cancer patients and warrants further clinical investigations. Citation Format: Sian Siu Soo, Char Hong Ng, Rozita Abdul Malik, Yew Ching Teh, Boon Shing Tan, Gwo Fuang Ho, Mee Hoong See, Nur Aishah Mohd Taib, Cheng Har Yip, Soo Hwang Teo, Chee Onn Leong. Metformin synergizes 5-fluorouracil, epirubicin, and cyclophosphamide (FEC) sensitivity in breast cancer stem cells and non-stem breast cancer cells. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 5493. doi:10.1158/1538-7445.AM2014-5493