Tailoring adjuvant treatments for the individual breast cancer patient

Adjuvant chemotherapy in resectable cholangiocarcinoma patients

BACKGROUND AND AIM

Cholangiocarcinoma patients usually have poor treatment outcome and a high mortality rate. The role of adjuvant chemotherapy (AC) is controversial. Our study aimed to evaluate benefits of AC in resectable cholangiocarcinoma patients.

METHODS

A retrospective study included 263 patients who underwent curative resection in Srinakarind University Hospital. These patients had pathological reports showing a clear margin (R0) or microscopic margin (R1) of lesion-free tissue.

RESULTS

There were 138 patients who received AC. This group had a significantly lower mean age than patients not receiving adjuvant chemotherapy (NAC) group (57.7 ± 8.5 vs 60.4 ± 9.0 years, P = 0.01). The level of serum albumin above 3 g/dL was more common in AC group than the NAC one (87.7% vs 79.2%, P = 0.04). Patients who received AC had significantly longer overall median survival time (21.6 vs 13.4 months, P = 0.01). Patients with a combination of gemcitabine and capecitabine regimen had the longest survival time (median overall survival time of gemcitabine and capecitabine 31.5, 5-fluorouracil and mitomycin 17.3, 5-fluorouracil alone 22.2, capecitabine alone 21.6, and gemcitabine alone 7.9 months, P = 0.02). Benefits of AC were likely to be found in patients who had high-risk features, that is, high level of carbohydrate antigen 19-9, advanced stage, T4 stage, lymph node involvement, and R1 margin.

CONCLUSIONS

AC significantly prolongs survival time in resectable cholangiocarcinoma patients, particularly in the high risk group.

Pro-oncogenic and anti-oncogenic pathways: opportunities and challenges of cancer therapy

Carcinogenesis is the uncontrolled growth of cells gaining the potential to invade and disrupt vital tissue functions. This malignant process includes the occurrence of 'unwanted' gene mutations that induce the transformation of normal cells, for example, by overactivation of pro-oncogenic pathways and inactivation of tumor-suppressive or anti-oncogenic pathways. It is now recognized that the number of major signaling pathways that control oncogenesis is not unlimited; therefore, suppressing these pathways can conceivably lead to a cancer cure. However, the clinical application of cancer intervention has not matched up to scientific expectations. Increasing numbers of studies have revealed that many oncogenic-signaling elements show double faces, in which they can promote or suppress cancer pathogenesis depending on tissue type, cancer stage, gene dosage and their interaction with other players in carcinogenesis. This complexity of oncogenic signaling poses challenges to traditional cancer therapy and calls for considerable caution when designing an anticancer drug strategy. We propose future oncology interventions with the concept of integrative cancer therapy.

Facts and controversies in the use of trastuzumab in the adjuvant setting

The human epidermal growth factor receptor-2 (HER2) is overexpressed and/or amplified in up to 25% of breast cancer patients, and this feature is associated with an aggressive phenotype, high recurrence rate and reduced survival. Until recently, combination chemotherapy (with or without endocrine therapy) was the only effective adjuvant treatment for HER2-positive patients. Trastuzumab is a monoclonal antibody directed against the HER2 extracellular domain, and five recent adjuvant breast cancer trials have demonstrated an astonishing and highly reproducible benefit in halving the recurrence rate and reducing mortality in patients with this phenotype. Many questions related to trastuzumab use in the adjuvant setting still remain; these include the optimum timing and duration of treatment, trastuzumab use with taxanes and radiotherapy, its role in small node-negative tumors, the optimum chemotherapy regimens and cost-effectiveness. This Review outlines the five adjuvant trastuzumab studies and discusses the controversies and challenges that have emerged for both the clinician and healthcare authorities worldwide as a consequence of the results from these trials.

Adjuvant chemotherapy--yes or no? Prognostic markers in early breast cancer

The question of whether to offer adjuvant chemotherapy to patients with early-stage breast cancer continues to challenge clinicians on a daily basis. Many patients with node-negative or low-risk breast cancer could be spared the trauma of receiving chemotherapy, but more reliable prognostic markers are still needed to aid our therapy decision making. Gene expression profiling is a welcome product of the 'omic' era and several multi-gene expression panels ('signatures') have now been developed that show promise in predicting which breast cancer patients are likely to develop metastatic disease if adjuvant chemotherapy is not administered. The value of gene expression profiling as a prognostic tool in clinical practice is currently being appraised more fully in two large, prospective, randomised studies--TAILORx and MINDACT. These studies should provide level I evidence of the prognostic power of gene expression profiling and will hopefully allow us to one day quantify risk of progression in the individual patient and tailor treatment accordingly. Genetic profiling of circulating tumour cells and micrometastases should further enhance our understanding of breast cancer biology and allow us to personalise therapy based on functional maps of critical tumour pathways. Close collaboration between clinicians and scientists will be essential to achieve this goal.

The evolution of treatment strategies: aiming at the target

Historically, the selection of adjuvant systemic therapy in early breast cancer has relied on risk assessment embodied by the TNM classification. Since the 2005 International St. Gallen Consensus, treatment selection now involves firstly identifying critical targets and then using risk to assess the trade-off between anticipated toxicity and efficacy. This evolution in treatment strategies began with the identification of the estrogen receptor, and culminated with the HER2 receptor, with recent astounding success in several adjuvant trials. Newer technologies including gene expression profiles and micrometastases tracking bear exciting potential in refining the treatment strategies further. Alongside the progress in developing agents that target different molecules across the whole breast cancer population, these newer technologies aim to tailor adjuvant treatment further by identifying breast cancer subgroups that may benefit most from being targeted with specific therapy, by defining molecular subtypes, recognizing chemo-sensitivity and resistance, identifying at-risk gene signatures, and by detecting stem cells capable of generating metastases. This paper will review this evolution of treatment strategies, from the lessons learnt from the past, to the exciting promise of tailored therapy of the future.

Survivin is an independent predictor of short-term survival in poor prognostic breast cancer patients

Established clinico–pathological factors can place patients with breast cancer into good and poor prognostic categories, but even within these groups behaviour and response to treatment can differ. This study examined the value of cell cycle and apoptotic regulatory proteins in predicting behaviour in a poor prognostic group. A total of 165 patients, all of whom had died of breast cancer with duration of survival 12–127 months, median 38 months, were examined using immunohistochemistry for proliferation, apoptosis, p53, phosphorylated p53, p21, checkpoint kinase 2 (Chk2), bcl-2, bax, survivin and XIAP. All had received chemotherapy and/or hormonal therapy and were predominantly T2, node positive, grade III with only half oestrogen-receptor (ER) positive. High proliferation, phosphorylated p53, Chk2 and survivin expression correlated with grade III and lack of ER, whereas low proliferation, p21 and bcl-2 related to better grade and presence of ER. On univariate analysis grade, proliferation, phosphorylated p53, bcl-2, ER and survivin related to duration of survival. In multivariate analysis, grade (P=0.001) and survivin (P=0.005) were independent prognostic factors, grade III and presence of survivin relating to shorter survival. The latter was particularly for those patients receiving neoadjuvant therapy and adjuvant chemo- and hormonal therapy. The presence of the inhibitor of apoptosis protein survivin is a highly significant independent predictor of shorter duration of survival of patients with poor prognostic features, and merits investigation as a marker in other prognostic groups.

Uses and abuses of tumor markers in the diagnosis, monitoring, and treatment of primary and metastatic breast cancer

Although breast cancer incidence continues to increase, mortality has been decreasing, principally as a result of earlier detection and improvements in adjuvant systemic therapy. Nonetheless, because antineo-plastic agents are associated with substantial morbidity and occasional mortality, efforts to individualize treatment strategies are desirable. In addition to classic histopathologic diagnosis, molecular and cellular tumor markers may help in establishing prognosis or prediction of benefit. Recommendations for routine use of tumor markers in breast cancer have been conservative. Although several studies have been reported, few are of sufficiently high level of evidence to permit solid conclusions. Three key issues in tumor marker evaluation are utility, magnitude, and reliability. Poorly conceived study designs cloud the issue of how the marker might be used. Reliance on p-values rather than the size of the differences in outcome between patients who are positive and those who are negative for the factor obscures the importance. Technical issues result in poor reproducibility and interpretability of assays. Analytical issues lead to poorly defined cutoff values for marker levels. Poor patient selection leads to difficulty interpreting results because of confounders such as differences in treatment regimens. This review focuses on these issues, with an emphasis on currently accepted tumor markers. Finally, new tumor marker reporting recommendations are discussed, the adoption of which may lead to improved design and publication of tumor marker studies in the future.

Clinical trials design and treatment tailoring: General principles applied to breast cancer research

Nowadays tailored therapy tends to replace standard cancer treatment approaches. Tailoring treatment is possible thanks to clinical trials results that identified subgroups of patients benefiting most from some treatments. Treatment can be tailored on the basis of specific clinical characteristics of the population or on the basis of predictive or prognostic markers. Finally treatment can be tailored for specific molecular targets. This evolution in cancer treatment has triggered the development of innovative trial designs to validate these new hypotheses. The real challenge of the next coming years resides in recruiting large number of patients from specific subgroups to validate tailored therapies.

Maintenance Therapy to Suppress Micrometastasis: The New Challenge for Adjuvant Cancer Treatment

The palliative efficacy of cytotoxic drugs is routinely assessed using tumor shrinkage (response) rates shown in clinical trials. Although adjuvant drug therapy has a goal distinct from that of palliative therapy (i.e., to prolong survival by inhibiting progression of micrometastatic disease), it is widely assumed that the adjuvant efficacy of a drug will parallel its response rate ("activity") in advanced stages of the disease. Reconsideration of this assumption seems timely in view of recent developments: the realization that many predictors of short-term tumor response correlate inversely with long-term survival outcomes; the characterization of tumor progression as a discontinuous process that may include dormant phases; the understanding that micrometastasis is therapeutically suppressible by a variety of mechanisms including direct tumor cell kill, cytotoxic disruption of paracrine growth signals from normal tissues, and targeted inhibition of prometastatic pathways; the recognition that tumor dormancy not only blocks the antimetastatic efficacy of cytotoxic drugs but also represents a therapeutic end point for metastasis-suppressive noncytotoxic drugs such as hormone inhibitors; and the insight that optimal adjuvant drug therapy is likely to include both induction and maintenance components. The traditional view of cytoreductive response as a prerequisite for adjuvant drug efficacy thus merits reappraisal, with a view to accelerating incorporation of novel noncytotoxic maintenance therapies into controlled studies.

Identity of an estrogen membrane receptor coupled to a G protein in human breast cancer cells

Although nonclassical estrogen actions initiated at the cell surface have been described in many tissues, the identities of the membrane estrogen receptors (mERs) mediating these actions remain unclear. Here we show that GPR30, an orphan receptor unrelated to nuclear estrogen receptors, has all the binding and signaling characteristics of a mER. A high-affinity (dissociation constant 2.7 nm), limited capacity, displaceable, single binding site specific for estrogens was detected in plasma membranes of SKBR3 breast cancer cells that express GPR30 but lack nuclear estrogen receptors. Progesterone-induced increases and small interfering RNA-induced decreases in GPR30 expression in SKBR3 cells were accompanied by parallel changes in specific estradiol-17beta (E2) binding. Plasma membranes of human embryonic kidney 293 cells transfected with GPR30, but not those of untransfected cells, and human placental tissues that express GPR30 also displayed high-affinity, specific estrogen binding typical of mERs. E2 treatment of transfected cell membranes caused activation of a stimulatory G protein that is directly coupled to the receptor, indicating GPR30 is a G protein-coupled receptor (GPCR), and also increased adenylyl cyclase activity. The finding that the antiestrogens tamoxifen and ICI 182,780, and an environmental estrogen, ortho,para-dichlorodiphenyldichloroethylene (o,p'-DDE), have high binding affinities to the receptor and mimic the actions of E2 has important implications for both the development and treatment of estrogen-dependent breast cancer. GPR30 is structurally unrelated to the recently discovered family of GPCR-like membrane progestin receptors. The identification of a second distinct class of GPCR-like steroid membrane receptors suggests a widespread role for GPCRs in nonclassical steroid hormone actions.