Evidence for the use of chemotherapy in breast cancer

Rosiglitazone amplifies the sensitivity of docetaxel and reduces the expression of CD44v6

Breast cancer seriously impairs physical and mental health in females. Currently, with further investigation into drugs, a number of new pharmacological effects have been found that offer new methods for clinical application in the treatment of breast cancer. As a widely used antidiabetic drug, rosiglitazone (Ros) has become well known for its anticancer effects, mediated by the activation of peroxisome proliferator-activated receptor γ and downregulated expression of the associated invasion gene. The objective of the present study was to investigate the combination of Ros and docetaxel (DOC) and whether DOC has any effect on breast cancer cell lines. The results showed that the combination of Ros and DOC may cooperate to increase anti-growth efficacy. The additive inhibitory effects on cell proliferation were sequence-dependent and are not likely to be associated with cell cycle arrest. This suggested that the target activation of associated factors of the signaling pathway by Ros may be a compelling ally in cancer treatment. In addition, evidence was provided for a convergence of Ros and DOC to induce the reduced expression of CD44v6. Future studies are required to confirm which associated gene of Ros is significant in blocking the signaling pathway.

Single agent versus combination chemotherapy for metastatic breast cancer

BACKGROUND

Combination chemotherapy regimens are frequently favoured over single agents for the treatment of metastatic breast cancer, in an attempt to achieve superior tumour response rates. It is not known however whether giving more intensive chemotherapy regimens results in better health outcomes, when both survival and toxicity are considered, and whether better response rates and rates of progression free survival actually translate to better overall survival.

OBJECTIVES

To compare single agent with combination chemotherapy for the treatment of metastatic breast cancer.

SEARCH STRATEGY

We searched the Cochrane Breast Cancer Group Specialised Register November 2008. Handsearching of recent conference proceedings was also undertaken.

SELECTION CRITERIA

Randomised trials of single agent chemotherapy compared to combination therapy in metastatic breast cancer.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed trials for eligibility and quality, and extracted data. Hazard ratios were derived for reported time-to-event outcomes.Response rates were analysed as dichotomous variables. Toxicity and quality of life data were extracted where present.

MAIN RESULTS

Forty three eligible trials (48 comparisons) were identified. These included 9742 women, 55% of whom were receiving first-line treatment for metastatic disease. For overall survival there was a statistically significant difference in favour of the combination regimens with no heterogeneity (HR 0.88, 95% CI 0.83-0.93, p<0.00001). Results were very similar when trials of first-line treatment were analysed, and for analyses where the single agent was also included in the combination regimen. Combination regimens showed a statistically significant advantage for survival over single agent taxane (HR 0.82; 95% CI 0.75-0.89, p<0.00001), but not anthracycline (HR 0.94.86-1.02, p=0.15).Combination regimens were also associated with significantly better time to progression (HR 0.78, 95% CI 0.74 - 0.82, p<0.00001) and response (RR 1.29, 95% CI 1.14 -1.45, p<0.0001) although heterogeneity was statistically significant in both instances and probably due to clinical diversity of the participants and interventions.Women receiving combination regimens experienced a statistically significant detrimental effect on white cell count, increased alopecia and nausea and vomiting.

AUTHORS' CONCLUSIONS

Combination chemotherapy regimens show a statistically significant advantage for survival, tumor response and time to progression in women with metastatic breast cancer but they also produce more toxicity. An unresolved question is whether combination regimens are more effective than single agents given sequentially.

Management of metastatic carcinoma of the uveal tract: an evidence-based analysis

Uveal metastasis from carcinoma is the most common cause of ocular malignancy in adults and represents an increasing problem in the context of an ageing population and enhanced survival of stage IV cancer patients. The reported prevalence of clinically evident uveal metastases in carcinoma patients ranges from 2% to 9%, with breast and lung cancer together accounting for between 71% and 92% of cases. Most patients (66-97%) have a known history of cancer and, although the majority have metastatic lesions elsewhere, up to 33% may present with an isolated ocular metastasis. These lesions may progress rapidly and are potentially sight-threatening. Early diagnosis and appropriate timely treatment are therefore of paramount importance to maintain patients' quality of life. The diagnosis is usually clinical and detailed descriptions of symptomatology and physical characteristics are provided. In 21-50% of patients, involvement is bilateral. External beam radiotherapy (EBRT), chemotherapy, hormone and biological therapies, brachytherapy, transpupillary thermotherapy, laser photocoagulation/photodynamic therapy and enucleation are therapeutic modalities described in the literature for the management of uveal metastases. The strongest evidence favours timely EBRT for the management of sight-threatening uveal metastases. The published evidence supporting EBRT for sight-threatening uveal metastases was given a grade B (strong support for recommendation). Newer alternative therapies are emerging and may have a role in selected patients; however, there are unfortunately few large studies examining such treatments for carcinoma metastatic to the eye. The role of these modalities will be further clarified with the results of larger comparative trials.

Antitumor efficacy and local distribution of doxorubicin via intratumoral delivery from polymer millirods

The purpose of this study was to evaluate the antitumor efficacy and local drug distribution from doxorubicin-containing poly(D,L-lactide-co-glycolide) (PLGA) implants for intratumoral treatment of liver cancer in a rabbit model. Cylindrical polymer millirods (length 8 mm, diameter 1.5 mm) were produced using 65% PLGA, 21.5% NaCl, and 13.5% doxorubicin. These implants were placed in the center of VX2 liver tumors (n = 16, 8 mm in diameter) in rabbits. Tumors were removed 4 and 8 days after millirod implantation, and antitumor efficacy was assessed using tumor size measurements, tumor histology, and fluorescent measurement of drug distribution. The treated tumors were smaller than the untreated controls on both day 4 (0.17 +/- 0.06 vs. 0.31 +/- 0.08 cm(2), p = 0.048) and day 8 (0.14 +/- 0.04 vs. 1.8 +/- 0.8 cm(2), p = 0.025). Drug distribution profiles demonstrated high doxorubicin concentrations (>1000 microg/g) at the tumor core at both time points and drug penetration distances of 2.8 and 1.3 mm on day 4 and 8, respectively. Histological examination confirmed necrosis throughout the tumor tissue. Biodegradable polymer millirods successfully treated the primary tumor mass by providing high doxorubicin concentrations to the tumor tissue over an eight day period.

Leukemia following breast cancer: an international population-based study of 376,825 women

PURPOSE

To quantify long-term temporal trends in the excess absolute risk (EAR) of secondary leukemia among breast cancer (BC) survivors, using multivariate analyses to evaluate the effects of subtype, age at BC diagnosis, attained age, and calendar year.

PATIENTS AND METHODS

We identified 376,825 1-year survivors of BC within 4 nationwide, population-based cancer registries in Sweden, Denmark, Finland, and Norway (1943-2001). Estimates of EAR (per 100,000 person-years) were modeled using Poisson regression methods and cumulative risks calculated using a competing risk model.

RESULTS

A total of 687 non-chronic lymphocytic leukemias (EAR = 9.05; 95% confidence interval (CI) = 7.5-10.7) was reported. Significantly elevated risks were observed for the first time for chronic myeloid leukemia (CML) (EAR = 2.06; 95% CI = 1.3-2.9) and acute lymphoblastic leukemia (ALL) (EAR = 0.62; 95% CI = 0.2-1.1), in addition to acute myeloid leukemia (AML) (EAR = 5.00; 95% CI = 3.9-6.2). Excesses of CML, ALL, AML and all leukemias combined persisted over 25 years after BC diagnosis. For all leukemias, EAR decreased with increasing calendar year (P = 0.04) of BC diagnosis. Risk for all leukemia and AML by calendar year of BC diagnosis depended on age at diagnosis. For women diagnosed with BC after 1985, the 10-year cumulative risk of leukemia for those diagnosed before and after age 50 was small, 0.10% and 0.14%, respectively.

CONCLUSIONS

Although secondary leukemia is a rare event, BC survivors experience statistically significant excesses for at least 25 years after diagnosis, including CML and ALL. Decreasing leukemia risks in recent calendar years likely reflect changes in treatment.

Amplification of the TOP2A gene does not predict high levels of topoisomerase II alpha protein in human breast tumor samples

Recent clinical trials have suggested that patients whose breast tumors overexpress HER2 may derive particular benefit from anthracycline-containing chemotherapy compared to that without anthracycline. It has been proposed that the HER2 gene amplification reported in these tumors might mask an underlying TOP2A gene amplification that occurs frequently and concurrently with HER2 amplification. Topoisomerase II alpha, encoded by TOP2A, is a direct molecular target of anthracycline drug action and is potentially useful as a predictive marker of response to anthracycline therapy for breast cancer. In this study, we examined whether TOP2A gene amplification is an appropriate marker for identifying breast tumors expressing high levels of topoisomerase II alpha. We determined topoisomerase II alpha protein expression by immunohistochemistry in 81 human breast tumors in relation to HER2 and TOP2A gene copy numbers analyzed by fluorescence in situ hybridization, histologic grade, cell proliferation fraction measured by MIB-1 expression, and HER2 protein expression determined by immunohistochemistry. The results showed no correlation between TOP2A gene copy number and topoisomerase II alpha protein expression levels in breast tumors, in contrast to the analogous situation for HER2 gene amplification and HER2 immunohistochemistry. Our results suggest that TOP2A gene amplification in breast tumors does not predict high expression of topoisomerase II alpha protein.

Are the biopositive effects of X-rays the only benefits of repetitive mammograms?

Breast cancer mortality rates fell between 1990 and 2000. When something positive occurs in medicine attempts are usually made to explain the observation or claim the credit. In this case, credit has been given to improvements in standard treatments and to increased use of mammography, each said to have made a contribution. Published data on the results of clinical trials utilising high-dose radiation or chemotherapy do not support this position. Improvements in breast cancer mortality are more likely to be the result of the biopositive effects of the low-dose radiation delivered during mammography, based on lower death rates from breast cancer in women subjected to repetitive mammographic screening, albeit with no significant change in all-cause death rates. This is supported by a study in which breast cancer rates were lowered by diagnostic X-rays of the chest.