Cancer dormancy: a model of early dissemination and late cancer recurrence

Cancer dormancy is a stage in tumor progression in which residual disease remains occult and asymptomatic for a prolonged period of time. Dormant tumor cells can be present as one of the earliest stages in tumor development, as well as a stage in micrometastases, and/or minimal residual disease left after an apparently successful treatment of the primary tumor. The general mechanisms that regulate the transition of disseminated tumor cells that have lain dormant into a proliferative state remain largely unknown. However, regulation of the growth from dormant tumor cells may be explained in part through the interaction of the tumor cell with its microenvironment, limitations in the blood supply, or an active immune system. An understanding of the regulatory machinery of these processes is essential for identifying early cancer biomarkers and could provide a rationale for the development of novel agents to target dormant tumor cells. This review focuses on the different signaling models responsible for early cancer dissemination and tumor recurrence that are involved in dormancy pathways.     

Perioperative tumor cell dissemination in patients with primary or metastatic colorectal cancer

Introduction

Although there is general correlation between the TNM stage of colorectal cancer (CRC) and its prognosis, there is often significant variability of tumor behaviour and individual patient outcome, which is unaccounted for by pathologic factors alone. Our aim was to estimate perioperative tumor cell dissemination in patients with primary or CRC liver metastases as a possible factor influencing the outcome.

Methods

Forty patients were prospectively enrolled in the study from the year 2007 to 2008. Eighteen patients had histologically proven CRC (50% rectal, 44% colonic, 6% colonic and rectal). Sixteen patients (47%) had CRC liver metastases only. The remaining six patients who underwent colon or liver resection for benign conditions, acted as the control group. All patients with malignant pathologies had R0 resections. Blood samples were taken before the surgical incision (T0), immediately after tumor resection (T1) and at the end of the surgical intervention (T2). Data acquisition was performed using a dual-laser FACSCalibur flow cytometer. Circulating malignant cells were identified as being CD45−/cytokeratin+.

Results

The analysis of patients overall (CRC resection subgroup and hepatectomy subgroup) revealed that there was no statistically significant difference of the tumoral cell count in the blood per million of hematopoietic cells at T0, T1 and T2.

Conclusions

This study demonstrates no differences in the detected circulating numbers of tumor cells at different stages of surgical intervention.     

Tumor cell dissemination to the bone marrow and blood is associated with poor outcome in patients with metastatic breast cancer

The purpose of this study was to assess the impact of disseminated tumor cells (DTCs) on progression-free and overall survival (OS) in patients with metastatic breast cancer (MBC) and to compare it to simultaneous detection of circulating tumor cells (CTCs) from the blood in a subgroup. Disseminated tumor cells were identified in bone marrow (BM) aspirates by immunocytochemistry (pancytokeratin antibody A45-B/B3) and cytomorphology prior to the beginning of a new-line therapy. CTCs were enumerated by the CellSearch^® technology. BM was obtained from 178 patients with MBC; 64/178 (36 %) patients were DTC-positive. Disseminated tumor cells occurred more frequently in patients with visceral metastases (p = 0.020) and ≥2 lines of therapy (p = 0.017). CTCs were assessed in 33 of these patients and 17/33 (52 %) patients had CTC counts ≥5 CTCs/7.5 ml blood. There was no significant association between the DTC and CTC status. Univariate analysis revealed DTC detection as a significant predictor of poor OS (p < 0.001); median OS in DTC-negative versus DTC-positive patients was 52 [95 % confidence interval (CI) 38–67] versus 28 [95 % CI 19–37] months. Moreover, as described previously, patients with ≥5 CTCs/7.5 ml blood were at an increased risk of disease progression (p = 0.026) and death (p = 0.025). Disseminated tumor cells are predictors of poor prognosis in MBC, highlighting the role of tumor cell dissemination into the BM for breast cancer progression. The absence of a significant association between concurrent DTCs and CTCs suggests they might represent different aspects of systemic BC spread.     

Immunocytological detection of residual marrow disease at clinical remission predicts metastatic relapse in small cell lung cancer

A panel of monoclonal antibodies against neural and epithelial associated antigens was used to examine bone marrow from patients in clinical remission from small cell lung cancer (SCLC). A standard peroxidase-antiperoxidase technique and Ficoll-Hypaque enrichment were used to detect SCLC-like cells at the 1-2% level of contamination in 8 of 12 patients who were disease free by conventional criteria, including routine marrow cytology and histology and endobronchoscopic biopsy or cytology. Six of these patients ultimately relapsed, with metastatic sites found between 2 and 6 months after restaging. Furthermore, 6 patients had undergone chemointensification including autologous marrow rescue with radical irradiation to the primary lung tumor. Four of these 6 subsequently relapsed, also with metastatic sites. Of the 4 patients without bone marrow metastases at restaging using this technique, 2 relapsed, with cells found at the primary site, and 2 remained in complete remission. Serum free cell culture was attempted in 9 of 12 cases and SCLC-like cell colonies grew, in suspension, in 4. The SCLC-like nature of these cells has been confirmed by electron microscopy in 1 case and by repeat immunocytochemistry for small cell associated antigens in 3 cases. Bone marrow positivity using these techniques appears to predict a high risk of metastatic relapse regardless of further therapy.     

New approaches in metastatic melanoma: biological and molecular targeted therapies

Classical metastatic melanoma therapy is disappointing but important progress has been made in the understanding of melanoma biology. Genetic lesions and several intracellular signaling pathways that could serve as targets for novel therapy have been identified and a number of new agents are under evaluation. Promising tumor cell targets were identified in the cell membrane, cytoplasm and nucleus. New therapeutic approaches, besides monoclonal antibodies and vaccination, include an increasing number of small molecules that have been shown to interfere restrictively with intracellular signaling pathways in melanoma and decrease proliferation, survival, migration or invasion. Other agents can interfere with stromal components of melanoma, such as angiogenesis and components of the immune system.     

New approaches in metastatic melanoma: biological and molecular targeted therapies

Classical metastatic melanoma therapy is disappointing but important progress has been made in the understanding of melanoma biology. Genetic lesions and several intracellular signaling pathways that could serve as targets for novel therapy have been identified and a number of new agents are under evaluation. Promising tumor cell targets were identified in the cell membrane, cytoplasm and nucleus. New therapeutic approaches, besides monoclonal antibodies and vaccination, include an increasing number of small molecules that have been shown to interfere restrictively with intracellular signaling pathways in melanoma and decrease proliferation, survival, migration or invasion. Other agents can interfere with stromal components of melanoma, such as angiogenesis and components of the immune system.     

Risk factors for brain relapse in patients with metastatic breast cancer.

BACKGROUND: The occurrence of brain metastases is an emerging problem in patients with metastatic breast cancer. In the present study, we looked at risk factors for brain metastasis among patients with metastatic breast cancer. PATIENTS AND METHODS: The risk factors for brain metastasis were first determined in a series of 215 patients with metastatic breast cancer. Risk factors identified in the multivariate analysis were re-evaluated in a confirmatory series of 199 patients with metastatic breast cancer. All the patients had been included in prospective randomized trials that evaluated chemotherapy or endocrine therapy in an adjuvant setting. RESULTS: In the first series, the presence of lung metastases (hazard ratio = 4.3, 95% CI: 1.9-9.3, P=0.0003) and negative hormone receptor status (hazard ratio = 4.2, 95% CI: 1.7-11, P=0.002) were the only predictive factors associated with the occurrence of brain metastases in the multivariate analysis. The second series confirmed that the presence of lung metastases and negative hormone receptor status were associated with the occurrence of brain metastases. CONCLUSION: The presence of lung metastases as the first site of relapse and a negative hormone receptor status are predictive for the occurrence of brain metastases in patients with metastatic breast cancer. A prophylactic treatment should be evaluated in these subsets of patients.     

Ixabepilone plus capecitabine for breast cancer patients with an early metastatic relapse after adjuvant chemotherapy: two clinical trials

BackgroundDespite recent advances in treating patients with metastatic breast cancer (MBC), outcomes remain poor. Ixabepilone is a semisynthetic analogue of epothilone B with low susceptibility to multiple mechanisms of tumor-cell resistance. This review examined the results of 2 phase III clinical trials of ixabepilone in patients with drug-resistant or heavily pretreated, locally advanced breast cancer or MBC.Patients and MethodsIn both studies, women with locally advanced breast cancer or MBC pretreated with, or resistant to, taxanes or anthracyclines were randomly assigned to ixabepilone plus capecitabine, or capecitabine alone, until disease progression or unacceptable toxicity occurred.ResultsIxabepilone plus capecitabine significantly prolonged progression-free survival (PFS) compared with capecitabine alone. The median PFS was prolonged by 1.5 months and 1.8 months in the 2 studies (hazard ratio, < 0.8 in both studies; P ≥ .001). These observations remained valid within several patient subsets: those receiving ixabepilone as first-line therapy, those with taxane-resistant disease, and those with particularly poor prognostic features. Ixabepilone plus capecitabine significantly improved overall survival (OS) compared with capecitabine in patients with symptomatic disease (12.3 vs. 9.5 months, respectively; P = .015). Peripheral neuropathy with ixabepilone was generally reversible and was effectively managed by dosage reduction in most patients. Ixabepilone did not exacerbate capecitabine-induced hand-foot syndrome or diarrhea.ConclusionThe results of these 2 large phase III trials suggest that ixabepilone plus capecitabine may improve treatment outcomes for patients with locally advanced breast cancer or MBC resistant to, or heavily pretreated with, taxanes or anthracyclines, even in those with poor prognostic features.     

Breast cancer adjuvant chemotherapy dosing in obese patients: dissemination of information from clinical trials to clinical practice

BACKGROUND: Substantial variation in adjuvant breast cancer chemotherapy dosing in obese women suggests that there is uncertainty about optimal practices. The purpose of this study was to investigate variations in dose determinations in clinical trial protocols and publications over the last 3 decades as potential sources of this uncertainty. METHODS: The National Cancer Institute database was used to identify protocols of breast cancer adjuvant chemotherapy conducted by cooperative groups between 1970-2000, and these protocols were then obtained directly from the cooperative groups. Dose determinations were categorized in each protocol and in published reports from each clinical trial. Fisher exact tests were used to compare the proportions of protocols that used full weight-based doses over time. RESULTS: Protocol-specified chemotherapy dosing was obtained for all of 44 eligible trials. A significant increase was identified in the use of full weight-based doses in the later time period compared with the earlier (P = .004; 2-sided Fisher exact test). A notable exception was 1 cooperative group that continues to require dose limitations for doxorubicin and cyclophosphamide in patients with a body surface area of more than 2.0 m(2). Regardless of publication date, published reports of clinical trials rarely provide information on use of full or limited weight-based doses. CONCLUSIONS: Variations in dose determinations among clinical trial protocols and lack of information on use of full weight-based doses in most publications are 2 likely sources of variation in chemotherapy dosing in obese women. Developing consensus and disseminating information on optimal chemotherapy dosing will likely reduce such variation and may improve survival among obese patients with breast cancer.     

Review of late complications of treatment and late relapse in testicular cancer

With testicular cancer, a disease with a cure rate of 95%, the challenge is to restore quality of life to pretreatment levels and sustain it long-term. Although the implementation of guidelines and optimization of treatment modalities over the past years have served this purpose, some complications remain inevitable and experts are still challenged with late complications of outdated treatment standards. This article focuses on the late complications of cisplatin-based chemotherapy without disregarding those of currently applied infradiaphragmatic radiation. The most serious long-term complications of chemotherapy or radiotherapy are cardiovascular toxicity and second malignancies, as each has a 25-year risk of approximately 16%. Compared with the general population, risk for second malignancies remains significantly increased for at least 35 years after treatment. Chemotherapy-related cardiovascular toxicity is probably a result of both direct endothelial damage induced by cisplatin and indirect hormonal and metabolic changes. The increased incidence of the metabolic syndrome identified in long-term survivors is most likely associated with the lower testosterone levels reported. Cisplatin-based chemotherapy affects not only Leydig cells but also Sertoli and germ cells, resulting in infertility in 30% to 50% of testicular cancer patients treated with chemotherapy. Chronic neurotoxicity occurs in half of men, whereas permanent ototoxicity and some degree of renal function impairment occur in up to 30%. Pulmonary fibrosis, occurring in 5% to 10% of patients treated with bleomycin, is fatal in 1%. Although current treatment of advanced disease has changed its natural course, we are challenged by an increasing incidence of late relapse, an entity with a distinct tumor biology characterized by latency and chemoresistance.     

Tumor dormancy: elevated expression of stanniocalcins in late relapsing breast cancer

BACKGROUND: Breast cancer is known for its propensity to recur even after decades. The biology behind this phenomenon of tumor dormancy is poorly understood. The stanniocalcins (stanniocalcin-1, STC-1 and stanniocalcin-2, STC-2) are 56kDa homodimeric proteins. They act as pro-survival factors and contribute to the endurance of terminally differentiated cells such as neurons and adipocytes. We investigated whether elevated expression of stanniocalcins also plays a part in the tumor dormancy of breast cancer. METHODS: The expression of STC-1, STC-2 and estrogen receptor (ER) was studied by immunohistochemistry in 72 primary breast cancers and in their metastatic relapses detected before two years, or after 5 or 10 years from primary surgery. RESULTS: When compared to primary tumors with early relapse and their metastases, the expression of STC-1 and STC-2 was significantly higher in relapses occurring after five year (STC-1 p=0.0012, STC-2 p=0.004) and even higher in very late relapses occurring 10 years after surgery (STC-1 p=0.0017, STC-2 p=0.0001). Moreover, primary tumors with a propensity of very late relapse displayed a higher initial expression of STC-2 (p=0.0001). A significantly increased frequency of ER expression was found in the very late relapses. CONCLUSION: These findings suggest that elevated expression of STC-1 or STC-2 act as survival factors also for breast cancer cells and thereby contribute to tumor dormancy.     

Risk factors for brain relapse in HER2-positive metastatic breast cancer patients

Brain relapse is a common occurrence in HER2-positive breast cancer patients. However, the factors determining the risk of brain metastasis in these patients remain to be established. The aim of this study was to assess the impact of particular clinical and pathological factors on the risk of brain relapse in HER2-positive advanced breast cancer patients. The study group included 264 consecutive HER-2 positive metastatic breast cancer patients, most of whom (210; 80%) were administered trastuzumab, usually in combination with chemotherapy. Time from the diagnosis to distant relapse ranged from 0 to 142 months (median 16 months). The most common dominant site of metastatic disease was viscera (80%), followed by soft tissue (11%) and bones (10%). After a median follow-up of 3.1 years, the symptomatic brain relapse occurred in 103 patients (39%). Median time from treatment dissemination to brain relapse was 15 months (range, 0–81 months), and the cumulative 1-year, 3-year and 5-year risk of brain relapse was 17, 42 and 55%, respectively. The average annual risk of brain relapse for surviving patients during consecutive 7 years of follow-up was 10.0% (95% CI, 6.6–13.5%). In the univariate analysis the only variable significantly related to the increased risk of brain relapse was time from initial diagnosis to distant relapse shorter than 2 years (HR = 1.55, 95% CI, 1.03–2.33, P = 0.034). Patients with dominant site of disease in soft tissue or bones tended to have lower risk of relapse (HR = 0.54 and 0.62; P = 0.098 and 0.203, respectively) compared to patients with visceral metastases. Treatment with trastuzumab was not associated with reduced risk of brain relapse (HR = 0.91, 95% CI, 0.47–1.77, P = 0.78). In the multivariate analysis, time from initial diagnosis to distant relapse shorter than 2 years remained the only significant variable related to increased risk of brain relapse (adjusted HR = 1.62, 95% CI, 1.07–2.44; P = 0.022). HER2-positive breast cancer patients remain at high and continuous risk of brain relapse for a prolonged period of time after diagnosis of disease dissemination. Short time from initial diagnosis to distant relapse is related to increased risk of brain relapse. Molecular predictors are sorely needed to better characterize patients with high probability of early brain relapse. Presented in part in oral form at the 2007 European Cancer Conference, Barcelona, Spain.     

Influence of tumor biological factors on tumor cell dissemination in primary breast cancer

BACKGROUND: The presence of disseminated tumor cells in the bone marrow (BM) of breast cancer patients is associated with poor prognosis and may therefore be related to aggressive breast cancer as indicated by tumor biological and clinicopathological factors. The aim of this study was to identify those features of the primary tumor related to the presence of disseminated tumor cells in the BM. PATIENTS AND METHODS: Clinical data from 508 primary breast cancer patients were analyzed. Tumor biological features of the primary tumor including HER2, p53, Ki-67, bcl-2 and hormone receptor status, as well as clinicopathological factors including histology, menopausal status, lymph node status, tumor size and grade, were studied for their association with BM involvement by univariate and multivariate analysis. RESULTS: Two-hundred and two out of 508 (40%) primary breast cancer patients had disseminated tumor cells in the BM. p53 expression, hormone receptor status, HER2 and Ki-67 were significantly related to BM involvement. The multivariate analysis revealed that p53 expression (OR: 1.9, 95% CI: 1.2 - 3.0) followed by progesterone receptor status (OR: 1.5, 95% CI: 1.0 - 2.2) were the only independent determinants for BM involvement. CONCLUSION: The presence of disseminated tumor cells in the BM was not influenced by tumor load as reflected by tumor size and lymph node involvement, whereas tumor biological factors were independently correlated to BM involvement. The results substantiate the important role of tumor biological factors of the primary tumor for tumor cell dissemination.     

Novel therapeutic approaches to the treatment of metastatic breast cancer

Metastatic breast cancer is ultimately an incurable disease, although recent data have shown that its incidence is decreasing and that patients with metastatic breast cancer live longer. This improvement in survival seems to be linked with the introduction of new therapeutic agents, novel combinations of existing therapies and targeted therapies. Our increasing understanding of the molecular biology of metastatic disease has allowed the development of therapies aimed at specific molecular targets. Some of these have already been approved for the treatment of metastatic breast cancer in combination with cytotoxics, and others have shown promising results regarding disease-free survival, overall response rates and time to disease progression. Given the enormous amount of information about drug discovery in cancer, it is important to be familiar with the present state of the treatment of metastatic breast cancer. The purpose of this review is to provide an update on the development of some of the most promising novel agents and treatment strategies in metastatic breast cancer.     

Metronomic chemotherapy combined with bevacizumab and erlotinib in patients with metastatic HER2-negative breast cancer: clinical and biological activity

BackgroundThe object of this study was to evaluate the safety and efficacy of metronomic chemotherapy in combination with bevacizumab and erlotinib in patients with HER2-negative (HER2^?) metastatic breast cancer (MBC) and poor hormone receptor expression.Patients and MethodsPatients with untreated MBC were candidates to receive metronomic oral capecitabine (500 mg thrice daily) and cyclophosphamide (50 mg daily) plus bevacizumab (15 mg/kg every 3 weeks) and erlotinib (100 mg daily).ResultsOf 24 patients assessable for response, we observed 1 complete response (CR, 4%), 14 partial responses (58%), 5 patients with stable disease greater than 9 weeks' duration (SD, 21%), and 1 patient (4%) with early progression of disease. The overall clinical benefit (CB) (CR + partial response + SD > 24 weeks) was 75% (95% confidence interval [CI], 53%-90%). Median time to progression was 43 weeks (95% CI, 21-69). Patients with low levels of circulating endothelial progenitors (CEPs) at baseline had a significantly improved progression-free survival (PFS). Toxicity was generally mild. Grade 3 toxicity included diarrhea (n = 1), thrombosis (n = 1), and hypertension (n = 2). Grade 2 adverse events included diarrhea (n = 5), hand-foot syndrome (n = 13), and hypertension (n = 4).ConclusionTreatment with metronomic chemotherapy in combination with bevacizumab and erlotinib was effective in HER2^?, estrogen receptor (ER)- and progesterone receptor (PR)-poor advanced breast cancer.     

Abnormal E-cadherin expression and prostate cell blood dissemination as markers of biological recurrence in cancer

Until now, no molecular parameter has been available for predicting the metastatic potential of prostate tumours, which leaves their outcome uncertain despite an apparent benign histology or early stage. Abnormal expression of adhesion molecules, such as E-cadherin, can be contributing factors for increased invasiveness and metastatic potential. Histological analysis for E-cadherin expression was carried out on paraffin-embedded tumour tissues. Tumour metastatic potential was indirectly evaluated by detecting circulating prostate cells (CPC), using reverse transciptase-polymerase chain reaction (RT-PCR) and prostate-specific membrane antigen (PSMA) as a target. Patients were followed-up for a median of 14 months (range 10--19 months) after surgery with serum prostate-specific antigen (PSA) level measurement. Interestingly, 23 of 44 localised tumours exhibited aberrant E-cadherin expression. Prior to primary surgery, PSMA RT-PCR detected the spread of prostate cells to the blood in 24 patients. Statistical analysis showed that abnormal E-cadherin expression in the tumours was the only variable that was independently correlated with prostate cell dissemination in the blood (P<0.0001). In logistic regression analysis, abnormal E-cadherin expression was a significant independent predictor for a later biological relapse. This impaired adhesion status was clearly correlated with a haematogenous spread of the primary tumour cells. It could therefore be an objective way to restrict the indications for radical surgery to patients not presenting with this feature.