Distant metastases do not metastasize

Breast cancer: emerging principles of metastasis, adjuvant and neoadjuvant treatment from cancer registry data

PURPOSE

Growing primary breast cancers (PT) can initiate local recurrences (LR), regional lymph nodes (pLN) and distant metastases (MET). Components of these progressions are initiation, frequency, growth duration, and survival. These characteristics describe principles which proposed molecular concepts and hypotheses must align with.

METHODS

In a population-based retrospective modeling approach using data from the Munich Cancer Registry key steps and factors associated with metastasis were identified and quantified. Analysis of 66.800 patient datasets over four time periods since 1978, reliable evidence is obtained even in small subgroups. Together with results of clinical trials on prevention and adjuvant treatment (AT) principles for the MET process and AT are derived.

RESULTS

The median growth periods for PT/MET/LR/pLN comes to 12.5/8.8/5/3.5 years, respectively. Even if 30% of METs only appear after 10 years, a pre-diagnosis MET initiation principle not a delayed one should be true. The growth times of PTs and METs vary by a factor of 10 or more but their ratio is robust at about 1.4. Principles of AT are 50% PT eradication, the selective and partial eradication of bone and lung METs. This cannot be improved by extending the duration of the previously known ATs.

CONCLUSION

A paradigm of ten principles for the MET process and ATs is derived from real world data and clinical trials indicates that there is no rationale for the long-term application of endocrine ATs, risk of PTs by hormone replacement therapies, or cascading initiation of METs. The principles show limits and opportunities for innovation also through alternative interpretations of well-known studies. The outlined MET process should be generalizable to all solid tumors.

Survival effects of primary and metastatic surgical treatment in metastatic small intestinal tumors: A propensity score–matching study

Objective

To analyze the effects of primary tumor resection and metastatic lesion resection on the survival of metastatic small intestinal tumors.

Methods

The research subjects were patients with metastatic small bowel tumors identified from 2004 to 2016 in the Surveillance, Epidemiology, and End Results (SEER) database. Propensity score matching and Kaplan–Meier analyses were performed to analyze the effect of surgery on the prognosis.

Results

A total of 4,034 patients from the SEER database were analyzed. Both before and after the propensity score–matching analysis, the prognosis of patients who underwent primary tumor surgery and metastatic surgery was better than that of patients who did not undergo surgery; all were patients with metastatic small bowel adenocarcinoma (mSIA) or metastatic small intestinal neuroendocrine tumors (mSI-NETs) (all p < .005). Patients with mSIA and adequate lymph node dissection had a longer prognosis than mSIA patients with inadequate lymph node dissection, but this survival benefit was not present in mSI-NET patients. It made no difference in the prognosis of mSIA and mSI-NETs whether localized surgery or intestine-ectomy was performed. Patients with mSIA who underwent primary and metastatic excision plus chemotherapy had the best overall survival and cancer-specific survival rates, whereas mSI-NET patients who underwent primary and metastatic excision had the best overall survival and cancer-specific survival rates (all p < .001).

Conclusion

In these carefully selected patients, primary tumor resection and/or metastatic lesion resection significantly improved the survival rates for patients with mSIA and mSI-NETs. The mSIA patients with resectable primary tumors seemed to require a sufficient number of lymph node dissections more than the patients with well-differentiated mSI-NETs.

Metastases from metastases: comparative metastatic potential of human cancer cell lines originated from primary tumors or metastases in various tissues

Although metastases from original (primary) tumors are highly studied, metastases from metastatic sites (secondary tumors) are far less studied. Here, using data from metastasis map (MetMap) project reported in a recent study (Jin et al. in Nature 588(7837): 331-336. https://doi.org/10.1038/s41586-020-2969-2 , 2020), we found that human cancer cell lines isolated from metastatic sites have higher potential to metastasize to another site in mice, compared to human cancer cell lines isolated from primary sites, for certain types of cancer including liver, lung and pancreas cancer. In contrast, for cancer types such as ovarian and skin cancer, human cancer cell lines originated from primary tumors have increased metastatic potential in mice, compared to human cancer cell lines originated from metastatic sites. This preliminary analysis points that the potential of metastases to further metastasize compared to that of primary tumors might be cancer type-dependent, and further research is needed to understand why certain cancer cell lines isolated from metastatic sites are more likely to spread to other organs.

Prediction of Microscopic Metastases in Patients with Metachronous Oligo-Metastases after Curative Treatment of Non-Small Cell Lung Cancer: A Microsimulation Study

Simple Summary

Many patients with metachronous oligo-metastases in non-small cell lung cancer have their recurrences surgically removed, although the 5-year recurrence-free survival of this group is 16%. This does not provide any benefit for patients with additional undetected metastases. Therefore, we aim to find patient characteristics that are predictive for having additional undetected microscopic metastases. Based on a theoretical approach, we identified the size and number of detected oligo-metastases, as well as the presence of symptoms that are the most important risk predictors.

Abstract

Metachronous oligo-metastatic disease is variably defined as one to five metastases detected after a disease-free interval and treatment of the primary tumour with curative intent. Oligo-metastases in non-small cell lung cancer (NSCLC) are often treated with curative intent. However additional metastases are often detected later in time, and the 5-year survival is low. Burdensome surgical treatment in patients with undetected metastases may be avoided if patients with a high versus low risk of undetected metastases can be separated. Because there is no clinical data on undetected metastases available, a microsimulation model of the development and detection of metastases in 100,000 hypothetical stage I NSCLC patients with a controlled primary tumour was constructed. The model uses data from the literature as well as patient-level data. Calibration was used for the unobservable model parameters. Metastases can be detected by a scheduled scan, or an unplanned scan when the patient develops symptoms. The observable information at time of detection is used to identify subgroups of patients with a different risk of undetectable metastases. We identified the size and number of detected oligo-metastases, as well as the presence of symptoms that are the most important risk predictors. Based on these predictors, patients could be divided into a low-risk and a high-risk group, having a model-based predicted probability of 8.1% and 89.3% to have undetected metastases, respectively. Currently, the model is based on a synthesis of the literature data and individual patient-level data that were not collected for the purpose of this study. Optimization and validation of the model is necessary to allow clinical usability. We describe the type of data that needs to be collected to update our model, as well as the design of such a validation study.

[It is unclear whether pelvic lymphadenectomy is of oncological benefit in prostate cancer]

Fossati's 2017 review questions the value of pelvic lymphadenectomy (pLA) in radical prostatectomy (RP) because available studies fail to show any oncological benefit. Our finding that no spread of metastatic lymph nodes (LN) has been demonstrated is based on registry data, clinical trials without evidence of pLA benefit and considerations of the genetic link between LN metastasis and distant metastases. The improved imaging with ⁶⁸GaPSMA-PET-CT facilitates the detection of metastases and thus the omission of pLA as diagnostic intervention, thereby avoiding typical complications. The question whether pLA, or a multimodal treatment concept, might benefit intermediate and high-risk patients can only be answered by an RCT which, above all, must consider the incompletely removed primary as a source of metastatic spread.

Cancer progression and the invisible phase of metastatic colonization

Metastatic dissemination occurs very early in the malignant progression of a cancer but the clinical manifestation of metastases often takes years. In recent decades, 5-year survival of patients with many solid cancers has increased due to earlier detection, local disease control and adjuvant therapies. As a consequence, we are confronted with an increase in late relapses as more antiproliferative cancer therapies prolong disease courses, raising questions about how cancer cells survive, evolve or stop growing and finally expand during periods of clinical latency. I argue here that the understanding of early metastasis formation, particularly of the currently invisible phase of metastatic colonization, will be essential for the next stage in adjuvant therapy development that reliably prevents metachronous metastasis.

A Mathematical Model to Predict Diagnostic Periods for Secondary Distant Metastases in Patients with ER/PR/HER2/Ki-67 Subtypes of Breast Cancer

Previously, a consolidated mathematical model of primary tumor (PT) growth and secondary distant metastasis (sdMTS) growth in breast cancer (BC) (CoMPaS) was presented. The aim was to detect the diagnostic periods for visible sdMTS via CoMPaS in patients with different subtypes ER/PR/HER2/Ki-67 (Estrogen Receptor/Progesterone Receptor/Human Epidermal growth factor Receptor 2/Ki-67 marker) of breast cancer. CoMPaS is based on an exponential growth model and complementing formulas, and the model corresponds to the tumor-node-metastasis (TNM) staging system and BC subtypes (ER/PR/HER2/Ki-67). The CoMPaS model reflects (1) the subtypes of BC, such as ER/PR/HER2/Ki-67, and (2) the growth processes of the PT and sdMTSs in BC patients without or with lymph node metastases (MTSs) in accordance with the eighth edition American Joint Committee on Cancer prognostic staging system for breast cancer. CoMPaS correctly describes the growth of the PT in the ER/PR/HER2/Ki-67 subtypes of BC patients and helps to calculate the different diagnostic periods, depending on the tumor volume doubling time of sdMTS, when sdMTSs might appear. CoMPaS and the corresponding software tool can help (1) to start the early treatment of small sdMTSs in BC patients with different tumor subtypes (ER/PR/HER2/Ki-67), and (2) to consider the patient almost healthy if sdMTSs do not appear during the different diagnostic periods.

Survival outcome of palliative primary tumor resection for colorectal cancer patients with synchronous liver and/or lung metastases: A retrospective cohort study in the SEER database by propensity score matching analysis

BACKGROUND

There is a great matter of controversies whether some of these synchronous metastatic colorectal cancer patients can benefit from palliative primary tumor resection (pPTR) and there is still no reported randomized control trial to address this issue.

METHODS

Patients with microscopically proven metastatic colorectal cancer were identified within the SEER database (2010-2016). Patients were propensity matched 1:1 into pPTR and non-surgery groups and among the matched cohort, the univariable and multivariable Cox proportional hazards regression models were performed to identify predictors of survival. Median survival was calculated by using the Kaplan-Meier method.

RESULTS

Of 21,405 colorectal cancer patients diagnosed with synchronous liver and/or lung metastases, 7386 were identified in the matched cohort. The median overall survival was 12.0 months, 22.0 months in the non-surgery, surgery groups, respectively (p < 0.001) and the corresponding median cancer-specific survival was 13.0 months, 22.0 months, respectively (p < 0.001). Multivariable Cox regression analysis demonstrated that surgery was independently associated with improved overall survival (hazard ratio, 0.531) as well as cancer-specific survival (hazard ratio, 0.516). In stratified analyses by primary site and patterns of distant metastases, those patients with pPTR had better prognosis. In addition, stratified analysis revealed that trimodality therapy was linked with the greatest therapeutic effect followed by addition of chemotherapy to pPTR.

CONCLUSIONS

pPTR may offer some therapeutic benefits among carefully selected patients, and surgery-based multimodality therapy was associated with better survival.

Breast cancer: are long-term and intermittent endocrine therapies equally effective?

Purpose

In breast cancer (BC), the duration of endocrine adjuvant therapies (AT) has been extended continuously up to 10 years. We present an alternative explanation for the effect, which could enable shorter treatments.

Method

The relevant literature on chemoprevention and (neo-)adjuvant therapy was reviewed. Data for initiation and growth of primary and contralateral BCs and their metastases (MET) were considered. Also, population-based data from the Munich Cancer Registry for MET-free survival, time trends of MET patterns, and survival achieved by improved ATs are used to estimate all events in the long-term follow-up.

Results

Extended ATs (EAT) that continue after 1, 2, or 5 years reduce mortality only slightly. The effect is delayed, occurring more than 5 years after extension. EATs does not affect the prognosis of 1stBCs, they preventively eradicate contralateral 2ndBCs and thus their future life-threatening METs. Because chemoprevention can eradicate BCs from the smallest clusters to almost detectable BCs, ATs can be temporarily suspended without imposing harm. Results equal to EATs can be achieved by short-term ATs of the 1stBC and by repeated neo-ATs targeted at the indefinitely developing 2ndBCs. Considering this potential in de-escalation, a 70–80% reduction of overtreatment seems possible.

Conclusion

Knowledge of initiation and growth of tumors with known effects of neo-ATs suggest that intermittent endocrine ATs may achieve the same results as EATs but with improved quality of life and survival because of fewer side effects and better compliance. The challenge for developments of repeated ATs becomes: how short is short enough.

Disease progression model of 4T1 metastatic breast cancer

Cancer metastasis is the main cause of death in various types of cancer. However, in the field of pharmacometrics, cancer disease progression models focus on the growth of primary tumors with tumor volume or weight as target values, while the metastasis process is less mentioned. We propose a series of mathematical models to quantitatively describe and predict the disease progression of 4T1 breast cancer in the aspect of primary breast tumor, lung metastasis and white blood cell. The 4T1 cells were injected into breast fat pad of female BALB/c mice to establish an animal model of breast cancer metastasis. The number and volume of lung metastases at different times were measured. Based on the above data, a disease progression model of breast cancer lung metastasis was established and parameter values were estimated. The white blood cell growth and the primary tumor growth of 4T1 mouse are also modeled. The established models can describe the lung metastasis of 4T1 breast cancer in three aspects: (1) the increase in metastasis number; (2) the growth of metastasis volume; (3) metastasis number-size distribution at different time points. Compared with the prior metastasis models based on von Forester equation, our models distinguished the growth rate of primary tumor and metastasis and got parameter values for 4T1 mouse model. And the current models optimized the metastasis number-size distribution model by utilizing logistic function instead of the prior power function. This study provides a comprehensive description of lung metastasis progression for 4T1 breast cancer model, as well as an alternative disease progression model structure for further pharmacodynamics modeling.

CCL5 promotes breast cancer recurrence through macrophage recruitment in residual tumors

Over half of breast-cancer-related deaths are due to recurrence 5 or more years after initial diagnosis and treatment. This latency suggests that a population of residual tumor cells can survive treatment and persist in a dormant state for many years. The role of the microenvironment in regulating the survival and proliferation of residual cells following therapy remains unexplored. Using a conditional mouse model for Her2-driven breast cancer, we identify interactions between residual tumor cells and their microenvironment as critical for promoting tumor recurrence. Her2 downregulation leads to an inflammatory program driven by TNFα/NFκB signaling, which promotes immune cell infiltration in regressing and residual tumors. The cytokine CCL5 is elevated following Her2 downregulation and remains high in residual tumors. CCL5 promotes tumor recurrence by recruiting CCR5-expressing macrophages, which may contribute to collagen deposition in residual tumors. Blocking this TNFα-CCL5-macrophage axis may be efficacious in preventing breast cancer recurrence.

The natural history of renal cell carcinoma with pulmonary metastases illuminated through mathematical modeling

The goal of this study is to uncover some unobservable aspects of the individual-patient natural history of metastatic renal cell carcinoma (RCC) through mathematical modeling. We analyzed four clear cell RCC patients who at the time of primary tumor resection already had pulmonary metastases. Our description of the natural history of cancer in these patients was based on a parameterized version of a previously proposed very general mathematical model adjusted to these clinical cases. For each patient, identifiable model parameters were estimated by the method of maximum likelihood from the volumes of lung metastases computed from CT scans taken at or around the time of surgery. The model-based distribution of the volumes of lung metastases with likelihood maximizing parameters provided an excellent fit to the data for all patients analyzed. We found that, according to the model, the most likely scenario in all four patients had the following clinically important features: (1) duration of metastatic latency was very small compared to the growth period; (2) seeding of the first lung metastasis occurred before primary tumor reached detectable size, which implies that early cancer detection would not have prevented metastasis; (3) primary tumor contained a relatively fast growing subpopulation of metastasis-producing cells, which is consistent with the observed aggressive course of the disease; and (4) the volume of the primary tumor at the time of metastasis survey does not seem to be correlated with such characteristics of the metastatic burden as the number of detected lung metastases, their total volume, and the volume of the largest detected lung metastasis.

Consolidated mathematical growth model of the primary tumor and secondary distant metastases of breast cancer (CoMPaS)

The goal of this research is to improve the accuracy of predicting the breast cancer (BC) process using the original mathematical model referred to as CoMPaS. The CoMPaS is the original mathematical model and the corresponding software built by modelling the natural history of the primary tumor (PT) and secondary distant metastases (MTS), it reflects the relations between the PT and MTS. The CoMPaS is based on an exponential growth model and consists of a system of determinate nonlinear and linear equations and corresponds to the TNM classification. It allows us to calculate the different growth periods of PT and MTS: 1) a non-visible period for PT, 2) a non-visible period for MTS, and 3) a visible period for MTS. The CoMPaS has been validated using 10-year and 15-year survival clinical data considering tumor stage and PT diameter. The following are calculated by CoMPaS: 1) the number of doublings for the non-visible and visible growth periods of MTS and 2) the tumor volume doubling time (days) for the non-visible and visible growth periods of MTS. The diameters of the PT and secondary distant MTS increased simultaneously. In other words, the non-visible growth period of the secondary distant MTS shrinks, leading to a decrease of the survival of patients with breast cancer. The CoMPaS correctly describes the growth of the PT for patients at the T1aN0M0, T1bN0M0, T1cN0M0, T2N0M0 and T3N0M0 stages, who does not have MTS in the lymph nodes (N0). Additionally, the CoMPaS helps to consider the appearance and evolution period of secondary distant MTS (M1). The CoMPaS correctly describes the growth period of PT corresponding to BC classification (parameter T), the growth period of secondary distant MTS and the 10-15-year survival of BC patients considering the BC stage (parameter M).

Pulmonary metastasis in rectal cancer: a retrospective study of clinicopathological characteristics of 404 patients in Chinese cohort

OBJECTIVES

This study aim to investigate the incidence, timing and risk factors of metachronous pulmonary recurrence after curative resection in patients with rectal cancer.

DESIGN

A retrospective cohort study.

SETTING

This study was conducted at a tertiary referral cancer hospital.

PARTICIPANTS

A total of 404 patients with rectal cancer who underwent curative resection from 2007 to 2012 at Beijing Hospital were enrolled in this study.

INTERVENTIONS

The pattern of recurrence was observed and evaluated.

PRIMARY AND SECONDARY OUTCOME MEASURES

The incidence and timing of recurrences by site were calculated, and the risk factors of pulmonary recurrence were analysed.

RESULTS

The 5-year disease-free survival for the entire cohort was 77.0%. The most common site of recurrence was the lungs, with an incidence of 11.4%, followed by liver. Median interval from rectal surgery to diagnosis of pulmonary recurrence was much longer than that of hepatic recurrence (20 months vs 10 months, P=0.022). Tumour location, pathological tumor-node-metastasis (TNM) stage and positive circumferential resection margin were identified as independent risk factors for pulmonary recurrence. A predictive model based on the number of risk factors identified on multivariate analysis was developed, 5-year pulmonary recurrence-free survival for patients with 0, 1, 2 and 3 risk factors was 100%, 90.4%, 77.3% and 70.0%, respectively (P<0.001).

CONCLUSIONS

This study emphasised that the lung was the most common site of metachronous metastasis in patients with rectal cancer who underwent curative surgery. For patients with unfavourable risk profiles, a more intensive surveillance programme that could lead to the early detection of recurrence is strongly needed.

Suppression of Metastasis by Primary Tumor and Acceleration of Metastasis Following Primary Tumor Resection: A Natural Law?

We study metastatic cancer progression through an extremely general individual-patient mathematical model that is rooted in the contemporary understanding of the underlying biomedical processes yet is essentially free of specific biological assumptions of mechanistic nature. The model accounts for primary tumor growth and resection, shedding of metastases off the primary tumor and their selection, dormancy and growth in a given secondary site. However, functional parameters descriptive of these processes are assumed to be essentially arbitrary. In spite of such generality, the model allows for computing the distribution of site-specific sizes of detectable metastases in closed form. Under the assumption of exponential growth of metastases before and after primary tumor resection, we showed that, regardless of other model parameters and for every set of site-specific volumes of detected metastases, the model-based likelihood-maximizing scenario is always the same: complete suppression of metastatic growth before primary tumor resection followed by an abrupt growth acceleration after surgery. This scenario is commonly observed in clinical practice and is supported by a wealth of experimental and clinical studies conducted over the last 110 years. Furthermore, several biological mechanisms have been identified that could bring about suppression of metastasis by the primary tumor and accelerated vascularization and growth of metastases after primary tumor resection. To the best of our knowledge, the methodology for uncovering general biomedical principles developed in this work is new.

Meta-analysis of outcomes following resection of the primary tumour in patients presenting with metastatic colorectal cancer

BACKGROUND

It is not clear whether resection of the primary tumour (when there are metastases) alters survival and/or whether resection is associated with increased morbidity. This systematic review and meta-analysis assessed the prognostic value of primary tumour resection in patients presenting with metastatic colorectal cancer.

METHODS

A systematic review of MEDLINE/PubMed was performed on 12 March 2016, with no language or date restrictions, for studies comparing primary tumour resection versus conservative treatment without primary tumour resection for metastatic colorectal cancer. The quality of the studies was assessed using the MINORS and STROBE criteria. Differences in survival, morbidity and mortality between groups were estimated using random-effects meta-analysis.

RESULTS

Of 37 412 initially screened articles, 56 retrospective studies with 148 151 patients met the inclusion criteria. Primary tumour resection led to an improvement in overall survival of 7·76 (95 per cent c.i. 5·96 to 9·56) months (risk ratio (RR) for overall survival 0·50, 95 per cent c.i. 0·47 to 0·53), but did not significantly reduce the risk of obstruction (RR 0·50, 95 per cent c.i. 0·16 to 1·53) or bleeding (RR 1·19, 0·48 to 2·97). Neither was the morbidity risk altered (RR 1·14, 0·77 to 1·68). Heterogeneity between the studies was high, with a calculated I² of more than 50 per cent for most outcomes.

CONCLUSION

Primary tumour resection may provide a modest survival advantage in patients presenting with metastatic colorectal cancer.

Intratumoral Cancer Cell Intravasation Can Occur Independent of Invasion into the Adjacent Stroma

Intravasation, active entry of cancer cells into the circulation, is often considered to be a relatively late event in tumor development occurring after stromal invasion. Here, we provide evidence that intravasation can be initiated early during tumor development and proceed in parallel to or independent of tumor invasion into surrounding stroma. By applying direct and unbiased intravasation-scoring methods to two histologically distinct human cancer types in live-animal models, we demonstrate that intravasation takes place almost exclusively within the tumor core, involves intratumoral vasculature, and does not involve vasculotropic cancer cells invading tumor-adjacent stroma and migrating along tumor-converging blood vessels. Highlighting an additional role for EGFR in cancer, we find that EGFR is required for the development of an intravasation-sustaining intratumoral vasculature. Intratumoral localization of intravasation supports the notion that overt metastases in cancer patients could be initiated much earlier during cancer progression than appreciated within conventional clinical tumor staging systems.

Cancer metastasis: enactment of the script for human reproductive drama

Based on compelling evidence from many biological disciplines, we put forth a hypothesis for cancer metastasis. In the hypothesis, the metastatic cascade is depicted as human reproduction in miniature. Illustrated in a reproductive light, the staggering resemblance of cancer metastasis to human reproduction becomes evident despite some ostensible dis-similarities. In parallel to the appearance of primordial germ cells during early embryogenesis, the cancer reproductive saga starts with the separation of metastasis initiating cells (MICs) from cancer initiating cells when the primary cancer is still in its infancy. Prime MICs embark on a journey to the host bone marrow where they undergo further development and regulation. Migrating MICs are guided by the same CXCR4/CYCL12 axis as used in the migration of primordial germ cells to the genital ridge. Like the ovary, the host bone marrow features immune privileges, coolness, hypoxia and acidity which are essential for stemness maintenance and regulation. Opportune activation of the MICs via fusion with bone marrow stem cells triggers a frenzy of cellular proliferation and sets them on the move again. This scenario is akin to oocyte fertilization in the Fallopian tube and its subsequent journey towards the decidum. Just as the human reproductive process is plagued with undesirable outcomes so is the cancer metastasis highly inefficient. The climax of the cancer metastatic drama (colonization) is reached when proliferating MIC clusters attempt to settle down on decidum-like premetastatic sites. Successfully colonized clusters blossom into overt macrometastases only after the execution of sophisticated immunomodulation, angiogenesis and vascular remodeling. Similarly, the implanted blastomere needs to orchestrate these feats before flourishing into a new life. What is more, the cancer reproductive drama seems to be directed by a primordial hypothalamus–pituitary–gonad axis. Pursuing this reproductive trail could lead to new frontiers and breakthroughs in cancer research and therapeutics.

Improved systemic treatment for early breast cancer improves cure rates, modifies metastatic pattern and shortens post-metastatic survival: 35-year results from the Munich Cancer Registry

PURPOSE

Systemic therapies (ATHs) in early breast cancer have improved the survival of breast cancer (BC) patients in recent decades. The magnitude of the changes in overall, metastasis-free (MFS) and post-metastatic (PMS) survival and in the metastasis (MET) pattern will be described.

PATIENT AND METHODS

We analysed 60,227 patients with a diagnosis of T-N-M0 BC between 1978 and 2013 and 11,983 patients with metastases (MET) in the Munich Cancer Registry. Patients will be divided into four time periods to identify relationships between BC and METs. Survival was estimated using Kaplan-Meier curves, and Cox proportional hazards models were used to explore the impact of the BC subtype and MET status on survival with the time periods as surrogate markers for ATH evolution.

RESULTS

During the observation period, 5-year relative survival has improved from 80.3 to 93.6% with an adjusted hazard ratio of 0.54 (P < 0.0001). Successful implementation of ATH has changed the MET pattern. The percentage of liver and CNS METs has more than doubled, the rate of lung METs remains stable, and the rate of bone METs has been reduced by approximately 50%. MFS has been prolonged with a hazard ratio 0.75 (P < 0.0001), but PMS has declined (hazard ratio 1.36; P < 0.0001); however, effects of adjuvant and palliative treatments cannot be separated. These results do not contradict improvements in advanced BC and do not suggest alterations of MET tumour biology by ATH.

CONCLUSIONS

Over the past three decades, ATHs have dramatically improved patient survival after BC diagnosis-most likely, by eradicating prevalent micro-METs; as a result, the MET pattern has changed. Eradicating only a portion of the first METs results in delaying the onset of subsequent MET, which leads to an apparently paradoxical effect: an extension of the MET-free interval and a reduction in PMS.

[Clinical and epidemiological cancer registration in Germany]

OBJECTIVE

Function and funding of detailed clinical cancer registries (CCRs) is defined by German Social Code Book V (SGB V) and shall be implemented by the end of 2017.

CONTENT

Cancer registration according to regionally defined catchment areas, feedback of results and quality assurance are the basis which determines principles of operation and use of data. Each clinical department delivers only its own findings and therapy, while compilation by the clinical cancer registry describes the patients' way through the regional network of medical care. In this way, oncological centers are not burdened by troublesome documentation of data which originate from other clinics.

CONCLUSION

After successful implementation of CCRs, interested physicians and clinics are able to spend time for analysis and use of meaningful data with the objective of improving quality of care within the region, implementing innovative therapies and presenting their results, and generating new hypotheses to stimulate research.

Cancer Metastases: Early Dissemination and Late Recurrences

BACKGROUND

Metastatic cells from a primary tumor can occur before the primary cancer is detected. Metastatic cells can also remain in the patient for many years after removal of the primary tumor without proliferating. These dormant malignant cells can awaken and cause recurrent disease decades after the primary treatment. The purpose of this article is to review the clinical evidence for early dissemination and late recurrences in human malignant tumors. We used the following definitions: dormancy of cells may be defined as a nonproliferating state or an arrest in the cell cycle that results in a prolonged G0 phase. If one accepts the term "late metastases" to indicate a period exceeding 10 years from the removal of the primary tumor, then the two malignancies in which this occurs most frequently are cutaneous malignant melanoma (CMM) and renal cell carcinoma (RCC).

METHODS

PubMed, Web of Science, and Scopus were searched with the keywords "metastases," "early dissemination," "late recurrences," "inadvertently transmitted cancer," "tumor growth rate," "dormancy," "circulating tumor cells," and "transplantation of cancer."

RESULTS

Several case reports of early dissemination and late recurrences of various types of malignancies were found. Analyses of the growth rates of several malignant tumors in the original host indicated that the majority of cancers had metastasized years before they were detected. CMM, RCC, and malignant glioblastoma were the three most common malignancies resulting from an organ transplantation. CMM and RCC were also the two most common malignancies that showed dormancy. In several cases of transplanted CMM and RCC, the donor did not have any known malignancy or had had the malignancy removed so long ago that the donor was regarded as cured.

CONCLUSION

(1) Metastases can frequently exist prior to the detection of the primary tumor. (2) Metastatic cells may reside in organs in the original host that are not usually the site of detectable secondary tumors, for example, the kidneys and heart. (3) Metastatic cells remain dormant for decades after the primary tumor has been removed. (4) Dormancy might be reversible and lead to late recurrences.

Patterns of metachronous metastases after curative treatment of colorectal cancer

BACKGROUND

This study aimed to provide information on timing, anatomical location, and predictors for metachronous metastases of colorectal cancer based on a large consecutive series of non-selected patients.

METHODS

All patients operated on with curative intent for colorectal cancer (TanyNanyM0) between 2003 and 2008 in the Dutch Eindhoven Cancer Registry were included (N=5671). By means of active follow-up by the Cancer Registry staff within ten hospitals, data on development of metastatic disease were collected. Median follow-up was 5.0 years.

RESULTS

Of the 5671 colorectal cancer patients, 1042 (18%) were diagnosed with metachronous metastases. Most common affected sites were the liver (60%), lungs (39%), extra-regional lymph nodes (22%), and peritoneum (19%). 86% of all metastases was diagnosed within three years and the median time to diagnosis was 17 months (interquartile range 10-29 months). Male gender (HR=1.2, 95%CI 1.03-1.32), an advanced primary T-stage (T4 vs. T3 HR=1.6, 95%CI 1.32-1.90) and N-stage (N1 vs. N0 HR=2.8, 95%CI 2.42-3.30 and N2 vs. N0 HR=4.5, 95%CI 3.72-5.42), high-grade tumour differentiation (HR=1.4, 95%CI 1.17-1.62), and a positive (HR=2.1, 95%CI 1.68-2.71) and unknown (HR=1.7, 95%CI 1.34-2.22) resection margin were predictors for metachronous metastases.

CONCLUSIONS

Different patterns of metastatic spread were observed for colon and rectal cancer patients and differences in time to diagnosis were found. Knowledge on these patterns and predictors for metachronous metastases may enhance tailor-made follow-up schemes leading to earlier detection of metastasized disease and increased curative treatment options.

Optimal timing of pulmonary metastasectomy--is a delayed operation beneficial or counterproductive?

INTRODUCTION

Pulmonary metastasectomy represents an established approach in the treatment of lung metastases related to several solid malignant tumors, promising the chance of long term survival. Regarding the proper timing of metastasectomy both operation promptly after diagnosis and delayed operation after an interval of 3 months are common practice.

MATERIALS AND METHODS

A systematic Medline search addressing the optimal timing of metastasectomy was performed. Since the search query "timing of metastasectomy" yields only a limited number of articles, the Medline search was expanded to include the main arguments for prompt metastasectomy ("metastases of metastasis", "growth rate of pulmonary metastases") and for delayed metastasectomy.

RESULTS

Based on the data available to date, there is no necessity to expedite the timing of the operation. On the other hand, there is no evidence that a delayed operation, for example after re-staging following an interval of 3 months, provides a benefit.

CONCLUSION

Therefore the timing of metastasectomy should only depend on the patient's requirements, such as general state of health and oncologic considerations, such as promising multimodal therapy concepts, extrathoracal tumor manifestations or oncologic type of the primary tumor. A delayed operation seems justified if the indication for resection is questionable due to a high risk of early multilocal recurrence.

Selection and adaptation during metastatic cancer progression

Cancer is often regarded as a process of asexual evolution driven by genomic and genetic instability. Mutation, selection and adaptation are by convention thought to occur primarily within, and to a lesser degree outside, the primary tumour. However, disseminated cancer cells that remain after 'curative' surgery exhibit extreme genomic heterogeneity before the manifestation of metastasis. This heterogeneity is later reduced by selected clonal expansion, suggesting that the disseminated cells had yet to acquire key traits of fully malignant cells. Abrogation of the cells' progression outside the primary tumour implies new challenges and opportunities for diagnosis and adjuvant therapies.

Metachronous peritoneal carcinomatosis after curative treatment of colorectal cancer

INTRODUCTION

Population-based data on metachronous peritoneal carcinomatosis (PC) after curative resection of colorectal origin are scarce. The aim of this study was to investigate the incidence of and risk factors for developing metachronous PC from colorectal cancer as well as survival since diagnosis of PC.

METHODS

Data on metachronous metastases were collected between 2010 and 2011 for all patients diagnosed with M0 colorectal cancer between 2003 and 2008 in the Dutch Eindhoven Cancer Registry. Median follow-up was 5.0 years. Survival was defined as time from metastases diagnosis to death.

RESULTS

Of the 5671 colorectal cancer patients, 1042 (18%) were diagnosed with metachronous metastases of whom 197 (19%) developed metachronous PC. The peritoneal surface was the only site of metastasis in 81 (41%) patients while 116 (59%) patients were diagnosed with both PC and metastases elsewhere. Median survival after diagnosis of PC was 6 months compared to 15 months for patients with distant metastases in other organs. Patients with an advanced primary tumour stage, positive lymph nodes at initial diagnosis, primary mucinous adenocarcinoma, positive resection margin and a primary tumour located in the colon were at increased risk of developing metachronous PC.

CONCLUSION

Of the colorectal cancer patients who developed metachronous metastases, approximately one fifth is diagnosed with PC. Prognosis of these patients is poor with a median survival of 6 months after diagnosis. Identifying patients at high risk for developing metachronous PC is important as it may contribute to more accurate patient information, tailor-made follow-up schemes, and more adequate treatment.

Risk of lymph node metastases after en bloc cold steel, en bloc laser-, and piecemeal laser surgical resection of auricular VX2 carcinoma

There is some controversy in the literature if lymph vessels are enduring sealed during piecemeal CO2 laser surgery of squamous cell carcinomas of the head and neck or a propagation of tumor cells into the lymphatics occurs. The aim of the present study was to analyze the incidence of lymph node and distant metastases after different methods of resection of a VX2 carcinoma in an animal model. A solid auricular VX2 carcinoma was induced in 200 rabbits. Seven days later, an en bloc cold steel (group A), en bloc laser surgical resection with CO2 laser in continuous wave mode with 2 W (group B), or piecemeal laser surgical resection after transection of the tumor with CO2 laser in continuous wave mode with 2 W (group C) or 20 W (group D) was performed. The animals were killed and the incidence of lymph node and distant metastases was compared between the different groups. Of the rabbits, 21.1 % developed lymph node metastases and 10 % pulmonary metastases. The incidence of lymph node metastases was 17.4 % in group A, 20.4 % in group B, 26 % in group C, and 20 % in group D. These differences were not statistically significant. En bloc cold steel, en bloc laser-, or piecemeal laser surgical resections include similar risk of postoperative metastases. Propagation of tumor cells cannot be excluded with certainty by any of these methods.

Positive lymph nodes do not metastasize

Our understanding of the role of lymph nodes (LN) in the metastasization process (MET) is marginal. Positive LNs (pLN) are the most important prognostic factor and lymph node dissection (LND) is still standard practice in primary treatment. However, up to now, there is almost no evidence that elective LND has a survival benefit. Based on many clinical and experimental findings, we propose that tumor foci in regional LN are incapable of metastasization and can therefore not infiltrate further LN and organs. Available data demonstrate a very early infiltration of MET capable tumor cells from the primary tumor into regional LN, and thereafter an increased probability of subsequent LN infiltrations. Disparate growth rates of the first versus subsequent infiltrating tumors as well as the asymptotic growth and prognosis of large tumor foci in LN explain many clinical observations for solid tumors. The consequence of the hypothesis "pLN do not metastasize" would impact clinical treatment and research and contribute to understanding the mounting evidence against LND.

Selectin-deficiency reduces the number of spontaneous metastases in a xenograft model of human breast cancer

Metastasis formation is a complex process still poorly understood. Previous work in a colon cancer xenograft model showed that E(ndothelial) and P(latelet) selectins mediate spontaneous metastasis to the lungs. To investigate the functional role of selectins in breast cancer, human DU4475 breast cancer cells were injected subcutaneously into pfp-/-rag2-/- mice and in all their selectin-deficient variants (EP-/-, E-/- and P-/-). Pfp-/-rag2-/- mice as well as all their selectin-deficient variants developed primary tumours and spontaneous metastases. Compared with the wild-type mice, disseminated tumours cells were significantly lower (74% reduction, P=0.046) in the bone marrow of selectin-deficient mice. Pfp-/-rag2-/- mice developed significantly higher numbers of lung metastases (6644.83±741.77) than the E-/- (4053.33±112.58; P=0.002) and the EP-/- pfp-/-rag2-/- mice (4665.65±754.50; P<0.001). The results indicate that E- and P-selectins play a role in spontaneous metastasis formation both into bone marrow and lungs. However, spontaneous metastasis was not completely abrogated, hence additional cell adhesion molecules must be involved in the metastatic spread.

Metastasis is an early event in mouse mammary carcinomas and is associated with cells bearing stem cell markers

Introduction

It is still uncertain whether metastasis is predominantly an early or late event in tumor progression. The detection of early metastases and cells responsible for the dissemination may therefore have significant clinical implications.

Methods

Lung dissemination and/or metastasis were investigated in mice carrying the polyomavirus middle-T oncogene (PyMT) during different stages of mammary tumorigenesis using the colony forming assay. Immunocytochemical or immunohistochemical staining was used to identify subpopulations of cells responsible for lung dissemination and metastasis. Histological examination was used to show primary and metastatic tumors. The tumor-initiating and metastatic capacity of cells expressing stem cell markers was assessed in syngeneic wild-type (WT) mice whose mammary fat pads were injected with these cells.

Results

Metastatic mammary epithelial cells were detected in the lungs of mice carrying the PyMT oncogene (MMT mice). These cells were observed early in breast tumorigenesis when the mammary tree appeared by histological inspection to be normal (or at a premalignant stage), suggesting the possession of disseminating and metastatic capacity even before full malignant transformation. Some of the disseminated cells and lung metastases displayed surface stem cell markers. These findings suggest that stem cells from apparently precancerous primary lesions could be a source of metastasis. Indeed, injection of lung tissue cells from MMT mice into syngeneic WT mice resulted in the formation of mammary tumors. These tumors resembled their parent mammary tumors in the MMT donors as well as grafted tumors derived from mammary tumor cells. Furthermore, when we injected lung tissue cells from GFP MMT mice into the fat pads of recipient WT mice, disseminated or metastatic GFP-expressing cells were detected in the lungs, lymph nodes and blood of the recipient WT mice. We finally identified a subpopulation of mammary epithelial/tumor cells expressing CD44 and Sca1 that was largely responsible for dissemination and metastasis in MMT mice.

Conclusions

The tumorigenic and metastatic potential of a subpopulation of mammary epithelial/tumor cells in MMT mice is endowed relatively early in mammary neoplasms and suggests a potential role for cancer stem cell sub-populations in metastasis.

Microenvironments dictating tumor cell dormancy

The mechanisms driving dormancy of disseminated tumor cells (DTCs) remain largely unknown. Here, we discuss experimental evidence and theoretical frameworks that support three potential scenarios contributing to tumor cell dormancy. The first scenario proposes that DTCs from invasive cancers activate stress signals in response to the dissemination process and/or a growth suppressive target organ microenvironment inducing dormancy. The second scenario asks whether therapy and/or micro-environmental stress conditions (e.g. hypoxia) acting on primary tumor cells carrying specific gene signatures prime new DTCs to enter dormancy in a matching target organ microenvironment that can also control the timing of DTC dormancy. The third and final scenario proposes that early dissemination contributes a population of DTCs that are unfit for immediate expansion and survive mostly in an arrested state well after primary tumor surgery, until genetic and/or epigenetic mechanisms activate their proliferation. We propose that DTC dormancy is ultimately a survival strategy that when targeted will eradicate dormant DTCs preventing metastasis. For these non-mutually exclusive scenarios we review experimental and clinical evidence in their support.

Surgery and cancer promotion: are we trading beauty for cancer?

It is well-known that cancer surgery can actually promote the growth of some tumors by a variety of mechanisms. There are observational data suggesting that surgery per se can increase the risk of cancer among individuals without a history of clinical cancer. Occult microscopic cancers are exceedingly common in the general population and are held in a dormant state by a balance between cell proliferation and cell death and also an intact host immune surveillance. The catecholamine surge from the stress of surgery and resulting β(2)-adrenergic signaling culminates in a transient and robust increased vascular endothelial growth factor expression locally and systemically that is enough to start tumor angiogenesis and end dormancy. The same catecholamine surge and β(2)-adrenergic signaling impairs cell-mediated immunity at a crucial time. Elegant animal studies have demonstrated that perioperative nonselective β-blockade abrogates surgical stress-induced angiogenesis and tumor growth. Prospective human trials are desperately needed and clinical implications are discussed.

ERK1/2 and p38α/β signaling in tumor cell quiescence: opportunities to control dormant residual disease

Systemic minimal residual disease after primary tumor treatment can remain asymptomatic for decades. This is thought to be due to the presence of dormant disseminated tumor cells (DTC) or micrometastases in different organs. DTCs lodged in brain, lungs, livers, and/or bone are a major clinical problem because they are the founders of metastasis, which ultimately kill cancer patients. The problem is further aggravated by our lack of understanding of DTC biology. In consequence, there are almost no rational therapies to prevent dormant DTCs from surviving and expanding. Several cancers, including melanoma as well as breast, prostate, and colorectal carcinomas, undergo dormant periods before metastatic recurrences develop. Here we review our experience in studying the cross-talk between ERK1/2 and p38α/β signaling in models of early cancer progression, dissemination, and DTC dormancy. We also provide some potential translational and clinical applications of these findings and describe how some currently used therapies might be useful to control dormant disease. Finally, we draw caution on the use of p38 inhibitors currently in clinical trials for different diseases as these may accelerate metastasis development.