The effects of surgery on tumor growth: a century of investigations

Does surgery for breast cancer induce angiogenesis and thus promote metastasis?

At the time of surgery for breast cancer, cancer cells released from the primary tumor have most likely entered blood or lymphatic vessels, leading to the development of micrometastases. Cancer cells directly produce angiogenesis stimulators, provoke the release of stimulators bound to the surrounding extracellular matrix and induce macrophages to secrete angiogenesis stimulators, thereby promoting angiogenesis. Metastasis dormancy is characterized by a balance between cell proliferation and apoptosis and is thought to be controlled by increased apoptosis, indirectly induced by angiogenesis inhibitors. Many patients with solid tumors already have micrometastases at the time of detection and surgical removal of their primary tumors. Primary tumor resection is believed to stimulate angiogenesis, initiating the proliferation of latent micrometastases. Latent micrometastases have already acquired angiogenic potential. The provision of additional therapy to inhibit angiogenesis after surgery is therefore considered a rational approach. The effectiveness of dormancy therapy should be evaluated in the prospective clinical trials of chemotherapy with drugs such as cyclophosphamide and UFT, which have been reported to inhibit angiogenesis as demonstrated by the numbers of circulating endothelial cells and circulating endothelial progenitors in peripheral blood before and after surgery in women with primary breast cancer.

Effects of Surgery and Chemotherapy on Metastatic Progression of Prostate Cancer: Evidence from the Natural History of the Disease Reconstructed through Mathematical Modeling

This article brings mathematical modeling to bear on the reconstruction of the natural history of prostate cancer and assessment of the effects of treatment on metastatic progression. We present a comprehensive, entirely mechanistic mathematical model of cancer progression accounting for primary tumor latency, shedding of metastases, their dormancy and growth at secondary sites. Parameters of the model were estimated from the following data collected from 12 prostate cancer patients: (1) age and volume of the primary tumor at presentation; and (2) volumes of detectable bone metastases surveyed at a later time. This allowed us to estimate, for each patient, the age at cancer onset and inception of the first metastasis, the expected metastasis latency time and the rates of growth of the primary tumor and metastases before and after the start of treatment. We found that for all patients: (1) inception of the first metastasis occurred when the primary tumor was undetectable; (2) inception of all or most of the surveyed metastases occurred before the start of treatment; (3) the rate of metastasis shedding is essentially constant in time regardless of the size of the primary tumor and so it is only marginally affected by treatment; and most importantly, (4) surgery, chemotherapy and possibly radiation bring about a dramatic increase (by dozens or hundred times for most patients) in the average rate of growth of metastases. Our analysis supports the notion of metastasis dormancy and the existence of prostate cancer stem cells. The model is applicable to all metastatic solid cancers, and our conclusions agree well with the results of a similar analysis based on a simpler model applied to a case of metastatic breast cancer.

Postoperative serum proteomic profiles may predict recurrence-free survival in high-risk primary breast cancer

PURPOSE

Better breast cancer prognostication may improve selection of patients for adjuvant therapy. We conducted a retrospective longitudinal study in which we investigated sera of high-risk primary breast cancer patients, to search for proteins predictive of recurrence-free survival.

METHODS

Sera of 82 breast cancer patients obtained after surgery, but prior to the administration of adjuvant therapy, were fractionated using anion-exchange chromatography, to facilitate the detection of the low-abundant serum peptides. Selected fractions were subsequently analysed by surface-enhanced laser desorption/ionisation time-of-flight mass spectrometry (SELDI-TOF MS), and the resulting protein profiles were searched for prognostic markers by appropriate bioinformatics tools.

RESULTS

Four peak clusters (i.e. m/z 3073, m/z 3274, m/z 4405 and m/z 7973) were found to bear significant prognostic value (P ≤ 0.01). The m/z 3274 candidate marker was structurally identified as inter-alpha-trypsin inhibitor heavy chain 4 fragment(658-688) in serum. Except for the m/z 7973 peak cluster, these peaks remained independently associated with recurrence-free survival upon multivariate Cox regression analysis, including clinical parameters of known prognostic value in this study population.

CONCLUSION

Investigation of the postoperative serum proteome by, e.g., anion-exchange fractionation followed by SELDI-TOF MS analysis is promising for the detection of novel prognostic factors. However, regarding the rather limited study population, validation of these results by analysis of independent study populations is warranted to assess the true clinical applicability of discovered prognostic markers. In addition, structural identification of the other markers will aid in elucidation of their role in breast cancer prognosis, as well as enable development of absolute quantitative assays.

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.

Cascading adoptive cell therapy for metastatic melanoma

Adoptive tumor-infiltrating lymphocytes (TILs) therapy has demonstrated drastic effects on advanced malignant melanoma. Intensive pretreatment such as chemotherapy and/or total body irradiation has been used to eliminate immunosuppressive components and therefore enhances the antitumor effects of TILs. However, these pretreatments may cause severe side effects, especially for elderly patients. This case observes the complete response of how a patient with metastatic melanoma was treated sequentially with local tumor resection, postoperative adoptive cytokine-induced killer cells and TILs infusion. In addition, the cascading adoptive cell therapy was well-tolerated by the patient. Therefore, being pretreated with cytokine-induced killer cells could ameliorate the immunosuppressive condition in the patient and provide a favorable circumstance for subsequent TILs infusion. The further adoptive TILs therapy could exert the most powerful antitumor activity in such an amicable circumstance.

Tumor cell seeding during surgery-possible contribution to metastasis formations

In spite of optimal local control in breast cancer, distant metastases can develop as a systemic part of this disease. Surgery is suspected to contribute to metastasis formation activating dormant tumor cells. Here we add data that seeding of cells during surgery may add to the risk of metastasis formation. The change in circulating epithelial tumor cells (CETC) was monitored in 66 breast cancer patients operated on with breast conserving surgery or mastectomy and during the further course of the disease, analyzing CETC from unseparated white blood cells stained with FITC-anti-EpCAM. An increase in cell numbers lasting until the start of chemotherapy was observed in about one third of patients. It was more preeminent in patients with low numbers of CETC before surgery and, surprisingly, in patients without involved lymph nodes. Patients with the previously reported behavior—Reincrease in cell numbers during adjuvant chemotherapy and subsequent further increase during maintenance therapy—were at increased risk of relapse. In addition to tumor cells already released during growth of the tumor, cell seeding during surgery may contribute to the early peak of relapses observed after removal of the primary tumor and chemotherapy may only marginally postpone relapse in patients with aggressively growing tumors.

The Bone Niche of Chondrosarcoma: A Sanctuary for Drug Resistance, Tumour Growth and also a Source of New Therapeutic Targets

Chondrosarcomas are malignant cartilage-forming tumours representing around 20% of malignant primary tumours of bone and affect mainly adults in the third to sixth decade of life. Unfortunately, the molecular pathways controlling the genesis and the growth of chondrosarcoma cells are still not fully defined. It is well admitted that the invasion of bone by tumour cells affects the balance between early bone resorption and formation and induces an “inflammatory-like” environment which establishes a dialogue between tumour cells and their environment. The bone tumour microenvironment is then described as a sanctuary that contributes to the drug resistance patterns and may control at least in part the tumour growth. The concept of “niche” defined as a specialized microenvironment that can promote the emergence of tumour stem cells and provide all the required factors for their development recently emerges in the literature. The present paper aims to summarize the main evidence sustaining the existence of a specific bone niche in the pathogenesis of chondrosarcomas.

Tumor-Specific Systemic Treatment in Advanced Breast Cancer - How Long does it Make Sense?

SUMMARY: Metastatic breast cancer (MBC) is a chronic and incurable disease which can be kept steady for a long time with continuous oncologic therapy. There are various treatment options. Disease-free as well as overall survival were prolonged in many pharmaceutical studies. The therapist focuses on these oncologic parameters as well as the patient's quality of life. One central point of the communication between doctor and patient is the prediction by the medical team of how long to continue oncologic therapy and when to start palliative medicine in terms of best palliative care. Treatment options currently available for MBC as well as the importance of this difficult communication between the involved parties are pointed out. The end of tumor-specific oncologic therapy does not necessarily mean the end of therapeutic measures for the individual patient.

Tumor control probability in radiation treatment

Patients undergoing radiation therapy (and their physicians alike) are concerned with the probability of cure (long-term recurrence-free survival, meaning the absence of a detectable or symptomatic tumor). This is not what current practice categorizes as "tumor control (TC);" instead, TC is taken to mean the extinction of clonogenic tumor cells at the end of treatment, a sufficient but not necessary condition for cure. In this review, we argue that TC thus defined has significant deficiencies. Most importantly, (1) it is an unobservable event and (2) elimination of all malignant clonogenic cells is, in some cases, unnecessary. In effect, within the existing biomedical paradigm, centered on the evolution of clonogenic malignant cells, full information about the long-term treatment outcome is contained in the distribution Pm(T) of the number of malignant cells m that remain clonogenic at the end of treatment and the birth and death rates of surviving tumor cells after treatment. Accordingly, plausible definitions of tumor control are invariably traceable to Pm(T). Many primary cancers, such as breast and prostate cancer, are not lethal per se; they kill through metastases. Therefore, an object of tumor control in such cases should be the prevention of metastatic spread of the disease. Our claim, accordingly, is that improvements in radiation therapy outcomes require a twofold approach: (a) Establish a link between survival time, where the events of interest are local recurrence or distant (metastatic) failure (cancer-free survival) or death (cancer-specific survival), and the distribution Pm(T) and (b) link Pm(T) to treatment planning (modality, total dose, and schedule of radiation) and tumor-specific parameters (initial number of clonogens, birth and spontaneous death rates during the treatment period, and parameters of the dose-response function). The biomedical, mathematical, and practical aspects of implementing this program are discussed.

Hallmarks of cancer: the next generation

The hallmarks of cancer comprise six biological capabilities acquired during the multistep development of human tumors. The hallmarks constitute an organizing principle for rationalizing the complexities of neoplastic disease. They include sustaining proliferative signaling, evading growth suppressors, resisting cell death, enabling replicative immortality, inducing angiogenesis, and activating invasion and metastasis. Underlying these hallmarks are genome instability, which generates the genetic diversity that expedites their acquisition, and inflammation, which fosters multiple hallmark functions. Conceptual progress in the last decade has added two emerging hallmarks of potential generality to this list-reprogramming of energy metabolism and evading immune destruction. In addition to cancer cells, tumors exhibit another dimension of complexity: they contain a repertoire of recruited, ostensibly normal cells that contribute to the acquisition of hallmark traits by creating the "tumor microenvironment." Recognition of the widespread applicability of these concepts will increasingly affect the development of new means to treat human cancer.

Metastatic tumor dormancy in cutaneous melanoma: does surgery induce escape?

According to the concept of tumor dormancy, tumor cells may exist as single cells or microscopic clusters of cells that are clinically undetectable, but remain viable and have the potential for malignant outgrowth. At metastatic sites, escape from tumor dormancy under more favorable local microenvironmental conditions or through other, yet undefined stimuli, may account for distant recurrence after supposed "cure" following surgical treatment of the primary tumor. The vast majority of evidence to date in support of the concept of tumor dormancy originates from animal studies; however, extensive epidemiologic data from breast cancer strongly suggests that this process does occur in human disease. In this review, we aim to demonstrate that metastatic tumor dormancy does exist in cutaneous melanoma based on evidence from mouse models and clinical observations of late recurrence and occult transmission by organ transplantation. Experimental data underscores the critical role of impaired angiogenesis and immune regulation as major mechanisms for maintenance of tumor dormancy. Finally, we examine evidence for the role of surgery in promoting escape from tumor dormancy at metastatic sites in cutaneous melanoma.

Risk of recurrence following delayed large flap reconstruction after mastectomy for breast cancer

BACKGROUND

The aim of this retrospective matched cohort study was to evaluate the rate of recurrence among women with delayed large flap breast reconstruction after mastectomy for breast cancer. The recurrence rate among women treated at a single hospital was compared with that in an individually matched control group of women with breast cancer who did not have reconstruction after mastectomy.

METHODS

Between 1982 and 2001, 125 women with previous invasive breast carcinoma underwent delayed large flap breast reconstruction with pedicled musculocutaneous or microvascular flaps (a median of 32 months after mastectomy). They were matched individually with 182 women with breast cancer who had a mastectomy but did not undergo breast reconstruction. Matching criteria were year of diagnosis, age at diagnosis and treating hospital. Medical records were evaluated until October 2007. Histopathological specimens for all included women were re-evaluated. The endpoint was locoregional or distant breast cancer recurrence. The risk of recurrent disease was calculated using a Cox proportional hazards analysis, adjusted for established prognostic factors.

RESULTS

Median follow-up for the entire cohort was 146 months. The reconstruction group had a 2·08 (95 per cent confidence interval 1·07 to 4·06) times higher risk of recurrent disease than the mastectomy only group.

CONCLUSION

Women with breast cancer who had delayed reconstruction with a large flap in this study had a higher risk of recurrent disease than those with mastectomy alone.

Why victory in the war on cancer remains elusive: biomedical hypotheses and mathematical models

We discuss philosophical, methodological, and biomedical grounds for the traditional paradigm of cancer and some of its critical flaws. We also review some potentially fruitful approaches to understanding cancer and its treatment. This includes the new paradigm of cancer that was developed over the last 15 years by Michael Retsky, Michael Baum, Romano Demicheli, Isaac Gukas, William Hrushesky and their colleagues on the basis of earlier pioneering work of Bernard Fisher and Judah Folkman. Next, we highlight the unique and pivotal role of mathematical modeling in testing biomedical hypotheses about the natural history of cancer and the effects of its treatment, elaborate on model selection criteria, and mention some methodological pitfalls. Finally, we describe a specific mathematical model of cancer progression that supports all the main postulates of the new paradigm of cancer when applied to the natural history of a particular breast cancer patient and fit to the observables.

Wound healing after trauma may predispose to lung cancer metastasis: review of potential mechanisms

Inflammatory oncotaxis, the phenomenon in which mechanically injured tissues are predisposed to cancer metastases, has been reported for a number of tumor types, but not previously for histologically proven lung cancer. We review clinical and experimental evidence and mechanisms that may underlie inflammatory oncotaxis, and provide illustrative examples of two patients with squamous cell carcinoma of the lung who developed distant, localized metastatic disease at sites of recent physical trauma. Trauma may predispose to metastasis through two distinct, but not mutually exclusive, mechanisms: (1) physical trauma induces tissue damage and local inflammation, creating a favorable environment that is permissive for seeding of metastatic cells from distant sites; and/or (2) micrometastatic foci are already present at the time of physical injury, and trauma initiates changes in the microenvironment that stimulate the proliferation of the metastatic cells. Further exploration of post-traumatic inflammatory oncotaxis may elucidate fundamental mechanisms of metastasis and could provide novel strategies to prevent cancer metastasis.

Exclusive and adjuvant radiotherapy in breast cancer patients with synchronous metastases

Background

Data from the Surveillance, Epidemiology, and End Results program and the European Concerted Action on survival and Care of Cancer Patients (EUROCARE) project indicate that about 6% of women newly diagnosed with breast cancer have stage IV disease, representing about 12 600 new cases per year in the United States in 2005. Historically, local therapy of the primary tumor in this setting has been aimed solely at symptom palliation. However, several studies suggest that surgical excision of the primary tumor can prolong these patients' survival.

Discussion

Exclusive locoregional radiotherapy is an alternative form of locoregional treatment in this setting and may represent an effective alternative to surgery in this setting. Here we discuss current issues regarding exclusive and adjuvant locoregional radiotherapy in breast cancer patients with synchronous metastases.

Summary

Several studies suggest that surgery or exclusive irradiation of the primary tumor is associated with better survival in breast cancer patients with synchronous metastases and that exclusive locoregional radiotherapy may represent an effective alternative to surgery in this setting. Results of well-designed prospective studies are needed to re-evaluate treatment of the primary breast tumor in patients with metastases at diagnosis, and to identify those patients who are most likely to benefit.

Treatment of the primary tumor in breast cancer patients with synchronous metastases

Data from the Surveillance, Epidemiology, and End Results program and the European Concerted Action on survival and Care of Cancer Patients (EUROCARE) project indicate that approximately 6% of women newly diagnosed with breast cancer have stage IV disease, representing approximately 12 600 new cases per year in the United States in 2005. Historically, local therapy of the primary tumor in this setting has been aimed solely at symptom palliation. However, several studies suggest that surgical excision or exclusive irradiation of the primary tumor can prolong these patients' survival. In contrast, the impact of surgical dissection of regional lymph nodes and postoperative radiotherapy is poorly documented, and the patient subgroups most likely to benefit from treatment of the primary tumor remain to be identified. Two prospective studies are currently examining the benefits of locoregional therapy compared with systemic therapy alone in this setting. Here, we discuss current issues regarding treatment of the primary tumor in breast cancer patients with synchronous metastases.

Breast and other cancer dormancy as a therapeutic endpoint: speculative recombinant T cell receptor ligand (RTL) adjuvant therapy worth considering?

BACKGROUND

Most individuals who died of trauma were found to harbour microscopic primary cancers at autopsies. Surgical excision of the primary tumour, unfortunately, seems to disturb tumour dormancy in over half of all metastatic relapses.

PRESENTATION OF THE HYPOTHESIS

A recently developed immune model suggested that the evolutionary pressure driving the creation of a T cell receptor repertoire was primarily the homeostatic surveillance of the genome. The model is based on the homeostatic role of T cells, suggesting that molecular complementarity between the positively selected T cell receptors and the self peptide-presenting major histocompatibility complex molecules establishes and regulates homeostasis, strictly limiting variations of its components. The repertoire is maintained by continuous peripheral stimulation via soluble forms of self-peptide-presenting major histocompatibility complex molecules governed by the law of mass action. The model states that foreign peptides inhibit the complementary interactions between the major histocompatibility complexes and T cell receptors. Since the vast majority of clinically detected cancers present self-peptides the model assumes that tumour cells are, paradoxically, under homeostatic T cell control.The novelty of our hypothesis therefore is that resection of the primary tumour mass is perceived as loss of 'normal' tissue cells. Consequently, T cells striving to reconstitute homeostasis stimulate rather than inhibit the growth of dormant tumour cells and avascular micrometastases. Here we suggest that such kick-start growths could be prevented by a recombinant T cell receptor ligand therapy that modifies T cell behaviour through a partial activation mechanism.

TESTING THE HYPOTHESIS

The homeostatic T cell regulation of tumours can be tested in a tri-transgenic mice model engineered to express potent oncogenes in a doxycycline-dependent manner. We suggest seeding dissociated, untransformed mammary cells from doxycycline naïve mice into the lungs of two mice groups: one carries mammary tumours, the other does not. Both recipient groups to be fed doxycycline in order to activate the oncogenes of the untransformed mammary cells in the lungs, where solitary nodules are expected to develop 6 weeks after injection. We expect that lung metastasis development will be stimulated following resection of the primary tumour mass compared to the tumour-free mice. A recombinant T cell receptor ligand therapy, starting at least one day before resection and continuing during the entire experimental period, would be able to prevent the stimulating effect of surgery.

IMPLICATIONS OF THE HYPOTHESIS

Recombinant T cell receptor ligand therapy of diagnosed cancer would keep all metastatic deposits microscopic for as long as the therapy is continued without limit and could be pursued as one method of cancer control. Improving the outcome of therapy by preventing the development of metastases is perhaps achievable more readily than curing patients with overt metastases.

Purinergic mechanisms in breast cancer support intravasation, extravasation and angiogenesis

Several advances have recently expanded models of tumor growth and promoted the concept of tumor homeostasis, the hypothesis that primary tumors exert an anti-proliferative effect on both themselves and subclinical secondary metastases. Recent trials indicate that the characterization of tumor growth as uncontrolled is inconsistent with animal models, clinical models, and epidemiological models. There is a growing body of evidence which lends support to an updated concept of tumor growth: tumor homeostasis. In the case of breast cancer, if not all metastasizing tumors, these advances suggest an inconvenient truth. That is, if breast tumor cells metastasize to distant sites early in the tumorigenesis process, then removal of a breast tumor may hasten the development of its metastases. We explore the heretofore unappreciated notion that nucleotides generated by tumor cells following the secretion of an ADP-kinase can promote metastasis and support angiogenesis. Evidence is presented that blockade of the actions of nucleotides in the setting of newly diagnosed breast cancer may provide a useful adjunct to current anti-angiogenesis treatment.

Recurrent breast cancer: treatment strategies for maintaining and prolonging good quality of life

BACKGROUND

Recurrent breast cancer remains a challenge for interdisciplinary treatment even though new therapeutic options are available.

METHODS

The PubMed database was selectively searched for articles that appeared from 1999 to 2009 and contained the key words "breast cancer," "recurrence," "metastatic," "advanced," and "treatment". Further sources consulted for this review included the German S3 guideline, the treatment recommendations of the German AGO-Mamma group, the NCCN guidelines, and the Cochrane database.

RESULTS

Locoregional recurrences are treated with curative intent. Metastatic breast cancer must be treated on an individualized basis: The treatment should be continued as long as its benefits for the individual patient outweigh its adverse side effects. Endocrine treatment is indicated for all patients whose tumors are hormone-receptor positive or of unknown receptor status and who have enough time for a response to be seen. Chemotherapy should be given if the tumor is hormone-receptor negative, if a rapid response is urgently needed, or if endocrine treatment has failed to produce a response. Combination chemotherapy improves response rates and prolongs progression-free survival, yet it does not prolong overall survival in comparison to monochemotherapy. In HER2-positive patients, first-line treatment with trastuzumab and monochemotherapy prolongs overall survival. Other treatment options include angiogenesis inhibitors, various tyrosine kinases inhibitors, radiotherapy, bisphosphonates, surgical or other ablative treatment of metastases, or a combination of these approaches, applied either simultaneously or consecutively.

CONCLUSIONS

While locoregional recurrences of breast cancer should be treated with curative intent, breast cancer with distant metastases is currently not curable. It is treated with the intention of restoring and maintaining good quality of life and relieving symptoms due to the metastases, rather than prolonging survival.

CNS and lung metastasis of sebaceous epithelioma in a dog

Sebaceous epithelioma is a common canine cutaneous neoplasm characterized by a preponderance of basaloid cells with few well-differentiated sebocytes. It is considered a low-grade malignancy, as it may occasionally recur at the excision site; the possibility of lymph node metastasis is anecdotally reported, and distant metastases have never been observed. This case report presents the clinical and pathological features of a sebaceous epithelioma of the upper lip with a highly aggressive behaviour. The patient was a 9-year-old female dachshund that developed local recurrence 11 months after the excision of the primary sebaceous epithelioma and multiple lung and central nervous system metastases 5 months later. The designation epitheliomatous sebaceous carcinoma has been suggested for aggressive sebaceous epitheliomas, although differential criteria are still to be determined.