Introduction: Role of Surgery in the Diagnosis and Management of Metastatic Cancer

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In the past several years, there have been tremendous advances in the field of surgical oncology. Surgical oncologists routinely perform procedures on patients with metastatic cancer aimed not only at palliating symptoms but also at improving survival. It was not that long ago that metastasectomy for most cancers was a fruitless endeavor. However, now with the advances in radiological imaging, medical oncology, and surgical technology, these procedures are becoming more and more commonplace. With these advances, the multidisciplinary care of our patients becomes more important and also more complex.

With the advent of functional imaging with positron emission tomography (PET) scanning, we are now able to determine where metabolically active metastatic disease is present. This enables the team to determine whether a patient is a candidate for metastasectomy based on imaging disease outside of the organ in question. Additionally, with improved magnetic resonance imaging (MRI) technology and three-dimensional computed tomography (CT) imaging of the pancreas and liver, we are better able to determine resectability. Radiation oncologists also have become more advanced in their radiation techniques to give high-quality local treatment with less toxicity, which then allows for more systemic therapy and decreased incidence of local recurrence of cancer. The advances in medical oncology, particularly in targeted therapies also have been tremendous. Targeted therapeutic agents, such as bevacizumab, have improved responses of metastatic disease such as liver metastases from colorectal cancer that now allow more patients to undergo potentially curative surgical resection.

Finally, surgical techniques have improved vastly. We now are using minimally invasive techniques such as thoracoscopy and laparoscopy to diagnose and treat primary and metastatic disease with increasing frequency. Many authors have demonstrated that this can be done effectively with minimal morbidity and no increased risk of cancer seeding. These techniques allow patients to recover faster so that they may receive other adjunctive therapies quicker and become less immunocompromised while they recover. Surgical oncologists also have been at the forefront in the advancement of ablative therapies for metastatic lesions, such as radiofrequency ablation (RFA) and cryosurgery. These techniques, especially RFA, are routinely employed by surgeons in the treatment of tumors metastatic to the liver and lungs.

In this issue of Seminars in Oncology, I have asked several nationally recognized surgical oncologists to discuss the cutting edge treatment of metastatic disease to particular organ systems. It is our hope that practicing medical and radiation oncologists will come away from these chapters with knowledge of what happens when they refer their patients to surgeons so that they can describe to their patients some of the details of what to expect.

I decided to organize the issue based on metastatic disease to various organ sites as opposed to the treatment of various metastatic cancers. The treatment of metastatic brain lesions is very nicely and concisely reviewed by David Andrews. In particular, he emphasizes minimally invasive approaches such as stereotactic radiation and gamma knife, and addresses quality of life. From the brain, we move down to lesions metastatic to the spinal cord. Here, Weinberg and colleagues from the M.D. Anderson Cancer Center discuss the indications for surgical therapy of spinal metastases and emphasis that tumors can be placed into one of four groups depending on their responsiveness to chemotherapy, radiotherapy, and hormonal therapy. Metastatic lesions to the bone are discussed extensively by Ogilvie et al from the University of Pennsylvania. In this chapter, the latest in bone fixation technology is discussed and interpreted. The numerous accompanying illustrations should help oncologists understand the ins and outs of treatment of tumors metastatic to the bone.

The remaining chapters discuss the treatment of tumors metastatic to various visceral sites. Mark Krasna, an innovator in the use of minimally invasive technology in thoracic surgery, discusses the use of video assisted thoracoscopic surgery (VATS) in the treatment of metastatic lesions as well as in the staging of esophageal cancer. This chapter also discusses the use of this technology in the palliation of thoracic cavity disease. Quiros et al from the Fox Chase Cancer Center put forth a comprehensive discussion of the burgeoning field of the resection of metastatic disease to the lungs and the best approaches to diagnose and treat these metastases. With advances in CT imaging as well as the advent of routine PET scans, less and less morbid operations are being performed. These operations are very nicely reviewed, but luckily the days of bilateral thoracotomies to palpate for disease are waning. The liver is another important site of metastases from numerous malignancies. Sigurdson and Arciero provide a timely review of the literature regarding the treatment of liver metastases. The majority of this chapter is appropriately spent discussing treatment of colorectal cancer metastases including a nice review of hepatic artery infusion, for which Sigurdson was an early leader in the advancement of that technology. A good review also is given of non-colorectal cancer metastases and of various ablative techniques.

In recent years, with the advances in surgical technologies and improvements in care of the surgical patient, we, as surgeons, have become more aggressive about metastasectomy in more and more sites with excellent success rates and improving 5-year survival rates. An extensive review is provided by Showalter et al on the treatment of metastatic disease to the pancreas and spleen. They demonstrate that these fairly extensive resections can be performed with minimal morbidity and mortality and with curative intent. Gittens et al provide a nice summary of surgical management of metastatic disease to the adrenal gland. These metastases are now frequently being removed with laparoscopic approaches with, again, minimal morbidity. The small intestines are one of the most frequent sites of metastases from other sites. These metastases can be solitary or part of multiple systemic sites. However, they are almost always symptomatic, and as such constitute an important disease entity. Rosato and Rosato from Thomas Jefferson have provided a well thought-out review of the literature and have discussed the presentation, diagnosis, and treatment of bowel metastases. Finally, there is an excellent overview of the treatment of peritoneal surface metastases from colorectal carcinoma by Royal and Pingpank from the Surgery Branch of the National Cancer Institute. Their approach of radical debulking following by hyperthermic peritoneal perfusion with high-dose chemotherapy has achieved dramatic results and more and more is becoming the standard treatment for these patients.

As one can see, the approach to patients with metastatic disease has dramatically changed in the last ten years. Now with multidisciplinary teams discussing and studying tumor pathophysiology and the guidance of improved imaging technologies, surgical approaches to eradicating metastatic disease are becoming more commonplace. As demonstrated in this issue, these approaches can provide chances at long-term cure with decreasing morbidity and mortality. I would like to thank all of the authors of chapters in this issue for their concise work and their patience through this process.