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Micrometastases: What They Are and Why We Might Care
The notorious and always welcomed words after surgery are, “we got it all”, providing great relief to the patients and families who hear the phrase. We know that surgeons can take out all identifiable disease that they see when they do surgery, and that there is no evidence of visible disease on CT scans or on newer imaging techniques like PET scans. But why do we see that approximately 30% of patients with stage I NSCLC or about 50% of patients with stage II NSCLC recur? How do so many patients with SCLC achieve a complete response, with no evidence of visible disease on scans, but then have recurrence months later? These recurrences occur because of micrometastases, too small to be visible to the eye at surgery or on any scans, but travelling through the bloodstream or lymphatic system, destined to grow into visible recurrent cancer in the future. So we’re actually mistakenly staging patients as early stage lung cancer, when they actually have metastatic disease, but undetectable by current practice. Continue reading
Bone Metastases in Lung Cancer: An Introduction
I’ve discussed the general management of metastatic lung cancer, both SCLC and NSCLC, but there are also several common complications that sometimes require particular management. Bone metastases, for instance, may be treated by the same “whole body” approach with chemotherapy that treats other areas of tumor involvement, but may also benefit from additional approaches. Bone metastases are common in oncology, and approximately 30-40% of lung cancer patients develop bone metastases at some point, about half presenting with evidence of bone involvement at the time of diagnosis (bone metastases general review abstract here). These metastases often have a significant impact on a patient’s quality of life, leading not only to pain but also a risk for pathologic fractures (bone breaks because the bone is weakened by cancer involvement leading to reduced structural integrity), potential compression of the spinal cord and other nerves, and high blood calcium levels as bone is broken down (which can lead to confusion, constipation, numbness/tingling, and other problems). With bone metastases comes a risk of impaired mobility, problems with sleeping and eating normally, and a somewhat worse prognosis overall, although there’s a lot of variability in the population. Continue reading
PET Scans For Restaging After Induction Treatment for Stage IIIA NSCLC
Purists have considered mediastinoscopy, which is invasive staging of the mediastinum through a small incision just at the base of the neck to get down behind the sternum, or breastbone, to be the “gold standard” for determining whether lymph nodes in the mediastinum, or middle of the chest, is involved with a cancer. The procedure is as shown:
(Click on image to enlarge)
As noted in an earlier post, these lymph nodes are very important in initial staging and also repeat staging after induction therapy; specifically, results after surgery appear to be far superior for patients who have no evidence of residual tumor in the mediastinal nodes after induction therapy, whether chemo or chemo and radiation together. Some thoracic surgeons have a patient undergo mediastinoscopy for initial staging followed by a repeat mediastinoscopy after induction therapy in order to assess response. In fact, that is probably the most definitive way to clarify staging before and after induction treatment. However, mediastinoscopies are not only an invasive procedure but are more complicated when done a second time, and they are also potentially more complicated after treatment, especially if radiation is included. One other potential option for reassessing the mediastinum after surgery is to use imaging, with particular attention to the value of PET scans for determining whether there was a response of the mediastinal lymph nodes. Continue reading
The Future of the Field: “Molecular Epidemiology” and SWOG Trial 0424
It’s only been in the past few years that we have begun to appreciate that there may be many different subgroups of patients who fit within the broader lung cancer population. We now have begun to see differences in the safety and/or activity of certain drugs in never-smokers vs. smokers, patients with adenocarcinomas (and especially bronchioloalveolar carcinoma, or BAC)vs. squamous cell carcinomas or other subtypes, and even in women compared with men. This work has been primarily involved looking back retrospectively at how patients with different clinical characteristics did on various treatments. But we are also starting to move into a new era of collecting tumor tissue and blood on patients with different characteristics in order to learn about the molecular epidemiology (study of various factors in disease) to learn about the different genes and proteins that may define new subgroups of lung cancer, and how they may relate to gender, smoking status, and other factors we already recognize. SWOG trial 0424 is an important new type of research that we hope will move the field forward. Continue reading
Mediastinal N2 Lymph Nodes after Induction Therapy as a Key Predictor of Outcome
For patients with locally advanced NSCLC, the question of whether to pursue a surgical or a non-surgical approach has a great deal to do with the extent of mediastinal (middle of the chest) lymph node involvement. The mediastinal nodes are shown here:
(click to enlarge)
First, at the time of initial staging, patients with bulky (>3 cm) disease in the mediastinum, or those with disease involvement more than one nodal station, are less appropriate candidates for surgery than those with non-bulky and single-station disease. In fact, a French retrospective review of over 700 patients with N2 disease who underwent surgery at any of six centers (Andre abstract here) demonstrated that there are quite varied long-term outcomes for different patients that all fall under the same stage of IIIA with N2 disease, and that the patients with a single-station and microscopic involvement (as opposed to clinical enlargement that is visible as abnormal on CT (greater than 1 cm in diameter):
That was in a group of patients who underwent surgery, and just a view of how patients did after the fact. Continue reading
Lung Cancer Work-Up and Surgery: Worth Finding A Well-Trained Thoracic Surgeon
As a medical oncologist, my primary role is to direct general management plans for many cancer patients and to develop chemotherapy and targeted therapy regimens. These regimens are sometimes directly administered through my office, and sometimes are coordinated with oncologists closer to a patient’s home. The treatment is pretty much a cookbook approach, so it’s really the same no matter who administers it. On the other hand, for the approximately 1/3 of NSCLC patients who are candidates for surgery, there are major differences in clinical outcomes depending on the skill level of the surgeon. Here I’ll illustrate some of the key differences that make it compelling to work with the best surgeon you can find, ideally a trained thoracic surgeon, and not just the closest surgeon or the first who has an opening on their schedule. Continue reading
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