Hello. My name is Andrew Chang. I'm one of the thoracic surgeons at the University of Michigan and I'll be talking today a little bit about surgical options for treatment of early stage lung cancer, mostly focusing on techniques of lung resection, wedge resection, segmentectomy, and lobectomy. We'll start with a pre-lecture question. So, which treatment is most appropriate for a 2.5-centimeter hilar right upper lobe lung nodule? Of course, there are all sorts of things that we want to consider when we recommend an operation for someone but just the most basic level, what will we cut out? A. Wedge resection, B. Segmental resection, C. Lobectomy, and D. Radiation therapy. We'll go over these different options over the next few minutes and as you might guess, the right answer will be one of the operative interventions since this is an operative discussion but, D. Radiation therapy is a possibility. So, the objectives for today's talk will be to review the reasons for lung resection, to describe the different levels of lung resection for early stage lung cancer. I'll talk about some of the basics of pulmonary anatomy and some of the indications that is some of the reasons for operation, and then a little bit about the techniques for resection. So chest anatomy, going back to a schematic for the chest and the chest wall. Basically, the chest consists of the outer skin, the muscular layer, the fatty layers, and then the rib cage provides the protection, breast bone in front, the sternum, and then the vertebral column in the back helps provide structure for the chest so that we can breathe properly. The lining of the lung, so if we look at the breastbone here, cartilage, ribs here, intercostal muscle, but then deeper to that on this cross section, we have the lining of the lungs. So, this is the outermost lining, the pleural lining called the parietal pleura. In between is a space where fluid and air can build up, but usually, just collapse on itself, and then this inner lining of the lung, the visceral pleura, and then the lung itself. The diaphragm is the muscle that provides the breathing, the impetus for breathing, but the chest wall muscles also help contribute to breathing. Now, what are the indications for operating on lung cancer? As described elsewhere in the course, the staging system is broken down into four basic stages with stage I being early stage that is where the tumor is contained within the lung, extending over to stage IV where tumor has spread to other parts of the body or other organs such as the liver, the adrenals, brain, et cetera. For early stage, that is stage I lung cancer, it's broken down itself into other criteria described in this figure here which shows that in eighth iteration of the AJCC criteria, there are now three sub-stages of stage I. There's stage IA1, IA2, and IA3, with the IA1 being tumors that are either sort of what used to called the bronchoalveolar or minimally invasive adenocarcinomas, and also stage T1a, tumors that are less than or equal to one centimeter, and then IA2 is the T1b tumor that is between one and two centimeters, and IA3, for tumors that are between two and three centimeters. Those tumors are all considered stage IA and can be resected by these techniques that I'll be talking about. Stage IB has been redesignated to include only the smaller T2 tumors, that is tumors that are between three and four centimeters. The old seventh edition used to also include tumors between four and five centimeters but that was changed in the eighth edition, again be described somewhere else. So, some of the indications for resection. Sublobar Resection is where we're actually removing not a lobe of the lung but a portion of the lung and there are two basic ways to do this. One is to remove a wedge of the lung and the way I tell the patients as I'm essentially lopping off a portion of the lung where the tumor is without really paying much attention to the vasculature that's supplying and draining that portion of the lung or the airway, that's going to that portion of the lung. That's usually reserved for patients who need a diagnosis. So, you're just having to take out that portion of the lung, the wedge. Those patients who have poor lung function, and those who are being recommended operation for a metastatic lesion, that is a tumor that spread from some other part of the body, where the goal is to try to take out the tumor, but also preserve as much normal lung functions possible. Segmentectomy is more anatomic resection where we're actually taking out a segment of the lung and I'll go over that in a little bit, and we also typically reserve that these days for patients who have poor lung function. But it's considered an anatomic resection because its part of the operation. We have to find a blood vessels that are going to that segment of the lung, cut those, seal those off, and then we also have to find the airway that's going to that portion of the lung. So, these are the basic lung segments, and it's a long list. I have a schematic which I don't know why I remember, but it's called APALM, A-P-A-L-M, and then APASI, A-P-A-S-I, and then SMELT, and for some reason, that stuck in my head for the last 20 years. But the lung segments are broken down as listed here, so you have apical, posterior, anterior, lateral, medial, and so on, and so forth. If you think about the lung or the bronchial anatomy like an upside down tree, we have the trachea which is the trunk of the tree, and then the two branches going to the right and left and really do arborize almost the same way that a tree would arborize. So, when we're doing an operation, whether we're trying to take out a segment, whether we're trying to take out an upper lobe, and actually, sorry, this is the middle lobe here, lateral and medial or lower lobe, we do try to take out the particular airway that goes to one of these segments or the main airway that goes to the lobe of the lung. So, I'm going to stop here and just got a little demonstration to show you what the segments are. So, just to go down the list of the segments a little bit and I won't go into all of them, but basically, this is a figure of the right side of the lung. So, the right side of the lung has three lobes. There's the upper lobe here with its segments, the apical, posterior, anterior, and then there's the middle lobe here which is a separate from the right upper lobe, and that's on the right side divided into medial and lateral, and then the lower lobe has its segments, the superior. Back here, and then the remaining are the base lower lobes. That is, medial base lower, anterior base lower, lateral base layer, and posterior base layer. This is important from a surgical standpoint because when we're doing segmentectomies, we can take out certain of these segments, but some of them just aren't amenable to a formal resection. So, for the lower lobe, typically we can perform a superior segmentectomy, but if we had to take out a nodule that was in one of the lower segments of the lower lobe, we would actually remove out for the most part all the basal segments. But this still preserves a considerable amount of the lower lobe. So, that's the segmentectomy possibilities on the right side. We would typically wouldn't want to do a segmentectomy of the middle lobe, because it's relatively small portion of the lung, and so any nodule that's within the middle lobe we would usually either remove it as a wedge, or as an entire middle lobectomy. On the left side, it's going to grab off to the left here. So, on the left lung, again, there the segments but here, the left lung is broken into two lobes. So, there's the upper lobe here, then the lower lobe down here. Left upper lobe is the apache, part of the mnemonic. So, there's the apical posterior segment, anterior segment, and then the what's called the lingular of left upper lobe is the equivalent to the middle lobe on the right side but instead of lateral and medial that we had on the right side, we have superior and inferior segments of the lingular of the left upper lobe on the left side. Then the left lower lobe anatomy is similar to that on the right. That is there's the superior segment of the left lower lobe, then the basal segments. Here it's medial, anterior, lateral, and posterior base layer again. So, that's the segmental anatomy and that's what drives whether we do- so when we're doing a wedge, we're essentially taking a wedge and literally just cutting off doesn't, we don't really pay much respect to the segments. But when we're performing a segmentectomy, we actually have to find the blood vessel that goes to and drains from the segment, as well as the airway that branch of the tree that goes directly to that segment. Now the indications for lobectomy are, one, also for diagnostic purposes. So, sometimes a nodule can be too deep to either get a biopsy of through percutaneous that is a nip passing a needle to the chest, or through the airway. As long as someone has good lung function, it is acceptable to perform what's called a diagnostic lobectomy. We do try to have a diagnosis before we take a patient operation for that. Then of course cancer resection. Pneumonectomy is where we actually remove the entire lung. I did not discuss this for this portion of the course because primarily pneumonectomy is reserved for larger tumors, occasionally early stage but central tumors might require pneumonectomy for resection. But we really try to avoid doing that because that basically takes out more than half of patients overall lung function. I'll touch a little bit on some of the techniques that we use to try to minimize the need for pneumonectomy. But again, this is reserved for a cancer resection. So, we would never want to do it diagnostic pneumonectomy, because it's just too big of an operation for purposes of diagnosis. A sleeve resection. So, that's where we're actually taking a portion basically patients who have a central tumor that might be involving for instance the orifice of the right upper lobe of the lung. Sometimes we would have to basically remove the entire right lung, perform a right pneumonectomy in order to remove that orificial tumor, but when we do a sealer section, sleeve resection will basically taking that branch of the tree, removing that as well as the lobe, and then reimplanting the rest of that part of the tree into the main trunk, and that's what we call a sleeve resection. We save that again for central tumors or involvement of a bronchial orifice, and we basically use the same techniques as one might use for a lung transplantation to reattach the downstream native lung in order to preserve lung function, and avoid a pneumonectomy. So, some of the complications for pulmonary resection include, wound infection, air leak is fairly common, that's where as much as the dummy that I showed you had nice queen planes, very often the lobes aren't as easily defined as and especially the segments aren't as easy to find. So, once we cut those areas away, then the exposed lung tissue can potentially have air leaks afterwards. Patients can also have effusions or a buildup of fluid in their chest after the operation. They can also develop infections or pneumonia is that along. With that, go back to the lecture question which is, what treatment is most appropriate for a 2.5 Centimeter hilar right upper lobe lung nodule? The options included, wedge resection, segmental resection, lobectomy, and radiation therapy. The proper answer is lobectomy. So, hilar nodule would be one that's towards the center of the lung, involving the right upper lobe, and in terms of cancer resections, we need to take out the entire lobe of the lung in order to get out the tumor, as well as the surrounding tissue. A wedge resection wouldn't be appropriate for something that's central as this that might be suspected for hilar nodule. Also if it's been diagnosed as a cancer, we wouldn't want to just remove that wedge of the lung. Segmental resection might be possible, but it's still potentially could leave cancer cells behind. There's actually a study that's ongoing comparing the results of sublobar, that it's a wedge or a segmental resection, versus lobectomy for smaller tumors. But that'll take a few years and is beyond the scope of this short talk. Then radiation therapy, we reserve for patients who are sick. Who have bad lung function, emphysema, who basically wouldn't tolerate an operation. So, for those reasons, lobectomy would be the most appropriate treatment for just a straight up 2.5 centimeter right upper lobe lung nodule. So, some of the take home points from today. Both segmentectomy and lobectomy require anatomic dissection. That is we have to find the branches of the pulmonary artery carrying blood to the segments or lobe, the branches of the pulmonary vein returning blood from the segment or lobe, and then the airway. Wedge resection and segmentectomy might be more appropriate for patients who have worse lung function. The other thing that I didn't really touch upon but that should be considered is that, for lung cancer patients, we also need to evaluate the lymph nodes. So, those are packets of tissue that are surrounding the lobes and the airway, and we just have to remember to take those out at least in a sampling to check for signs of cancer spread to those areas. So, over the last few minutes, I've discussed a little bit of the indications and the anatomy for lung resection, and also showing you some of the anatomic considerations for lung resection, and I hope that with this, this will add to what you learned already through this course. Thank you for your time.
