Dr. David Tom Cooke is a thoracic surgeon at the University of California, Davis Medical Center, in Sacramento. He underwent medical school training at Harvard, general surgery training at the Massachusetts General Hospital in Boston, and Cardiothoracic training at the University of Michigan. He was born and raised in Oakland, CA, and therefore, a self-proclaimed suffering A’s and Raiders fan.
Lung Cancer Surgery Demystified
In the following post, I hope to illustrate the need and use of surgery for the treatment of lung cancer. Surgery is an indispensable tool in the fight against lung cancer. It is the standard of care for early stage lung cancer (Stage I and II) for which it is the best chance for cure, and is frequently utilized along with chemotherapy and radiation for many cases of stage IIIA lung cancer.
Below I will provide:
1) Brief description of lung anatomy
2) Describe the staging process
3) Discuss the types of surgery
4) Answer a few commonly asked questions I get from patients
Lung tissue is most commonly removed surgically for the treatment of lung cancer, and less commonly for metastatic cancer to the lung from other organs. Air is brought from the mouth to the lungs via the trachea, which connects to both lungs via the bronchi (Figure 1).
The left lung has two parts to it; an upper part called a lobe and a left lower lobe. The right lung has three parts to it, an upper lobe, middle and lower lobe (Figure 2). That’s pretty much the way it is in every human being, because as you are developing as an embryo, you heart shifts to the left, so you have space for two lobes on the left, and three lobes on the right.
Lung tumors or cancers are categorized by size. We call anything < 2cm a nodule and anything ≥ 2cm a mass. That is nomenclature, so we don’t confuse everyone by calling things spots or shadows. The lung cancer example in Figure 2 is a left upper lobe lung nodule.
When we talk about lung cancer, we must refer to the stage (7th Edition TNM Staging System for Lung Cancer). The stage of a cancer refers to the information that is used to determine how much that tumor has spread through the organ, and if it has spread to other organ systems.
There are two types of stage: clinical stage and pathologic stage.
Clinical stage refers to our best guess based on imaging studies, such as chest CT, PET/CT and brain MRI, and minor procedures, such as mediastinoscopy, lung biopsy and something called endobronchial ultrasound needle biopsy, or EBUS.
Pathologic stage refers to the final stage determined after the cancer has been surgically removed, and all lymph nodes have been examined by a pathologist.
Lung cancer has IV stages (for some reason we use Roman numerals); Stage I, II, III (A, B) and IV. We can draw a line between stage II and III and a line between stage IIIA and IIIB (Figure 3). For the lung cancer stages left of the green line (Stage I and II) the treatment of choice, in a medically fit patient, is surgery.
During the surgery we will take out all of the lymph nodes (which I will explain later), and if there is tumor in the lymph nodes, then the patient may need chemotherapy. However, upfront therapy, or what is the first treatment for patients with Stage I and II lung cancer is surgery (National Comprehensive Cancer Network 2011 Guidelines).
Everything to the right of the red line (Stage IIIB or IV) the treatment of choice is chemotherapy +/- radiation. There are exceptions to every rule, but surgery for cure does not really offer any benefit for patients with Stage IIIB or IV lung cancer.
There are many different subtypes of Stage IIIA, and depending on the type of IIIA, there are two treatment options: 1) chemotherapy + radiation (neoadjuvant), let the patients body rest 4-8 weeks, then surgery, and 2) chemotherapy and high dose radiation (definitive) and no surgery.
To determine the stage of Lung Cancer, we need to determine the Tumor, Lymph Node and Metastasis (T, N and M) stage.
T refers to the tumor. How big is it? What is the depth of penetration, etc…? For Lung Cancer there are 5 types of T, T0 through T4. We use a CT scan to determine the T stage.
N refers to lymph nodes. Cancer can spread through the blood stream and/or through the lymphatic system to the lymph nodes. Lymph nodes are basically your body’s filter. If you have strep throat, then your tonsils (which are lymph nodes in your mouth) might swell up because they are filtering bacteria out of your blood. If you the flu, then your lymph nodes in your neck or arm pits might swell up, because your body is filtering influenza virus out of your blood. If a patient has cancer in their blood stream, their lymph nodes near the cancer might become enlarged.
For Lung Cancer there are 4 types of N, N0 through N3 (Figure 4):
- N0 are normal lymph nodes
- N1 are abnormal lymph nodes closest to the tumor
- N2 are abnormal lymph nodes that are along the trachea on the same side as the tumor
- N3 are abnormal lymph nodes that are along the trachea on the opposite side of the tumor
We use CT, PET/CT, mediastinoscopy and sometimes EBUS to help us determine lymph node stage.
M stands for metastasis. For lung cancer, it is basically binary, M0 or M1. Lung cancer can spread to the liver, brain, lungs, bone, adrenal glands (a gland that sits on top of the kidneys), and lymph nodes outside the area of the tumor. We use PET scan to determine M stage. PET takes a sugar molecule, glucose, and attaches a harmless piece of radiation to it (FDG).
Cancer is generally very metabolically active, and will eat up the glowing sugar. We inject the FDG into the patient, place them back in the CT scanner and see what glows. Ideally the primary cancer, as well as any metastatic spots or cancerous lymph nodes will glow. Some normal cells will glow anyway. One’s brain is very active so that will glow, so a brain MRI is needed to find brain metastasis. The heart beats continuously, so that will glow. And we have to get rid of the FDG somehow, so we urinate it out, so the kidney’s ureter and bladder will glow.
By determining the combination of TNM, you have a stage. For example, in Figure 2, the lung cancer is 1cm, confined to one lobe, with no lymph node involvement, and no metastasis; clinical T1aN0M0 or clinical Stage IA. The standard of care therapy for the stage of lung cancer in Figure 2 is surgery.
Types of Surgery
Curative surgery for lung cancer is based currently on lobectomy, or removing the entire lobe (-ectomy means to cut out, e.g. an appendectomy is cutting out your appendix, a tonsillectomy is cutting out your tonsils), and rarely pneumonectomy, or removing an entire lung on one side. So if a patient has a left upper lobe lobectomy for lung cancer (Figure 5) we would remove the left upper lobe, and the patient would be left with 4/5 of their lung capacity.
Lobectomy is traditionally done via a thoracotomy (-cotomy meaning cut, or cut the thorax or chest). Through the thoracotomy (Figure 6), the lung is exposed, and a lobectomy is performed.
Just like the gallbladder and the appendix are currently removed minimally invasively, or laparoscopically (via a camera and small instruments), currently in highly specialized centers, lobectomy is performed the same way. This is called video assisted thoracic surgery or VATS. VATS lobectomy is performed through 3-4 small incisions, the largest one the size of a thumb, and using a small camera and instruments (Figure 7).
Patients who undergo VATS lobectomy have been shown to have less post-operative pain, shorter hospital stay and less respiratory complications compared to patients who undergo “open” lobectomy.
For instance it is a difficulty procedure with a steep learning curve; therefore only highly trained physicians should perform it. It is unclear as to how many VATS lobectomies a surgeon should perform before they are considered proficient, but the conventional wisdom is 25.
Another disadvantage is that VATS lobectomy should generally be reserved for early stage tumors, and tumors < 5-6 cm in size. Whether by VATS or the traditional open technique, lobectomy is generally a safe procedure. But with any surgical procedure there is a risk of death. The mortality for lobectomy (VATS or open) is <2%.
Fifty percentof thoracic surgery in the United States is performed by general surgeons. However, there is growing data that patients who undergo lobectomy by board certified cardiothoracic surgeons have better outcomes, reduced risk of operative death and reduced hospital length of stay (Schipper et al 2009, Farjah F et al 2009).
In fact, the reduction in mortality for lobectomy performed by board certified cardiothoracic surgeons is equivalent to the number of lives saved by the flu shot (Wood DE et al 2009).
Alternatives to Lobectomy?
For patients who are not surgical candidates (e.g. really bad emphysema), a sublobar resection or wedge is performed (Figure 8). Sublobar or wedge resection is thought to have a higher recurrence rate compared to lobectomy, however there is data to suggest that for tumors < 2cm, and that are near the periphery of the lung, sublobar resection may be just as effective as lobectomy.
Currently, there is a clinical trial comparing sublobar resection and lobectomy for < 2cm lung cancers: CALGB 140503. Although there are exceptions to every rule, outside of a clinical trial, in the physically fit patient, lobectomy should be performed.
Other alternatives to lobectomy are radiofrequency ablation (RFA) and stereotactic body radiotherapy (SBRT). RFA involves inserting a needle into the tumor percutaneously under CT guidance, and then cooking the tumor with heat (Figure 9).
SBRT is a focused beam of external radiation that is shot into the tumor and also cooks it (Figure 9). Although effective, RFA and SBRT has no proven long term benefit, and is reserved for people who are physically unfit for surgery.
At U.C. Davis, there is active research going on in the surgical treatment of lung cancer, such as:
- Metabolomic studies attempting to discover clinical markers in blood and breath condensate specimen in attempt to develop a simple screening technique similar to the PSA test available to screen for prostate cancer
- Molecular profiling studies, which take a patient’s tumor, perform molecular analysis and tailors chemotherapy to the molecular profile of the tumor
- Numerous clinical trials and there are multiple thoracic surgery outcomes research projects ongoing at U.C. Davis. These projects include analysis of national clinical datasets including the Nationwide Inpatient Sample (NIS) and the Surveillance, Epidemiology and End Results (SEER) Program national cancer database
- Evaluation of clinical outcomes in and application of lung cancer surgery and minimally invasive thoracic surgery, thoracic surgical education, and the role of the internet in thoracic surgery
Development of thoracic surgery education is important, as we work to instill into medical students, general and cardiothoracic surgery trainees the same level of patient care commitment, compassion and technical acumen of our surgeons. These programs include summer research fellowships for medical students, and shadowing programs for pre-medical undergraduate students.
For more information on Lung Cancer clinical trials, click here.
Frequently Asked Questions
Q: How long would I be in the hospital after surgery?
A: The average stay in the hospital after VATS lobectomy is 3-4 days, and for open lobectomy 5-7 days.
Q: Would taking out my entire lobe (1/5 of my lungs) affect me?
A: We are able to somewhat predict a patient’s post-operative lung capacity or how much their residual lung would compensate for losing a lobe by measuring their pre-operative pulmonary function tests (PFT), and determine quantitatively the probability of a patient requiring oxygen post-operatively, or from a physiologic standpoint if a lobectomy or pneumonectomy is prohibitive. If the pre-operative pulmonary function tests are favorable, then most people are able to return to their usual activities of daily living after surgery.
Q: Does surgery or exposure to air cause the cancer to spread?
A: No. The belief that surgery or exposure to air causes cancer to spread is most likely left over from the days before we had high tech CT scans and PET scanning. As a result, patients who were being operated on were probably under staged, or actually had a higher stage then thought. Currently, clinical staging is very accurate.
Q: Are you going to crack my ribs?
A: No. For the VATS lobectomy no rib spreading is needed. For the open lobectomy, we remove a small thumb nail sized piece of rib. This allows us to spread the ribs without breaking them. Once the surgery is completed, we sew the ribs back into their normal position.
Q: So I have a lung nodule, do I need a biopsy?
A: Not necessarily. Some nodules and most masses have certain radiographic characteristics that are highly suspicious for cancer. Activity on a PET scan also is suggestive of cancer. In addition, patient characteristics such as current or former smoker (a smoker is anyone who has smoked over a 100 cigarettes in their lifetime) or age > 40 with a suspicious lung nodule or mass may suggest malignancy, and a lung biopsy would not be necessary. The reason a biopsy may not be necessary is because there can be false negatives. And if the clinical suspicion is high enough, a negative biopsy could be misleading.
The information provided by me is for educational purposes only, and not
intended for medical care, advice or professional services. For direct health problem guidance, please contact your primary care physician or other local licensed health professional.
David Tom Cooke, MD, FCCP, FACS
Thoracic Surgery, University of California, Davis Medical Center