Not All Lung Cancers are the Same (Neither are the Patients)
There is no shortage of variables that newly diagnosed lung cancer patients will encounter. To begin with, lung cancer is among the more common of the broad types of cancer; well over 200,000 cases of "lung cancer" are diagnosed in the United States each year. Not only do these lung cancer cases vary in type, but individual patients exhibit a wide variety of genetic mutations. Beyond the unique nature of individual cancers, patients also respond differently to treatment options. Because of this, there is no "one size fits all" treatment for lung cancer.
Understanding the Different Types of Lung Cancer
The two major categories of lung cancer are "small cell" and "non-small cell." A third type of lung cancer, known as either a lung carcinoid tumor or lung neuroendocrine tumor, accounts for less than 5% of all lung cancers. Small cell cancer, sometimes referred to as oat cell, accounts for between 10% and 15% of lung cancer cases -- it is generally a fast-spreading disease. Non-small cell lung cancer is the most common type of lung cancer, but is further divided into adenocarcinoma, squamous cell carcinoma, and large cell carcinoma.
Adenocarcinoma, the most common of non-small cell lung cancers (over 80%), also tends to grow more slowly than other lung cancers, perhaps contributing to the greater likelihood that it will be found in earlier stages before it spreads. It is also more common among women and younger patients. While many patients may be current or former smokers, it is also the most common lung cancer among non-smoking patients.
Squamous cell (or epidermoid) carcinoma mostly affect the airways or central areas of the lungs. There is a high correlation between smoking and squamous cell carcinoma. Over a quarter of lung cancers are of this variety.
Large cell (or undifferentiated) carcinoma might occur in any section of the lung. A fast-growing type of cancer, it also tends to spread quickly, which makes it more difficult to treat than other lung cancers. The closely related large cell neuroendocrine carcinoma behaves very much like small cell carcinoma. These large cell carcinomas affect less than 15% of lung cancer patients.
Also in the non-small lung cancer pantheon, adenosquamous carcinoma and sarcomatoid carcinoma are fairly rare variations. Outside of the major categories of lung cancer, there are a few rare tumor types such as adenoid cystic carcinomas, lymphomas, and sarcomas. There are also cancer types that originate elsewhere in the body but spread to the lungs. Treatment (and naming) for such cancers is based on where it originated, before it metastasized.
No Two Cancers, or People, Are Alike
Regardless of the type of lung cancer a patient is diagnosed with, each patient's genetics will vary, possibly offering unique methods for treatment. Very specific mutations have been identified that can be targeted by new drugs. Designations like EGFR and ROS1 and even ERBb2 have been working their way into more patients' vocabularies as these targeted therapies become more commonplace. Other markers, like PD-L and PD-L1, have been identified that allow for some patients to use immunotherapy drugs. But this is only the proverbial tip of the iceberg.
While some patients will be fortunate enough that their cancer is caught early enough for curative surgery or radiotherapy, others will still rely on traditional chemotherapy when there is no genetic component available to act on. Even when a patient has an actionable mutation, the targeted therapies do not always work, because everyone's biology is somewhat unique. Sometimes a drug that is tolerable to one patient is intolerable to another.
An Ever-Evolving Process
The best plan on paper will not always work in practice. Cancer care and treatment is an ever-evolving process, requiring quite a bit of patience and understanding by all parties involved. But knowledge is power and we live in a time when the scientific understanding of cancer is growing exponentially. While the right treatment might not yet exist for every patient, more and more of them do each year.
By recognizing the diversity of cancer types -- and the diversity of the patient's own genetics -- more cures are within reach.1
Editor’s Note: We are extremely saddened to say that on October 21, 2018, Jeffrey Poehlmann passed away. Jeffrey’s advocacy efforts and writing continue to reach many. He will be deeply missed.
Which do you most want to learn more about on LungCancer.net?