What is Small Cell Lung Cancer (SCLC)?

SCLC is a highly aggressive cancer of the lung which accounts for approximately 15% of bronchial carcinomas.  At the time of diagnosis, approximately 30% of patients with SCLC will have tumors confined to the hemithorax of origin, the mediastinum, or the supraclavicular lymph nodes. These patients are designated as having limited-stage disease (LD). Patients with tumors that have spread beyond the supraclavicular areas are said to have extensive-stage disease (ED).

SCLC is more responsive to chemotherapy and radiation therapy than other cell types of lung cancer; however, a curative approach is difficult to achieve because SCLC has a greater tendency to be widely disseminated by the time of diagnosis.  Immunotherapy to successfully treat SCLC remains elusive.  As an example of incidence and prevalence, the overall incidence and mortality rates of SCLC in the United States have decreased during the past few decades.  This aligns with falls in smoking, but not all cancers of the lung are caused by smoking.  In fact, Dustin Diamond was recorded as a non-smoker. 

Estimated new cases and deaths from lung cancer (SCLC and non-small cell lung cancer (NSCLC) combined) in the United States in 2022:

SCLC vs Neuroendocrine Carcinoma of Lung Origin

The World Health Organisation (WHO) categorises SCLC as a Neuroendocrine Carcinoma (NEC).   Reference: WHO Classification of Tumours, Thoracic Tumours, 5th Edition. Travis WD, Al Dayel FH, Bubendorf L, Chung JH, Rekhtman N and Scagliotti G. Tumours of the lung. SCLC vs Neuroendocrine Carcinoma (NEC)

As you can see from these numbers, the incidence is relatively high, but prevalence is lower than many other cancers given the aggressive course of this disease.  Approximately 15% of all cancers of the lung are SCLC. From that, you can see that SCLC as a Neuroendocrine Carcinoma would be the most common type of NEN and the lung would be the most common primary location at 35,511 cases of SCLC in 2022. 

However, it’s complicated.  Some SCLC cases are multiple cell, e.g. SCLC combined with a NSCLC component, most often adenocarcinoma or squamous cell carcinoma. A case revealing foci of both SCLC and adenocarcinoma would therefore be termed “combined SCLC and adenocarcinoma.” SCLC may also be combined with LCNEC and is classified under the term “combined SCLC and LCNEC.”  It is estimated to affect up to 25% of cases.  I could not find any statistics to indicate if the Neuroendocrine element was the dominant cell type in mixed cell cases.  Unlike the term used in Gastroenteropancreatic NENs (GEPNENs) – Mixed Neuroendocrine Non-Neuroendocrine Neoplasms (MINEN), the Thoracic committee decided to call them “combined” suffixed with the cell types in the examples indicated above.  Getting accurate statistics for the Neuroendocrine component of SCLC is difficult but taking the worst case of 25% “combined” would still make the numbers of SCLC (NEC) the most common type of NEN and the lung would remain the most common primary site for NENs. 

In many countries, SCLC is not treated by NEC specialists, rather Thoracic or Lung Multidisciplinary Teams (MDTs) tend to manage these patients.  Additionally, some countries (UK is one example) do not even include SCLC in their Neuroendocrine Neoplasm (NEN) epidemiological data. Many other countries are similar, for example when you look at US statistics, it is patently obvious that SCLC is not included.  I’m quite confident this situation would be replicated in many other countries.

So, did Dustin Diamond have Lung Cancer or Neuroendocrine Carcinoma? 

One thing I have learned over the years is that doctors are trained to talk about cancer in anatomical terms, this is to the disadvantage to Neuroendocrine Neoplasms in terms of celebrity publicity when they get ill or die and it makes the news.  If you do an internet search on Dustin Diamond, you will find many instances of “Lung Cancer” but also many instances of “Small Cell Carcinoma” of lung origin.  

But based on morphology, there is at least a 75% chance that he had something which could equally be called a Neuroendocrine Carcinoma.