When someone has cancer, the first crucial step is to decide how serious the condition is and his/her chances of survival. This act of estimation of how the disease will treat the patient is – ‘prognosis’. This blog is an assessment of clinical and genetic traits found in never-smoker patients with SCLC.

Factors affecting prognosis:

  • The type of cancer and affected body organ
  • Stage of the cancer and the extent of its reach
  • Grade of the cancer i.e. how abnormal it looks upon microscopic inspection
  • Behavior of the cancer cell
  • Age of the patient and previous health conditions
  • Response to the treatment

Never-smokers are identified with a distinct clinical entity; meaning a different set of conditions and existence. According to a study in South Korea on a number of Small Cell Lung Cancer patients (n=391), the number of nonsmoker SCLC patients have increased over time yet are found to have a better prognosis than smokers. This suggest that, they can be approached with a specific set of treatment procedures and can have better chances of survival. However, in medical terms a ‘never-smoker’ refers to an individual who has smoked fewer than 100 cigarettes in his/her lifetime.

Procedures:

SCLC patients were grouped into never-smokers and smokers. For the former, a somatic mutation profiling was done using AmpliSeqTM Cancer Hotspot Panel V2 along with next-generation ion Torrent semiconductor sequencing technology. PNAClampTM was used to confirm Epidermal Growth Factor Receptor (EGFR) mutation.

Results:

The clinical result of both the group were then compared. A total of 391 patients with SCLC were treated for a period of 5 years.

The findings are:

  • 50 (13%) patients were found never-smokers.
  • The median overall survival was 18.2 months for never-smokers and 13.1 months for smokers (p = 0.054)

[Note: p = 0.054 indicates acceptable level of statistical significance between groups]

  • Never-smoking alone gives a good prognostic factor: (HR=0.645, 95% CI: 0.456 – 0.914) at lower age (HR=0.709, 95% CI: 0.566 – 0.888)

[Note: Prognostic factor is the condition of a patient that determines the chance of recovery from a disease.]

  • The objective response rate (ORR) to Etoposide and Cisplatin Chemotherapy (EP/PE) were similar for never-smoker(75%) and smoker(81%) patients.

[Note: ORR is the proportion of tumor size reduction of a predefined mass and for a minimum period of time]

Among 28 never-smoker patients; 4 cases of EGRF mutations were found:

  • Two cases with L858R (mutation within the exon 21 which encodes part of Kinase domain)
  • One case with exon 19 deletion
  • One case with G719A (mutation within the exon 18 which encodes part of Kinase domain)
  • Other mutations include: TP53, RB1, PTEN, MET, SMAD4

Conclusion:

The above mentioned findings suggest that SCLC among never-smokers is pervasive and increasing significantly. Moreover they are proved to have a better prognosis than smokers. In other words they are in better shape