Lung cancer

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Lung Cancer
Reference Fletcher 4th edition and Robbins 9th edition

1. Most frequently diagnosed cancer in the world

2. Most common cause of cancer mortality worldwide

3. Most frequent malignancy in individuals exposed to asbestos (latent period 10-30 years) particularly when coupled with smoking

4. The WHO estimates that 25% of lung cancer worldwide occurs in never smokers. This percentage is probably closer to 10% to 15% in Western countries. These cancers occur more commonly in women and most are adenocarcinomas

5. More than 90% of lung cancers develop as a direct result of exposure to tobacco smoke. Approximately 10% of smokers eventually develop lung cancer.

6. The gene known to be mutated most frequently in lung cancers is P53. P53 mutations are found in about 50% of NSCLC

7. Squamous cell carcinoma shows the highest frequency of Tp53 mutations among all histological subtypes of lung cancer

8. Small cell carcinoma shows the strongest association with smoking

9. Many smoking-associated mutations are G→T transversions that occur in known hotspots of the P53 open reading frame. These characteristic mutations can be directly attributed to bulky adducts caused by exposure to BPDE, a carcinogen in cigarette smoke.

10. RB is inactivated in 30–40% of NSCLC and in nearly all SCLC tumors.

11. Among NSCLC, RB mutations are associated with more advanced tumors, implying that RB loss occurs during later stages of tumorigenesis

12. Most common histological subtype - adenocarcinoma

13. Most common site of metastasis - brain

14. Cancers in non smokers more likely to have EGFR mutations and KRAS mutations almost never happen

15. Any histologic type of tumor may occasionally produce any one of the hormones, but tumors that produce ACTH and ADH are predominantly small cell carcinomas, whereas those that produce hypercalcemia are mostly squamous cell carcinomas.

16. Most common lung cancer to cause SVC syndrome : small cell > squamous

17. Broncheoalveolar carcinoma is now called Adenocarcinoma with Mucinous features