Other cancers in lung cancer families are overwhelmingly smoking-related cancers

Potential genetic modifiers for somatic EGFR mutation in lung cancer: a meta-analysis and literature review

BACKGROUND

Accumulating evidence indicates inherited risk in the aetiology of lung cancer, although smoking exposure is the major attributing factor. Family history is a simple substitute for inherited susceptibility. Previous studies have shown some possible yet conflicting links between family history of cancer and EGFR mutation in lung cancer. As EGFR-mutated lung cancer favours female, never-smoker, adenocarcinoma and Asians, it may be argued that there may be some underlying genetic modifiers responsible for the pathogenesis of EGFR mutation.

METHODS

We searched four databases for all original articles on family history of malignancy and EGFR mutation status in lung cancer published up to July 2018. We performed a meta-analysis by using a random-effects model and odds ratio estimates. Heterogeneity and sensitivity were also investigated. Then we conducted a second literature research to curate case reports of familial lung cancers who studied both germline cancer predisposing genes and their somatic EGFR mutation status; and explored the possible links between cancer predisposing genes and EGFR mutation.

RESULTS

Eleven studies have been included in the meta-analysis. There is a significantly higher likelihood of EGFR mutation in lung cancer patients with family history of cancer than their counterparts without family history, preferentially in Asians (OR = 1.35[1.06-1.71], P = 0.01), those diagnosed with adenocarcinomas ((OR = 1.47[1.14-1.89], P = 0.003) and those with lung cancer-affected relatives (first and second-degree: OR = 1.53[1.18-1.99], P = 0.001; first-degree: OR = 1.76[1.36-2.28, P < 0.0001]). Familial lung cancers more likely have concurrent EGFR mutations along with mutations in their germline cancer predisposition genes including EGFR T790 M, BRCA2 and TP53. Certain mechanisms may contribute to the combination preferences between inherited mutations and somatic ones.

CONCLUSIONS

Potential genetic modifiers may contribute to somatic EGFR mutation in lung cancer, although current data is limited. Further studies on this topic are needed, which may help to unveil lung carcinogenesis pathways. However, caution is warranted in data interpretation due to limited cases available for the current study.

Impact of family history of cancer on risk and mortality of second cancers in patients with prostate cancer

BACKGROUND

Survival rates are increasing in patients with prostate cancer, and second primary cancers (SPCs) are becoming more common in these patients. However, the etiology and clinical consequences of SPCs are not well-known. We define the impact of family history on SPC and causes of mortality in these patients.

PATIENTS AND METHODS

A nation-wide cohort study based on the Swedish Family-Cancer Database covering 4.4 million men and 80,449 prostate cancers diagnosed between 1990 and 2015. Relative risks (RRs) and cumulative incidence for SPCs and for familial SPC were calculated for prostate cancer patients.

RESULTS

SPC was diagnosed in 6,396 men and more than a third of these patients had a first-degree family history of any cancer; the familial risk was 1.37 (95% CI: 1.27-1.40), compared to 1.10 (1.08-1.16), without a family history. Cumulative incidence by the age of 83 years reached 21% for prostate cancer alone, 28% in those with SPC, and 35% in patients with SPC and family history. Family history was associated with the risk of seven specific SPCs, including colorectal, lung, kidney, bladder and skin (both melanoma and squamous cell) cancers, and leukemia. Colorectal and lung cancers were common SPCs, and family history doubled the risk of these SPCs. In patients with SPC, half of all causes of death were due to SPC and only 12.77% were due to prostate cancer. Most deaths in SPC were caused by lung and colorectal cancers.

CONCLUSIONS

SPCs were an important cause of death in patients with prostate cancer and family history was an important risk factor for SPCs. Prevention of SPC should be essential when prostate cancer survival rates are being improved and this could start by conducting a thorough assessment of family history at the time of prostate cancer diagnosis.