[1815] Are Bronchioloalveolar Carcinoma and Early Invasive Adenocarcinoma More Frequent in Elderly Caucasians Than in Young Asian Women?

Ann E Walts, Amin Riley-Portuges, Andy Pao, Tam Truong, Lara Baden, Jean Lopategui, Alberto M Marchevsky. Cedars-Sinai Medical Center, Los Angeles, CA

Background: Bronchioloalveolar carcinoma/adenocarcinoma-in-situ (BAC) and early invasive adenocarcinoma (BAC with <5 mm of invasion;EIA) have generally been described in Asian, never-smoking women <50 years of age. However, it has been our impression that most BAC and EIA patients in our practice are elderly and similar in age and gender ratio to patients with pulmonary mixed adenocarcinoma (MAC) (mean age 71 yrs; median age 70 yrs; 60% female; approximately 90% Caucasian).
Design: 77 consecutive single pulmonary lesions diagnosed as BAC (27) and EIA (50) were retrieved from among 1081 pulmonary adenocarcinomas excised at our hospital during a 5 year period. After slides were reviewed and diagnoses confirmed, EGFR and KRAS mutation analysis was performed on DNA extracted from each formalin fixed paraffin embedded tumor. Age, gender ratio, smoking history, tumor size, and frequency of EGFR (deletion in exon 19 and L858R mutation in exon 21) and KRAS mutations were tabulated and compared using the chi-square test.
Results: Results are shown in the table below.

Bronchioloalveolar Carcinoma and Early Invasive Adenocarcinoma: Demographics & Mutation Analysis
 Age Mean/Range CaucasianSmokerFemaleMedian SizeEGFR mutationKRAS mutation
BAC71/55-89 yrs92.6%69.2%59%1.1 cm34.6%7.7%
      del in EX19 (19.2%) 
      L858R in EX21 (15.4%) 
EIA72/53-89 yrs90%65.2%66%1.6 cm19.2%20.5%
      del in EX19 (10.6%) 
      L858R in EX21 (8.5%) 

Chi-square test showed no significant difference (p>0.05) in age, gender ratio, ethnicity, smoking status, tumor size, or mutation results by diagnosis. Although EGFR and KRAS mutations are generally mutually exclusive, both an EGFR deletion in exon 19 and a KRAS mutation were identified in one EIA.
Conclusions: -In contrast to reports from Asia, the majority of our BAC and EIA patients were elderly Caucasians in their 7th-8th decades of life. A population-based study is needed to confirm whether this observation applies to BAC and EIA patients in the U.S. at large. -The proportions of EGFR and KRAS mutations in our patients are comparable to those reported in Asian patients. -As the rate of progression from BAC to EIA and to MAC is unclear and patients in the 7th and 8th decades of life frequently have comorbidities, the demographics of our patients raises a question as to whether selected individuals with ground glass opacity on chest imaging could be better managed conservatively with watchful waiting as is currently recommended for selected prostate cancer patients.
Category: Pulmonary

Tuesday, March 1, 2011 1:00 PM

Poster Session IV # 275, Tuesday Afternoon


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