Camelia S. Sima

Analysis of Tumor Specimens at the Time of Acquired Resistance to EGFR-TKI Therapy in 155 Patients with EGFR-Mutant Lung Cancers

Purpose: All patients with EGF receptor (EGFR)–mutant lung cancers eventually develop acquired resistance to EGFR tyrosine kinase inhibitors (TKI). Smaller series have identified various mechanisms of resistance, but systematic evaluation of a large number of patients to definitively establish the frequency of various mechanisms has not been conducted. Experimental Design: Patients with lung adenocarcinomas and acquired resistance to erlotinib or gefitinib enrolled onto a prospective biopsy protocol and underwent a rebiopsy after the development of acquired resistance. Histology was reviewed. Samples underwent genotyping for mutations in EGFR, AKT1, BRAF, ERBB2, KRAS, MEK1, NRAS and PIK3CA, and FISH for MET and HER2. Results: Adequate tumor samples for molecular analysis were obtained in 155 patients. Ninety-eight had second-site EGFR T790M mutations [63%; 95% confidence interval (CI), 55%–70%] and four had small cell transformation (3%, 95% CI, 0%–6%). MET amplification was seen in 4 of 75 (5%; 95% CI, 1%–13%). HER2 amplification was seen in 3 of 24 (13%; 95% CI, 3%–32%). We did not detect any acquired mutations in PIK3CA, AKT1, BRAF, ERBB2, KRAS, MEK1, or NRAS (0 of 88, 0%; 95% CI, 0%–4%). Overlap among mechanisms of acquired resistance was seen in 4%. Conclusions: This is the largest series reporting mechanisms of acquired resistance to EGFR-TKI therapy. We identified EGFR T790M as the most common mechanism of acquired resistance, whereas MET amplification, HER2 amplification, and small cell histologic transformation occur less frequently. More comprehensive methods to characterize molecular alterations in this setting are needed to improve our understanding of acquired resistance to EGFR-TKIs. Clin Cancer Res; 19(8); 2240–7. ©2013 AACR.

Clinical Characteristics of Patients With Lung Adenocarcinomas Harboring BRAF Mutations

PURPOSE BRAF mutations occur in non-small-cell lung cancer. Therapies targeting BRAF mutant tumors have recently been identified. We undertook this study to determine the clinical characteristics of patients with lung adenocarcinomas harboring BRAF mutations. PATIENTS AND METHODS We reviewed data from consecutive patients with lung adenocarcinoma whose tumors underwent BRAF, EGFR, and KRAS mutation testing as well as fluorescence in situ hybridization for ALK rearrangements. Patient characteristics including age, sex, race, performance status, smoking history, stage, treatment history, and overall survival were collected. RESULTS Among 697 patients with lung adenocarcinoma, BRAF mutations were present in 18 patients (3%; 95% CI, 2% to 4%). The BRAF mutations identified were V600E (50%), G469A (39%), and D594G (11%). Mutations in EGFR were present in 24%, KRAS in 25%, and ALK translocations in 6%. In contrast to patients with EGFR mutations and ALK rearrangements who were mostly never smokers, all patients with BRAF mutations were current or former smokers (P < .001). The median overall survival of advanced-stage patients with BRAF mutations was not reached. In comparison, the median overall survival of patients with EGFR mutations was 37 months (P = .73), with KRAS mutations was 18 months (P = .12), and with ALK rearrangements was not reached (P = .64). CONCLUSION BRAF mutations occur in 3% of patients with lung adenocarcinoma and occur more commonly in current and former smokers. The incidence of BRAF mutations other than V600E is significantly higher in lung cancer than in melanoma.

Acquired Resistance to EGFR Tyrosine Kinase Inhibitors in EGFR-Mutant Lung Cancer: Distinct Natural History of Patients with Tumors Harboring the T790M Mutation

Purpose: Patients with epidermal growth factor receptor (EGFR)-mutant lung adenocarcinoma develop acquired resistance to EGFR tyrosine kinase inhibitors (TKI) after a median of 10 to 16 months. In half of these cases, a second EGFR mutation, T790M, underlies acquired resistance. We undertook this study to examine the clinical course of patients harboring the T790M mutation following progression on TKI. Experimental Design: EGFR-mutant lung cancer patients with acquired resistance to EGFR TKIs were identified as part of a prospective rebiopsy protocol in which postprogression tumor specimens were collected for molecular analysis. Postprogression survival and characteristics of disease progression were compared in patients with and without T790M. Results: We identified T790M in the initial rebiopsy specimens from 58 of 93 patients (62%, 95% CI: 52–72). T790M was more common in biopsies of lung/pleura tissue and lymph nodes than in more distant sites (P = 0.014). Median postprogression survival was 16 months (interquartile range = 9–29 months); patients with T790M had a significantly longer postprogression survival (P = 0.036). Patients without T790M more often progressed in a previously uninvolved organ system (P = 0.014) and exhibited a poorer performance status at time of progression (P = 0.007). Conclusions: Among patients with acquired resistance to EGFR TKIs, the presence of T790M defines a clinical subset with a relatively favorable prognosis and more indolent progression. Knowledge of T790M status is therefore important both for the clinical care of these patients and for the optimal design and interpretation of clinical trials in this setting. Clin Cancer Res; 17(6); 1616–22. ©2010 AACR.

Disease Flare after Tyrosine Kinase Inhibitor Discontinuation in Patients with EGFR-Mutant Lung Cancer and Acquired Resistance to Erlotinib or Gefitinib: Implications for Clinical Trial Design

Purpose: Treatment of patients with oncogene-addicted cancers with tyrosine kinase inhibitors (TKI) is biologically and clinically different than with cytotoxic chemotherapy. We have observed that some patients with EGFR-mutant lung cancer and acquired resistance to erlotinib or gefitinib (RECIST progression after initial benefit) have accelerated progression of disease after discontinuation of TKI. To examine this observation and define the course of patients following TKI discontinuation, we systematically evaluated patients enrolled on clinical trials of agents to treat acquired resistance to erlotinib or gefitinib. Methods: We evaluated patients with EGFR-mutant lung cancer who participated in trials for patients with acquired resistance that mandated TKI discontinuation before administration of study therapy. Disease flare was defined as hospitalization or death attributable to disease progression during the washout period. Results: Fourteen of 61 patients (23%; 95% CI: 14–35) experienced a disease flare. The median time to disease flare after TKI discontinuation was 8 days (range 3–21). Factors associated with disease flare included shorter time to progression on initial TKI (P = 0.002) and the presence of pleural (P = 0.03) or CNS disease (P = 0.01). There was no association between disease flare and the presence of T790M at the time of acquired resistance. Conclusions: In patients with EGFR-mutant lung cancer and acquired resistance to epidermal growth factor receptor TKIs, discontinuation of erlotinib or gefitinib before initiation of study treatment is associated with a clinically significant risk of accelerated disease progression. Clinical trials in this patient population must minimize protocol-mandated washout periods. Clin Cancer Res; 17(19); 6298–303. ©2011 AACR.

Immunohistochemical algorithm for differentiation of lung adenocarcinoma and squamous cell carcinoma based on large series of whole-tissue sections with validation in small specimens

Immunohistochemistry is increasingly utilized to differentiate lung adenocarcinoma and squamous cell carcinoma. However, detailed analysis of coexpression profiles of commonly used markers in large series of whole-tissue sections is lacking. Furthermore, the optimal diagnostic algorithm, particularly the minimal-marker combination, is not firmly established. We therefore studied whole-tissue sections of resected adenocarcinoma and squamous cell carcinoma (n=315) with markers commonly used to identify adenocarcinoma (TTF-1) and squamous cell carcinoma (p63, CK5/6, 34βE12), and prospectively validated the devised algorithm in morphologically unclassifiable small biopsy/cytology specimens (n=38). Analysis of whole-tissue sections showed that squamous cell carcinoma had a highly consistent immunoprofile (TTF-1-negative and p63/CK5/6/34βE12-diffuse) with only rare variation. In contrast, adenocarcinoma showed significant immunoheterogenetity for all ‘squamous markers’ (p63 (32%), CK5/6 (18%), 34βE12 (82%)) and TTF-1 (89%). As a single marker, only diffuse TTF-1 was specific for adenocarcinoma whereas none of the ‘squamous markers,’ even if diffuse, were entirely specific for squamous cell carcinoma. In contrast, coexpression profiles of TTF-1/p63 had only minimal overlap between adenocarcinoma and squamous cell carcinoma, and there was no overlap if CK5/6 was added as a third marker. An algorithm was devised in which TTF-1/p63 were used as the first-line panel, and CK5/6 was added for rare indeterminate cases. Prospective validation of this algorithm in small specimens showed 100% accuracy of adenocarcinoma vs squamous cell carcinoma prediction as determined by subsequent resection. In conclusion, although reactivity for ‘squamous markers’ is common in lung adenocarcinoma, a two-marker panel of TTF-1/p63 is sufficient for subtyping of the majority of tumors as adenocarcinomas vs squamous cell carcinoma, and addition of CK5/6 is needed in only a small subset of cases. This simple algorithm achieves excellent accuracy in small specimens while conserving the tissue for potential predictive marker testing, which is now an essential consideration in advanced lung cancer specimens.

A grading system of lung adenocarcinomas based on histologic pattern is predictive of disease recurrence in stage I tumors.

Currently no objective grading system for pulmonary adenocarcinomas exists. To determine whether specific histologic patterns or combinations thereof could be linked to an objective grading system, the histologic patterns in metastatic tumor deposits was compared with the patterns seen in the corresponding 73 primary tumor to determine whether a specific pattern had higher propensity to metastasize. The concordance of the predominant histologic pattern in the primary tumor and the metastases was of 100% for micropapillary, 86% for solid, 42% for acinar, and 23% for papillary types of adenocarcinoma. Informed by these results, a 3-tier grading system based on the histologic subtypes was established. Grade I, a pattern with low metastatic potential (BAC); Grade II, patterns with intermediate metastatic potential (acinar and papillary); and Grade III, patterns with high metastatic potential (solid and micropapillary). These grades were combined into a number of different scoring systems, whose ability to predict recurrence or death from disease was tested in 366 stage 1 adenocarcinomas. A score based on the 2 most predominant grades was able to stratify patients into low-to-high risk for recurrence or death of disease (P=0.001). The 5-years disease-free survival for patients in the highest score group was of 0.73, compared with 0.84 and 0.92 in the intermediate and lowest score groups. Concordance probability estimate was 0.65 (95% confidence interval 0.57-0.73). Therefore, this scoring system provides valuable information in discriminating patients with different risk of disease-recurrence in a highly homogeneous population of patients with stage I cancer.

Incidence of EGFR Exon 19 Deletions and L858R in Tumor Specimens From Men and Cigarette Smokers With Lung Adenocarcinomas

PURPOSE EGFR mutations underlie the sensitivity of lung cancers to erlotinib and gefitinib and can occur in any patient with this illness. Here we examine the frequency of EGFR mutations in smokers and men. METHODS We determined the frequency of EGFR mutations and characterized their association with cigarette smoking status and male sex. RESULTS We tested 2,142 lung adenocarcinoma specimens for the presence of EGFR exon 19 deletions and L858R. EGFR mutations were found in 15% of tumors from former smokers (181 of 1,218; 95% CI, 13% to 17%), 6% from current smokers (20 of 344; 95% CI, 4% to 9%), and 52% from never smokers (302 of 580; 95% CI, 48% to 56%; P < .001 for ever v never smokers). EGFR mutations in former or current smokers represented 40% of all those detected (201 of 503; 95% CI, 36% to 44%). EGFR mutations were found in 19% (157 of 827; 95% CI, 16% to 22%) of tumors from men and 26% (346 of 1,315; 95% CI, 24% to 29%) of tumors from women (P < .001). EGFR mutations in men represented 31% (157 of 503; 95% CI, 27% to 35%) of all those detected. CONCLUSION A large number of EGFR mutations are found in adenocarcinoma tumor specimens from men and people who smoked cigarettes. If only women who were never smokers were tested, 57% of all EGFR mutations would be missed. Testing for EGFR mutations should be considered for all patients with adenocarcinoma of the lung at diagnosis, regardless of clinical characteristics. This strategy can extend the use of EGFR tyrosine kinase inhibitors to the greatest number individuals with the potential for substantial benefit.

Coexistence of PIK3CA and Other Oncogene Mutations in Lung Adenocarcinoma–Rationale for Comprehensive Mutation Profiling

Phosphoinositide-3-kinase catalytic alpha polypeptide (PIK3CA) encodes the p110α subunit of the mitogenic signaling protein phosphoinositide 3-kinase (PI3K). PIK3CA mutations in the helical binding domain and the catalytic subunit of the protein have been associated with tumorigenesis and treatment resistance in various malignancies. Characteristics of patients with PIK3CA-mutant lung adenocarcinomas have not been reported. We examined epidermal growth factor receptor (EGFR), Kirsten rate sarcoma viral oncogene homolog (KRAS), v-Raf murine sarcoma viral oncogene homolog B1 (BRAF), human epidermal growth factor receptor 2 (HER2), PIK3CA, v-akt murine thymoma vial oncogene homolog 1 (AKT1), v-ras neuroblastoma viral oncogene homolog (NRAS), dual specificity mitogen-activated protein kinase kinase 1 (MEK1), and anaplastic lymphoma kinase (ALK) in patients with adenocarcinoma of the lung to identify driver mutations. Clinical data were obtained from the medical records of individuals with mutations in PIK3CA. Twenty-three of 1,125 (2%, 95% CI: 1–3) patients had a mutation in PIK3CA, 12 in exon 9 (10 E545K and 2 E542K), and 11 in exon 20 (3 H1047L and 8 H1047R). The patients (57% women) had a median age of 66 at diagnosis (range: 34–78). Eight patients (35%) were never smokers. Sixteen of 23 (70%, 95% CI: 49–86) had coexisting mutations in other oncogenes—10 KRAS, 1 MEK1, 1 BRAF, 1 ALK rearrangement, and 3 EGFR exon 19 deletions. We conclude that PIK3CA mutations occur in lung adenocarcinomas, usually concurrently with EGFR, KRAS, and ALK. The impact of PIK3CA mutations on the efficacy of targeted therapies such as erlotinib and crizotinib is unknown. Given the high frequency of overlapping mutations, comprehensive genotyping should be carried out on tumor specimens from patients enrolling in clinical trials of PI3K and other targeted therapies. Mol Cancer Ther; 11(2); 485–91. ©2011 AACR.

Impact of Micropapillary Histologic Subtype in Selecting Limited Resection vs Lobectomy for Lung Adenocarcinoma of 2cm or Smaller

BACKGROUND We sought to analyze the prognostic significance of the new International Association for the Study of Lung Cancer (IASLC), American Thoracic Society (ATS), and European Respiratory Society (ERS) lung adenocarcinoma (ADC) classification for patients undergoing resection for small (≤2cm) lung ADC and to investigate whether histologic subtyping can predict recurrence after limited resection (LR) vs lobectomy (LO). METHODS Comprehensive histologic subtyping was performed according to the IASLC/ATS/ERS classification on all consecutive patients who underwent LR or LO for small lung ADC between 1995 and 2009 at Memorial Sloan-Kettering Cancer Center. Clinical characteristics and pathologic data were retrospectively evaluated for 734 consecutive patients (LR: 258; LO: 476). Cumulative incidence of recurrence (CIR) was calculated using competing risks analysis and compared across groups using Greys test. All statistical tests were two-sided. RESULTS Application of IASLC/ATS/ERS lung ADC histologic subtyping to predict recurrence demonstrates that, in the LR group but not in the LO group, micropapillary (MIP) component of 5% or greater was associated with an increased risk of recurrence, compared with MIP component of less than 5% (LR: 5-year CIR = 34.2%, 95% confidence interval [CI] = 23.5% to 49.7% vs 5-year CIR = 12.4%, 95% CI = 6.9% to 22.1%, P < .001; LO: 5-year CIR = 19.1%, 95% CI = 12.0% to 30.5% vs 15-year CIR = 12.9%, 95% CI = 7.6% to 21.9%, P = .13). In the LR group, among patients with tumors with an MIP component of 5% or greater, most recurrences (63.4%) were locoregional; MIP component of 5% or greater was statistically significantly associated with increased risk of local recurrence when the surgical margin was less than 1cm (5-year CIR = 32.0%, 95% CI = 18.6% to 46.0% for MIP ≥ 5% vs 5-year CIR = 7.6%, 95% CI = 2.3% to 15.6% for MIP < 5%; P = .007) but not when surgical margin was 1cm or greater (5-year CIR = 13.0%, 95% CI = 4.1% to 22.1% for MIP ≥ 5% vs 5-year CIR = 3.4%, 95% CI = 0% to 7.7% for MIP < 5%; P = .10). CONCLUSIONS Application of the IASLC/ATS/ERS classification identifies the presence of an MIP component of 5% or greater as independently associated with the risk of recurrence in patients treated with LR.

Patterns of recurrence and second primary lung cancer in early-stage lung cancer survivors followed with routine computed tomography surveillance

OBJECTIVE At present, there is no consensus on the optimal strategy for follow-up care after curative resection for lung cancer. We sought to understand the patterns of recurrence and second primary lung cancer, and their mode of detection, after resection for early-stage non-small cell lung cancer in patients who were followed by routine surveillance computed tomography scan. METHODS We reviewed the outcomes of consecutive patients who underwent resection for early-stage non-small cell lung cancer at Memorial Sloan-Kettering Cancer Center between 2004 and 2009. RESULTS A total of 1294 consecutive patients with early-stage non-small cell lung cancer underwent resection. The median length of follow-up was 35 months. Recurrence was diagnosed in 257 patients (20%), and second primary lung cancer was diagnosed in 91 patients (7%). The majority of new primary cancers (85 [93%]) were identified by scheduled routine computed tomography scan, as were a smaller majority of recurrences (157 [61%]). During the first 4 years after surgery, the risk of recurrence ranged from 6% to 10% per person-year but decreased thereafter to 2%. Conversely, the risk of second primary lung cancer ranged from 3% to 6% per person-year and did not diminish over time. Additional testing after false-positive surveillance computed tomography scan results was performed for 329 patients (25%), but only 4 of these patients (0.3%) experienced complications as a result of subsequent invasive diagnostic procedures. CONCLUSIONS Almost all second primary cancers and the majority of recurrences were detected by post-therapeutic surveillance computed tomography scan. The risk of recurrence for early-stage non-small cell lung cancer survivors persisted during the first 4 years after resection, and vigilance in surveillance should be maintained.