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Introduction: This study assessed (i) the ability to identify the solid components of part-solid nodules (PSN) during computed tomography (CT) guided lung biopsy (CTGLB), (ii) the ability of CTGLB to assess the invasive nature of a nodule on pathology., Materials and Methods: Sixty-nine nodules were studied in 68 patients who underwent CTGLB between 1/1/2014 and 10/31/2015. Diagnostic CT images and CTGLB images were reviewed. On diagnostic CT images, nodules were classified as ground glass nodules (GGN) or PSNs. Nodule size, location, and percentage of solid component were recorded. At the time of biopsy, the ability to visualize the solid component of a PSN, depth of lesion from skin, and ability to identify the needle within the solid component were recorded., Results: There were 42 (61%) part-solid nodules and 27 (39%) GGNs. During biopsy, it was possible to differentiate the solid from the ground glass components in 35 (83%) PSNs. Fifty-nine (86%) nodules were neoplastic based on biopsy pathology (all non-small cell lung carcinoma). Thirty-nine (66%) were resected. In all cases biopsy pathology and surgical pathology agreed regarding the presence of lung carcinoma. In 6 (15%) cases biopsy pathology demonstrated purely lepidic growth but had some non-lepidic growth on surgical pathology, including 2 cases with acinar growth as a dominant pattern., Conclusion: In most patients, the solid and ground glass components of a PSN were distinguishable when performing a CTGLB. In a minority of patients, discrepancy was noted between biopsy pathology and surgical pathology regarding the invasive nature of a nodule., (Copyright © 2020. Published by Elsevier Inc.)

Objectives: To describe the radiological phenotype of HER2-mutant lung cancers on CT at presentation., Methods: Eligible patients with lung adenocarcinomas with HER2 mutations were stage-matched with two control groups (EGFR- and KRAS-mutant groups). Evaluated CT features of the primary tumor included size, location, consistency, contour, presence of pleural tags and pleural retractions. Presence of pleural effusions, lung metastases, adenopathy, chest wall invasion, and were also recorded. Wilcoxon rank-sum and Fisher's exact tests were used to compare continuous and categorical features, respectively., Results: One hundred and fifty-four patients were identified: 50 (33%) harbored HER2 mutations, 56 (36%) harbored KRAS mutations, and 48 (31%) harbored EGFR mutations. Compared with KRAS, HER2 tumors presented as smaller lesions (2.3 cm versus 2.9 cm, p = 0.005 for length; 1.6 cm versus 2.1 cm, p = 0.002 for width) with the presence of pleural tags (74% vs. 52%, p = 0.03), pleural retractions (58% vs. 39%, p = 0.006), ipsilateral hilar (36% vs. 16%, p = 0.03) and scalene/supraclavicular N3 adenopathy (24% vs. 7%, p = 0.03). Compared with EGFR, pleural retractions were more prevalent among the HER2 tumors (58% vs. 37%, p = 0.05)., Conclusions: Lung adenocarcinomas with HER2 gene mutation exhibit an aggressive behavior manifesting by higher incidence of local invasion, compared to KRAS and EGFR mutant controls, and a nodal metastatic spread compared to KRAS-mutant control. This is the first radiogenomics study of HER2 mutations in lung cancer., (Copyright © 2018 The Authors. Published by Elsevier Inc. All rights reserved.)

Tumor genetic testing is standard of care for patients with advanced lung adenocarcinoma, but the fraction of patients who derive clinical benefit remains undefined. Here, we report the experience of 860 patients with metastatic lung adenocarcinoma analyzed prospectively for mutations in >300 cancer-associated genes. Potentially actionable genetic events were stratified into one of four levels based upon published clinical or laboratory evidence that the mutation in question confers increased sensitivity to standard or investigational therapies. Overall, 37.1% (319/860) of patients received a matched therapy guided by their tumor molecular profile. Excluding alterations associated with standard-of-care therapy, 14.4% (69/478) received matched therapy, with a clinical benefit of 52%. Use of matched therapy was strongly influenced by the level of preexistent clinical evidence that the mutation identified predicts for drug response. Analysis of genes mutated significantly more often in tumors without known actionable mutations nominated STK11 and KEAP1 as possible targetable mitogenic drivers. Significance: An increasing number of therapies that target molecular alterations required for tumor maintenance and progression have demonstrated clinical activity in patients with lung adenocarcinoma. The data reported here suggest that broader, early testing for molecular alterations that have not yet been recognized as standard-of-care predictive biomarkers of drug response could accelerate the development of targeted agents for rare mutational events and could result in improved clinical outcomes. Cancer Discov; 7(6); 596-609. ©2017 AACR. See related commentary by Liu et al., p. 555 This article is highlighted in the In This Issue feature, p. 539 ., (©2017 American Association for Cancer Research.)

Introduction: We studied computed tomography (CT) features associated with BRAF mutated lung cancer., Materials and Methods: CT features of BRAF mutated lung cancers were compared to stage matched lesions without BRAF mutation., Results: 47 (25%) patients with BRAF mutation and 141 (75%) without BRAF mutation were included. BRAF lesions were most frequently solid 37 (84%), spiculated 22 (50%), and peripheral 37 (84%). No feature of the primary tumor was significantly different between BRAF and non-BRAF groups. BRAF patients were more likely than KRAS patients to have pleural metastases [5 (11%) vs 0 (0%), p=0.045]., Conclusion: No feature of the primary tumor differentiates BRAF lesions from non-BRAF lesions., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Introduction: Many patients with lung cancers cannot receive platinum-containing regimens owing to comorbid medical conditions. We designed the PPB (paclitaxel, pemetrexed, and bevacizumab) regimen to maintain or improve outcomes while averting the unique toxicities of platinum-based chemotherapies., Methods: We enrolled patients with untreated, advanced lung adenocarcinomas with measurable disease and no contraindications to bevacizumab. Participants received paclitaxel, 90 mg/m(2), pemetrexed, 500 mg/m(2), and bevacizumab, 10 mg/kg, every 14 days for 6 months and continued to receive pemetrexed and bevacizumab every 14 days until progression or unacceptable toxicity., Results: Of the 44 patients treated, 50% were women; the median age was 61 years and 89% had a Karnofsky performance status of at least 80%. We genotyped 38 patients with the following results: Kirsten rat sarcoma viral oncogene homolog gene (KRAS), 16; anaplastic lymphoma receptor tyrosine kinase gene (ALK), three; B-Raf proto-oncogene, serine/threonine kinase gene (BRAF) V600E, two; erb-b2 receptor tyrosine kinase 2 gene (HER2)/phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit alpha gene (PIK3CA), one; epidermal growth factor receptor gene (EGFR) exon 20 insertion, one; and driver 15, none. A total of 23 patients achieved a PR (52%, 95% confidence interval: 37-68), including seven of 16 with KRAS-mutant tumors. The overall survival rate at 2 years was 43% with a median of 17 months (95% confidence interval: 10-29). Grade 3/4 treatment-related toxicities included elevated alanine transaminase level (16%), fatigue (16%), leukopenia (9%), anemia (7%), elevated aspartate transaminase level (7%), edema (5%), and pleural effusions (5%). Two patients died of respiratory failure without disease progression., Conclusions: The PPB regimen produced a high response rate in patients with lung adenocarcinomas regardless of mutational status. Survival and toxicities were comparable to those in the phase II reports testing platinum-containing doublets with bevacizumab. These results justify use of the PPB regimen in fit patients in whom three-drug regimens including bevacizumab are appropriate., (Copyright © 2016 International Association for the Study of Lung Cancer. Published by Elsevier Inc. All rights reserved.)

Purpose: To examine the correlations between uni-dimensional RECIST and volumetric measurements in patients with lung adenocarcinoma and to assess their association with overall survival (OS) and progression-free survival (PFS)., Materials and Methods: In this study of patients receiving chemotherapy for lung cancer in the setting of a clinical trial, response was prospectively evaluated using RECIST 1.0. Retrospectively, volumetric measurements were recorded and response was assessed by two different volumetric methods at each followup CT scan using a semi-automated segmentation algorithm. We subsequently evaluated the correlation between the uni-dimensional RECIST measurements and the volumetric measurements and performed landmark analyses for OS and PFS at the completion of the first and second follow-ups. Kaplan-Meier curves together with log-rank tests were used to evaluate the association between the different response criteria and patient outcome., Results: Forty-two patients had CT scans at baseline, after the first follow up scan and second followup scan, and then every 8 weeks. The uni-dimensional RECIST measurements and volumetric measurements were strongly correlated, with a Spearman correlation coefficient (ρ) of 0.853 at baseline, ρ=0.861 at the first followup, ρ=0.843 at the 2nd followup, and ρ=0.887 overall between-subject. On first follow-up CT, partial responders and non responders as assessed by an "ellipsoid" volumetric criteria showed a significant difference in OS (p=0.008, 1-year OS of 70% for partial responders and 46% for non responders). There was no difference between the groups when assessed by RECIST criteria on first follow-up CT (p=0.841, 1-year OS rate of 64% for partial responders and 64% for non responders)., Conclusion: Volumetric response on first follow-up CT may better predict OS than RECIST response., Clinical Relevance Statement: Assessment of tumor size and response is of utmost importance in clinical trials. Volumetric measurements may help to better predict OS than uni-dimensional RECIST criteria., (Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.)

Introduction: Recurrent gene rearrangements are important drivers of oncogenesis in non-small cell lung cancers. RET and ROS1 rearrangements are each found in 1-2% of lung adenocarcinomas and represent distinct molecular subsets. This study assessed the computed tomography (CT) imaging features of patients with RET- and ROS1-rearranged lung cancers., Methods: Eligible patients included pathologically-confirmed lung adenocarcinomas of any stage with a RET or ROS1 rearrangement via fluorescence in-situ hybridization or next-generation sequencing, and available pre-treatment baseline imaging for review. A cohort of EGFR-mutant lung cancers was identified as a control group. CT features assessed included location, consistency, contour, presence of cavitation, and calcification of the primary tumor. Presence of an effusion, lung metastases, adenopathy and extrathoracic disease were recorded. The Wilcoxon rank-sum/Kruskal-Wallis and Fisher's exact tests were used to compare features between groups., Results: 73 patients with lung adenocarcinomas were identified: 17 (23%) with ROS1 fusions, 25 (34%) with RET fusions and 31 (43%) with EGFR mutations. ROS1-rearranged lung cancers were more likely to present as peripheral tumors in comparison to EGFR-mutant lung cancers (32% vs. 65%, p=0.04). RET-rearranged lung cancers did not significantly differ from EGFR-mutant lung cancers radiographically. The consistency of the primary lesion for RET and ROS fusions and EGFR mutations were most frequently solid and spiculated., Conclusions: Lung adenocarcinomas with RET and ROS1 fusions share many radiographic features and those with ROS1 fusions are more likely to present as peripheral lesions in comparison to EGFR-mutant lung cancers., (Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.)

Unlabelled: Mutations in the MET exon 14 RNA splice acceptor and donor sites, which lead to exon skipping, deletion of the juxtamembrane domain containing the CBL E3-ubiquitin ligase-binding site, and decreased turnover of the resultant aberrant MET protein, were previously reported to be oncogenic in preclinical models. We now report responses to the MET inhibitors crizotinib and cabozantinib in four patients with stage IV lung adenocarcinomas harboring mutations leading to MET exon 14 skipping, highlighting a new therapeutic strategy for the 4% of lung adenocarcinoma patients whose tumors harbor this previously underappreciated genetic alteration., Significance: Oncogenic mutations in the MET exon 14 splice sites that cause exon 14 skipping occur in 4% of lung adenocarcinomas. We report responses to the MET inhibitors crizotinib and cabozantinib in patients with lung adenocarcinomas harboring MET exon 14 splice site mutations, identifying a new potential therapeutic target in this disease., (©2015 American Association for Cancer Research.)

Introduction: The objective of this study is to identify computed tomography (CT) features of local recurrence (LR) after stereotactic body radiation therapy (SBRT) for lung cancer., Methods: Two hundred eighteen patients underwent SBRT for lung cancer from January 1st, 2006 to March 1st, 2011. Signs of LR recorded: opacity with new bulging margin, opacification of air bronchograms, enlarging pleural effusion, new or enlarging mass, and increased lung density at the treatment site., Results: A new bulging margin at the treatment site was the only feature significantly associated with LR (P<.005)., Conclusion: Most CT features classically associated with LR following conventional radiation therapy are unreliable for predicting LR following SBRT., (Copyright © 2015 Elsevier Inc. All rights reserved.)

Introduction: 5% of lung adenocarcinomas harbor rearrangements of the anaplastic lymphoma kinase (ALK) gene. This study compared computed tomography (CT) imaging features in patients with ALK rearrangements and those with EGFR mutations., Material/methods: 30 patients with ALK rearrangements were studied. 97 patients with epidermal growth factor receptor (EGFR) mutations were used as controls. Features assessed included size and location of thoracic lymphadenopathy, and the size, contour, consistency and location of the primary tumor., Results: 127 lung adenocarcinomas were examined. 30 (24%) tumors harbored ALK rearrangements, 97 (76%) tumors harbored EGFR mutations. ALK tumors had larger thoracic lymphadenopathy than the control group (p=0.005). Both readers identified 17 (57%) patients in the ALK group with lymph nodes >1.5cm. Reader 1 identified 19 (20%) patients in the EGFR group with lymph nodes >1.5cm, and reader 2 identified 18 (19%) (kappa 0.969). Patients with ALK rearrangements were more likely to have multifocal lymphadenopathy. Reader 1 identified 22 (73%) ALK patients versus 35 (36%) EGFR patients with multifocal thoracic nodal enlargement, while reader 2 identified 20 (67%) ALK patients versus 30 (31%) EGFR patients (kappa 0.953). 92% of ALK positive lesions were solid., Conclusion: ALK positive lung adenocarcinomas are more likely than EGFR mutant lung adenocarcinomas to be associated with larger volume, multifocal thoracic lymphadenopathy. While routine testing for ALK should be standard, the presence of such characteristics in a solid tumor should further prompt testing for ALK rearrangement., (Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.)

Objective: To prospectively compare the ability of flourodeoxyglucose-positron emission tomography (FDG-PET) and computed tomography (CT) to identify a pathological complete response (pCR) in patients with rectal cancer treated by chemoradiation., Background: A major obstacle in pursuing nonoperative management in patients with rectal cancer after chemoradiation is the inability to identify a pCR preoperatively., Methods: A total of 121 patients with rectal cancer were prospectively enrolled. FDG-PET scans and helical CT scans were obtained before and after neoadjuvant chemoradiation. Consensus readings of PET and CT scans were used to classify certainty of disease (5-point confidence rating scale). The ability of PET and CT scans to accurately distinguish a pCR (ypT0) from an incomplete response (ypT1-4) was estimated using the area under the receiver operating characteristic curve (AUC)., Results: Of the 121 patients, 26 (21%) had a pCR. PET and CT scans were equally inadequate at distinguishing a pCR from an incomplete response (AUC = 0.64 for both, P = 0.97). Among the 26 patients with a pCR, 14 (54%) and 5 (19%) were classified as complete responders on PET and CT scans, respectively. Among the 95 patients with an incomplete pathological response, 63 (66%) and 90 (95%) were classified as incomplete responders on PET and CT scans, respectively. None of the individual PET parameters, including visual response score, mean standard uptake value (SUVmean), maximum SUV (SUVmax), and total lesion glycolysis, accurately distinguished a pCR (AUCs = 0.57-0.73)., Conclusions: Neither PET nor CT scans have adequate predictive value to be clinically useful in distinguishing a pCR from an incomplete response and, therefore, should not be obtained for the purpose of attempting to predict a pCR after neoadjuvant chemoradiation for rectal cancer.

Introduction: In patients with resected lung cancer, sarcomatoid carcinomas are reputed to carry a worse prognosis. Although generally felt to be chemo-refractory, little data are available about chemotherapy in these patients. We sought to determine the effect of perioperative chemotherapy in patients with completely resected sarcomatoid carcinomas of the lung., Methods: We reviewed the pathology reports of 4675 patients consecutively resected at Memorial Sloan-Kettering between 2000 and 2010. Charts and images were reviewed for patients with a histologic diagnosis of sarcomatoid carcinoma. Response to neoadjuvant chemotherapy was assessed radiographically. Kaplan-Meier disease-free probability (DFP) curves were compared for patients who did and did not receive perioperative chemotherapy, stratified by pathological stage., Results: Of the 4675 patients who underwent an R0 lung cancer resection, 56 (1%) were diagnosed with sarcomatoid carcinomas. Twenty received neoadjuvant and/or adjuvant chemotherapy. Overall radiographic response rate (minor + major) to neoadjuvant chemotherapy was 73% (95% confidence interval 48-90%) in the 15 evaluable patients. The median DFP of patients who received chemotherapy was 34 months versus 12 months in those who did not (p = 0.37). Subset analysis did not reveal a benefit to perioperative chemotherapy in patients with stage Ib-IIa, whereas a benefit was seen in patients with IIb-IIIa disease (p = 0.02)., Conclusions: Although sarcomatoid carcinomas are felt to be chemo-refractory, our results demonstrate radiographic responses to neoadjuvant chemotherapy and an improvement in DFP in patients with stage IIb-IIIa disease. The use of pathological stage in this analysis may underestimate this benefit. Perioperative chemotherapy should be considered in these patients.

Purpose: Epidermal growth factor receptor (EGFR) genotyping is now standard in the management of advanced lung adenocarcinoma, as this biomarker predicts marked benefit from treatment with EGFR tyrosine kinase inhibitors (TKI). EGFR exon 19 insertions are a poorly described family of EGFR mutations, and their association with EGFR-TKI sensitivity in lung adenocarcinoma is uncertain., Experimental Design: Patients with lung cancers harboring EGFR exon 19 insertions were studied. The predicted effects of the insertions on the structure of the EGFR protein were examined, and EGFR exon 19 insertions were introduced into Ba/F3 cells to assess oncogenicity and in vitro sensitivity to EGFR-TKIs. In patients receiving TKI, response magnitude was assessed with serial computed tomographic (CT) measurement., Results: Twelve tumors harboring EGFR exon 19 insertions were identified; patients were predominately female (92%) and never-smokers (75%). The 11 specimens available for full sequencing all showed an 18-bp insertion that resulted in the substitution of a Pro for Leu at residue 747. The mutant EGFR transformed the Ba/F3 cells, which were then sensitive to EGFR-TKI. Six patients with measurable disease received TKI and five had a response on serial CT., Conclusions: EGFR exon 19 insertions are a newly appreciated family of EGFR-TKI-sensitizing mutations, and patients with tumors harboring these mutations should be treated with EGFR-TKI. While these mutations may be missed through the use of some mutation-specific assays, the addition of PCR product size analysis to multigene assays allows sensitive detection of both exon 19 insertion and deletion mutations.

Objective: To compare preoperative size of stage I and stage II lung adenocarcinoma as measured by Computed Tomography (CT) and as assessed on gross pathology specimens., Materials and Methods: 47 patients diagnosed with stage I or II lung adenocarcinoma were evaluated. Institutional Review Board permission was obtained. Tumor contours were delineated using a semi-automated segmentation algorithm and adjusted based on a radiologist's input. Based on the tumor perimeter, maximal in-plane tumor diameter was calculated automatically. The largest single diameter from the pathology gross report was utilized. A paired t-test was used to examine the measurement difference between CT and pathology., Results: The mean largest diameter of the tumors at CT and pathology was 29.53 mm and 24.04 mm, respectively. There was a statistically significant difference between the mean CT measurement and mean pathology measurement of 5.49 mm (standard deviation 9.08 mm, p<0.001). The percent relative difference between the two measurements was 18.3% (standard deviation 28.2%)., Conclusion: There is a statistically significant difference between the tumor diameter as measured by CT and on pathology gross specimen. These differences could have implications in the treatment and prognosis of patients with early stage lung adenocarcinoma., (Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.)

Introduction: KRAS mutations are present in 30% of lung adenocarcinomas. Salirasib prevents Ras membrane binding thereby blocking the function of all Ras isoforms. This phase II study determined the activity of salirasib in patients with advanced lung adenocarcinomas with KRAS mutations., Methods: Two cohorts of patients with stage IIIB/IV lung adenocarcinoma were eligible: patients with tumors with KRAS mutations who were previously treated with chemotherapy and patients receiving initial therapy who had ≥15 pack-year smoking history. Salirasib was given orally from days 1 to 28 of a 35-day cycle. The primary end point was the rate of nonprogression at 10 weeks., Results: Thirty-three patients were enrolled. Thirty patients had KRAS mutations (23 patients who were previously treated and 7/10 patients who had no prior therapy). Of the previously treated patients, 7 of 23 (30%) had stable disease at 10 weeks, and 4 of 10 (40%) previously untreated patients had stable disease at 10 weeks. No patient had a radiographic partial response (0% observed rate, 95% confidence interval 0-12%). The median overall survival was not reached (>9 months) for previously untreated patients and it was 15 months for patients who received prior chemotherapy. Diarrhea, nausea, and fatigue were the most common toxicities., Conclusions: Salirasib at the current dose and schedule has insufficient activity in the treatment of KRAS mutant lung adenocarcinoma to warrant further evaluation. The successful enrollment of 30 patients with tumors with KRAS mutant lung adenocarcinoma over 15 months at a single site demonstrates that drug trials directed at a KRAS-specific genotype in lung cancer are feasible.

Introduction: Dual inhibition of SRC- and EGFR-dependent pathways may overcome acquired resistance to epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) for patients with lung adenocarcinoma with EGFR mutations. The SRC inhibitor dasatinib demonstrates antitumor activity in gefitinib-resistant cells lines and xenografts. Dasatinib is tolerable for patients with advanced non-small cell lung cancer, and in combination with erlotinib., Methods: We conducted this phase II study of dasatinib 70 mg twice daily in patients with EGFR-mutant lung adenocarcinoma and acquired resistance to EGFR-TKIs. After a protocol amendment based on evolving data about both drugs, patients received dasatinib at a dose of 100 mg daily with continued erlotinib after developing acquired resistance. Enrolled patients either harbored an activating mutation in EGFR or experienced clinical benefit with single-agent erlotinib or gefitinib, followed by RECIST documented progression while being treated with an EGFR-TKI., Results: Twenty-one patients were enrolled, 9 under the original trial design and 12 after the protocol amendments. We observed no complete or partial responses (0% observed rate, 95% confidence interval: 0-18%). The median time to progression was 0.5 months (range, 0.2-1.8 months) in patients treated with dasatinib and 0.9 months (range, 0.4-5 months) for patients treated with dasatinib and erlotinib in combination. Pleural effusions and dyspnea were frequent toxicities., Conclusions: Dasatinib has no activity in patients with EGFR-mutant lung adenocarcinoma with acquired resistance to erlotinib and gefitinib.

Purpose: In patients with epidermal growth factor receptor (EGFR) mutant lung adenocarcinoma, treatment with erlotinib or gefitinib is associated with a 75% radiographic response rate and progression-free survival of approximately 12 months. The most common mechanism of acquired resistance to erlotinib is development of a secondary mutation in EGFR, suggesting that these tumors continue to depend on EGFR signaling. We hypothesized that combined EGFR blockade would overcome acquired resistance to erlotinib in patients with lung adenocarcinoma. To evaluate the toxicity and efficacy of cetuximab and erlotinib in patients with acquired resistance to erlotinib, we conducted this phase I/II clinical trial., Experimental Design: Patients with lung adenocarcinoma and clinically defined acquired resistance to erlotinib were treated with erlotinib 100 mg daily, along with cetuximab every 2 weeks in three escalating dose cohorts (250 mg/m(2), 375 mg/m(2), and 500 mg/m(2)). The recommended phase II dose was then evaluated in a two-stage trial, with a primary end point of objective response rate., Results: A total of 19 patients were enrolled. The most common toxicities for the combination of cetuximab and erlotinib were rash, fatigue, and hypomagnesemia. The recommended phase II dose identified was cetuximab 500 mg/m(2) every 2 weeks and erlotinib 100 mg daily. At this dose and schedule, no radiographic responses were seen (0 of 13, 0%, 95% CI, 0-25)., Conclusions: Combined EGFR inhibition, with cetuximab 500 mg/m(2) every 2 weeks and erlotinib 100 mg daily, had no significant activity in patients with acquired resistance to erlotinib., (©2011 AACR.)

Context: A subset of lung adenocarcinomas appears preferentially sensitive to epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs). EGFR-activating mutations and never smoking are associated with response to TKIs., Objectives: To describe the morphology of adenocarcinomas responsive to TKIs, compare it to tumors in nonresponding patients, and correlate findings with EGFR mutations, gene copy number, and protein expression., Design: Material from 52 EGFR TKI-treated patients was studied: 29 responders and 23 nonresponders. Adenocarcinoma subtypes and morphologic features were defined in histologic and cytologic material. EGFR mutations were detected by sequencing, copy number by chromogenic in situ hybridization, and expression by immunohistochemistry., Results: Tumors from TKI responders tended to be better-differentiated adenocarcinomas with bronchioloalveolar carcinoma components. Nonresponders showed more heterogeneous morphology, higher grade, and more subtypes, and were more likely to show solid growth. In nonresponders, the only pure bronchioloalveolar carcinoma was mucinous, a subtype known to be negative for EGFR mutations. Using World Health Organization criteria, all tumors in both groups other than pure bronchioloalveolar carcinomas would be classified as adenocarcinomas, mixed subtype, thereby obscuring some of these distinctions. EGFR mutations were significantly more common in responders (22/29 vs 0/23; P < .001). Immunohistochemistry and chromogenic in situ hybridization results were not significantly correlated with EGFR mutations or response to TKIs in this study., Conclusions: Overall, histologic differences exist between tumors that respond to TKIs and those that do not, although sampling affects classification, and there is significant histologic overlap between the 2 groups. Response is strongly associated with EGFR mutations.

Purpose: After preoperative chemoradiotherapy of rectal cancer, the number of retrievable and metastatic lymph nodes is decreased. The current TNM classification is based on number and not location of lymph node metastases and may understage disease after chemoradiotherapy. The aim of this study was to examine the prognostic significance of location of involved lymph nodes in rectal cancer patients after preoperative chemoradiotherapy., Patients and Methods: We prospectively examined whole-mount specimens from 121 patients with uT3-4 and/or N+ rectal cancer who received preoperative chemoradiotherapy followed by resection. Location of involved lymph nodes was compared with median number of lymph nodes involved as well as presence of distant metastasis at presentation., Results: Lymph node metastases were detected in 37 patients (31%). Thirteen patients with lymph node involvement along major supplying vessels (proximal lymph node metastases) had a significantly higher rate of distant metastatic disease at time of surgery than patients without proximal lymph node involvement (P < .001); median number of lymph nodes involved was two for patients with proximal lymph node metastases and 1.5 for patients with mesorectal lymph node involvement alone., Conclusion: Our data suggest that, after preoperative chemoradiotherapy, proximal lymph node involvement is associated with a high incidence of metastatic disease at time of surgery. Because the median number of involved lymph nodes is low after preoperative chemoradiotherapy, the TNM staging system may not provide an accurate assessment of metastatic disease. Therefore, the ypTNM staging system should incorporate distribution as well as number of lymph node metastases after preoperative chemoradiotherapy for rectal cancer.