PD-L1 assessment in cytology samples predicts treatment response to checkpoint inhibitors in NSCLC.

BACKGROUND: Testing for tumor programmed death ligand-1 (PD-L1) expression was initially developed with histology specimens in non-small cell lung cancer (NSCLC). However, cytology specimens are widely used for primary diagnosis and biomarker studies in clinical practice. Limited clinical data exist on the predictiveness of cytology-derived PD-L1 scores for response to immune checkpoint inhibitor (ICI) therapy. METHODS: We reviewed all NSCLC specimens clinically tested at the University Health Network (UHN) for PD-L1 with 22C3pharmDx, from 01/2013 to 04/2021. Treatment outcomes in patients treated with single agent ICI therapy were reviewed and compared according to cytology- and histology-derived PD-L1 scores. RESULTS: We identified 494 and 1942 unique patients with cytology- and histology-derived tumor proportion scores, respectively, during the study period. Informative testing rates were 95 % vs 98 % for cytology and histology, respectively. Clinical data were available for 152 patients treated with single agent ICI: 61 cytology and 91 histology. Overall response rates (ORR) were similar for cytology and histology (36 % vs 34 %; p = 0.23), as well as median progression free survival (PFS) (4.9 vs 4.2 months; p = 0.99) and overall survival (23.4 vs 19.7 months; p = 0.99). The results remained similar even after adjusting for PD-L1 expression levels and line of ICI treatment (PFS HR 1.15; 95 %CI 0.78-1.70; p = 0.47). CONCLUSIONS: Treatment outcomes to single agent ICI based on cytology-derived PD-L1 scores were comparable to histology controls. Our results support PD-L1 biomarker testing on both cytology and histology specimens.

Middle Mediastinal Mass Compressing the Pulmonary Trunk in a Patient With a History of Breast Cancer.

CASE PRESENTATION: A 61-year-old White woman, nonsmoker, was referred to Respirology for evaluation of small pulmonary nodules discovered incidentally on surveillance imaging 3 years after breast cancer treatment. She had a remote left breast ductal carcinoma in situ treated with lumpectomy followed by radiation therapy, and recurrent stage 1 breast cancer (estrogen receptor/progesterone receptor-positive, human epidermal growth factor receptor 2-negative) treated with mastectomy, axillary lymph node dissection, and reconstructive surgery, followed with adjuvant chemotherapy, radiation therapy, and letrozole maintenance. Her other medical conditions included compensated cirrhosis secondary to nonalcoholic fatty liver disease, type 2 diabetes, hypertension, OSA, restless legs syndrome, obesity, anxiety, and depression. She reported no dyspnea or constitutional symptoms.

Low interobserver agreement in cytology grading of mucinous pancreatic neoplasms.

BACKGROUND: Identifying high-grade features in patients with pancreatic mucinous neoplasms (MNs) is important for patient management. The reproducibility of MN cytology grading has been evaluated to a limited extent. In the current study, the authors evaluated interobserver variability in grading MNs and the identification of neoplastic mucin in endoscopic ultrasound-guided fine-needle aspiration specimens. METHODS: A 54-case grading set was created from histologically confirmed MNs (44 MNs) and nonmucinous lesions with abundant gastrointestinal contamination (10 nonmucinous lesions). Six observers received a tutorial, reviewed prescreened slides, and recorded: 1) a diagnosis according to a 6-tiered system (TS) (nondiagnostic, atypical [ATP], mucinous cyst low grade [MCLG], mucinous cyst high grade, suspicious for adenocarcinoma, and positive for adenocarcinoma); 2) the cyst fluid carcinoembryonic antigen diagnosis (CEADX); and 3) the presence of neoplastic musin. Interobserver agreement (IOA) was evaluated by calculation of kappa coefficients (Kappa). Diagnostic accuracy was not evaluated. RESULTS: The IOA was lowest for the 6-TS (Kappa, 0.13; P<.001). The CEADX was available for 18 cases (33%), including 6 of 24 MCLG cases (25%). CEADX modestly improved IOA for combined tiers of the 6-TS with ATP and MCLG as separate categories. The highest IOA was noted with a 3-TS (nondiagnostic, ATP/MCLG, and mucinous cyst high grade/suspicious for adenocarcinoma/positive for adenocarcinoma [Kappa, 0.28; P<.001]) and various 4-TS (Kappa, 0.22-0.23). IOA was found to be low for neoplastic mucin (Kappa = 0.15; P<.001). CONCLUSIONS: In a study using simulated cytology practice, observers demonstrated fair IOA for grading MNs and low IOA for identifying neoplastic mucin. Knowledge of the cyst fluid CEA level was found to modestly improve the IOA for low-grade lesions.

Impact of touch preparations on core needle biopsies.

BACKGROUND: Touch preparations (TPs) can be performed for on-site adequacy assessment of core needle biopsies (CNBs). Although TPs can play a role in decreasing the number of nondiagnostic core biopsies, the impact of TPs on CNB has not been extensively evaluated. METHODS: Computerized tomography-guided CNBs performed in a tertiary cancer center were retrospectively identified. On-site adequacy assessment was performed in all cases. The matching TPs and CNBs were evaluated for diagnostic accuracy of the TP. The relation between the site of biopsy and the cellularity of the CNB was also analyzed. RESULTS: A total of 1100 CNB cases with associated TPs were identified over a 6-month period. Eighty-four cases (8%) showed marked differences in cellularity between CNB and TP, and 43 of these 84 cases (4.3%) showed the presence of diagnostic cells in either CNB or TP, but not in both. Lung was the biopsy site where CNB was most affected by loss of diagnostic cells. CONCLUSIONS: TP and CNB findings must be integrated to prevent a misdiagnosis. Lung CNBs were more frequently affected by performing TPs.

Subclassification of lymphoproliferative disorders in serous effusions: a 10-year experience.

BACKGROUND: Rare studies have reported the application of multiple ancillary tests to the diagnosis of lymphoproliferative disorder in serous effusions. In the current study, the authors evaluated the effectiveness of using an algorithm for the triage of serous effusions and the contribution of ancillary studies to achieve a specific subtype of lymphoproliferative disorder. METHODS: Serous effusion samples that had a final diagnosis of lymphoproliferative disorder or suspicious for lymphoma were selected from cases that were diagnosed between 2001 and 2010. Data were collected on patient and sample characteristics as well as results from immunophenotype and molecular studies. RESULTS: In total, 168 serous effusions were identified from 110 patients. The most common site of involvement was the pleural cavity (n = 133) followed by the peritoneal cavity (n = 30) and pericardial cavity (n = 5). The volume of serous effusions ranged from 2 mL to 1000 mL (mean, 238 mL). In 42 patients (38.2%), serous effusions were the primary source of diagnosis. In 129 patients who had a diagnosis of LPD, either generic (n = 82) or specific (n = 47) ancillary tests were performed as a single test in 58 samples (67.4%) or as a combination of multiple studies in 19 samples (23.2%). Immunophenotyping was successful in almost all samples that had a specific subtype with 16 B-cell and 4 T-cell lymphomas being diagnosed. More samples with a specific subtype of lymphoma underwent molecular tests compared with those who had a generic diagnosis (19.1% vs 13.4%). CONCLUSIONS: Successful, specific subtyping of lymphoproliferative disorders was achieved in approximately 33% of cases that were tested for ancillary studies following an approach for the triage and aliquoting of serous effusion samples.

The effect of prolonged fixation on the immunohistochemical evaluation of estrogen receptor, progesterone receptor, and HER2 expression in invasive breast cancer: a prospective study.

Expression of estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2) is important in predicting a response to targeted therapies in breast cancer. Immunohistochemical assays to determine hormone receptor (HR) and HER2 status must therefore be accurate and reproducible. Tissue fixation has been shown to play a crucial role in determining consistency in quality. Although guidelines impose upper limits for the fixation period, the data on which these limits are based are scant. This study aimed to prospectively examine the effect of fixation of >72 hours on these assays. In 101 invasive breast cancer samples, HR and HER2 status was compared between tumor blocks undergoing a short fixation period with those undergoing a period of prolonged fixation (PF). Discordances were classified as an incremental change between categories of (i) a single order of magnitude, that is a difference in the status of low positive (Allred score 3) compared with positive (Allred score 4 to 8) or negative (Allred score 0 or 2) and vice versa for HRs and a difference in HER2 status of equivocal compared with negative or positive and vice versa or (ii) greater than a single order of magnitude, that is a difference in the status of positive compared with negative or vice versa. The median fixation time for the short fixation group was 13 hours and 18 minutes (mean, 13 h 17 min; range, 10 h 33 min to 17 h 45 min) and for the PF group was 79 hours 22 minutes (mean, 79 h 35 min; range, 73 h 33 min to 102 h 30 min). Eight cases showed discordances, all of which were of a single order of magnitude including 1 for ER, 5 for PR, and 2 for HER2. In 6 of these, a higher score was seen in the PF group. In conclusion, fixation for limited periods beyond 72 hours does not result in a reduction in assay sensitivity in the determination of ER, PR, or HER2 immunohistochemical status.