Objectives
PD‐L1 immunohistochemistry (IHC) is an essential predictive biomarker for patients with non‐small cell lung cancer (NSCLC), required to inform treatment decisions regarding anti‐PD‐1 ...immune checkpoint inhibitor therapy. This study aims to investigate the concordance between PD‐L1 IHC assessed on NSCLC cytology and histology specimens and to determine the impactce of tumour cellularity.
Methods
Matched cytology and histology NSCLC specimens were retrieved from the archives of the Royal Melbourne Hospital and the Royal Prince Alfred Hospital. PD‐L1 IHC was performed concurrently on both specimens at the Peter MacCallum Cancer Centre using the SP263 assay kit on the Ventana Benchmark Ultra staining platform and scored by two experienced pathologists.
Results
Overall agreement between matched cytology and histology specimens was good (intraclass correlation coefficient = 0.653, n = 58); however, markedly increased when the analysis was limited to cell‐blocks with >100 tumour cells (intraclass correlation coefficient = 0.957, n = 29). Specificity at both 1% and 50% cut‐offs was high regardless of cellularity; however, sensitivity decreased in samples with <100 tumour cells.
Conclusions
PD‐L1 IHC on cytology cell‐block specimens in NSCLC is an acceptable alternative to histological specimens, provided adequate tumour cells are present. Clinicians and pathologists should be mindful of the risk of false negative PD‐L1 IHC in samples with low tumour cellularity, to avoid excluding patients from potentially beneficial treatment.
This paper demonstrates that cytology cell blocks are acceptable specimens to assess PD‐L1 by immunohistochemistry in non‐small cell lung cancer, provided adequate tumour cells are present. Assessing insufficiently cellular samples risks a rate of false negatives, which may exclude patients from potentially beneficial treatment.
Full text
Available for:
BFBNIB, DOBA, FZAB, GIS, IJS, IZUM, KILJ, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBMB, UILJ, UKNU, UL, UM, UPUK
Background
Emphysema severity is frequently measured on CT via densitometry. Correlation with scintigraphic and spirometric functional measures of ventilation or perfusion varies widely, and no prior ...study has evaluated correlation between densitometry and lobar ventilation/perfusion in patients with severe emphysema. The aim of this study was to evaluate the utility and findings of gallium-68 (
68
Ga) ventilation/perfusion positron emission tomography-CT (
68
Ga-VQ/PET-CT) in severe emphysema assessment.
Methods
Fourteen consecutive patients undergoing evaluation for bronchoscopic lung volume reduction between March 2015 and March 2018 underwent
68
Ga-VQ/PET-CT assessment for lobar functional lung mapping, in addition to CT densitometry. Correlations between CT densitometry and
68
Ga-VQ/PET-CT parameters for individual lobar lung function were sought.
Results
CT densitometry assessment of emphysema correlated only weakly (
R
2
= 0.13) with lobar perfusion and was not correlated with ventilation (
R
2
= 0.04). Densitometry was moderately (
R
2
= 0.67) correlated with V/Q units in upper lobes, though poorly reflected physiological function in lower lobes (
R
2
= 0.19). Emphysema severity, as measured by CT densitometry, was moderately correlated with proportion of normal V/Q units and matched V/Q defects in individual lobes.
Conclusions
Assessment of lobar pulmonary function by
68
Ga-VQ/PET-CT provides physiologic information not evident on CT densitometry such as ventilation and perfusion specifics and matched defects. Further research is needed to see if the discordant findings on
68
Ga-VQ/PET-CT provide prognostic information or can be used to modify patient management and improve outcomes.
PDF
