Effects of treatments on blood flow values in lung squamous carcinoma and adenocarcinoma assessed with CT perfusion

Purpose: To analyse the changes of blood flow values in adenocarcinoma (ADK) and squamous cell carcinoma (SCC) after treatments. The assessments have been carried out during several CT perfusion (CTp) follow-ups. Methods and Materials: 13 patients with primary NSCLC, 10 ADK and 3 SCC, were considered. Patient groups underwent 14 and 12 follow-ups respectively, yielding 39 examinations, baseline included. Both chemotherapy and biologic targeted therapies have been administered. BF values were computed according to the maximum slope method and values undergoing high fitting errors were automatically removed. The mean values referring to baseline CTp and to the set of follow-ups were computed for each subtype. The difference between subtypes was assessed by the one-tail Welch's t-test, with p-value<0.001 for statistical significance. Results: At baseline, BF values of the ADK group [72.5±51.4] result significantly greater than the BF values of SCC subtype [53.0±38.7], with a p-value<10-5. On the opposite, as regards the two follow-ups subgroups, BF values are greater for SCC subtype [51.2±36.0], rather than for ADK group [43.5±29.0], with a p-value<10-8. Conclusions: Therapies have a far more relevant effect, in terms of reduction of vascularization, for ADK lung tumours, reducing perfusion values by 27% on average, against 15% of SCC. This can be probably motivated by the initial higher vascularization of ADK that facilitates conveyance of pharmaceuticals to tumour. The mean BF value computed on colorimetric maps, where unreliable values have been removed, should be considered as a surrogate biomarker to assess the effectiveness of therapies on these NSCLC subtypes.