Heparin Background Lung cancer is globally the most common c

Background Lung cancer is globally the most common cause of cancer related death [1]. Compared to other developed countries, mortality rates among Danish lung cancer patients have historically been high [2]. Stage at diagnosis is the most significant prognostic factor, and serves as a proxy for disease burden and as a treatment indicator [[3], [4], [5]]. Under consideration of their general condition, it Heparin is pivotal for the prognosis that the patients receive the most effective and safest treatment modality [6,7]. For early stage lung cancer, several treatment options exist and surgery is associated with the most favourable outcome [8,9]. However, stereotactic body radiotherapy is an effective alternative, particularly for patients that are medically unfit for surgery [10,11]. More recently, radiofrequency ablation (RFA) and microwave therapy (MWA) have been suggested as treatment options [12,13]. After staging, patient-specific factors as age, physical performance and burden of comorbidity including lung function need to be considered in the evaluation of the patient’s ability to tolerate the treatment modality of choice [14,15].
Material and methods Data sources for the present study were the Danish Lung Cancer Registry (DLCR) and medical records. The DLCR has since year 2000 collected data regarding tumour, patient characteristics and treatment details reported to the registry by the departments involved with primary care of lung cancer patients [16]. DLCR has a completeness of more than 95%. Via the DLCR, we identified all patients diagnosed with stage I lung cancer from 2011 - 2014. For this cohort of patients, we assessed the one-year mortality according to treatment modality as registered in the DLCR.
Results
Discussion According to the DLCR, 85% of Danish stage I lung cancer patients diagnosed from 2011 to 2014 were curatively treated. Surgery was associated with the best short-term prognosis, probably due to both an effective treatment modality and selection of younger patients with a good lung function and a favourable performance status into this treatment group. The weakened association between the surgical and oncological treatment and one-year mortality in the adjusted analysis supports this mechanism, and is in accordance with the findings of several other retrospective studies as concluded in a review by Shultz et al [18]. Not surprisingly, the palliative group had significantly higher one-year mortality as compared to the group that received curatively intended oncologic therapy. We retrieved additional information regarding patients that based on performance status were a priori candidates for curative therapy, but had no treatment registration and found that the majority of these patients were misclassified. Consequently, we identified an additional 57 patients (2% of all stage I patients) that received curatively intended therapy. A subgroup of the curatively treated patients received either radio frequency ablation or microwave therapy and at time for entry into the DLCR, there was no registration code for these procedures, which explains our findings regarding these patients. Concerning misclassified patients, there was no obvious reason for misclassification. Thus, simply failing to report treatment details to the DLCR, correcting or informing the DLCR about patients who were initially wrongfully suspected of having lung cancer but were later found to have another disease (mesothelioma) are the most feasible explanations. This study was not designed to assess the overall data validity of the DLCR and the overall rate of misclassification. We have reported the types of misclassification encountered in a highly selected group of patients, with opposing registrations of PS and treatment. Furthermore, among the 108 matched controls, none were misclassified, thus the overall rate of misclassification in the DLCR is arguably much lower. In general, fewer diagnostic procedures were undertaken among the non-treated patients as compared to the surgically treated controls. Albeit only reaching statistical significance in terms of PET-scans, target cell association is in accordance with the Danish lung cancer guidelines that recommend that a PET scan should be undertaken if the patient is a candidate for curative therapy. Hence curability may have been questioned in these patients already during the staging phase. Furthermore, there was a significant difference in burden of comorbidity between the no-treatment group and the controls. Limited utilization of diagnostic procedures and comorbidity has to our knowledge not been studied in depth, however a retrospective cohort study of several cancers including 14,096 patients by Gurney et al. found that a high burden of comorbidity was associated with not receiving a final stage designation [19]. Furthermore, the CCI has in addition to being a validated prognostic marker [20,21] also been found to be a predictor for receiving guideline-consistent treatment [22,23], which our findings support. In addition to the CCI, we specifically assessed the reason for not undergoing treatment. The primary non-malignant disease relating to not receiving curative treatment was severe COPD, which has been linked to an adverse outcome in surgically lung cancer patients [24]. For patients who had another cancer, the primary reasons for not undergoing treatment for the lung cancer were either dissemination of or severe treatment complications to the second cancer, and probably merely reflect a prioritized and individually assessed order of treatments.