Incidental detection by computed tomography is an independent prognostic factor for survival in patients operated for nonsmall cell lung carcinoma

Increased use of computed tomography in Denmark: stage shift toward early stage lung cancer through incidental findings

BACKGROUND

Computed tomography (CT) examinations are increasingly used worldwide and incidental findings are growing likewise. Lung cancer stage at diagnosis is pivotal to survival. The earliest stage of lung cancer, stage IA is in most cases asymptomatic. Potentially, increased use of clinical CTs could induce a stage shift toward earlier lung cancer diagnosis.

MATERIALS AND METHODS

Data on the number of CT thorax in Denmark and the stage distribution of Danish lung cancer patients 2013-2020 were acquired from, respectively, the Danish Health Data Authority and the Danish Lung Cancer Registry. Clinical auditing of stage IA lung cancer patients was performed in the period 2019-2021 in a Danish region to assess the reasons for referral. Auditing of stage IV lung cancer patients was done to see whether a CT thorax was performed in a two-year period before diagnosis.

RESULTS

All regions showed an increase in CTs per 1000 inhabitants. However, the number of CTs performed in 2013 differed by more than 50% among regions, and the increase per year also differed, from an increase of 1.9 to 3.4 more examinations per year. A significant correlation between CTs and fraction of stage IA lung cancers was seen in four out of the five regions. The audit of stage IA lung cancer cases revealed that 86.8% were incidental findings. Audit of stage IV lung cancer found that 4.3% had a nodule/infiltrate on a previous CT within a 2-year period prior to the diagnosis of lung cancer that was the probable origin of stage IV lung cancer.

CONCLUSION

The study found that the vast majority of early-stage lung cancers were incidental findings. It highlights that follow-up algorithms of incidental findings should be used in accordance with guidelines and it should be unequivocally how the CT follow-up of pulmonary infiltrates is managed.

Increased use of diagnostic CT imaging increases the detection of stage IA lung cancer: pathways and patient characteristics

Background

At Silkeborg Regional Hospital, Denmark, the number of stage IA lung cancer increased after implementation of increased use of CT investigations and a corresponding reduction in chest X-ray. The aim of the present study was to understand the changes in referral pathways, patient characteristics and imaging procedures behind the observed increase in early-stage lung cancer.

Methods

The referral and imaging pathways for all patients diagnosed with lung cancer in 2013–2018 were described based on manually curated information from the electronic health care systems and staging information from the Danish Lung Cancer Registry. We compared the clinical characteristics of patients diagnosed in 2013–2015 and in 2016–2018 after implementation of a change in the use of low dose CT scan (LDCT). For patients diagnosed in 2016–2018, stage IA lung cancer were compared to higher stages using univariable logistic regression analysis.

Results

Five hundred and forty-seven patients were diagnosed with lung cancer in 2013–2018. Stage IA constituted 13.8% (34/247) in 2013–2015, and 28.3% (85/300) in 2016–2018. Stage IA patients in 2016–2018 were characterised by more comorbidity, fewer packyears and tended to be older than patients with higher stages. In 2016–2018, the largest proportion of stage IA patients (55%) came from within-hospital referrals. The majority of these lung cancers were detected due to imaging procedures with other indications than suspicion of lung cancer.

The proportion of stage IA increased from 12% (12/99) to 36% (47/129) (p < 0.001) for hospital referrals and from 17% (22/129) to 23% (38/165) for GP referrals (p = 0.21). The imaging procedures contributing to the increase in stage IA was contrast enhanced CT (22%¸11/51), LDCT (35%; 18/51) and X-ray followed by LDCT (25%; 13/51).

Conclusion

The increased access to LDCT for patients referred from general practice and the increased hospital requested CT activity resulted in an increase in the number of stage IA lung cancers. Incidental findings on imaging performed for diagnostic purposes unrelated to suspicion of lung cancer contributed a large proportion of the increase.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-022-09585-2.

Stage I lung cancer patients with or without symptoms - are the patients different and should we treat them differently?

INTRODUCTION

A large proportion of stage I cancers are found incidentally, which appears to be a prognostic factor. We investigated stage I lung cancers according to whether, or not, there had been clinical suspicion of lung cancer prior to referral and to see, if we could detect any difference regarding patient characteristics, work-up and mortality for incidental vs non-incidental findings as well as for asymptomatic vs symptomatic patients.

METHODS

Medical records and referral documents for 177 patients diagnosed with stage I lung cancer were reviewed and divided based on whether the initial CT scan leading to diagnosis had been made due to suspicion of lung cancer or not. Patient characteristics and mortality between groups were compared, as well as mortality between patients with and without symptoms at the time of diagnosis.

RESULTS

One-hundred-and-eight patients were diagnosed incidentally, while 69 patients were non-incidental findings. Among the incidental findings, 55% had no symptoms, whereas none in the non-incidental group were asymptomatic. Personal characteristics were comparable between the groups. Significantly more patients in the incidental group had malignant comorbidity. Non-malignant chronic co-morbidity was more prevalent in the non-incidental group, in particular lung disease. There was no difference in tumour size, histology, or survival for incidental vs non-incidental or for asymptomatic vs symptomatic patients.

CONCLUSION

A large proportion of stage I lung cancers are found incidentally, especially in patients with malignant co-morbidity. We found no difference in survival to indicate that we did or should handle these patient groups differently.

Improved long-term survival following pulmonary resections for non-small cell lung cancer: results of a nationwide study from Iceland

Background

We studied the outcome of pulmonary resection with curative intent for non-small cell lung cancer (NSCLC) in a nationwide study covering a 24-year period, focusing on survival.

Methods

All patients who underwent pulmonary resection for NSCLC in Iceland in the period 1991-2014 were reviewed for demographics, TNM stage and survival. Median length of follow-up was 45 months. Three 8-year periods were compared, overall survival was estimated, and prognostic factors for survival were identified.

Results

Altogether, 652 surgical resections were performed on 644 individuals (52% females): 492 lobectomies (75%), 77 pneumonectomies (12%), and 83 sublobar resections (13%). Mean age increased from 65 to 68 yrs during the study period (P=0.002). The number of cases operated at stage IA increased substantially between the first and last periods (29% vs. 37%; P<0.001). Survival improved from 75% to 88% at 1 year and from 38% to 53% at 5 years (P<0.001). Independent prognostic factors for mortality were advanced TNM stage (HR =2.68 for stage IIIA vs. I), age (HR =1.04), ischaemic heart disease (HR =1.26), any minor complication (HR =1.26), and sublobar resection (HR =1.33), but surgical margins free from tumour growth (HR =0.59) and treatment during the latter two eight-year periods were predictors of lower mortality. The best survival was seen between 2007 and 2014 (HR =0.61, 95% CI: 0.48-0.78; P<0.001).

Conclusions

Survival of patients who have undergone pulmonary resection for NSCLC has improved significantly in Iceland. This may be explained by the increased number of patients diagnosed at lower stages and improved preoperative staging, with fewer understaged patients.

Prevalence of and risk factors for presenting initial respiratory symptoms in patients undergoing surgery for lung cancer

Background: Patients with early stage lung cancer seldom present initial respiratory symptoms, causing a delayed diagnosis and missed opportunity to receive operation. This study aimed to investigate the prevalence of initial respiratory symptoms and identity what factors would predispose lung cancer patients to present initial respiratory symptoms in patients undergoing lung cancer surgery. Methods: A retrospective chart review was conducted on 3,203 patients undergoing surgery for primary lung cancer. The prevalence of initial respiratory symptoms was investigated and the comparisons of clinicopathological parameters were performed between patients with and without initial respiratory symptoms or between patients with single and multiple initial respiratory symptoms. Independent risk factors for presenting initial respiratory symptoms or multiple initial respiratory symptoms were identified using a logistic regression. Results: A total of 1,474 (46.0%) patients with lung cancer were admitted to hospital due to present initial respiratory symptoms. Symptom clusters of cough or sputum (33.1%) and bloody sputum or hemoptysis (16.7%) presented as the two major chief complaints for medical consultation while chest pain (6.9%) and chest distress or dyspnea (5.6%) remained relatively unusual. Multiple analyses found that coexisting chronic obstructive pulmonary disease (OR=1.70, 95% CI=1.41-2.05), tumor size >3 cm (OR=2.27, 95% CI=1.93-2.67), squamous cell carcinoma (OR=2.22, 95% CI=1.86-2.65), tumor located in left lower lung (OR=1.39, 95% CI=1.10-1.74) and advanced tumor stage (OR=1.27, 95% CI=1.06-1.52) were independent risk factors for presenting initial respiratory symptoms. Furthermore, current smoking (OR=1.36, 95% CI=1.07-1.73), tumor size >3 cm (OR=1.53, 95% CI=1.21-1.93) and squamous cell carcinoma (OR=1.68, 95% CI=1.32-2.15) were demonstrated to be independent risk factors for presenting multiple initial respiratory symptoms. Conclusions: Presenting initial respiratory symptoms was the common cause for medical consultation in patients undergoing lung cancer surgery. Patients with lung cancer in larger tumor size or squamous cell carcinoma more likely presented initial and even multiple initial respiratory symptoms.