The frequency and significance of radiologically detected indeterminate pulmonary nodules in patients with colorectal cancer

Is chest imaging needed as part of pT1a renal cell carcinoma surveillance after surgical resection?

INTRODUCTION

Following surgical excision of pT1a renal cell carcinoma (RCC), 2% to 5% will recur, with 50% to 60% being lung metastases. The ideal surveillance strategy to identify recurrences is unclear. Guidelines are mixed, with NCCN and AUA recommending surveillance via chest x-ray (CXR) at least annually for 5 years, while EAU guidelines do not specifically recommend the use of CXR. In an effort to clarify the utility of surveillance CXR, we retrospectively evaluated pT1a patients following surgical treatment at a single institution.

METHODS

We performed retrospective analysis of unique patients who underwent surgical excision of pT1 RCC between January 2000 and January 2020. In addition to demographic information, we collected RCC pathology, recurrence details, and most recent chest imaging. We excluded non-RCC pathology, and patients with pulmonary nodules on baseline imaging.

RESULTS

We identified 463 unique patients (mean age 58.3 years, range 23-87) that underwent surgical excision of pT1a RCC with mean follow-up of 47.6 months (range 1-201). On the most recent pulmonary surveillance imaging, 72.4% (335/463) had CXR while 27.6% (128/463) had chest CT performed. Regardless of modality, pulmonary recurrence was not detected on any surveillance imaging (0/463).

CONCLUSION

In patients without baseline preoperative lung pathology, we found that there is questionable clinical value in surveillance for pulmonary recurrence after resection of pT1a RCC.

An Exploratory Study on the Stable Radiomics Features of Metastatic Small Pulmonary Nodules in Colorectal Cancer Patients

Objectives

To identify the relatively invariable radiomics features as essential characteristics during the growth process of metastatic pulmonary nodules with a diameter of 1 cm or smaller from colorectal cancer (CRC).

Methods

Three hundred and twenty lung nodules were enrolled in this study (200 CRC metastatic nodules in the training cohort, 60 benign nodules in the verification cohort 1, 60 CRC metastatic nodules in the verification cohort 2). All the nodules were divided into four groups according to the maximum diameter: 0 to 0.25 cm, 0.26 to 0.50 cm, 0.51 to 0.75 cm, 0.76 to 1.0 cm. These pulmonary nodules were manually outlined in computed tomography (CT) images with ITK-SNAP software, and 1724 radiomics features were extracted. Kruskal-Wallis test was performed to compare the four different levels of nodules. Cross-validation was used to verify the results. The Spearman rank correlation coefficient is calculated to evaluate the correlation between features.

Results

In training cohort, 90 features remained stable during the growth process of metastasis nodules. In verification cohort 1, 293 features remained stable during the growth process of benign nodules. In verification cohort 2, 118 features remained stable during the growth process of metastasis nodules. It is concluded that 20 features remained stable in metastatic nodules (training cohort and verification cohort 2) but not stable in benign nodules (verification cohort 1). Through the cross-validation (n=100), 11 features remained stable more than 90 times.

Conclusions

This study suggests that a small number of radiomics features from CRC metastatic pulmonary nodules remain relatively stable from small to large, and they do not remain stable in benign nodules. These stable features may reflect the essential characteristics of metastatic nodules and become a valuable point for identifying metastatic pulmonary nodules from benign nodules.

KRAS-mutation incidence and prognostic value are metastatic site-specific in lung adenocarcinoma: poor prognosis in patients with KRAS mutation and bone metastasis

Current guidelines lack comprehensive information on the metastatic site-specific role of KRAS mutation in lung adenocarcinoma (LADC). We investigated the effect of KRAS mutation on overall survival (OS) in this setting. In our retrospective study, 500 consecutive Caucasian metastatic LADC patients with known KRAS mutational status were analyzed after excluding 32 patients with EGFR mutations. KRAS mutation incidence was 28.6%. The most frequent metastatic sites were lung (45.6%), bone (26.2%), adrenal gland (17.4%), brain (16.8%), pleura (15.6%) and liver (11%). Patients with intrapulmonary metastasis had significantly increased KRAS mutation frequency compared to those with extrapulmonary metastases (35% vs 26.5%, p = 0.0125). In contrast, pleural dissemination and liver involvement were associated with significantly decreased KRAS mutation incidence (vs all other metastatic sites; 17% (p < 0.001) and 16% (p = 0.02) vs 33%, respectively). Strikingly, we found a significant prognostic effect of KRAS status only in the bone metastatic subcohort (KRAS-wild-type vs KRAS-mutant; median OS 9.7 v 3.7 months; HR, 0.49; 95% CI, 0.31 to 0.79; p  = 0.003). Our study suggests that KRAS mutation frequency in LADC patients shows a metastatic site dependent variation and, moreover, that the presence of KRAS mutation is associated with significantly worse outcome in bone metastatic cases.

Predictive factors for malignancy in incidental pulmonary nodules detected in breast cancer patients at baseline CT

OBJECTIVES

Pulmonary nodules are commonly encountered at staging CTs in patients with extrathoracic malignancies, but their significance on a per-patient basis remains uncertain.

METHODS

We undertook a retrospective analysis of pulmonary nodules identified in patients with a diagnosis of breast cancer from 2010 - 2015, evaluating nodules present at a baseline CT (i.e. prevalent nodules). We reviewed 211 patients with 248 individual nodules.

RESULTS

The rate of malignancy in prevalent nodules is low, approximately 13 %. Variables associated with metastasis include pleural studding, hilar lymphadenopathy and the presence of extrapulmonary metastasis, as well as number of nodules, nodule size and nodule shape. Using a combination of these factors, we have developed an evidence-based multivariate decision tree to predict which nodules are malignant in these patients, which is 91 % accurate and 100 % sensitive for metastasis.

CONCLUSIONS

We propose a simplified clinical prediction algorithm to guide radiologists and oncologists in managing patients with breast cancer and incidental pulmonary nodules.

KEY POINTS

• Incidental pulmonary nodules are common on computed tomography in breast cancer patients. • Nodules present at baseline have a lower malignancy risk than incident nodules. • We present an evidence-based decision algorithm predicting which nodules are likely malignant. • This algorithm can help direct patient management.

What is the Significance of Indeterminate Pulmonary Nodules in Patients Undergoing Resection for Pancreatic Adenocarcinoma?

OBJECTIVE

The significance of indeterminate pulmonary nodules (IPNs) in patients undergoing resection of pancreatic ductal adenocarcinoma (PDAC) is unknown. We sought to define the prevalence and impact of IPN in such patients.

METHODS

We studied all patients who underwent surgical resection of PDAC between 1980 and 2013. IPN was defined as ≥1 well-defined lung nodule(s) less than 3 cm in diameter. Survival was assessed using univariate and multivariate Cox models.

RESULTS

Of the 2306 resected patients, 374 (16.2 %) had a preoperative chest computed tomography (CT) scan. Of these patients, 183 (49 %) had ≥1 IPN. Demographic and clinicopathological characteristics were similar among patients with or without IPN (all P>0.05). Median survival was comparable among patients who did (15.6 months) or did not (18.0 months) have IPN (P=0.66). Of the 183 patients with IPN, 29 (16 %) progressed to clinically recognizable metastatic lung disease compared to 13 % without IPN (P=0.38). The presence of >1 IPN was associated with the development of lung metastasis (relative risk 1.58, 95 % CI 1.03-2.4; P=0.05). However, lung metastasis was not associated with survival (P=0.24).

CONCLUSIONS

An IPN proved to be a lung metastasis in only one of six patients with PDAC undergoing surgical resection in this study. Survival was not impacted, even among patients who developed lung metastasis. Patients with PDAC who have IPN should not be precluded from surgical consideration.

Indeterminate pulmonary nodules at colorectal cancer staging: a systematic review of predictive parameters for malignancy

BACKGROUND

This study aimed to estimate the prevalence of indeterminate pulmonary nodules and specific radiological and clinical characteristics that predict malignancy of these at initial staging chest computed tomography (CT) in patients with colorectal cancer. A considerable number of indeterminate pulmonary nodules, which cannot readily be classified as either benign or malignant, are detected at initial staging chest CT in colorectal cancer patients.

METHODS

A systematic review based on a search in EMBASE, Medline, the Cochrane library and science citation index, PubMed databases, Google scholar, and relevant conference proceedings was performed in cooperation with the Cochrane Colorectal Cancer Group.

RESULTS

A total of 2,799 studies were identified, of which 12 studies met the inclusion criteria. The studies primarily consisted of case series and included a total of 5,873 patients. Of these patients, 9% (95% confidence interval [95% CI] 8.9-9.2%) had indeterminate pulmonary nodules at chest CT, of which 10.8% (95% CI 10.3-11.2%) turned out to be colorectal cancer metastases at follow-up. Generally, regional lymph node metastasis, and multiple numbers of indeterminate pulmonary nodules were reported to predict malignancy, whereas calcification of the nodules indicated benign lesions.

CONCLUSION

It was found that 1 in 100 colorectal cancer patients subjected to preoperative staging chest CT will have an indeterminate pulmonary nodule that proves to be metastatic disease. Such a low risk suggests that indeterminate pulmonary nodules should not cause further preoperative diagnostic workup or follow-up besides routine regimens.