Indeterminate pulmonary nodules in colorectal cancer

Colorectal Cancer Pulmonary Metastasectomy: When, Why and How

Colorectal cancer is the third-most-diagnosed cancer in males and in females, representing 8% of estimated new cases, and the third cause of cancer-related death in both sexes, accounting for 9% of cancer deaths in men and 8% in women. About 20% of patients diagnosed with CRC present metastatic disease. Although lung metachronous or synchronous metastatic spread without other involved sites has been reported in only a small proportion of patients, considering that this tumor is frequently diagnosed, the clinical approach to CRC pulmonary metastases represents a major issue for thoracic surgeons and CRC oncologists. Among patients diagnosed with pulmonary metastases from CRC, about 9-12% are eligible for local treatments with radical intent, including surgical resection, SBRT (stereotactic body radiation therapy) and ablation therapy. Due to the lack of randomized controlled trials among different local strategies, there is no definitive evidence about the optimal approach, although surgical resection is considered the most effective therapeutic option in this clinical scenario. Oncological achievement of primary radical resection, the biology of primary tumor and metastatic sites, disease free interval and or progression free survival are independent prognostic factors which make it possible to define a cohort of patients which might significantly benefit from pulmonary metastasectomy.

A novel diagnostic model for differentiation of lung metastasis from primary lung cancer in patients with colorectal cancer

Objective

This study aimed to evaluate the ¹⁸F-FDG PET/CT in differentiating lung metastasis(LM) from primary lung cancer(LC) in patients with colorectal cancer (CRC).

Methods

A total of 120 CRC patients (80 male, 40 female) who underwent ¹⁸F-FDG PET/CT were included. The diagnosis of primary lung cancer or lung metastasis was based on histopathology The patients were divided into a training cohort and a validation cohort randomized 1:1. Independent risk factors were extracted through the clinical information and ¹⁸F-FDG PET/CT imaging characteristics of patients in the validation cohort, and then a diagnostic model was constructed and a nomograms was made. ROC curve, calibration curve, cutoff, sensitivity, specificity, and accuracy were used to evaluate the prediction performance of the diagnostic model.

Results

One hundred and twenty Indeterminate lung lesions (ILLs) (77 lung metastasis, 43 primary lung cancer) were analyzed. No significant difference in clinical characteristics and imaging features between the training and the validation cohorts (P > 0. 05). Using uni-/multivariate analysis, pleural tags and contour were identified as independent predictors. These independent predictors were used to establish a diagnostic model with areas under the receiver operating characteristic curves (AUCs) of 0.92 and 0.89 in the primary and validation cohorts, respectively. The accuracy rate of the diagnostic model for differentiating LM from LC were higher than that of subjective diagnosis (P < 0.05).

Conclusions

Pleural tags and contour were identified as independent predictors. The diagnostic model of ILLs in patients with CRC could help differentiate between LM and LC.

The decreased platelet-to-lymphocyte ratio could predict a good prognosis in patients with oligometastatic colorectal cancer: a single-center cohort retrospective study

BACKGROUND

Inflammation markers have an important effect on tumor proliferation, invasion, and metastasis. Oligometastatic disease (OMD) is an intermediate state between widespread metastases and locally confined disease, where curative strategies may be effective for some patients. We aimed to explore the predictive value of inflammatory markers in patients with oligometastatic colorectal cancer (OMCC) and build a nomogram to predict the prognosis of these patients.

METHODS

Two hundred nine patients with OMCC were retrospectively collected in this study. The Kaplan-Meier survival curves and Cox regression analysis were used to estimate overall survival (OS) and progression-free survival (PFS). A multivariate Cox analysis model was utilized to establish the nomogram. The concordance index (C-index), calibration curve, and receiver operating characteristics (ROC) were established to verify the validity and accuracy of the prediction model.

RESULTS

According to the multivariate analysis, decreased platelet-to-lymphocyte ratio (PLR) might independently improve OS in patients with OMCC (HR = 2.396, 95% CI 1.391-4.126, P = 0.002). Metastases of extra-regional lymph nodes indicated poor OS (HR = 2.472, 95% CI 1.247-4.903, P = 0.010). While the patients with early N stage had better OS (HR = 4.602, 95% CI 2.055-10.305, P = 0.001) and PFS (HR = 2.100, 95% CI 1.364-3.231, P = 0.007). Primary tumor resection (HR = 0.367, 95% CI 0.148-0.908, P = 0.030) and lower fibrinogen (HR = 2.254, 95% CI 1.246-4.078, P = 0.007) could significantly prolong the OS in patients with OMCC. PLR, metastases of extra-regional lymph nodes, N stage, primary tumor resection, and fibrinogen were used to make up the nomogram. The C-index and area under the curve (AUC) of the ROC in nomogram were 0.721 and 0.772 respectively for OS, showed good consistency between predictive probability of OS and actual survival.

CONCLUSIONS

Decreased PLR could predict a good prognosis in patients with OMCC. The nomogram including inflammatory factors and clinicopathological markers was credible and accurate to predict survivals in patients with OMCC.

Dealing with indeterminate pulmonary nodules in colorectal cancer patients; a systematic review

INTRODUCTION

Indeterminate pulmonary nodules (IPNs) are frequently encountered on staging computed tomography (CT) in colorectal cancer (CRC) patients and they create diagnostic dilemmas. This systematic review and pooled analysis aims to estimate the incidence and risk of malignancy of IPNs and provide an overview of the existing literature on IPNs in CRC patients.

MATERIALS AND METHODS

EMBASE, Pubmed and the Cochrane database were searched for papers published between January 2005 and April 2020. Studies describing the incidence of IPNs and the risk of malignancy in CRC patients and where the full text was available in the English language were considered for inclusion. Exclusion criteria included studies that used chest X-ray instead of CT, liver metastasis cohorts, studies with less than 60 CRC patients and reviews.

RESULTS

A total of 18 studies met the inclusion criteria, involving 8637 patients. Pooled analysis revealed IPNs on staging chest CT in 1327 (15%) of the CRC patients. IPNs appeared to be metastatic disease during follow up in 16% of these patients. Regional lymph node metastases, liver metastases, location of the primary tumour in the rectum, larger IPN size and multiple IPNs are the five most frequently reported parameters predicting the risk of malignancy of IPNs.

CONCLUSION

A risk stratification model for CRC patients with IPNs is warranted to enable an adequate selection of high risk patients for IPN follow up and to diminish the use of unnecessary repetitive chest CT-scans in the many low risk patients.

Differentiation of primary lung cancer from solitary lung metastasis in patients with colorectal cancer: a retrospective cohort study

Background

This study aimed to evaluate the computed tomography (CT) features of solitary pulmonary nodule (SPN), which can be a non-invasive diagnostic tool to differentiate between primary lung cancer (LC) and solitary lung metastasis (LM) in patients with colorectal cancer (CRC).

Methods

This retrospective study included SPNs resected in CRC patients between January 2011 and December 2019. The diagnosis of primary LC or solitary LM was based on histopathologic report by thoracoscopic wedge resection. Chest CT images were assessed by two thoracic radiologists, and CT features were identified by consensus. Predictive parameters for the discrimination of primary LC from solitary LM were evaluated using multivariate logistic regression analysis.

Results

We analyzed CT data of 199 patients (mean age, 65.95 years; 131 men and 68 women). The clinical characteristic of SPNs suggestive of primary LC rather than solitary LM was clinical stages I–II CRC (P < 0.001, odds ratio [OR] 21.70). The CT features of SPNs indicative of primary LC rather than solitary LM were spiculated margin (quantitative) (P = 0.020, OR 8.34), sub-solid density (quantitative) (P < 0.001, OR 115.56), and presence of an air bronchogram (quantitative) (P = 0.032, OR 5.32).

Conclusions

Quantitative CT features and clinical characteristics of SPNs in patients with CRC could help differentiate between primary LC and solitary LM.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12957-021-02131-7.

Management of Pulmonary Nodules in Oncologic Patients: AJR Expert Panel Narrative Review

Cancer survivors are at higher risk than the general population for development of a new primary malignancy, most commonly lung cancer. Current lung cancer screening guidelines recommend low-dose chest CT for high-risk individuals, including patients with a history of cancer and a qualifying smoking history. However, major lung cancer screening trials have inconsistently included cancer survivors, and few studies have assessed management of lung nodules in this population. This narrative review highlights relevant literature and provides expert opinion for management of pulmonary nodules detected incidentally or by screening in oncologic patients. In patients with previously treated lung cancer, a new nodule most likely represents distant metastasis from the initial lung cancer or a second primary lung cancer; CT features such as nodule size and composition should guide decisions regarding biopsy, PET/CT, and CT surveillance. In patients with extrapulmonary cancers, nodule management requires individualized risk assessment; smoking is associated with increased odds of primary lung cancer, whereas specific primary cancer types are associated with increased odds of pulmonary metastasis. Nonneoplastic causes, such as infection, medication toxicity, and postradiation or postsurgical change, should also be considered. Future prospective studies are warranted to provide evidence-based data to assist clinical decision-making in this context.

Use of lung-specific exosomes for miRNA-126 delivery in non-small cell lung cancer

Engineered exosomes have become popular drug delivery carriers for cancer treatment. This is partially due to the interesting property, i.e. exosome organotropism, which plays an important role in organ distribution post systemic administration. Here, we demonstrated that breast cancer (MDA-MB-231) cell-derived exosomes (231-Exo) could be specifically internalized by non-small cell lung cancer cells via a specific interaction between overexpressed integrin β4 (on exosomes) and surfactant protein C (SPC) on the cancer cells. We showed that 231-Exo was capable of recognizing A549 cells in blood and effectively escaping from the immune surveillance system in vitro. Once loaded with microRNA molecules in the exosome carriers, the resulting, miRNA-126 loaded 231-Exo (miRNA-231-Exo) strongly suppressed A549 lung cancer cell proliferation and migration through the interruption of the PTEN/PI3K/AKT signaling pathway. Intravenous administration of the miRNA-126 laden exosomes led to an effective lung homing effect in mice. When tested in a lung metastasis model, miRNA-231-Exo resulted in an efficacious effect in inhibiting the formulation of lung metastasis in vivo. Collectively, our data demonstrated the possibility of using the organotropism feature of exosomes in exosome carrier design, generating a potent anti-metastasis effect in a mouse model.

Expert consensus on multidisciplinary therapy of colorectal cancer with lung metastases (2019 edition)

The lungs are the second most common site of metastasis for colorectal cancer (CRC) after the liver. Rectal cancer is associated with a higher incidence of lung metastases compared to colon cancer. In China, the proportion of rectal cancer cases is around 50%, much higher than that in Western countries (nearly 30%). However, there is no available consensus or guideline focusing on CRC with lung metastases. We conducted an extensive discussion and reached a consensus of management for lung metastases in CRC based on current research reports and the experts' clinical experiences and knowledge. This consensus provided detailed approaches of diagnosis and differential diagnosis and provided general guidelines for multidisciplinary therapy (MDT) of lung metastases. We also focused on recommendations of MDT management of synchronous lung metastases and initial metachronous lung metastases. This consensus might improve clinical practice of CRC with lung metastases in China and will encourage oncologists to conduct more clinical trials to obtain high-level evidences about managing lung metastases.

The potential role of circulating tumor DNA (ctDNA) in the further investigation of colorectal cancer patients with nonspecific findings on standard investigations

Early detection of metastatic colorectal cancer, at initial diagnosis or during routine surveillance, can improve survival outcomes. Current routine investigations, including CEA and CT, have limited sensitivity and specificity. Recent studies of colorectal cancer cohorts under post surgery surveillance indicate circulating tumor DNA (ctDNA) evidence of recurrence can occur many months before clinical detection. Another possible role for ctDNA is in the further assessment of indeterminate findings on standard CEA or CT investigations. To further explore this potential, we undertook a prospective study. Further investigation, including FDG-PET imaging, was at clinician discretion, blinded to ctDNA analysis. Forty-nine patients were enrolled. Analyzed here are the 45 patients with an evaluable blood sample of whom 6 had an isolated elevated CEA, 30 had indeterminate CT findings, and 9 had both. FDG-PET scans were performed in 30 patients. Fourteen of 45 patients (31%) had detectable ctDNA. At completion of the planned 2 year follow-up, recurrence has occurred in 21 (47%) patients. Detectable ctDNA at study entry was associated with inferior relapse free survival (HR 4.85, p < 0.0001). Where FDG-PET scan was normal/equivocal (n = 15, 50%) 1 of 1 with detectable ctDNA versus 3 of 14 with undetectable ctDNA ultimately had recurrence confirmed. In summary, for colorectal cancer patients with indeterminate findings on routine investigations, ctDNA detection increases the probability that the findings indicate metastatic disease, including in a nonpredefined subset that also underwent FDG-PET imaging. Further studies of the value of ctDNA analysis during patient surveillance are warranted.

Role of 18F-FDG PET/CT vs CT-scan in patients with pulmonary metastases previously operated on for colorectal liver metastases

OBJECTIVE

There is currently no conclusive scientific evidence available regarding the role of the ¹⁸F-FDG PET/CT for detecting pulmonary metastases from colorectal cancer (PMCRC) in patients operated on for colorectal liver metastases (CRLM). In the follow up of patients who underwent surgery for CRLM, we compare CT-scan and ¹⁸F-FDG PET/CT in patients with PMCRC.

METHODS

We designed the study prospectively performing an ¹⁸F-FDG PET/CT on all patients operated on for CRLM where the CT-scan detected PMCRC during the follow up. We included patients who were operated on for PMCRC because the histological findings were taken as a control rather than biopsies.

RESULTS

Of the 101 pulmonary nodules removed from 57 patients, the CT-scan identified a greater number (89 nodules) than the ¹⁸F-FDG PET/CT (75 nodules) (p < 0.001). Sensitivity was greater with the CT-scan (90 vs 76%, respectively) with a lower specificity (50 vs 75%, respectively) than with the ¹⁸F-FDG PET/CT. There were no differences between positive-predictive value and negative-predictive value. The ¹⁸F-FDG PET/CT detected more pulmonary nodules in four patients (one PMCRC in each of these patients) and more extrapulmonary disease in six patients (four mediastinal lymph nodes, one retroperitoneal lymph node and one liver metastases) that the CT-scan had not detected.

CONCLUSION

Although CT-scans have a greater capacity to detect PMCRC, the ¹⁸F-FDG PET/CT could be useful in the detection of more pulmonary and extrapulmonary disease not identified by the CT-scan. Advances in knowledge: We tried to clarify the utility of ¹⁸F-FDG PET/CT in the management of this subpopulation of patients.

Role of 18F-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography in the Diagnosis of Newly Found Suspected Malignant Solitary Pulmonary Lesions in Patients Who Have Received Curative Treatment for Colorectal Cancer

Background. Positron emission tomography/computed tomography (PET/CT) is recommended for colorectal cancer (CRC) patients with suspected malignant pulmonary lesions. This study aims to systematically discuss the ¹⁸F-FDG-PET/CT diagnosis of solitary pulmonary lesions that are strongly suspected to be malignant in CRC patients who have previously undergone curative therapy. Methods. This retrospective study involved 49 consecutive CRC patients who had previously undergone curative therapy and then underwent PET/CT for the investigation of solitary pulmonary lesions that were strongly suspected to be malignant. Results. Pathological examination confirmed the presence of pulmonary metastases (29 patients, 59.2%), primary lung cancer (15 patients, 30.6%), and benign pulmonary disease (5 patients, 10.2%). Small lung lesions, advanced pathological stage, adjuvant chemotherapy after CRC surgery, solitary pulmonary lesions with lower border irregularity, higher carcinoembryonic antigen level, and the lack of concomitant mediastinal lymph node metastasis were more likely to be associated with pulmonary metastasis than with primary lung cancer. None of these factors was independently significant in the multivariate analysis. Conclusion. Clinicopathological characteristics help to differentiate metastasis and primary lung cancer to some extent during the diagnosis of solitary pulmonary lesions suspected to be malignant in this group of patients. This may provide valuable information to clinicians.