Optimal management of pulmonary metastases from colorectal cancer

Imaging Characteristics and Prognostic Value of Isolated Pulmonary Metastasis from Colorectal Cancer Demonstrated with18F-FDG PET/CT

Objective. Solitary pulmonary lesions (SPNs) in patients with a history of colorectal cancer (CRC) may be attributed to metastatic lung tumors, primary lung cancer, or benign nodules. We aimed to analyze the imaging characteristics of SPNs in CRC patients to differentiate these pulmonary nodules and evaluate the prognostic value of isolated pulmonary metastasis from CRC using 18F-FDG PET/CT. Methods. From January 2013 to January 2021, 62 CRC patients with SPNs demonstrated with 18F-FDG PET/CT were retrospectively enrolled in the present study. We compared the radiological and clinical characteristics of these patients. In addition, survival time and prognostic factors were statistically analyzed using the Kaplan-Meier method and multivariable Cox proportional hazards models. Results. There were 33 cases of isolated lung metastasis, 20 cases of second primary lung cancer (SPLC), and nine cases of benign nodules. The proportion of nodules with a maximal diameter greater than the median value was lower in the isolated lung metastasis group compared with the SPLC group ( $p<0.05$ ), showing polygonal shape, ill-defined margin, pleural indentation, air bronchogram, speculation, and ground-glass opacity. Patients with isolated lung metastasis had a significantly higher maximal diameter of lung lesion, SUVmax of lung lesion, and 18F-FDG uptake compared with the benign nodule group ( $p<0.05$ ). Multivariate analysis revealed that the following two factors were significant independent predictors of PLC: air bronchogram (hazard ratio [HR] =22.327; 95% confidence interval [CI]: 1.910-261.061; $p=0.013$ ) and spiculation (HR =6.148; 95% CI 1.469-25.725; $p=0.013$ ). Initial TNM stage IV (HR =19.831, 95% CI 1.061-370.782; $p=0.046$ ) was extremely associated with a decreased lifespan of CRC patients with isolated lung metastasis. Conclusions. The result showed that CT features, including air bronchogram and spiculated margins, could be used to differentiate SPLC from single isolated lung metastasis in CRC patients. In patients with isolated lung metastasis, primary CRC TNM stage IV was associated with a poorer prognosis, and patients with such conditions might need more care.

Critical steps to tumor metastasis: alterations of tumor microenvironment and extracellular matrix in the formation of pre-metastatic and metastatic niche

For decades, cancer metastasis has been a heated topic for its high mortality. Previous research has shown that pre-metastatic niche and metastatic niche are the 2 crucial steps in cancer metastasis, assisting cancerous cells' infiltration, survival, and colonization at target sites. More recent studies have unraveled details about the specific mechanisms related to the modification of pro-invasion environments. Here, we will review literatures on extracellular matrix (ECM) alterations, general cancer metastasis, organ specificity, pre-metastatic niche, metastatic niche, colony formation and impact on the course of metastasis. Respectively, the metastatic mechanisms like effect of hypoxia or inflammation on pre-metastatic niche construction, as well as the interaction between cancer cells and local milieu will be discussed. Based on the evidences of metastatic niches, we revisit and discussed the "Seed and Soil" hypothesis by Paget. This review will seek to provide insight into the mechanism of metastatic organ specificity which pre-metastatic niche and metastatic niche might suggest from an evolutionary aspect.

Genomic profiling of colorectal cancer with isolated lung metastasis

BACKGROUND

Metastasis is a major cause of failed colorectal cancer (CRC) treatment. While lung metastasis (LM) is observed in 10-15% of patients with CRC, the genetic mechanisms that cause CRC to metastasize to the lung remain unclear.

METHODS

In this study, we employed whole exome sequencing (WES) of primary CRC tumors and matched isolated LM lesions to compare their genomic profiles. Comprehensive genomic analyses of five freshly frozen primary tumor lesions, five paired LM lesions, and matched non-cancerous tissues was achieved by WES.

RESULTS

An integrated analysis of somatic mutations, somatic copy number alterations, and clonal structures revealed that genomic alterations were present in primary and metastatic CRCs with various levels of discordance, indicating substantial levels of intertumor heterogeneity. Moreover, our results suggest that the founder clone of the primary tumor was responsible for the formation of the metastatic lesion. Additionally, only a few metastasis-specific mutations were identified, suggesting that LM-promoting mutations might be pre-existing in primary tumors.

CONCLUSIONS

Primary and metastatic CRC show intertumor heterogeneity; however, both lesions were founded by the same clone. These results indicate that malignant clones contributing to disease progression should be identified during the genetic prognosis of cancer metastasis.

Does adjuvant chemotherapy improve the prognosis of patients after resection of pulmonary metastasis from colorectal cancer? A systematic review and meta-analysis

BACKGROUND

It remains controversial whether patients benefit from adjuvant chemotherapy (ACT) after resection of pulmonary metastasis (PM) from colorectal cancer (CRC). This meta-analysis was intended to evaluate the efficacy of ACT in patients after resection of PM from CRC.

METHODS

We systematically retrieved articles from PMC, PubMed, Cochrane Library, and Embase (up to March 5, 2019). Survival data, including overall survival (OS) and disease-free survival (DFS), were tested by hazard ratios (HRs) and 95% confidence intervals (CIs).

RESULTS

We included 18 cohort studies with a total of 3885 patients. The meta-analysis showed that ACT had no significant effect on OS (HR = 0.78; 95% CI = 0.60-1.03; P = 0.077) and DFS (HR = 0.91; 95% CI = 0.74-1.11; P = 0.339) in patients after resection of PM from CRC. There was no significant difference in OS (HR = 0.79; 95% CI = 0.42-1.50; P = 0.474) in patients after resection of PM from CRC treated with bevacizumab (BV). Subgroup analysis showed that ACT did not improve OS (HR = 0.86; 95% CI = 0.57-1.29; P = 0.461) in patients who had undergone previous resection of extra PM. ACT did not improve OS in patients who had positive hilar/mediastinal lymph node metastasis (HR = 0.80; 95% CI = 0.57-1.14; P = 0.22).

CONCLUSION

In conclusion, ACT does not provide survival benefits for patients after resection of PM from CRC. ACT and targeted agents (BV) are not suggested for these patients.

Pulmonary metastasis in newly diagnosed colon-rectal cancer: a population-based nomogram study

BACKGROUND

Colorectal cancer (CRC) has a high worldwide incidence with a tendency to metastasize to the lungs. We aimed to identify clinical factors related to lung metastasis (LM) and analyze the prognosis of patients after LM.

METHODS

Multivariate logistic regression analysis was used to identify risk factors for LM from CRC. Univariate and multivariate Cox proportional hazard models were performed to identify potentially important prognostic factors for patients with LM.

RESULTS

Age (p = 0.010), tumor size (p < 0.001), T stage (p < 0.001), N stage (p < 0.001), race (p < 0.001), tumor site (p < 0.001), liver metastasis (p < 0.001), brain metastasis (p < 0.001), bone metastasis (p < 0.001), serum levels of carcinoembryonic antigen (CEA) (p < 0.001), and circumferential resection margin (CRM) (p < 0.001) were associated with a risk of LM from CRC. All factors (all, p < 0.001) except tumor size (p = 0.095) and race (p = 0.650) were related to the overall survival of patients. Two nomograms were formulated to visually predict lung metastasis risk and 1-, 3-, and 5- year overall survivals for patients with LM. The concordance indices were 0.754 and 0.749, respectively.

CONCLUSIONS

Age, tumor size, histological grade, serum levels of CEA, tumor site, surgery modalities of CRC, CRM, number of positive lymph nodes, and chemotherapy were independent risk factors for LM from CRC. The nomograms we developed can be effectively used to forecast the risk of LM and predict the survival for LM from CRC.

Pulmonary metastasectomy: an overview

Metastasectomy is the most frequent surgical resection undertaken by thoracic surgeons, being the lung the second common site of metastases. The present oncological criteria for pulmonary metastasectomy are: (I) the primary cancer need to be controlled or controllable; (II) no extrathoracic metastasis-that is not controlled or controllable-exists; (III) all of the tumor must be resectable, with adequate pulmonary reserve; (IV) there are no alternative medical treatment options with lower morbidity. General favourable prognostic features in patients with pulmonary metastases are: (I) one or few metastases; (II) long disease free interval; (III) normal CEA levels in colorectal cancers. Negative predictive features in patients candidate to pulmonary metastasectomies are: (I) active primary cancer; (II) extrathoracic metastases; (III) inability to obtain surgical radicality; (IV) mediastinal lymphatic spread. The lack of controlled trials and studies limited by short follow-up and small cohorts did not allow to overcome some skepticism; moreover, the heterogeneity of these patients in terms of demographic, biologic and histologic characteristics represents a clear limit even in the largest series. On the basis of present knowledge, without results coming from on-going randomized trials, radical resection, histology, and disease free interval seem to be independent prognostic factors identifying a cohort of patients maximally benefitting from lung metastasectomy.

Factors influencing choice of chemotherapy in metastatic colorectal cancer (mCRC)

Management of metastatic colorectal cancer requires a multimodal approach and must be performed by an experienced, multidisciplinary expert team. The optimal choice of the individual treatment modality, according to disease localization and extent, tumor biology, and patient clinical characteristics, will be one that can maintain quality of life and long-term survival, and even cure selected patients. This review is an overview of the different therapeutic approaches available in metastatic colorectal cancer, for the purpose of defining personalized therapeutic algorithms according to tumor biology and patient clinical features.

Novel insights of oligometastases and oligo-recurrence and review of the literature

Oligometastases and oligo-recurrence are among the most important notions of metastatic and recurrent cancer. The concept of oligometastases is related to the notion that cancer patients with 1–5 metastatic or recurrent lesions that could be treated by local therapy achieve long-term survival or cure, while the concept of oligo-recurrence is related to the notion that cancer patients with 1–5 metastatic or recurrent lesions that could be treated by local therapy have controlled primary lesions. Achievement of long-term survival or cure in patients with oligometastases and oligo-recurrence is cancer and organ specific. These facts rely on the seed and soil theory and multiple steps of cancer progression. Oligo-recurrence is considered to have a better prognosis than oligometastases. In patients with oligometastases and oligo-recurrence, the oligometastases and oligo-recurrence are sometimes cured with only local therapy, which is an example of the abscopal effect, previously described in relation to cure of lesions outside of the field of radiation therapy without systemic therapy. Oligometastases and oligo-recurrence can now be cured by less invasive local treatment methods combined with systemic therapy. The mechanisms of oligometastases and oligo-recurrence, as well as novel insights into these important concepts, are presented in this paper.

The role of lung metastasis resection in improving outcome of colorectal cancer patients: results from a large retrospective study

BACKGROUND

The role of surgery for lung metastases (LM) secondary to colorectal cancer (CRC) remains controversial. The bulk of evidence is derived from single surgical series, hampering any definitive conclusions. The aim of this study was to compare the outcomes of CRC patients with LM submitted to surgery with those who were not.

PATIENTS AND METHODS

Data from 409 patients with LM as the first evidence of advanced disease were extracted from a database of 1,411 patients. Patients were divided into three groups: G1, comprised of 155 patients with pulmonary and extrapulmonary metastases; G2, comprised of 104 patients with LM only and no surgery; G3, comprised of 50 patients with LM only and submitted to surgery.

RESULTS

No difference in response rates emerged between G1 and G2. Median progression-free survival (PFS) times were: 10.3 months, 10.5 months, and 26.2 months for G1, G2, and G3, respectively. No difference in PFS times was observed between G1 and G2, whereas there was a statistically significant difference between G2 and G3. Median overall survival times were 24.2 months, 31.5 months, and 72.4 months, respectively. Survival times were longer in resected patients: 17 survived >5 years and three survived >10 years. In patients with LM only and no surgery, four survived for 5 years and none survived >10 years.

CONCLUSIONS

Even though patients with resectable LM are more likely to be those with a better outcome, our study provides evidence suggesting an active role of surgery in improving survival outcomes in this patient subset.