Pulmonary Metastasectomy versus Continued Active Monitoring in Colorectal Cancer (PulMiCC): a multicentre randomised clinical trial

A randomized phase III trial of stereotactic ablative radiotherapy for patients with up to 10 oligometastases and a synchronous primary tumor (SABR-SYNC): study protocol

BACKGROUND

Emerging randomized data, mostly from phase II trials, have suggested that patients with oligometastatic cancers may benefit from ablative treatments such as stereotactic ablative radiotherapy (SABR). However, phase III data testing this paradigm are lacking, and many studies have examined SABR in the setting of metachronous oligometastatic disease. The goal of the SABR-SYNC trial is to assess the effect of SABR in patients with oligometastatic cancers and a synchronous primary tumor.

METHODS

One hundred and eighty patients will be randomized in a 1:2 ratio between standard of care (SOC) palliative-intent treatments vs. SOC + ablative therapy (SABR preferred) to all sites of known disease. Randomization will be stratified based on histology and number of metastases at enrollment. SABR may be delivered in 1-, 3- and 5-fraction regimens, with recommended doses of 20 Gy, 30 Gy, and 35 Gy, respectively. Non-SABR local modalities (e.g. surgery, thermal ablation, conventional radiation) may be used for treatment of the primary or metastases at the discretion of the treating physicians, if those modalities are clinically preferred. The primary endpoint is overall survival, and secondary endpoints include progression-free survival, time to development of new metastatic lesions, time to initiation of next systemic therapy, quality of life, and toxicity. Translational endpoints include assessment of circulating tumor DNA and immunological predictors of outcomes.

DISCUSSION

SABR-SYNC will provide phase III data to assess the impact of SABR on overall survival in a population of patients with synchronous oligometastases. The translational component will attempt to identify novel prognostic and predictive biomarkers to aid in clinical decision making.

TRIAL REGISTRATION

Clinicaltrials.gov NCT05717166 (registration date: Feb. 8, 2023).

Nd-YAG laser-assisted pulmonary metastasectomy: initial experience from a tertiary care cancer center in India

Introduction

Pulmonary metastasectomy is recommended for metastatic lung lesions when R0 resection is possible, the primary site is in controlled status, surgery is of low risk, and extrathoracic metastases are absent. We present the initial experiences of laser-assisted surgery (LAS) for pulmonary metastatic lesions from a tertiary care cancer center in India.

Materials

All patients undergoing non-anatomical pulmonary metastasectomy between September 2022 and January 2023 for synchronous and metachronous lesions, operated on by a single consultant thoracic oncosurgeon in a tertiary care center of India, were identified from a prospective database. Ten patients with 124 metastatic lesions were included in the study. A hybrid approach (video-assisted thoracoscopic surgery (VATS) with mini-thoracotomy) was performed. Measurements of total lesion volume and lung parenchyma resected were taken from the final histopathological analysis of the intraoperative sample.

Results

LAS was performed for 102 lesions and stapled wedge resection for 22 lesions. Evidence of malignancy was noted in 88/102 (86.3%) of the lesions excised. Patients with LAS had advantages of parenchyma preservation, less postoperative morbidities, and shorter hospital stays.

Conclusion

LAS of pulmonary metastatic lesions addresses more lesions in a single sitting; the bilateral lung lesions can be operated and has parenchyma preserving and good sealant properties.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12055-024-01723-8.

Comparison of the Long-term Survival Outcome of Surgery versus Stereotactic Body Radiation Therapy as Initial Local Treatment for Pulmonary Oligometastases from Colorectal Cancer: A Propensity Score Analysis

PURPOSE

Optimal local treatment for pulmonary oligometastases from colorectal cancer (CRC) remains unclear. We aimed to compare the long-term survival outcomes between surgery and stereotactic body radiation therapy (SBRT) as the initial local treatment for CRC pulmonary oligometastases.

MATERIALS AND METHODS

We retrospectively reviewed 335 consecutive patients who initially underwent surgery or SBRT for CRC pulmonary metastases from 2011 to 2022, and 251 patients (173 surgery and 78 SBRT) were ultimately included. Freedom from intrathoracic progression (FFIP), progression-free survival (PFS), and overall survival (OS) were compared using stabilized inverse probability of treatment weighting (sIPTW) analysis. In addition, patterns of intrathoracic progression and subsequent treatment were analyzed.

RESULTS

Median follow-up was 61.6 months for surgery and 54.4 months for SBRT. After sIPTW adjustment, significant differences emerged in both FFIP and PFS between surgery and SBRT (FFIP: hazard ratio [HR] = 0.50, 95% confidence interval [CI], 0.31-0.79; PFS: HR = 0.56, 95% CI, 0.36-0.87). The 3- and 5-year FFIP rates were 58.6% and 54.8%, respectively, after surgery, and 34.6% and 31.3%, respectively, after SBRT (P = .006). The 3- and 5-year PFS rates were 49.4% and 45.2%, respectively, after surgery, and 28.8% and 26.1%, respectively, after SBRT (P = .010). However, OS was not significantly affected by treatment approach (HR = 0.93, 95% CI, 0.49-1.76). The 3- and 5-year OS rates were 85.9% and 73.1%, respectively, after surgery, and 78.9% and 68.7%, respectively, after SBRT (P = .849). Recurrence at the treated site was more prevalent after SBRT than after surgery (33.3% vs 16.9%), whereas new intrathoracic tumors occurred more frequently after surgery than after SBRT (71.8% vs 43.1%). Both groups chose radiation therapy as the primary local salvage treatment.

CONCLUSIONS

Notwithstanding the significant differences in FFIP and PFS between surgery and SBRT, the long-term survival of patients with CRC pulmonary oligometastases did not depend on the initial choice of the local treatment approach.

Do Children With Osteosarcoma Benefit From Pulmonary Metastasectomy?: A Systematic Review of Published Studies and "Real World" Outcomes

OBJECTIVE

To critically examine the evidence-base for survival benefit of pulmonary metastasectomy (PM) for osteosarcoma (OS) in the pediatric population.

BACKGROUND

PM for OS is recommended as the standard of care in both pediatric and adult treatment protocols. Recent results from the "Pulmonary Metastasectomy in Colorectal Cancer" trial demonstrate no survival benefit from PM in colorectal cancer in adults.

METHODS

A systematic review was undertaken according to "Preferred Reporting Items for Systematic Reviews and Meta-Analysis" guidelines. Medline, Embase, and 2 clinical trial registers were searched for all studies detailing pediatric patients with OS (<18 years) undergoing PM with a comparison cohort group that did not receive PM.

RESULTS

Eleven studies met inclusion criteria dating from 1984 to 2017. All studies were retrospective and none directly compared PM versus no PM in pediatric patients as its main objective(s). Three-year survival rates ranged from 0% to 54% for PM and 0% to 16% for no PM. No patients receiving PM were usually those with unresectable disease and/or considered to have a poor prognosis. All studies were at high risk of bias and there was marked heterogeneity in the patient selection.

CONCLUSIONS

There is a weak evidence base (level IV) for a survival benefit of PM for OS in pediatric patients likely due to selection bias of "favorable cases." The included studies many of which detailed outdated treatment protocols were not designed in their reporting to specifically address the questions directly. A randomized controlled trial-while ethically challenging in a pediatric population-incorporating modern OS chemotherapy protocols is needed to crucially address any "survival benefit."

The Clinical Efficacy of Colorectal Cancer Patients with Pulmonary Oligometastases by Sterotactic Body Ablative Radiotherapy: A Meta-Analysis

PURPOSE

There is increasing interest in the efficacy of stereotactic ablative radiotherapy (SABR) for treating colorectal cancer (CRC) patients with oligometastases (OM), recently. The purpose of this meta-analysis was to evaluate local control (LC), progression-free survival (PFS), and overall survival (OS) of CRC patients with pulmonary OM treated with SABR and toxicities.

MATERIALS AND METHODS

Studies that reported SABR for CRC patients with pulmonary OM were searched from MEDLINE and Embase. Treatment outcomes including LC, PFS, OS, and toxicities of grade 3 or higher were assessed.

RESULTS

A total of 19 studies with 1,668 patients were chosen for this meta-analysis. Pooled 1-, 2-, and 3-year LC rates were 83.1%, 69.3%, and 63.9%, respectively. PFS rates were 44.8%, 26.5%, and 21.5% at 1, 2, and 3 years, respectively. OS rates at 1-, 2-, and 3-year were 87.5%, 69.9%, and 60.5%, respectively. The toxicity rate of grade 3 or higher was 3.6%. The effect of dose escalation was meta-analyzed using available studies.

CONCLUSION

Application of SABR to CRC patients with pulmonary OM achieved modest local control with acceptable toxicity according to the present meta-analysis. Further studies establishing the clinical efficacy of SABR are guaranteed.

Cancer-specific dose and fractionation schedules in stereotactic body radiotherapy for oligometastatic disease: An interim analysis of the EORTC-ESTRO E2-RADIatE OligoCare study

BACKGROUND AND INTRODUCTION

Optimal dose and fractionation in stereotactic body radiotherapy (SBRT) for oligometastatic cancer patients remain unknown. In this interim analysis of OligoCare, we analyzed factors associated with SBRT dose and fractionation.

MATERIALS AND METHODS

Analysis was based on the first 1,099 registered patients. SBRT doses were converted to biological effective doses (BED) using α/β of 10 Gy for all primaries, and cancer-specific α/β of 10 Gy for non-small cell lung and colorectal cancer (NSCLC, CRC), 2.5 Gy for breast cancer (BC), or 1.5 Gy for prostate cancer (PC).

RESULTS

Of the interim analysis population of 1,099 patients, 999 (99.5 %) fulfilled inclusion criteria and received metastasis-directed SBRT for NSCLC (n = 195; 19.5 %), BC (n = 163; 16.3 %), CRC (n = 184; 18.4 %), or PC (n = 457; 47.5 %). Two thirds of patients were treated for single metastasis. Median number of fractions was 5 (IQR, 3-5) and median dose per fraction was 9.7 (IQR, 7.7-12.4) Gy. The most frequently treated sites were non-vertebral bone (22.8 %), lung (21.0 %), and distant lymph node metastases (19.0 %). On multivariate analysis, the dose varied significantly for primary cancer type (BC: 237.3 Gy BED, PC 300.6 Gy BED, and CRC 84.3 Gy BED), and metastatic sites, with higher doses for lung and liver lesions.

CONCLUSION

This real-world analysis suggests that SBRT doses are adjusted to the primary cancers and oligometastasis location. Future analysis will address safety and efficacy of this site- and disease-adapted SBRT fractionation approach (NCT03818503).

The Case for Pulmonary Metastasectomy-Clinical Practice Narrative Review and Commentary

Pulmonary metastasectomy has become a well-established procedure for patients with certain types of solid tumors. Patients are usually scheduled for staged lung metastasectomy in case of primary tumor control, the absence of distant non-lung metastases, and when complete resection is achievable. Nodules are removed with precision resection in order to ensure radical resection with minimal margins; this technique permits good oncological results, preserving the surrounding pulmonary parenchyma and causing minimal distortion compared to staplers. When possible, anatomical resections should be avoided since they are not justified by real oncological advantages and, in the majority of cases, sacrifice too much healthy tissue, possibly leading to inoperability in the case of metachronous relapses. Thus, preserving the maximum amount of pulmonary parenchyma is crucial because repeated metastasectomies are possible and frequent, with no theoretical limits to the number of reinterventions. In our multidisciplinary board team, we support the role of pulmonary metastasectomy as a useful curative therapy, with acceptable morbidity and mortality, with indications to be discussed case-by-case.

Lung Metastasectomy: Where Do We Stand? Results from an Italian Multicentric Prospective Database

Background/Objectives: The surgical resection of pulmonary metastases is considered a therapeutic option in selected cases. In light of this, we present the results from a national multicenter prospective registry of lung metastasectomy. Methods: This retrospective analysis involves data collected prospectively and consecutively in a national multicentric Italian database, including patients who underwent lung metastasectomy. The primary endpoints were the analysis of morbidity and overall survival (OS), with secondary endpoints focusing on the analysis of potential risk factors affecting both morbidity and OS. Results: A total 470 lung procedures were performed (4 pneumonectomies, 46 lobectomies/bilobectomies, 13 segmentectomies and 407 wedge resections) on 461 patients (258 men and 203 women, mean age of 63.1 years). The majority of patients had metastases from colorectal cancer (45.8%). In most cases (63.6%), patients had only one lung metastasis. A minimally invasive approach was chosen in 143 cases (30.4%). The mean operative time was 118 min, with no reported deaths. Morbidity most frequently consisted of prolonged air leaking and bleeding, but no re-intervention was required. Statistical analysis revealed that morbidity was significantly affected by operative time and pulmonary comorbidities, while OS was significantly affected by disease-free interval (DFI) > 24 months (p = 0.005), epithelial histology (p = 0.001) and colorectal histology (p = 0.004) during univariate analysis. No significant correlation was found between OS and age, gender, surgical approach, surgical extent, surgical device, the number of resected metastases, lesion diameter, the site of lesions and nodal involvement. Multivariate analysis of OS confirmed that only epithelial histology and DFI were risk-factors, with p-values of 0.041 and 0.031, respectively. Conclusions: Lung metastasectomy appears to be a safe procedure, with acceptable morbidity, even with a minimally invasive approach. However, it remains a local treatment of a systemic disease. Therefore, careful attention should be paid to selecting patients who could truly benefit from surgical intervention.

Survival outcome following surgical versus non-surgical treatment of colorectal lung metastasis-a retrospective cohort study

PURPOSE

The optimal management of colorectal lung metastases (CRLM) is still controversial. The aim of this study was to compare surgical and non-surgical treatment for CRLM regarding the prognostic outcome.

METHODS

This retrospective single-center cohort study included 418 patients, who were treated from January 2000 to December 2018 at a German University Hospital due to their colorectal carcinoma and had synchronous or metachronous lung metastases. Patients were stratified according the treatment of the CRLM into two groups: surgical resection of CRLM versus no surgical resection of CRLM. The survival from the time of diagnosis of lung metastasis was compared between the groups.

RESULTS

Two- and 5-year overall survival (OS) from the time of diagnosis of lung metastasis was 78.2% and 54.6%, respectively, in our cohort. Patients undergoing pulmonary metastasectomy showed a significantly better 2- and 5-year survival compared to patients with non-surgical treatment (2-year OS: 98.1% vs. 67.9%; 5-year OS: 81.2% vs. 28.8%; p < 0.001). Multivariate Cox regression revealed the surgical treatment (HR 4.51 (95% CI = 2.33-8.75, p < 0.001) and the absence of other metastases (HR 1.79 (95% CI = 1.05-3.04), p = 0.032) as independent prognostic factors in patients with CRLM.

CONCLUSION

Our data suggest that patients with CRLM, who qualify for surgery, benefit from surgical treatment. Randomized controlled trials are needed to confirm our findings.

CLINICAL TRIAL REGISTRY NUMBER

The work has been retrospectively registrated at the German Clinical Trial Registry (DRKS00032938).

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.

Multicentre retrospective analysis on pulmonary metastasectomy: an European perspective

OBJECTIVES

To assess the current practice of pulmonary metastasectomy at 15 European Centres. Short- and long-term outcomes were analysed.

METHODS

Retrospective analysis on patients ≥18 years who underwent curative-intent pulmonary metastasectomy (January 2010 to December 2018). Data were collected on a purpose-built database (REDCap). Exclusion criteria were: previous lung/extrapulmonary metastasectomy, pneumonectomy, non-curative intent and evidence of extrapulmonary recurrence at the time of lung surgery.

RESULTS

A total of 1647 patients [mean age 59.5 (standard deviation; SD = 13.1) years; 56.8% males] were included. The most common primary tumour was colorectal adenocarcinoma. The mean disease-free interval was 3.4 (SD = 3.9) years. Relevant comorbidities were observed in 53.8% patients, with a higher prevalence of metabolic disorders (32.3%). Video-assisted thoracic surgery was the chosen approach in 54.9% cases. Wedge resections were the most common operation (67.1%). Lymph node dissection was carried out in 41.4% cases. The median number of resected lesions was 1 (interquartile range 25-75% = 1-2), ranging from 1 to 57. The mean size of the metastases was 18.2 (SD = 14.1) mm, with a mean negative resection margin of 8.9 (SD = 9.4) mm. A R0 resection of all lung metastases was achieved in 95.7% cases. Thirty-day postoperative morbidity was 14.5%, with the most frequent complication being respiratory failure (5.6%). Thirty-day mortality was 0.4%. Five-year overall survival and recurrence-free survival were 62.0% and 29.6%, respectively.

CONCLUSIONS

Pulmonary metastasectomy is a low-risk procedure that provides satisfactory oncological outcomes and patient survival. Further research should aim at clarifying the many controversial aspects of its daily clinical practice.

Treatment of Oligometastatic GI Cancers

Oligometastatic state is believed to potentially represent a transitional stage between early, locoregional state disease and widely metastatic disease. Historically, locoregional approaches, particularly in advanced colorectal cancers, have demonstrated efficacy in select patients with limited burden of metastatic disease. Recent strides in systemic therapies, including biomarker-based treatments and immunotherapy, alongside innovations in surgical techniques and novel locoregional approaches such as stereotactic radiotherapy and ablation, have ushered in a new era of therapeutic possibilities across all oligometastatic GI cancers. Despite these advancements, there remains a significant gap in high-quality prospective evidence guiding patient selection and treatment decisions across various disease types. Ongoing clinical trials are anticipated to provide crucial insights into oligometastatic states, fostering the refinement of disease-specific oligometastatic state definitions and treatment algorithms. This article reviews existing data on the management of oligometastatic GI cancer, summarizes current state of knowledge for each disease state, and provides updates on ongoing studies in this space.

Isolated pulmonary metastases in pancreatic ductal adenocarcinoma: a review of current evidence

Despite recent advances in cancer therapeutics, pancreatic ductal adenocarcinoma (PDAC) remains a lethal disease with a 5-year overall survival of only 10%. Since either at or within a few months of diagnosis, most patients with PDAC will present with metastatic disease, a more individualized approach to select patients who may benefit from more aggressive therapy has been suggested. Although studies have reported improved survival in PDAC and isolated pulmonary metastasis (ISP) compared to extrapulmonary metastases, such findings remain controversial. Furthermore, the added benefit of pulmonary metastasectomy and other lung-directed therapies remains unclear. In this review, we discuss the metastatic pattern of PDAC, evaluate the available evidence in the literature for improved survival in PDAC and ISP, evaluate the evidence for the added benefit of pulmonary metastasectomy and other lung-directed therapies, identify prognostic factors for survival, discuss the biological basis for the reported improved survival and identify areas for further research.

Stereotactic Body Radiotherapy for Management of Pulmonary Oligometastases in Stage IV Colorectal Cancer: A Perspective

In pulmonary oligometastases from colorectal cancer (POM-CRC), metastasectomy is the primarily recommended treatment. Stereotactic body radiotherapy (SBRT) has been suggested as a viable alternative therapy. SBRT efficacy for POM-CRC is poorly delineated compared to selected non-CRC primaries. This perspective article aims to critically summarize the existing evidence regarding efficacy of SBRT in terms of overall survival (OS) and local control (LC), and factors modulating this, in the treatment of POM-CRC. Overall, reasonable LC and OS rates were observed. The wide range of expansions in planning target volume margins introduced variation in pretreatment protocols. Dose-fractionation schedules varied according to patient and tumor characteristics, though leverage of BED10 in select studies enabled standardization. An association between SBRT dose and improved OS and LC was observed across multiple studies. Prognostic factors that were associated with improved LC included: fewer oligometastases, absence of extra-pulmonary metastases, primary tumor histology, and smaller gross tumor volume. Differences in SBRT modality and techniques over time further confounded results. Many studies included patients receiving additional systemic therapies; preprotocol and adjuvant chemotherapies were identified as prognostic factors for LC. SBRT compared with metastasectomy showed no differences in short-term OS and LC outcomes. In conclusion, SBRT is an efficacious treatment for POM-CRC, in terms of OS and LC. Heterogeneity in study design, particularly pertaining to dose protocols, patient selection, and additional therapies should be controlled for future randomized studies to further validate SBRT efficacy.

Local interventions for colorectal cancer metastases to liver and lung

BACKGROUND

Colorectal cancer is a common cause of cancer-related deaths. About 1/3 of all cases present with distant metastasis, with the liver as the leading site and the lung as the most common extra-abdominal site.

AIMS

It was aimed to evaluate the clinical characteristics and the outcomes of colorectal cancer patients with liver or lung metastasis who had received local treatments.

METHODS

This is a retrospective, cross-sectional, and descriptive study. The study was performed with colorectal cancer patients that referred to the medical oncology clinic of a university hospital between December 2013 and August 2021.

RESULTS

A total number of 122 patients who have received local treatments were included. Radiofrequency ablation was applied in 32 patients (26.2%), metastasis was surgically resected in 84 patients (68.9%), and stereotactic body radiotherapy was preferred in six patients (4.9%). At the first follow-up control after completion of local or multimodal treatment, no residual tumor was determined with radiological assessment in 88 patients (72.1%). The median progression-free survival (16.7 months vs 9.7 months) (p = .000) and the median overall survival (37.3 months vs 25.5 months) (p = .004) of these patients were significantly better than the patients with residual disease.

CONCLUSIONS

Local interventions that are applied to highly selected patients may improve the survival of metastatic colorectal cancer patients. A close follow-up after local therapies is important to diagnose recurrent disease because repeated local interventions may be possible to achieve better outcomes.

Survival outcomes of lung metastases from colorectal cancer treated with pulmonary metastasectomy or modern systemic chemotherapy: a single institution experience

BACKGROUND

Although pulmonary metastasectomy is an accepted treatment strategy for resectable lung metastases (LM) from colorectal cancer (CRC), its survival benefits are controversial. In contrast, recent advancements in chemotherapy have significantly improved metastatic CRC prognosis. This study aimed to evaluate survival outcome of LM from CRC in the age of newly developed chemotherapy.

METHODS

We retrospectively reviewed 50 patients who underwent complete resection and 22 patients who received chemotherapy as definitive treatment for LM from resected CRC at our hospital. The present study was limited to patients who started treatment for isolated LM after molecular targeted drugs became available in Japan.

RESULTS

Overall survival (OS), cancer-specific survival (CSS), disease-free survival (DFS) rates after pulmonary resection were 64.5%, 66.4%, and 32.6% at five years, respectively. OS and CSS rates of chemotherapy patients were 26.8% and 28.3% at five years, with a median progression-free survival time of 10.0 months. When compared the characteristics of surgical and chemotherapy patients, patients with pN factors of CRC (p = 0.013), smaller size (p < 0.001), larger number (p < 0.001), and bilateral (p < 0.001) LM received chemotherapy. Univariate analysis showed that multiple LM and rectal lesions were poor prognostic factors for OS (p = 0.012) and DFS (p = 0.017) in surgical patients, and rectal lesions were a poor prognostic factor for OS (p = 0.013) in chemotherapy patients.

CONCLUSIONS

Pulmonary metastasectomy showed a favorable survival in patients with LM from CRC. Despite the high recurrence rate after metastasectomy and recent advances in chemotherapy, surgical resection could still be considered as a valid option among multidisciplinary treatments.

TRIAL REGISTRATION

The research plan was approved by the Institutional Review Board of Shinko Hospital (No. 2142) on February 7, 2022.

Laser-assisted lung metastasectomy: a systematic review

Laser-assisted resection (LAR) of pulmonary metastases offers several potential advantages compared to conventional surgical techniques. However, the technical details, indications and outcomes of LAR have not been extensively reviewed. We conducted a systematic literature search to identify all original articles reporting on LAR of pulmonary metastases. All relevant outcomes, including morbidity rate, R0 rate, pulmonary function tests, overall- (OS) and relapse-free survival (RFS) rates were collected. Additionally, a comparison between outcomes obtained by laser-assisted and conventional resection techniques was provided. Of 2629 articles found by the initial search, 12 were selected for the systematic review. Following LAR, the R0 rate ranged between 72 and 100% and the morbidity rate ranged from 0 to 27.5%. The postoperative decline in forced expiratory volume in 1 s varied between 3.4 and 11%. Median OS and RFS were 42-77.6 months and 9-34.1 months, respectively. Compared with patients treated by other resection techniques, patients treated by LAR frequently had a higher number of metastases and a higher rate of bilateral disease. Despite this, no significant differences were observed in R0 rate, morbidity rate, and median OS rate, while only 1 study found a lower RFS rate in the LAR cohort. Although selection bias limits the comparability of outcomes, the findings of this review suggest that LAR is a valid alternative to conventional procedures of lung metastasectomy. The main difficulties of this technique consist in the adoption of a video-assisted thoracoscopic approach, and in the pathologic assessment of resection margins.

Importance of Local Ablative Therapies for Lung Metastases in Patients With Colorectal Cancer

OBJECTIVE

To assess the effect of local ablative therapy (LAT) on overall survival in patients with lung metastases from colorectal cancer (CRC) compared with patients treated with systemic therapy.

SUMMARY BACKGROUND DATA

CRC affects approximately 1.4 million individuals worldwide every year. The lungs are commonly affected by CRC, and there is no treatment standard for a secondary lung metastasis from CRC.

METHODS

This longitudinal, retrospective cohort study (2010-2018) quantified the pulmonary and extrapulmonary tumor burden of 1143 patients by retrospectively reviewing computed tomography images captured at diagnosis. A comprehensive multidisciplinary approach informed how and when surgery and/or stereotactic body radiotherapy was administered.

RESULTS

Among 1143 patients, 473 patients (41%) received LAT, with surgery first (n = 421) or stereotactic ablative radiation therapy first (n = 52) either at the time of diagnosis (n = 288), within 1 year (n = 132), or after 1 year (n = 53). LAT was repeated in 158 patients (33.4%, 384 total sessions) when new lung metastases were detected. The 5- and 10-year survival rates for patients treated with LAT (71.2% and 64.0%, respectively) were significantly higher than those of patients treated with systemic therapy alone (14.2% and 10.0%, respectively; P <0.001). The overall survival of patients who received LAT intervention increased as the total tumor burden decreased.

CONCLUSIONS

A high long-term survival rate was achievable in a significant portion of patients with lung metastasis from CRC by the timely administrations of LAT to standard systemic therapy. The tumor burden and LAT feasibility should be included in a discussion during the follow-up period.

Case Report: Long-term survival of a patient with advanced rectal cancer and multiple pelvic recurrences after seven surgeries

Background

Rectal cancer has a high risk of recurrence and metastasis, with median survival ranging from 24 months to 36 months. K-RAS mutation is a predictor of poor prognosis in rectal cancer. Advanced rectal cancer can be stopped in its tracks by pelvic exenteration.

Case summary

A 51-year-old woman was diagnosed with advanced rectal cancer (pT4bN2aM1b, stage IV) with the KRAS G12D mutation due to a change in bowel habits. The patient had experienced repeated recurrences of rectal cancer after initial radical resection, and the tumor had invaded the ovaries, sacrum, bladder, vagina and anus. Since the onset of the disease, the patient had undergone a total of seven surgeries and long-term FOLFIRI- or XELOX-based chemotherapy regimens, with the targeted agents bevacizumab and regorafenib. Fortunately, the patient was able to achieve intraoperative R0 resection in almost all surgical procedures and achieve tumor-free survival after pelvic exenteration. The patient has been alive for 86 months since her diagnosis.

Conclusions

Patients with advanced rectal cancer can achieve long-term survival through active multidisciplinary management and R0 surgery.

The Management of Oligometastatic Disease in Colorectal Cancer: Present Strategies and Future Perspectives

Oligometastatic disease has been described as an intermediate clinical state between localized cancer and systemically metastasized disease. Recent clinical studies have shown prolonged survival when aggressive locoregional approaches are added to systemic therapies in patients with oligometastases. The aim of this review is to outline the newest options to treat oligometastatic colorectal cancer (CRC), also considering its molecular patterns. We present an overview of the available local treatment strategies, including surgical procedures, stereotactic body radiation therapy (SBRT), thermal ablation, as well as trans-arterial chemoembolization (TACE) and selective internal radiotherapy (SIRT). Moreover, since imaging methods provide crucial information for the early diagnosis and management of oligometastatic CRC, we discuss the role of modern radiologic techniques in selecting patients that are amenable to potentially curative locoregional treatments.

Preoperative prognostic factors for 5-year survival following pulmonary metastasectomy from colorectal cancer: a systematic review and meta-analysis

OBJECTIVES

We seek to identify preoperative prognostic factors and measure their effect on 5-year survival following pulmonary metastasectomy (PM) for Colorectal Cancer (CRC).

METHODS

We systematically reviewed the databases of Cochrane Library, MEDLINE, Embase and Google Scholar from January 2000 to April 2021 to identify preoperative factors that have been investigated for their prognostic effect on survival following PM. Quality assessment was performed using the QUIPS tool. The prognostic effect of each identified factor on 5-year survival post-PM was estimated using random-effects meta-analyses.

RESULTS

We identified 115 eligible articles which included 13 294 patients who underwent PM from CRC. The overall 5-year survival after resection of the lung metastasis was 54.1%. The risk of bias of the included studies was at least moderate in 93% (107/115). Seventy-seven preoperative factors had been investigated for their prognostic effect. Our analysis showed that 11 factors had favourable and statistically significant prognostic effect on 5-year survival post-PM. These included solitary metastasis, size <2 cm, unilateral location, N0 thoracic disease, no history of extra-thoracic or liver metastasis, normal carcinoembryonic antigen levels both before PM and CRC excision, no neo-adjuvant chemotherapy before PM, CRC T-stage < T4 and no p53 mutations on CRC. Disease-free interval at 24 months did not appear to affect 5-year survival.

CONCLUSIONS

Despite the considerable risk of bias in the literature, our study consolidates the available evidence on preoperative prognostic factors for PM from CRC. These findings can complement both clinical practice and the design of future research on the field of PM.

Outcomes Following Treatment with FOLFOX for Patients with Resectable or Potentially Resectable Metastatic Colorectal Cancer: A Population-based Cohort Study

AIMS

To evaluate the safety and effectiveness of oxaliplatin-based combination chemotherapy for patients with metastatic colorectal cancer (mCRC) to extrahepatic sites.

MATERIALS AND METHODS

We conducted a population-based retrospective study examining the safety and effectiveness of perioperative oxaliplatin for resectable or potentially resectable colorectal metastases in Ontario, Canada. Outcomes were also compared with patients with liver-only metastases. Patients received oxaliplatin for mCRC between 1 January 2013 and 30 June 2020.

RESULTS

In total, 192 patients had extrahepatic metastases. Seventy per cent had R0 metastasectomy. The 3-year disease-free survival and overall survival were 62% and 79%, respectively; <4% of patients died within 60 days of metastasectomy and 74-90% of patients received treatment according to recommendations from a multidisciplinary setting. Compared with liver-only controls (n = 1306), patients had mCRC to the lung only (n = 115), lung and liver (n = 55) and liver with non-pulmonary site (n = 22). Extrahepatic metastases were more likely to be found for patients whose primary colorectal resection had positive margins (14% versus 7%, P = 0.005) and primary tumours located in the rectum [odds ratio 4.01 (2.31-6.97)]. After adjustment, there was no difference in overall survival between liver-only controls and patients with lung-only [hazard ratio 0.82 (0.59-1.15)] or liver and lung metastases [hazard ratio 1.26 (0.85-1.87)] (P = 0.24). In total, 79/115 (69%) of patients with lung-only metastases had a metastasectomy compared with 645/1306 (49%) and 15/55 (27%) of patients with liver-only and liver and lung metastases, respectively. Hospital visits were similar between patients with liver-only and extrahepatic metastases.

CONCLUSION

Oxaliplatin-based chemotherapy for patients with resectable or potentially resectable mCRC with extrahepatic metastases was safe and resulted in similar outcomes in appropriately selected patients when compared with patients with liver-only metastases.

Pulmonary Metastasectomy

The lung represents the most common site for metastatic spread of extrathoracic primary malignancies. Pulmonary metastatic disease occurs in a wide breadth of cancers with a multitude of histologies, and, historically, has been managed predominantly with systemic therapy. However, in appropriately selected patients, pulmonary metastasectomy can provide extended disease-free intervals, relief from systemic therapy, and prolonged survival. Thus, pulmonary metastasectomy serves a vital role in the armamentarium against a multitude of primary malignancies. Moreover, as systemic agents improve and more patients live longer with stage IV cancer, pulmonary metastasectomy will likely have increasing relevance in the future.

Improving survival after pulmonary metastasectomy for sarcoma: analysis of prognostic factors

BACKGROUND

Metastatic sarcoma confers a grave prognosis to patients and poses a management dilemma for clinicians. Pulmonary metastasectomy is frequently performed for the recurrence of sarcomatous tumours in the lung, but the evidence-base is poor. No guidelines exist to inform clinicians on appropriate patient selection and surgical technique.

AIM

This review aims to establish and analyse the most important prognostic factors for survival post pulmonary metastasectomy for recurrent sarcoma. We summarise the key tumour, peri-operative and patient characteristics that should guide surgical management.

METHODS

A comprehensive search of the literature utilising OVID Medline and PubMed databases was conducted to identify all relevant research within the past 15 years. We evaluated all articles that specifically studied sarcoma patients (both bone and soft tissue).

CONCLUSION

Disease-free interval and tumour burden remain important prognostic factors, while tumour grade is likely not significant. VATS is a safe and viable alternative to thoracotomy without sacrificing survival outcomes. No single peri-operative characteristic provides useful prognostic information in isolation.

Metastasectomy for colorectal pulmonary metastases: a survey among members of the European Society of Thoracic Surgeons

OBJECTIVES

Surgical management of pulmonary metastases in colorectal cancer patients is a debated topic. There is currently no consensus on this matter, which sparks considerable risk for international practice variation. The European Society of Thoracic Surgeons (ESTS) ran a survey to assess current clinical practices and to determine criteria for resection among ESTS members.

METHODS

All ESTS members were invited to complete an online questionnaire of 38 questions on current practice and management of pulmonary metastases in colorectal cancer patients.

RESULTS

In total, 308 complete responses were received (response rate: 22%) from 62 countries. Most respondents consider that pulmonary metastasectomy for colorectal pulmonary metastases improves disease control (97%) and improves patients' survival (92%). Invasive mediastinal staging in case of suspicious hilar or mediastinal lymph nodes is indicated (82%). Wedge resection is the preferred type of resection for a peripheral metastasis (87%). Minimally invasive approach is the preferred approach (72%). For a centrally located colorectal pulmonary metastasis, the preferred form of treatment is a minimally invasive anatomical resection (56%). During metastasectomy, 67% of respondents perform mediastinal lymph node sampling or dissection. Routine chemotherapy is rarely or never given following metastasectomy (57% of respondents).

CONCLUSIONS

This survey among the ESTS members underlines the change in practice of pulmonary metastasectomy with an increasing tendency in favour of minimally invasive metastasectomy and surgical resection is preferred over other types of local treatment. Criteria for resectability vary and controversy remains regarding lymph node assessment and the role of adjuvant treatment.

Oncologic Outcome after Pulmonary Metastasectomy as Part of Multidisciplinary Treatment in a Tertiary Oncological Center

(1) Background: Pulmonary metastases are encountered in approximately one-third of patients with malignancies, especially from colorectal, lung, breast, and renal cancers, and sarcomas. Pulmonary metastasectomy is the ablative approach of choice, when possible, as part of the multidisciplinary effort to integrate and personalize the oncological treatment. (2) Methods: The study includes 58 consecutive cases of pulmonary metastasectomies, retrospectively analyzed, performed in 12 consecutive months, in which the pathology reports confirmed lung metastases. (3) Results: Most frequent pathological types of metastases were: 14 of colorectal cancer, 10 breast, 8 lung, and 8 sarcomas. At the time of primary cancer diagnosis, 14 patients (24.14%) were in the metastatic stage. The surgical approach was minimally invasive through uniportal VATS (Video-Assisted Thoracic Surgery) in 3/4 of cases (43 patients, 74%). Almost 20% of resections were typical (lobectomy, segmentectomy). Lymphadenectomy was associated in almost 1/2 of patients and lymph node metastases were found in 11.11% of cases. The mortality rate (intraoperative and 90 days postoperative) is zero. The OS after pulmonary metastasectomy is 87% at 18 months, and the estimated OS for cancer is 90% at 5 years. The worst outcome presents the patients with sarcomas and the best outcome-colorectal and lung cancer. The patients with 1 or 2 resected metastases presented 96% survival at 24 months. (4) Conclusions: After pulmonary metastasectomy, survival is favored by the small number of metastases resected (1 or 2), and by the dimension of metastases under 20.5 mm. The non-anatomic (wedge) type of lung resection may present a lower risk of death compared to lobectomy. No statistical significance on survival has the presence of lymphadenectomy, the laterality right/left lung, the upper/lower lobes. In the future, longer follow-up and prospective randomized trials are needed for drawing definitive conclusions.

Curative-intent treatment of pulmonary metastases from colorectal cancer: A comparison between imaging-guided thermal ablation and surgery

BACKGROUND

Pulmonary metastases (PM) are the most frequent extra-abdominal metastases from colorectal cancer. Lung resection and imaging-guided thermal ablation (IGTA) are used as curative-intent treatment. We compared the outcomes of patients with PM, treated with resection or ablation.

METHODS

We retrospectively analyzed data from patients who underwent surgery or IGTA for colorectal PM between April 2011 and November 2020. Surgery was performed for peripheral PM and IGTA for deep-located PM not in contact with major vessels. Patients who had both procedures were excluded. Patients were compared using propensity score matching (PSM) analysis, stratified according to number, size, and unilaterality of PM.

RESULTS

One hundred and fourty-six patients were included, 65 (44.5%) underwent surgery and 81 (55.5%) underwent IGTA. After PSM analysis, each group contained 46 patients. IGTA patients had a lower morbidity rate (13.1% vs. 15.2%, p = 0.028) and a shorter length of stay (5.13 vs. 2.63 days, p < 0.001). Oncological outcomes were similar in both groups with 5-year OS of 80% and 5-year progression-free survival (PFS) of 30% (p = 0.657 and p = 0.504, respectively) with similar recurrence patterns.

CONCLUSION

Lung resection and IGTA seem to have similar oncologic outcomes for both OS and PFS. IGTA could be an alternative effective treatment for small PM, whenever technically feasible.

Top Ten Lessons Learned from Trials in Oligometastatic Cancers

Recent evidence supports the role of aggressive local treatment in the oligometastatic setting. In this review, we discuss the top 10 lessons we have learned from trials in oligometastatic cancers. Major lessons learned pertain to definitions of oligometastatic disease, outcomes, toxicity, costs, and the combination of ablative therapies with systemic therapy, including immunotherapy. Barriers to accrual for trials and upcoming phase III trials are also reviewed. These lessons may help to inform clinical practice and may be the basis for future research in the oligometastatic space.

Oligometastases: Emerging Evidence

The hypothesis that ablative therapies (such as surgery or radiation) can be used to cure patients with a limited number of metastases was influential in changing practice. Early assertions of efficacy were based on observational studies, often without control groups, showing better-than-expected outcomes. However, in the past decade, new evidence from randomized trials has emerged, which in some cases have affirmed old hypotheses, but in other cases have raised new questions. In this review, we discuss the challenges in defining oligometastatic disease, summarize the randomized evidence evaluating metastasis-directed therapy in patients with oligometastatic disease, provide context for the difficulty in generating randomized evidence, and examine ongoing phase III studies.

Role of subxiphoid uniportal video-assisted thoracoscopic surgery in pulmonary metastasectomy

Optimal management for patients with pulmonary metastasis is still debated. True survival benefit from widely practiced pulmonary metastasectomy (PM) is yet to be proved from high-quality randomized controlled trials. The ideal surgical approach for PM is also not generally agreed. VATS offers enhanced recovery and superior functional outcomes but at the expense of less detection of lung nodules and higher possibility of narrow/positive resection margins. The subxiphoid uniportal VATS (uVATS) approach is an evolving new approach with potential advantages including simultaneous access to both lung fields, less pain and faster rehabilitation. These advantages make it a favorable approach for PM, particularly in the setting of bilateral metastases. However, its use is still limited to case reports of a small number of patients. There is room for improvements in subxiphoid uVATS due to reported technical challenges and limitations. Herein, we aim to publicize a comprehensive review of literature on applications of subxiphoid uVATS in PM.

The Management of Oligometastases in Non-small Cell Lung Cancer - is Stereotactic Ablative Radiotherapy now Standard of Care?

Oligometastatic non-small cell lung cancer encompasses a number of distinct clinical scenarios with a pattern of limited tumour burden on imaging. Delivering local ablative therapy to individual metastatic lesions may assist in disease modification and contribute to improved outcomes. We review the published randomised clinical trials that support the implementation of stereotactic ablative radiotherapy as a standard of care in certain oligometastatic non-small cell lung cancer clinical scenarios, and highlight the current knowledge gaps and areas of ongoing research.

PET-Uptake in Liver Metastases as Method to Predict Tumor Biological Behavior in Patients Transplanted for Colorectal Liver Metastases Developing Lung Recurrence

The objective of the study was to determine the impact of PET uptake on liver metastases on overall survival (OS) after resection of pulmonary metastases in patients who had received liver transplantation (LT) due to unresectable colorectal liver-only metastases. Resection of pulmonary colorectal metastases is controversial. Some hospitals offer this treatment to selected patients, whereas other hospitals do not perform the procedure in colorectal cancer patients who develop pulmonary metastases. All patients included in the LT studies who developed pulmonary metastases as first site of relapse, and had resection of these as first treatment, were included in this report. Metabolic tumor volume (MTV) in liver was derived from the pre-transplant PET examinations. OS from time of resection was calculated by the Kaplan−Meier method. Patients with low MTV (<70 cm3) had significantly longer OS from time of resection of pulmonary metastases compared to patients with high MTV (>70 cm3). Patients with low MTV in the liver had 10-year OS from time of pulmonary resections of 86%. Liver MTV values from pre-transplant PET examinations may predict long OS in colorectal cancer patients with a resection of pulmonary metastases developing after LT. Thus, in selected colorectal cancer patients developing pulmonary metastases resection of these metastases should be the treatment of choice.

Patients with Pulmonary Metastases from Head and Neck Cancer Benefit from Pulmonary Metastasectomy, A Systematic Review

Background and Objectives: The incidence of distant metastases in patients with head and neck cancer (HNC) is approximately 10%. Pulmonary metastases are the most frequent distant location, with an incidence of 70-85%. The standard treatment options are chemo-, immuno- and radiotherapy. Despite a benefit for long-term survival for patients with isolated pulmonary metastases, pulmonary metastasectomy (PM) is not the treatment of choice. Furthermore, many otorhinolaryngologists are not sufficiently familiar with the concept of PM. This work reviews the recent studies of pulmonary metastatic HNC and the results after pulmonary metastasectomy. Materials and Methods: PubMed, Medline, Embase, and the Cochrane library were checked for the case series' of patients undergoing metastasectomy with pulmonary metastases published since 1 January 2000. Results: We included the data of 15 studies of patients undergoing PM. The 5-year survival rates varied from 21% to 59%, with median survival from 10 to 77 months after PM. We could not identify one specific prognostic factor for long-term survival after surgery. However, at least most studies stated that PM should be planned if a complete (R0) resection is possible. Conclusions: PM showed reliable results and is supposedly the treatment of choice for patients with isolated pulmonary metastases. Patients not suitable for surgery may benefit from other non-surgical therapy. Every HNC patient with pulmonary metastases should be discussed in the multidisciplinary tumor board to optimize the therapy and the outcome.

The oligometastatic spectrum in the era of improved detection and modern systemic therapy

Metastases remain the leading cause of cancer-related mortality. The oligometastasis hypothesis postulates that a spectrum of metastatic spread exists and that some patients with a limited burden of metastases can be cured with ablative therapy. Over the past decade, substantial advances in systemic therapies have resulted in considerable improvements in the outcomes of patients with metastatic cancers, warranting re-examination of the oligometastatic paradigm and the role of local ablative therapies within the context of the improved therapeutic responses, shifting patterns of disease recurrence and possible synergy with systemic treatments. Herein, we reframe the oligometastatic phenotype as a dynamic state for which locally ablative, metastasis-directed therapy improves clinical outcomes, including by prolonging survival and increasing cure rates. Important risk factors defining the metastatic spectrum are highlighted that inform both staging and therapy. Finally, we synthesize the literature on combining local therapies with modern systemic treatments, identifying general themes to optimally integrate ablative therapies in this context.

Impact of the extent of lung resection on postoperative outcomes of pulmonary metastasectomy for colorectal cancer metastases: an exploratory systematic review

Background

Pulmonary metastasectomy (PM) with curative intent has become a widely accepted treatment for lung metastases from solid tumours in selected patients, with low perioperative morbidity and mortality. In particular, PM is strongly recommended in selected patients with secondary lesions from colorectal cancer (CRC), due to its excellent postoperative prognosis. Nevertheless, the impact of the extent of PM on recurrence and survival remains controversial. This review aimed at assessing differences in short- and long-term postoperative outcomes depending on the extent of lung resection for lung metastases.

Methods

A systematic literature review of studies comparing anatomical and non-anatomical resections of lung metastases was performed (Prospective Register of Systematic Reviews Registration: 254931). A literature search for articles published in English between the date of database inception and January 31, 2021 was performed in EMBASE (via Ovid), MEDLINE (via PubMed) and Cochrane CENTRAL. Retrospective studies, randomised and non-randomised controlled trials were included. The Cochrane Collaboration tool was used to determine the risk of bias for the primary outcome for included studies.

Results

Out of 432 papers, three retrospective non-randomised studies (1,342 patients) were selected for systematic reviewing. Although our search design did not exclude any primary tumour histology, all selected studies investigated surgical resection of lung metastases from CRC. Because of variations in the compared surgical approaches to pulmonary metastases, a meta-analysis proved unfeasible. There was a tendency to perform anatomical resections for larger metastases. Multivariate analyses revealed that anatomical resections were protective for recurrence-free survival (RFS), while the impact of such procedures on overall survival (OS) remained uncertain. A significantly higher incidence of resection-margin recurrences was observed in patients who underwent non-anatomical resections.

Discussion

Anatomical resections of lung metastases from CRC seem to be associated with improved RFS. However, well-constructed comparative clinical trials focusing on the extent of PM are needed.

Time to Incurable Recurrence for Patients Treated With Pulmonary Metastasectomy for Colorectal Cancer

BACKGROUND

Probability of cure is important for patients with lung metastasis who must decide whether to undergo metastasectomy. Although progression-free survival (PFS) is thought to reflect this, it does not include curative effects by repeat metastasectomy. Thus, the authors developed a new indicator, time to incurable recurrence (TTIR), in which only incurable recurrence was set as an event that included death, with incurable recurrence defined as recurrence not treated by definitive local therapy (DLT), recurrence treated by DLT but with PFS maintained less than 2 years, or recurrence followed by re-recurrence.

METHODS

This multi-institutional study included 339 patients who underwent lung metastasectomy for colorectal cancer between 1990 and 2008.

RESULTS

Among the 339 patients, 191 experienced recurrence, 77 received DLT for recurrence, 38 had a PFS of 2 years or longer after the treatment, and 33 had maintained a PFS at the last follow-up date. The patients had PFS ranging from 39 to 212 months (median, 101 months). The 5-year OS, PFS, and TTIR rates were respectively 63.4%, 42.2%, and 51.9%. The TTIR curve was similar to the OS curve 7 years after the initial metastasectomy. The difference between TTIR and PFS at 7 years was 9.7%, indicating probability of cure by repeat DLT. Multivariable analysis showed different prognostic factors among OS, PFS, and TTIR.

CONCLUSION

At the initial metastasectomy, TTIR may reflect probability of a cure, including cure by repeat DLT, and can be used to analyze prognostic factors associated with cure.

Steering decision making by terminology: oligometastatic versus argometastatic

Allowing selected patients with few distant metastases to undergo potentially curative local ablation, the designation “oligometastatic” has become a widely popular concept in oncology. However, accumulating evidence suggests that many of these patients harbour an unrecognised microscopic disease, leading either to the continuous development of new metastases or to an overt polymetastatic state and questioning thus an indiscriminate use of potentially harmful local ablation. In this paper, reviewing data on oligometastatic disease, we advocate the importance of identifying a true oligometastatic disease, characterised by a slow speed of development, instead of relying solely on a low number of lesions as the term “oligometastatic” implies. This is particularly relevant in clinical practice, where terminology has been shown to influence decision making. To define a true oligometastatic disease in the context of its still elusive biology and interaction with the immune system, we propose using clinical criteria. As discussed further in the paper, these criteria can be classified into three categories involving a low probability of occult metastases, low tumour growth rate and low tumour burden. Such cases with slow tumour-cell shedding and slow proliferation leave a sufficiently broad window-of-opportunity to detect and treat accessible lesions, increasing thus the odds of a cure.