Analyses of local control and survival after stereotactic body radiotherapy for pulmonary oligometastases from colorectal adenocarcinoma

Transcontinental Differences in Management of Pulmonary Metastatic Disease: Europe

Several international registries, including 4 from Europe-Italy, Spain, the Netherlands, and the European Society of Thoracic Surgeons-are dedicated to addressing deficiencies in pulmonary metastasectomy research. The randomized PulMiCC and SABR-COMET trials provide contradictory outcomes and new randomized trials have been initiated. Europe's metastasectomy approach transitioned from open thoracotomy to video-assisted thoracoscopic surgery, with 72% of surgeons favoring minimally invasive methods by 2023. European Society for Medical Oncology guidelines recommend surgery for completely resectable lesions and propose ablative approaches as supplementary or alternative treatments for inoperable cases due to frailty or unfavorable anatomy.

Metastasectomy versus stereotactic body radiotherapy for patients with oligometastatic colorectal lung metastases: a systematic review

Metastasectomy and stereotactic body radiotherapy (SBRT) are both guideline-recommended treatment modalities for patients with oligometastatic colorectal lung metastases (CLM). Few evidence is available comparing different local therapies in an oligometastatic population. This systematic review aimed to compare the efficacy of metastasectomy with SBRT for patients with oligometastatic CLM. A systematic literature search was performed according to the PRISMA guidelines to identify studies on metastasectomy and SBRT for patients with oligometastatic CLM. Studies published between 2000 and 2023 were identified through Medline, Embase, and the Cochrane databases. Overall survival (OS), progression-free survival (PFS), and local recurrence rate (LRR) were assessed and compared between both groups. The risk of bias was assessed using the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) tool. A total of 141 studies on metastasectomy (n = 29932) and 16 studies on SBRT (n = 1381) were included in the final analysis. The pooled five-year OS was 52.2 % (CI: 49.8-54.5) and 45.0 % (CI: 31.2-58.9) following metastasectomy and SBRT, respectively (p = 0.213). The pooled five-year PFS was 35.1 % (CI: 32.2-38.1) following metastasectomy and 11.7 % (CI: 0-38.2) following SBRT (p < 0.001). The pooled LRR was 10.5 % (CI: 5.5-15.5) following metastasectomy and 28.1 % (CI: 20.8-35.4) following SBRT (p < 0.001). The average GRADE score of the included studies was low. The data suggest that patients with oligometastatic CLM have a comparable OS rate after metastasectomy or SBRT, but PFS and LRR favour a surgical approach. This systematic review supports initiating a randomized controlled trial comparing surgery and SBRT in operable patients with oligometastatic CLM.

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.

The optimal stereotactic body radiotherapy dose with immunotherapy for pulmonary oligometastases: a retrospective cohort study

Background

Stereotactic body radiotherapy (SBRT) is a precise and effective treatment for pulmonary oligometastases, offering high local control (LC) rates. However, the optimal SBRT dose when combined with immunotherapy remains unclear, and there is a lack of comprehensive studies focusing on dose optimization in this setting. This study addresses this knowledge gap by exploring different SBRT dose regimens and their impact on progression-free survival (PFS), overall survival (OS), and LC in patients receiving concurrent immunotherapy, offering novel insights into the synergistic effects of these treatments.

Methods

A retrospective cohort study was conducted of 101 patients with 141 pulmonary oligometastases treated from April 2018 to April 2022. Inclusion criteria included patients with a maximum of five lung metastases and an Eastern Cooperative Oncology Group performance status of ≤2. Patients received SBRT with doses ranging from 50-70 Gy in 5-10 fractions. Follow-up was performed quarterly, and the best dose was determined by comparing survival outcomes across different dose groups. The patients received SBRT with doses ranging from 50-70 Gy in 5-10 fractions. Patient demographics, tumor characteristics, treatment details, and outcomes were collected. The Kaplan-Meier method was used for the survival analysis, and Cox regression models were used to identify prognostic factors for LC, PFS, and OS.

Results

The median follow-up for the 101 patients was 22.4 months (range, 1-58 months). The cohort comprised 82.2% male patients with a median age of 64 years (range, 36-81 years). The majority of the patients (64.4%) had primary tumors originating from non-lung sites, with adenocarcinoma being the predominant histological subtype (47.5%). The median tumor size was 13.5 mm. Across the entire cohort, the median OS was 39 months, and the median PFS was 11 months. Pre-treatment with immunotherapy significantly improved outcomes: the PFS increased to 13 months compared to 7 months for those who did not receive immunotherapy [P=0.02, hazard ratio (HR) = 0.523, 95% confidence interval (CI): 0.302-0.906], and the OS was also significantly improved (P=0.008, HR =0.411, 95% CI: 0.214-0.792). The SBRT regimen of 60 Gy in 10 fractions provided the best outcomes, with a median OS of 39 months, a median PFS of 10 months, and a LC rate of 92.4%, with relatively low toxicity compared to other regimens.

Conclusions

SBRT is a potent, minimally invasive option for managing pulmonary oligometastases, especially when preceded by immunotherapy. The 60 Gy in 10 fractions regimen demonstrated significant efficacy in terms of OS and LC, while maintaining manageable toxicity. Although the retrospective nature of the study introduces some selection bias, this dose regimen appears to offer a promising therapeutic option for pulmonary oligometastases. Further validation through well-designed prospective studies would help confirm the optimal SBRT dose and clarify the role of immunotherapy in this setting.

Stereotactic body radiation therapy in non-liver colorectal metastases: a scoping review

Background

In oligometastatic colorectal cancer (CRC), stereotactic body radiation therapy (SBRT) represents a valid non-invasive local ablative treatment with high rates of local control (LC) and a low toxicity profile. This literature review was performed to evaluate the clinical benefit and toxicity of SBRT on non-liver metastases in CRC oligometastatic patients.

Methods

After searching PubMed, Medscape and Embase databases, 18 retrospective studies focused on body oligometastases excluding bone metastases were included in the analysis.

Results

A total of 1,450 patients with 3,227 lung metastases and 53 patients with 66 nodes lesions were analyzed. BED10 ranged from 76 to 180 Gy. In the lung group, the LC rate was 62-91%, 54-81% and 56-77% after 1, 3 and 5 years, respectively. In the nodes group, the 3-year LC rate was 65-75%. The 1-, 3- and 5-year OS rates were 73-100%, 51-64% and 34-43%, respectively for the lung group, and 63-81% at 3 years for the nodes group.

Conclusions

In CRC patients with non-liver oligometastases, the use of SBRT is effective and safe reaching high LC and survival, with few severe side effects. However, prospective randomized studies are needed to validate the results. These studies will also be useful for identifying any predictive factors that allow us to select the subgroup of patients who benefit from SBRT.

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.

Salvage surgery for local recurrences after stereotactic ablative radiotherapy of colorectal pulmonary metastases

INTRODUCTION

Local control following stereotactic ablative radiotherapy (SABR) for patients with colorectal pulmonary metastases is reportedly lower than for metastases from other tumors. Such recurrences may still be amenable to salvage therapy. We describe our experience with salvage surgery in 17 patients.

METHODS

Patients who underwent salvage metastasectomy for a local recurrence following SABR for colorectal pulmonary metastases were identified from the surgical institutional databases of three Dutch major referral hospitals. Kaplan-Meier survival analysis was performed to determine survival.

RESULTS

Seventeen patients underwent 20 salvage resections for local recurrence of colorectal pulmonary metastases. All patients had a progressive lesion on consecutive CT scans, with local uptake on 18 fluorodeoxyglucose-positron emission tomography computed tomography (FDG-PET CT), and were discussed in a thoracic oncology tumor board. Median time to local recurrence following SABR was 20 months (interquartile range [IQR]: 13-29). Fourteen procedures were performed minimally invasively. Extensive adhesions were observed during three procedures. A Clavien-Dindo grade III-IV complication occurred after four resections (20%). The 90-day mortality was 0%. The estimated median overall survival and progression-free survival following salvage resection were 71 months (confidence intervals [CI]: 50-92) and 39 months (CI: 19-58), respectively. Salvage resections were significantly more extensive, compared to the potential resection assessed on pre-SABR imaging.

CONCLUSIONS

Our experience with 20 salvage pulmonary metastasectomy procedures for local recurrences following SABR in colorectal cancer patients demonstrates that salvage resection is a feasible option with acceptable morbidity and good oncological outcome in a highly selected cohort.

Colorectal Pulmonary Metastases: Pulmonary Metastasectomy or Stereotactic Radiotherapy?

BACKGROUND

Pulmonary metastasectomy and stereotactic ablative radiotherapy (SABR) are both guideline-recommended treatments for selected patients with oligometastatic colorectal pulmonary metastases. However, there is limited evidence comparing these local treatment modalities in similar patient groups.

METHODS

We retrospectively reviewed records of consecutive patients treated for colorectal pulmonary metastases with surgical metastasectomy or SABR from 2012 to 2019 at two Dutch referral hospitals that had different approaches toward the local treatment of colorectal pulmonary metastases, one preferring surgery, the other preferring SABR. Two comparable patient groups were identified based on tumor and treatment characteristics.

RESULTS

The metastasectomy group comprised 40 patients treated for 69 metastases, and the SABR group had 60 patients who were treated for 90 metastases. Median follow-up was 38 months (IQR: 26-67) in the surgery group and 46 months (IQR: 30-79) in the SABR group. Median OS was 58 months (CI: 20-94) in the metastasectomy group and 70 months (CI: 29-111) in the SABR group (p = 0.23). Five-year local recurrence-free survival (LRFS) was 44% after metastasectomy and 30% after SABR (p = 0.16). Median progression-free survival (PFS) was 15 months (CI: 3-26) in the metastasectomy group and 10 months (CI: 6-13) in the SABR group (p = 0.049). Local recurrence rate was 12.5/7.2% of patients/metastases respectively after metastasectomy and 38.3/31.1% after SABR (p < 0.001). Lower BED Gy10 was correlated with an increased likelihood of recurrence (p = 0.025). Clavien Dindo grade III-V complication rates were 2.5% after metastasectomy and 0% after SABR (p = 0.22).

CONCLUSION

In this retrospective cohort study, pulmonary metastasectomy and SABR had comparable overall survival, local recurrence-free survival, and complication rates, despite patients in the SABR group having a significantly lower progression-free survival and local control rate. These data would support a randomized controlled trial comparing surgery and SABR in operable patients with radically resectable colorectal pulmonary metastases.

Single-organ pulmonary metastasis is a favorable prognostic factor in metastatic colorectal cancer patients treated with FOLFIRI and vascular endothelial growth factor inhibitors

BACKGROUND

Few studies have focused on the impact of single-organ pulmonary metastases on progression-free survival and overall survival in patients with metastatic colorectal cancer. Recognizing differences in prognosis and chemotherapeutic efficacy based on metastasized organs may help in optimizing treatment strategies. The exploratory study was conducted to evaluate the comparative clinical outcomes and prognoses of patients with metastatic colorectal cancer presenting with single-organ pulmonary metastases and treated with folinic acid, 5-fluorouracil, irinotecan, and vascular endothelial growth factor inhibitors as second-line chemotherapy.

METHODS

This retrospective study included 289 patients with metastatic colorectal cancer treated with second-line folinic acid, 5-fluorouracil, irinotecan, and vascular endothelial growth factor inhibitors. The response rate, disease control rate, progression-free survival, and overall survival were assessed in the participants.

RESULTS

Among the 289 patients enrolled, 26 (9.0%) had single-organ pulmonary metastasis with left-sided primary locations, lower levels of tumor markers at the initiation point of chemotherapy, a significantly higher disease control rate (96.2% vs. 76.7%, P = .02), and a longer progression-free survival (median 29.6 months vs. 6.1 months, P < .001) and overall survival (median 41.1 months vs. 18.7 months, P < .001) than patients with other forms of metastatic colorectal cancer. Multivariate analysis showed that single-organ pulmonary metastasis was an independent predictor of longer progression-free survival (hazard ratio 0.35, P = .00075) and overall survival (hazard ratio 0.2, P = .006).

CONCLUSION

Single-organ pulmonary metastasis was a strong predictor of progression-free survival and overall survival in patients with metastatic colorectal cancer treated with folinic acid, 5-fluorouracil, irinotecan, and vascular endothelial growth factor inhibitors as second-line chemotherapy; this provides preliminary evidence for medical guidelines and clinical decision-making on novel therapeutic strategies for these patients.

Comprehensive analysis of Japanese nationwide cohort data of particle beam therapy for pulmonary, liver and lymph node oligometastases: particle beam therapy versus high-precision X-ray radiotherapy

Japanese national oncological experts convened to evaluate the efficacy and safety of particle beam therapy (PT) for pulmonary, liver and lymph node oligometastases (P-OM, L-OM and LN-OM, respectively) and to conduct a statistically comparative analysis of the local control (LC) rate and overall survival (OS) rate of PT versus those of X-ray stereotactic body radiotherapy (X-SBRT) and X-ray intensity-modulated radiotherapy (X-IMRT). They conducted [1] an analysis of the efficacy and safety of metastasis-directed therapy with PT for P-OM, L-OM and LN-OM using a Japanese nationwide multi-institutional cohort study data set; [2] a systematic review of X-ray high-precision radiotherapy (i.e. X-SBRT/X-IMRT) and PT for P-OM, L-OM and LN-OM; and [3] a statistical comparison between LC and OS of the cohort data set in PT and that of the extracted historical data set in X-SBRT/X-IMRT from the preceding systematic review. Safety was evaluated as the incidence of grade ≥ 3 adverse events, while statistical comparisons of LC and OS were conducted by estimating the incidence rate ratios (IRR) for local progression and mortality, respectively. This study demonstrated that PT provided durable LC (3-year LC rate: 72.8-83.2%) with acceptable OS (3-year OS rate: 38.5-68.1%) and risk of severe toxicity incidence of 0.8-3.5% in radical metastasis-directed therapy for P-OM, L-OM and LN-OM. Compared to LC with X-SBRT or X-IMRT, LC with PT was potentially superior for P-OM; superior for L-OM; and equivalent for LN-OM. In particular, this study demonstrated that PT may be a new treatment option for L-OM tumors measuring > 5 cm.

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.

Stereotactic Body Radiation Therapy for Pulmonary Metastasis from Colorectal Adenocarcinoma: Biologically Effective Dose 150 Gy is Preferred for Tumour Control

AIMS

To compare the local control rate of pulmonary metastatic lesions in colorectal adenocarcinoma treated with stereotactic body radiation therapy (SBRT) using a biologically effective dose with an α/β ratio of 10 (BED₁₀) of 150 Gy.

MATERIALS AND METHODS

We analysed 231 pulmonary metastatic lesions from colorectal adenocarcinoma treated with SBRT in 135 patients. The patients were referred for the control of oligometastatic or oligoprogressive disease in the lungs. A dose of 40-60 Gy in three to eight fractions was delivered. The local control per tumour (LCpT) by BED₁₀ was evaluated. The local control per patient (LCpP), pulmonary progression-free survival (PPFS), any progression-free survival (APFS) and overall survival were also reported as clinical outcomes.

RESULTS

A significant difference was observed in the LCpT between the BED₁₀ groups (P < 0.001). The 1-, 2- and 3-year LCpT were 38.9%, 25.9% and 25.9% in BED₁₀ < 100 group; 84.1%, 62.6% and 60.4% in 100 ≤ BED₁₀ < 150 Gy group; and 97.3%, 94.9% and 85.2% in BED₁₀ ≥ 150 Gy group, respectively. BED₁₀ ≥ 150 Gy remained significant in the multivariate analysis of LCpT. The 3-year LCpP, PPFS, APFS and overall survival rates were 62.7%, 26.5%, 24.8% and 67.7%, respectively. Oligoprogression (versus oligometastasis), multiple pulmonary nodules and extrapulmonary metastasis were associated with a poor prognosis.

CONCLUSION

A BED₁₀ ≥ 150 Gy may be required to achieve sufficient local control. The indications for SBRT and the extent of metastatic disease should be assessed for proper estimation of the clinical outcomes.

Is it time for redefining oligometastatic disease? Analysis of lung metastases CT in ten tumor types

BACKGROUND

Oligometastatic disease (OD) is usually defined arbitrarily as a condition in which there are ≤ 5 metastases. Given limited disease, it is expected that patients with OD should have better prognosis compared to other metastatic patients and that they can potentially benefit from metastasis-directed therapy (MDT). In this study, we attempted to redefine OD based upon objective evidence that fulfill these assumptions.

METHODS

Chest CTSs of 773 patients with 15,947 lung metastases originating from ten malignancy types were evaluated. The number and largest diameter of each metastasis was recorded. Metastatic cluster was defined as a cluster of two or more metastases with diameter difference ≤ 1 mm. The prognostic power of seven statistical models on overall survival (OS) was analyzed.

FINDINGS

Both the number of metastases and metastatic clusters had a highly significant impact on OS (p < 0.0001, p = 0.003 respectively). Patients with a single metastasis or a single cluster of metastases (regardless of metastases number), equaling 16.2% of all patients, had significantly better prognosis compared to other patients (p = 0.0002). If metastases diameter variability is ignored, as in the standard definition of OD, then patients with 2-5 and 6-10 metastases would have a similar prognosis.

INTERPRETATION

Patients with a single cluster of metastases, theoretically originating from a single clone, have significantly better prognosis compared to patients with more than one cluster. Using this definition can potentially improve the results of MDT. The upper limit of metastases number should be determined by the technical capabilities of the MDT used.