Definitive results of a prospective non-randomized phase 2 study on stereotactic body radiation therapy (sbrt) for medically inoperable lung and liver oligometastases from breast cancer

BACKGROUND AND PURPOSE

To report mature results for local control and survival in oligometastatic (OM) breast cancer patients treated with stereotactic body radiotherapy (SBRT) on lung and/or liver lesions in a phase II trial.

METHODS

This is a prospective non-randomized phase II trial (NCT02581670) which enrolled patients from 2015 to 2021. Eligibility criteria included: age > 18 years, ECOG 0-2, diagnosis of breast cancer, maximum of 4 lung/liver lesions (with a maximum diameter < 5 cm), metastatic disease confined to the lungs and liver or extrapulmonary or extrahepatic disease stable or responding to systemic therapy. The primary end-points were local control (LC) and treatment-related toxicities. The secondary end-points included overall survival (OS), distant metastasis-free survival (DMFS), time to next systemic therapy (TTNS), poly-progression free survival (PPFS).

RESULTS

The study included 64 patients with a total of 90 lesions treated with SBRT. LC at 1 and 2 years was 94.9 %, 91 % at 3 years. Median local control was not reached. Median OS was 16.5 months, OS at 1, 2 and 3 years was 87.5 %, 60.9 % and 51.9 %, respectively. Median DMFS was 8.3 months, DMFS at 1, 2 and 3 years was 38.1 %, 20.6 % and 16 % respectively. At univariate analysis, local response to SBRT was found to be statistically linked with better OS, DMFS and STFS.

CONCLUSION

SBRT is a safe and valid option in oligometastatic breast cancer patients, with very high rates of local control. An optimal selection of patients is likely needed to improve survival outcomes and reduce the rate of distant progression.

Prospective phase II trial on ablative stereotactic body radiation therapy (SBRT) for medically inoperable thoracic nodes metastases

BACKGROUND

Oligometastases in mediastinal nodes are increasingly prevalent, posing challenges for treatment with stereotactic body radiotherapy (SBRT) due to proximity to organs at risk (OARs). We report the results of a single prospective observational phase II trial on ablative SBRT for medically inoperable thoracic nodes metastases (NCT02970955).

MATERIAL AND METHODS

Since 2017, patients with < 3 nodal metastases were evaluated by the tumor board and included if deemed inoperable. SBRT was delivered using risk adaptive approach based on number, site and size of metastatic nodes (50 Gy/5fractions, 60 Gy/8fractions, 70 Gy/10 fractions). Planning target volume (PTV) partial underdosage was allowed. The primary end point was local control (LC) at 12 months. Secondary end points were: acute and late toxicities, overall survival (OS), progression free survival (PFS), and time to next systemic therapy (TTNS).

RESULTS

Between 03/2017-11/2021, 32 patients (41 nodal metastases) were included. NSCLC (13pts), breast (5pts) and colorectal cancer (4pts) were the most represented primary tumour. In 66 % cases, partial PTV undercoverage was necessary. LC at 1 and 2 years was 93.5 % and 82.3 %, respectively. Treatment was well-tolerated with no acute or late toxicity ≥ G3. Median OS was 59.7 months. OS at 1 and 2 years was 96.9 % and 83.8 % respectively. Median PFS was 12.2 months. PFS at 1 and 2 years was 53.1 % and 31.3 %, respectively.

CONCLUSION

This trial supported the feasibility and safety of ablative SBRT for thoracic nodes metastases thanks to risk adaptive approach allowing to delay of new systemic therapies. Larger studies are needed to confirm these observations.

Adjuvant Hypofractionated Whole Breast Irradiation (WBI) vs. Accelerated Partial Breast Irradiation (APBI) in Postmenopausal Women with Early Stage Breast Cancer: 5Years Update of the HYPAB Trial

Therapeutical strategies in breast cancer are continuously updating. Recent researches assessed the possibility of irradiating only the surgical bed in selected patients (Partial Breast Irradiation, PBI). In 2014 we designed a study to evaluate toxicity and cosmesis of APBI using Volumetric Modulated Arc Therapy-Rapid Arc compared with hypofractionated whole breast irradiation (WBI). We present here the 5-years updated data. HYPAB was a single-institution randomized trial that recruited 172 patients from 2015 to 2018. Patients underwent conserving surgery and were randomized to either adjuvant WBI (40.5Gy/15 fractions with simultaneous boost to 48 Gy to tumoral bed) or APBI (30Gy/5 fractions), both delivered with VMAT-RA technique. Clinical evaluation was performed during the first visit, once a week during radiotherapy and during follow up. Cosmesis was assessed using the Harvard Scale for Breast Cosmesis. At the time of the analysis 161 patients were eligible, 53% in the WBI and 47% in the APBI group, with a median follow-up of 67 months. Most common late skin toxicities were G1 fibrosis (32%) and oedema (28%) and were higher in the WBI group; no G3 toxicities were observed. Cosmesis was rated poor in only 6 cases. 147 patients had no evidence of disease at the last follow-up, and no patients died of the disease. Mature results confirm the safety and efficacy of APBI in selected early stage breast cancer patients. Late toxicity is improved in the APBI arm at the cost of a slight increase in local relapse. Further studies are ongoing to better elucidate the use of APBI as a de-escalation approach.

Oligometastatic sarcoma treated with Curative intent Ablative Radiotherapy (OSCAR): A multicenter study on behalf of AIRO (Italian association of Radiotherapy and clinical Oncology)

BACKGROUND AND PURPOSE

Stereotactic Ablative Radiotherapy (SABR) is emerging as a valid alternative to surgery in the oligometastatic setting in soft tissue sarcomas (STS), although robust data are lacking. The aim of this study is to evaluate toxicity and efficacy of SABR in oligometastatic STS.

MATERIALS AND METHODS

This is a retrospective multicenter study including adult patients affected by stage IV STS, treated with SABR for a maximum of 5 cranial or extracranial metastases in up to 3 different organs. SABR was delivered with ablative purposes. Study endpoints were overall survival (OS), local control (LC), distant progression free survival (DPFS), time to polymetastatic progression (TTPP), time to new systemic therapy (TTNS) and toxicity.

RESULTS

From 10 Italian RT centers, 138 patients (202 metastases) treated between 2010 and 2022 were enrolled in the study. Treatment was generally well tolerated, no acute or late toxicity ≥ G3 was recorded. Median follow up was 42.5 months. Median OS was 39.7 months. Actuarial OS at 1 and 2 years was 91.5 % and 72.7 %. Actuarial LC at 1 and 2 years was 94.8 % and 88.0 %. Median DPFS was 9.7 months. Actuarial DPFS at 1 and 2 years was 40.8 % and 19.4 %.

CONCLUSION

SABR is a safe and effective approach for the treatment of oligometastatic sarcoma. One out of 5 patients is free of progression at 2-years.

Oligometastatic Prostate Cancer Treated with Stereotactic Body Radiation Therapy: The Role of Three-Dimensional Tumour Volume in Patient Survival

AIMS

The definition of oligometastatic prostate cancer (OPCa) is currently based solely on the maximum number of detectable metastases, as there are no validated biomarkers available. The aim of this study was to identify novel predictive factors for OPCa patients who underwent metastases-directed therapy.

MATERIALS AND METHODS

This monocentre, retrospective study included consecutive OPCa patients with a maximum of five metastases in up to two organs, detected with choline- or PSMA-positron emission tomography, who were treated with metastases-directed stereotactic body radiation therapy. Endpoints were overall survival and progression-free survival, assessed with Kaplan-Meier analysis. Univariate and multivariable Cox regression was carried out to evaluate the association between clinical factors and survival outcomes.

RESULTS

Between 2009 and 2021, 163 patients and 320 metastases were treated with 226 stereotactic body radiation therapy courses. The median three-dimensional metastatic tumour volume was 4.1 cm3, with a range from 0.01 to 233.4 cm3. In total, 87 (53.4%), 21 (12.9%) and 55 (33.7%) metastases were classified as cN1, cM1a and cM1b, respectively. The median follow-up was 28.5 months. The rates of overall survival at 1, 3 and 5 years were 89.5% (95% confidence interval 83.4-93.4), 74.9% (95% confidence interval 66.1-81.7) and 57.2% (95% confidence interval 45.8-67.1), respectively. Multivariable analysis showed that overall survival reduced with the increase in three-dimensional total tumour volume (hazard ratio 1.93, 95% confidence interval 1.06-3.52; P = 0.030) and confirmed a significant difference between cN1 versus cM1a-b disease (hazard ratio 1.81, 95% confidence interval 1.01-3.25; P = 0.046). The cut-off value of total volume correlated with the highest risk of death was 20 cm3 (hazard ratio 2.37, 95% confidence interval 1.34-4.18; P = 0.003). The median progression-free survival was 17.8 months, with 1-, 3- and 5-year rates of 63.7% (95% confidence interval 55.4-70.9), 31.5% (95% confidence interval 22.8-40.6) and 24.7% (95% confidence interval 16.0-34.3).

CONCLUSIONS

This study identified three-dimensional total tumour volume and the site of oligometastases as significant predictors of survival in OPCa patients treated with metastases-directed therapy. These parameters can potentially be used to personalised treatment and improve patient outcome.

A multicenter LArge retrospectIve daTabase on the personalization of Stereotactic ABlative Radiotherapy use in lung metastases from colon-rectal cancer: the LaIT-SABR study

INTRODUCTION

stereotactic ablative radiotherapy (SABR) has been shown to increase survival in oligometastatic disease, but local control of colorectal metastases remains poor. We aimed to identify potential predictive factors of SBRT response through a multicenter large retrospective database and to investigate the progression to the polymetastatic disease (PMD).

MATERIAL AND METHODS

the study involved 23 centers, and was approved by the Ethical Committee (Prot. Negrar 2019-ZT). 1033 lung metastases were reported. Clinical and biological parameters were evaluated as predictive for local progression-free survival (FLP). Secondary end-point was the time to the polymetastatic conversion (tPMC).

RESULTS

Two-year FLP was 75.4%. Two-year FLP for lesions treated with a BED <100 Gy, 100-124 Gy, and ≥125 Gy was 76.1%, 70.6%, and 94% (p=0.000). Two-year FLP for lesion measuring ≤10 mm, 10-20 mm, and >20 mm was 79.7%, 77.1%, and 66.6% (p=0.027). At the multivariate analysis a BED ≥125 Gy significantly reduced the risk of local progression (HR 0.24, 95%CI 0.11-0.51; p=0.000). Median tPMC was 26.8 months. Lesions treated with BED ≥125 Gy reported a significantly longer tPMC as compared to lower BED. The median tPMC for patients treated to 1, 2-3 or 4-5 simultaneous oligometastases was 28.5, 25.4, and 9.8 months (p=0.035).

CONCLUSION

The present is the largest series of lung colorectal metastases treated with SABR. The results support the use of SBRT in lung oligometastatic colorectal cancer patients as it might delay the transition to PMD or offer relatively long disease-free period in selected cases. Predictive factors were identified for treatment personalization.

Long term results of a phase II trial of hypofractionated adjuvant radiotherapy for early-stage breast cancer with volumetric modulated arc therapy and simultaneous integrated boost

PURPOSE

to report toxicity and cosmetic outcome with a median follow-up of 6 years of a phase II trial of hypofractionated radiotherapy with volumetric modulated arc therapy (VMAT) and simultaneous integrated boost (SIB) for early-stage breast cancer after conservative surgery.

MATERIALS AND METHODS

From August 2010 to September 2014, patients requiring adjuvant radiotherapy for early-stage breast cancer were treated according to a phase I-II protocol with SIB to 40.5 and 48 Gy to the breast and the boost region, respectively, with VMAT technique. The primary endpoint evaluated the treatment feasibility regarding adherence to required dose constraints for target, heart and lungs. Acute and late toxicity, local and distant control were secondary endpoints.

RESULTS

450 patients were included in the trial and analysed after a median follow-up of 6 years. Acute toxicity was already presented in a previous paper. Regarding late toxicity, 93% of patients had no skin alteration at five years, while 5.3% and 1.3% did record G1 and G2 residual toxicity, respectively. Cosmetic outcome was scored good or excellent in almost all cases (97.2%), fair only in 2.3% of patients. Residual tenderness in the irradiated breast was reported by 10% of patients. Cosmesis and breast pain improved during follow-up. Two cases of G2 pneumonitis and two cases of ischemic cardiopathy were registered during follow-up. Five cases presented local recurrence in the homolateral breast, four patients had a new primary cancer in the contralateral breast, while distant metastasis developed in 7 patients.

CONCLUSION

After more than six years, hypofractionated VMAT with SIB for adjuvant radiotherapy in early-stage breast cancer patients remains a safe and effective approach. Mature data on skin toxicity and cosmetic outcome are encouraging. However, longer follow-up is required to evaluate local control, cardiac toxicity and secondary carcinogenesis.

Lung cancer management: monitoring and treating resistance development in third-generation EGFR TKIs

INTRODUCTION

Patients treated with third-generation EGFR TKIs will develop resistance to treatment at a certain point. Early detection of resistance occurrence could allow more options for treatment.

AREAS COVERED

We discuss the development of third-generation EGFR TKIs, focusing on osimertinib and discuss the most common resistance mechanisms under evaluation. We also debate how this resistance can be detected; particularly we review the possible application of liquid biopsy in this scenario. Lastly we discuss available treatment options when resistance occurs, with an eye on ongoing trials and possible future developments.

EXPERT OPINION

As resistance will ultimately develop, a strict instrumental follow-up as per international guidelines is required with the aim of detecting this resistance in an early phase. Detecting an oligoprogression could allow the integration of local ablative therapies while further delaying the need for a systemic therapy change. By exploiting the increasing potentiality of liquid biopsy, in the near future, physicians could be able to understand why a patient develops resistance and therefore can choose the best possible individualized treatment option.

The use of radiation therapy for oligoprogressive/oligopersistent oncogene-driven non small cell lung cancer: State of the art

Oncogene-driven non small cell lung cancer (NSCLC) is a distinct entity in thoracic oncology. The availability of effective target therapies, like EGFR inhibitors or ALK inhibitors, have revolutionized the prognosis of these patients. However, despite an initial response in the majority of patients, drug resistance ultimately occurs. In some cases, this resistance develops in few clonal cells (oligoprogression), so that a local ablation of these resistant deposits could allow to maintain the same systemic therapy and possibly to prolong patients' survival. For these purposes, stereotactic body radiation therapy (SBRT) is an ideal local ablative treatment, because it is effective, non invasive and with limited side effects. In this review, we aim to analyze available clinical data to verify whether SBRT can allow these patients to continue with existing target therapy longer, delay the switch to other systemic therapies and improve their outcome modifying the natural history of the disease.

RapidPlan knowledge based planning: iterative learning process and model ability to steer planning strategies

Purpose

To determine if the performance of a knowledge based RapidPlan (RP) planning model could be improved with an iterative learning process, i.e. if plans generated by an RP model could be used as new input to re-train the model and achieve better performance.

Methods

Clinical VMAT plans from 83 patients presenting with head and neck cancer were selected to train an RP model, CL-1. With this model, new plans on the same patients were generated, and subsequently used as input to train a novel model, CL-2. Both models were validated on a cohort of 20 patients and dosimetric results compared. Another set of 83 plans was realised on the same patients with different planning criteria, by using a simple template with no attempt to manually improve the plan quality. Those plans were employed to train another model, TP-1. The differences between the plans generated by CL-1 and TP-1 for the validation cohort of patients were compared with respect to the differences between the original plans used to build the two models.

Results

The CL-2 model presented an improvement relative to CL-1, with higher R² values and better regression plots. The mean doses to parallel organs decreased with CL-2, while D_1% to serial organs increased (but not significantly). The different models CL-1 and TP-1 were able to yield plans according to each original strategy.

Conclusion

A refined RP model allowed the generation of plans with improved quality, mostly for parallel organs at risk and, possibly, also the intrinsic model quality.

The Potential Role of Intensity-modulated Proton Therapy in the Regional Nodal Irradiation of Breast Cancer: A Treatment Planning Study

AIMS

To investigate the role of intensity-modulated proton therapy (IMPT) for regional nodal irradiation in patients with breast carcinoma in comparison with volumetric-modulated arc therapy (VMAT).

MATERIALS AND METHODS

A cohort of 20 patients (10 in the breast-conserving surgery group and 10 post-mastectomy patients with tissue expander implants) was investigated. Proton plans were also computed using robust optimisation methods. Plan quality was assessed by means of dose-volume histograms and scored with conventional metrics. Estimates of the risk of secondary cancer induction (excess absolute risk, EAR) were carried out, taking into account fractionation, repopulation and repair.

RESULTS

Concerning target coverage, the data proved a substantial equivalence of VMAT and IMPT: for example, coverage for the 50 Gy target, expressed in terms of V_98%, was 47.8 ± 0.4, 47.6 ± 0.4, 47.3 ± 0.8, consistent with the objective of 47.5 Gy, for post-mastectomy patients for the three groups of patients. Also, the conformality of the dose distributions was similar for the two techniques, about 1.1, without statistically significant differences. Organ at risk planning aims were achieved for all structures for both techniques. The mean dose to the ipsilateral lung was 10.8 ± 1.1, 6.2 ± 0.8, 7.2 ± 1.0; for the contralateral lung was 3.2 ± 0.7, 0.3 ± 0.2, 0.4 ± 0.2; for the contralateral breast was: 3.1 ± 0.7, 0.3 ± 0.3 and 0.3 ± 0.3, whereas it was 3.9 ± 0.9, 0.4 ± 0.3 and 0.5 ± 0.5, respectively, for the heart for VMAT, IMPT and robust IMPT plans over the whole group of patients. Robust optimisation affected the near-to-maximum dose values for contralateral lung and breast, the mean dose for the heart and ipsilateral lung, with a deterioration ranging from 20 to 40% of the nominal value of IMPT plans (e.g. from 8.1 ± 6.4 to 11.4 ± 8.8 for the heart compared with 16.2 ± 5.2 for the VMAT plans). The numerical values of EAR per 10 000 patient-years were about one order of magnitude higher for VMAT than for IMPT for contralateral structures: 11.66 ± 2.01, 0.89 ± 0.80, 0.98 ± 0.77 for the contralateral breast and the three groups of plans, respectively; 14.31 ± 2.75, 1.42 ± 0.80, 1.78 ± 0.87 for the contralateral lung; and 34.86 ± 2.64, 18.85 ± 2.15, 20.98 ± 2.35 for the ipsilateral lung.

CONCLUSION

IMPT with or without robust optimisation seems to be a potentially promising approach for the radiation treatment of breast cancer when nodal volumes should be irradiated. This was measured in terms of dosimetric advantage and predicted clinical benefit. In fact, the significant reduction in estimated EAR could add further clinical value to the dosimetric sparing of the organs at risk achievable with IMPT.

Innovative therapy, monoclonal antibodies, and beyond: Highlights from the eighth annual meeting

The eighth annual conference of "Innovative therapy, monoclonal antibodies, and beyond" was held in Milan on Jan. 26, 2018, and hosted by Fondazione IRCCS-Istituto Nazionale dei Tumori (Fondazione IRCCS INT). The conference was divided into two main scientific sessions, of i) pre-clinical assays and novel biotargets, and ii) clinical translation, as well as a third session of presentations from young investigators, which focused on recent achievements within Fondazione IRCCS INT on immunotherapy and targeted therapies. Presentations in the first session addressed the issue of cancer immunotherapy activity with respect to tumor heterogeneity, with key topics addressing: 1) tumor heterogeneity and targeted therapy, with the definition of the evolutionary Index as an indicator of tumor heterogeneity in both space and time; 2) the analysis of cancer evolution, with the introduction of the TRACERx Consortium-a multi-million pound UK research project focused on non-small cell lung cancer (NSCLC); 3) the use of anti-estrogen agents to boost immune recognition of breast cancer cells; and 4) the high degree of functional plasticity within the NK cell repertoire, including the expansion of adaptive NK cells following viral challenges. The second session addressed: 1) the effectiveness of radiotherapy to enhance the proportion of patients responsive to immune-checkpoint blockers (ICBs); 2) the use of MDSC scores in selecting melanoma patients with high probability to be responsive to ICBs; and 3) the relevance of the gut microbiome as a predictive factor, and the potential of its perturbation in increasing the immune response rate to ICBs. Overall, a picture emerged of tumor heterogeneity as the main limitation that impairs the effectiveness of anti-cancer therapies. Thus, the choice of a specific therapy based on reproducible and selective predictive biomarkers is an urgent unmet clinical need that should be addressed in order to increase the proportion of long-term responding patients and to improve the sustainability of novel drugs.

Can Stereotactic Body Radiation Therapy Be a Viable and Efficient Therapeutic Option for Unresectable Locally Advanced Pancreatic Adenocarcinoma? Results of a Phase 2 Study

PURPOSE

To assess the efficacy of stereotactic body radiotherapy in patients with unresectable locally advanced pancreatic cancer.

MATERIALS AND METHODS

All patients received a prescription dose of 45 Gy in 6 fractions. Primary end point was freedom from local progression. Secondary end points were overall survival, progression-free survival, and toxicity. Actuarial survival analysis and univariate or multivariate analysis were investigated.

RESULTS

Forty-five patients were enrolled in a phase 2 trial. Median follow-up was 13.5 months. Freedom from local progression was 90% at 2 years. On univariate ( P < .03) and multivariate analyses ( P < .001), lesion size was statistically significant for freedom from local progression. Median progression-free survival and overall survival were 8 and 13 months, respectively. On multivariate analysis, tumor size ( P < .001) and freedom from local progression ( P < .002) were significantly correlated with overall survival. Thirty-two (71%) patients with locally advanced pancreatic cancer received chemotherapy before stereotactic body radiotherapy. Median overall survival from diagnosis was 19 months. Multivariate analysis showed that freedom from local progression ( P < .035), tumor diameter ( P < .002), and computed tomography before stereotactic body radiotherapy ( P < .001) were significantly correlated with overall survival from diagnosis.

CONCLUSION

Stereotactic body radiotherapy is a safe and effective treatment for patients with locally advanced pancreatic cancer with no G3 toxicity or greater and could be a promising therapeutic option in multimodality treatment regimen.

RapidPlan head and neck model: the objectives and possible clinical benefit

Background

To evaluate a knowledge based planning model for RapidPlan (RP) generated for advanced head and neck cancer (HNC) patient treatments, as well its ability to possibly improve the clinical plan quality. The stability of the model was assessed also for a different beam geometry, different dose fractionation and different management of bilateral structures (parotids).

Methods

Dosimetric and geometric data from plans of 83 patients presenting HNC were selected for the model training. All the plans used volumetric modulated arc therapy (VMAT, RapidArc) to treat two targets at dose levels of 69.96 and 54.45 Gy in 33 fractions with simultaneous integrated boost. Two models were generated, the first separating the ipsi- and contra-lateral parotids, while the second associating the two parotids to a single structure for training. The optimization objectives were adjusted to the final model to better translate the institutional planning and dosimetric strategies and trade-offs. The models were validated on 20 HNC patients, comparing the RP generated plans and the clinical plans. RP generated plans were also compared between the clinical beam arrangement and a simpler geometry, as well as for a different fractionation scheme.

Results

RP improved significantly the clinical plan quality, with a reduction of 2 Gy, 5 Gy, and 10 Gy of the mean parotid, oral cavity and laryngeal doses, respectively. A simpler beam geometry was deteriorating the plan quality, but in a small amount, keeping a significant improvement relative to the clinical plan. The two models, with one or two parotid structures, showed very similar results. NTCP evaluations indicated the possibility of improving (NTCP decreasing of about 7%) the toxicity profile when using the RP solution.

Conclusions

The HNC RP model showed improved plan quality and planning stability for beam geometry and fractionation. An adequate choice of the objectives in the model is necessary for the trade-offs strategies.

Organs at risk in lung SBRT

Lung stereotactic body radiotherapy (SBRT) is an accurate and precise technique to treat lung tumors with high 'ablative' doses. Given the encouraging data in terms of local control and toxicity profile, SBRT has currently become a treatment option for both early stage lung cancer and lung oligometastatic disease in patients who are medically inoperable or refuse surgical resection. Dose-adapted fractionation schedules and ongoing prospective trials should provide further evidence of SBRT safety trying to reduce toxicities and complications. In this heterogeneous scenario, a non-systematic review of dose constraints for lung SBRT was performed, including the main organs at risk in the thorax.