SUMMARY: The American Society for Radiation Oncology (ASTRO) and European Society for Radiotherapy and Oncology (ESTRO) convened a task force to review evidence and provide recommendations on the use of local therapy in the management of extracranial oligometastatic Non Small Cell Lung Cancer (NSCLC). Local therapy is defined as definitive comprehensive treatment of all known cancer (primary tumor, regional nodal metastases, and metastases). This joint guideline by ASTRO and ESTRO addressed 5 important questions focused on the use of local (radiation, surgery, other ablative methods) and systemic therapy in the management of oligometastatic NSCLC. The questions addressed clinical scenarios for using local therapy, sequencing and timing when integrating local with systemic therapies, radiation techniques critical for oligometastatic disease targeting and treatment delivery, and the role of local therapy for oligoprogression or recurrent disease.
Oligorecurrence refers to the general growth of limited numbers of metastatic deposits in patients off systemic therapy. For patients with oligometastates receiving active systemic treatment, they are considered as having oligoprogressive disease if current imaging establishes progression of disease in a limited number of existing and/or new sites, and oligopersistent disease if current imaging establishes stable disease or partial response to therapy, of the existing limited disease. The following recommendations were based on a systematic literature review, and created using ASTRO guidelines methodology. These recommendations focus on the management of extracranial disease with local therapy. This guideline and its recommendations with respect to the multimodally treatment strategy do not differentiate between patients with and without brain metastases.
Key Questions and Recommendations
What are the optimal patient/disease characteristics to select patients with oligometastatic NSCLC for definitive treatment combining systemic and local therapies?
1. Treatment decisions should be made using a patient-centered multidisciplinary team approach.
2. The integration of definitive local therapy is only recommended if technically feasible and clinically safe for all disease sites.
3. A discussion of definitive local therapy as a component of multimodality treatment approach is recommended irrespective of presence of activating driver mutations.
4. Definitive local therapy is recommended only for patients having up to 5 distant metastases, diagnosed with appropriate imaging. Implementation remark: Despite some prospective trials including patients with up to 5 extracranial metastases, most patients enrolled had 1-2 treated oligometastatic lesions, which should be factored into decision-making.
5. For patients with synchronous oligometastatic NSCLC, definitive local therapy to all cancer sites in addition to standard of care systemic therapy is conditionally recommended.
6. For patients with metachronous oligorecurrent NSCLC, definitive local therapy to all oligorecurrent cancer sites in addition to standard of care systemic therapy is conditionally recommended.
7. For patients with induced oligopersistent NSCLC, definitive local therapy to all persistent cancer sites in addition to standard of care systemic therapy is conditionally recommended.
8. For patients with induced oligoprogressive NSCLC receiving systemic therapy, definitive local therapy to all progressive cancer sites is conditionally recommended while continuing the current line of systemic therapy.
What are the selection criteria for choice of local treatment modality in the management of patients with oligometastatic NSCLC?
1. A patient-centered multidisciplinary discussion of the most appropriate local treatment strategy of RT and/or surgery, either alone or in combination, is recommended.
2. RT and/or surgery are recommended as definitive local treatment modalities for the locoregional primary and all oligometastases.
3. Highly conformal RT approaches and minimally invasive techniques for surgery are recommended to minimize morbidity.
4. Deciding between RT and surgery as the definitive local treatment modality should a) Favor RT when multiple organ systems are being treated b) Favor RT when the clinical prioritization is to minimize breaks from systemic therapy c) Favor surgery when large tissue sampling is needed for molecular testing, to guide systemic therapy.
What are the appropriate sequencing and timing of systemic therapy and definitive local therapies for patients with oligometastatic NSCLC?
1. For patients with synchronous oligometastatic NSCLC, 3 months or more of systemic therapy is recommended prior to definitive local therapy.
2. For patients with oligometastatic NSCLC, up-front definitive local treatment for symptomatic lesions should be prioritized. Implementation remark: Symptomatic disease sites (eg, brain metastases) are treated with up-front definitive local therapy.
3. For patients with synchronous oligometastatic NSCLC, the temporary pause of systemic therapy during definitive local therapy versus concomitant treatment should be discussed using a multidisciplinary team approach.
4. For patients with synchronous oligometastatic NSCLC, maintenance systemic therapy is conditionally recommended after completion of definitive local therapy.
What are the optimal dose-fractionation regimens, planning, and delivery technique of RT for patients with oligometastatic NSCLC?
1. Appropriate staging with FDG PET, cranial MRI, and MRI in cases of suspect or proven spine or liver metastases are recommended.
2. Individual assessment of respiratory motion for targets in the lungs and upper abdomen using 4-D CT, fluoroscopy, or MR-cine with appropriate motion compensation is recommended.
3. Highly conformal RT using inverse dose planning, appropriate motion management strategies and image-guided RT delivery are recommended.
4. A risk adapted approach using stereotactic RT (preferred), hypofractionated RT, or alternatively definitive chemoradiation based on the location and burden of disease is recommended.
5. Definitive local RT should use doses and fractionations which achieve durable local control.
Implementation remarks: a) Durable local control defined as minimum 85% local control at 2 years b) Higher BED10 (typically >75 Gy) with SBRT alone is associated with optimal local control c) Lower BED10 (50-75 Gy range) is associated with acceptable local control, typically in the setting of combination systemic therapy and SBRT.
After a definitive local therapy approach for oligometastatic NSCLC, what are the indications for additional local therapy upon disease progression?
1. Systemic therapy is recommended as the preferred treatment option.
2. Additional local therapy should be discussed using a multidisciplinary team approach.
3. Local therapy is conditionally recommended.
4. In patients previously treated with definitive local therapy for oligometastatic NSCLC who subsequently develop repeat oligoprogression or recurrence at sites previously treated with local therapy, re-treatment is conditionally recommended if systemic treatment options are limited, and local therapy can be delivered with toxicity acceptable to the multidisciplinary team and patient.
Treatment of Oligometastatic Non-Small Cell Lung Cancer: An ASTRO/ESTRO Clinical Practice Guideline. Iyengar P, All S, Berry MF, et al. Published:April 25, 2023. https://doi.org/10.1016/j.prro.2023.04.004