Bryan J. Schneider, MD
Brendon M. Stiles, MD
As reported in the Journal of Clinical Oncology by Bryan J. Schneider, MD, of the University of Michigan, Ann Arbor, and colleagues, ASCO has endorsed the recently released American Society for Radiation Oncology (ASTRO) evidence-based guideline on stereotactic body radiotherapy (SBRT) in early stage (T1–2, N0) non–small cell lung cancer (NSCLC).1 Endorsement was based on an updated literature search and review of guideline content by an ASCO expert panel co-chaired by Dr. Schneider and Brendon M. Stiles, MD, of Weill Cornell Medical College.
Patients with stage I NSCLC should be evaluated by a thoracic surgeon, preferably within a multidisciplinary cancer care team, to determine operability.— Bryan J. Schneider, MD and colleagues
Tweet this quote
Key recommendations are summarized here. The ASCO panel changes to ASTRO recommendations are shown in bold. ASCO qualifying statements and ASTRO ratings for evidence quality and strength of recommendations are omitted, due to space considerations. More information is available at ASCO.org. The ASTRO guideline can be found at www.practicalradonc.org/article/S1879-8500(17)30121-2/fulltext.2
Part 1: SBRT for Patients With T1–2, N0 NSCLC Who Are Medically Operable
1A. Patients with stage I NSCLC should be evaluated by a thoracic surgeon, preferably within a multidisciplinary cancer care team, to determine operability. The decision to undergo an operation should be made by the surgeon and patient, in collaboration with family members.
1B. For patients with a standard operative risk and stage I NSCLC, SBRT is not recommended as an alternative to surgery outside of a clinical trial. Discussions about SBRT among members of the multidisciplinary cancer care team may be appropriate. For this population, lobectomy with systematic mediastinal/hilar lymph node evaluation remains the recommended treatment, though a sublobar resection may be considered in select clinical scenarios.
1C. For patients with a high operative risk and stage I NSCLC, discussions about SBRT as a potential alternative to surgery are encouraged within the multidisciplinary cancer care team. In cases where SBRT is offered, patients should be informed that although SBRT may have decreased risks from treatment in the short term, the longer-term outcomes > 3 years are not well established.
Part 2: SRBT for Medically Inoperable Patients With T1–2, N0 NSCLC
For patients with centrally located tumors:
2A. SBRT directed toward centrally located lung tumors carries unique and significant risks when compared with treatment directed at peripherally located tumors. The use of three fraction regimens is not recommended in this setting.
2B. Providers should use caution when considering SBRT for central tumors. Delivery of SBRT in more than 3 (ie, 4 or 5) fractions may reduce the risk of severe toxicity. Adherence to volumetric and maximum dose constraints may optimize the safety profile of this treatment. For central tumors for which SBRT is deemed to be too high risk (eg, tumors directly abutting or invading the esophagus or proximal bronchial tree), hypofractionated radiotherapy utilizing 6 to 15 fractions or conventionally fractionated radiotherapy may be considered.
For patients with tumors > 5 cm in diameter:
2C. SBRT may be an appropriate option for select tumors > 5 cm in diameter with an acceptable therapeutic ratio. Adherence to volumetric and maximum dose constraints may optimize the safety profile of this treatment.
For patients lacking tissue confirmation (diagnosis):
2D. Whenever possible, obtain a biopsy prior to treatment with SBRT to confirm a histologic diagnosis of a malignant lung nodule.
2E. SBRT may be delivered to patients who refuse a biopsy, have undergone nondiagnostic biopsy, or who are thought to be at prohibitive risks of biopsy. Prior to SBRT in patients lacking tissue confirmation of malignancy, treatment options should be discussed within a multidisciplinary cancer care team with a consensus that the lesion is radiographically and clinically consistent with a malignant lung lesion based on tumor, patient, and environmental factors.
For patients with synchronous primary or multifocal tumors:
2F. Multiple primary lung cancers can be difficult to differentiate from intrathoracic metastatic lung cancer and pose unique issues for parenchymal preservation; therefore, it is recommended that they are evaluated by a multidisciplinary cancer care team.
2G. Positron-emission tomography/computed tomography and brain magnetic resonance imaging are recommended in patients suspected of having multiple primary lung cancers to help differentiate them from intrathoracic metastatic lung cancer. Invasive mediastinal/hilar staging with endobronchial ultrasound/mediastinoscopy should be strongly considered.
2H. SBRT may be considered by the multidisciplinary cancer care team as a potentially curative treatment option for patients with synchronous multiple primary lung cancers.
2I. SBRT may be considered by the multidisciplinary cancer care team as a potentially curative treatment option for patients with metachronous multiple primary lung cancers.
For patients who underwent pneumonectomy and now have a new primary tumor in their remaining lung:
2J. SBRT may be considered by the multidisciplinary cancer care team as a potentially curative treatment option for patients with metachronous multiple primary lung cancer in a postpneumonectomy setting.
Part 3: Patients With Tumors With Intimal Proximity/Involvement of Mediastinal Structures (Bronchial Tree, Esophagus, Heart, etc)
3A. Providers should use caution when considering SBRT for tumors in close proximity to the proximal bronchial tree. Delivery of SBRT in 4 to 5 fractions may reduce the risks of severe toxicity. Physicians should endeavor to meet the constraints that have been used in prospective studies, given the severe toxicities that have been reported.
3B. Where a discussion within the multidisciplinary cancer care team results in a recommendation for SBRT for tumors in close proximity to the esophagus, physicians should endeavor to meet the constraints that have been used in prospective studies or otherwise reported in the literature, given the severe esophageal toxicities that have been reported.
3C. For tumors in close proximity to the heart and pericardium, SBRT should be delivered in 4 to 5 fractions with a low incidence of serious toxicities to the heart, pericardium, and large vessels observed. Adherence to volumetric and maximum dose constraints used in prospective trials or reported in the literature may optimize the safety profile of this treatment.
For tumors abutting or invading the chest wall:
3D. SBRT is an appropriate option for treatment and may be offered for T1–2 tumors that abut the chest wall. Grade 1 and 2 chest wall toxicity, presenting most commonly as pain due to rib fracture or irritation of the intercostal nerves, is a common occurrence after SBRT that usually resolves with conservative management. Patients with peripheral tumors approximating the chest wall should be counseled on the possibility of this common toxicity.
3E. Until further evidence becomes available to inform the topic, the ASCO expert panel defers a decision for or against endorsement of the use of SBRT in patients with cT3 disease due to chest wall invasion.
Part 4: Role of SBRT in Medically Inoperable -Patients, as Salvage Therapy for Early-Stage Lung Cancer That Recurs
After conventionally fractionated radiotherapy, SBRT, or sublobar resection:
4A. The use of salvage SBRT after primary conventionally fractionated radiation may be offered to selected patients who are identified as appropriate candidates following a discussion among members of the multidisciplinary cancer care team.
4B. Patient selection for salvage SBRT after prior treatment, including primary conventionally fractionated radiation, SBRT, or sublobar resection, is a highly individualized process. Radiation oncologists should assess evidence-based patient, tumor, and treatment factors prior to treatment initiation. ■
DISCLOSURE: For full disclosures of the study authors, visit www.jco.ascopubs.org.
REFERENCES
2. Videtic GMM, Donington J, Giuliani M, et al: Stereotactic body radiation therapy for early-stage non-small cell lung cancer: Executive Summary of an ASTRO evidence-based guideline. Pract Radiat Oncol 7:295-301, 2017.
