Integrating stereotactic body radiation therapy in stage II/III non-small cell lung cancer: is local control important?

Abstract

Local control for advanced non-small cell lung cancer (NSCLC) remains a significant problem with chemoradiation local failure rates in the chest of 30–50%. Despite attempts at dose escalation with conventional radiation therapy techniques, toxicities limit the amount of radiation that can be delivered. For stage I NSCLC, mounting evidence supports the use of hypofractionated radiation therapy (SBRT) to gain high local control rates with acceptable toxicity. For healthy patients with stage II/III NSCLC, the National Comprehensive Cancer Network guidelines suggest surgery is the preferred standard of care for patients with <N2 nodes or T3 tumors. In select patients who are surgical candidates or have more extensive disease, guidelines may include pre-operative chemoradiation followed by surgery, although this remains controversial and is the subject of a current national clinical trial (RTOG 0839). Dose escalation through conventional radiation therapy planning suggests that we can improve outcomes in stage III patients, but toxicity remains problematic. It follows that with improvements in imaging and delivery of radiotherapy, dose escalation with SBRT incorporation may improve local control in stage II/III NSCLC for medically inoperable patients. The rationale for dose escalation and some of the considerations for incorporation of SBRT dose escalation in stage III lung cancer are reviewed here.

Keywords::

• local control
• stage III lung cancer
• stereotactic body radiation therapy

Financial & competing interests disclosure

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

No writing assistance was utilized in the production of this manuscript.

Key issues

• Patients with inoperable node-positive or locally advanced lung cancer treated with chemoradiation have significant rates of local failure.

• The selected patients who are surgical candidates have improved local control and survival.

• Dose escalation studies have suggested that increased radiation dose may result in improved outcome but are hampered by toxicities.

• Stereotactic body radiation therapy for early stage lung cancer has a high level of local control with low toxicity risk.

• Thus the key question is what factors need to be considered in translating the excellent results of stereotactic body radiation therapy to the treatment of locally advanced or node-positive lung cancers for improving nonsurgical treatment of these patients.