Local failure after primary radiotherapy in lung cancer: Is there a role for SBRT?

Abstract

Aim: Our purpose is to construe the role of stereotactic body radiation therapy (SBRT) in the management of lung cancer from our early experience with SBRT for salvage treatment in patients with recurrent lung cancer after initial radiation therapy.

Background: Locoregional recurrences are a frequent challenge in patients treated with radio-chemotherapy for locally advanced NSCLC. Conventional external beam radiation therapy (EBRT) is rarely given as salvage treatment because of the risk of toxicity. There is a paucity of published studies evaluating the role of SBRT in this clinical setting.

Materials and methods: Between 2008 and present, 10 patients with biopsy proven non-small cell lung cancer (NSCLC) underwent 14 radiosurgical procedures for salvage therapy after failing initial radiation treatment. Patients' age ranged from 54 to 88 years with a median of 74 years in 6 males and 4 females. Intervals from initial radiation treatment to salvage SBRT were 3-33 months with a median of 13 months. SBRT treatments were delivered using Intensity Modulated Volumetric Arc Therapy (VMAT). All patients received concomitant chemotherapy.

Results: Overall survival after salvage radiosurgery ranged from 6 to 41 months (mean 20 months, median 18 months). Four of the ten patients are alive with disease locally controlled. Of the remaining 6 patients, 4 had distant progression of disease with brain metastases and one had both brain and lung metastases. The other patient had a regional failure. Toxicities were found in three of the ten (30%) patients with grade I pneumonitis.

Conclusion: In our early experience, salvage SBRT is an effective modality of treating patients who failed after conventional irradiation, achieving excellent results in terms of local control with acceptable toxicity. Further prospective studies are needed to determine optimal fractionation schemes.

Keywords: Lung cancer; Radiation therapy; Radiosurgery; SBRT; Salvage.

Fig. 1

(A) Representative planning images of 74-year-old male with stage III lung cancer for initial course of conventional fractionated RT in October 2008. (B) SBRT plan for salvage of in-field recurrence in the same patient in September 2011. Dose delivered was 3 fractions of 10 Gy each to the ITV. At 41 months follow-up after SBRT retreatment the patient is alive with no evidence of disease.

Fig. 2

(A) Initial fractionated RT to the lung primary lung cancer (July 2012) in an 88-year-old female with stage IV lung cancer who originally presented with spine metastases in June 2012. (B) Infield relapse treated in February 2012 with SBRT: 40 Gy in 4 fractions of 10 Gy each. The patient died from multiple brain metastases with local control in August 2014.

Fig. 3

This is a 59-year-old female originally treated elsewhere for superior vena cava syndrome using conventional RT. (A) Retreatment of the voluminous tumor in the mediastinum using EBRT with 45 Gy. (B and C) Salvage radiosurgery for hilar (B) and mediastinal (C) disease after 3 months using 3 fractions of 5 Gy each with 7 Gy in the center respectively.