Treatment outcomes of re-irradiation using stereotactic ablative radiotherapy to lung: a propensity score matching analysis

Efficacy and safety analysis in metastatic cancer patients treated with multiple courses of repeat radiation therapy

Background and purpose

Due to advances in oncology, a growing proportion of patients is treated with repetitive courses of radiotherapy. The aim of this study is to analyze whether radiotherapy maintains its safety and efficacy profile in patients treated with multiple repeat courses of irradiation.

Material and methods

All patients treated between 2011 and 2019 at our institution were screened for a minimum of five repeat irradiation courses, to analyze treatment characteristics, survival, safety and efficacy. The type of re-irradiation was classified according to ESTRO-EORTC consensus guidelines.

Results

A total of n = 112 patients receiving n = 660 radiotherapy courses were included in this retrospective cohort study. The most frequent primary tumors were lung cancer in 41.9 % (n = 47) and malignant melanoma in 8.9 % (n = 10). The most frequent re-irradiation types were repeat irradiation and Type 2 re-irradiation in 309 (46.8 %) and 113 (17.1 %) cases, respectively. Median survival after the first course of radiotherapy was 3.6 (0.3-13.4) years. Response to radiotherapy was observed in 548 (83.0 %) cases and CTCAE toxicity grade ≥ 3 was observed in 21 (3.2 %) cases. An increasing number of RT courses (HR: 1.30, p=<0.0001), Type 1 re-irradiation (HR 3.50, p = 0.008) and KPS ≤ 80 % (HR: 2.02, p = 0.002) were associated with significantly worse treatment responses. Toxicity rates remained stable with increasing numbers of RT courses.

Conclusion

Multiple courses of repeat radiotherapy maintain a favorable therapeutic ratio of high response combined with reasonable safety profile.

Ultra-Hypofractionated Re-Irradiation with Anti-PD-1 Immunotherapy for Locoregionally Recurrent (after Radical Chemo-Radiotherapy) Non-Small Cell Lung Cancer

Large fractions of radiotherapy of 8 Gy (ultra-hypofractionated RT, ultra-hypoRT) promote anti-tumor immune responses that have been clinically substantiated in combination trials with immune checkpoint inhibitors (ICIs). In the current study, we postulated that ultra-hypoRT in combination with ICIs may enhance tumor clearance in NSCLC patients with locoregional relapse after radical chemo-RT. Between 2019 and 2021, eleven patients received re-irradiation with one or two fractions of 8 Gy concurrently with anti-PD1 immunotherapy (nivolumab or pembrolizumab). RT-related toxicities were negligible, while immune-related adverse events enforced immunotherapy interruption in 36% of patients. The overall response rate was 81.8%. Tumor reduction between 80 and 100% was noted in 63.5% of patients. Within a median follow-up of 22 months, the locoregional relapse-free rate was 54.5%, while the projected 2-year disease-specific overall survival was 62%. The results were independent of PD-L1 status. The current report provides encouraging evidence that a relatively low biological dose of RT delivered with 8 Gy fractions is feasible and can be safely combined with anti-PD-1 immunotherapy. Despite the low number of patients, the significant tumor regression achieved and the long-lasting locoregional control and overall progression-free intervals provide a basis to pursue immuno-RT trials with U-hypoRT schemes in this group of NSCLC patients of poor prognosis.

Regional lymph node recurrence after stereotactic body radiation therapy for lung cancer: Patterns of recurrence, treatment approaches, and clinical outcomes (KROG 21-09)

PURPOSE

To present the multi-institutional data on patterns of recurrence, treatment approaches, and clinical outcomes for regional lymph node (LN) recurrence after stereotactic body radiation therapy (SBRT) for primary lung cancer.

MATERIALS AND METHODS

The medical records of 114 patients who experienced regional LN recurrence as the first recurrence after lung SBRT were retrospectively reviewed. Patterns of recurrence were classified as local recurrence, regional recurrence, and distant metastasis. Clinical outcomes including progression-free survival (PFS) and overall survival (OS) were analyzed.

RESULTS

Half of the patients had regional LN recurrence only. The most common simultaneous recurrence was distant metastasis (38.6 %). Common sites of regional recurrence were ipsilateral hilar (47.2 %), ipsilateral upper mediastinal (40.6 %), and subcarinal (42.5 %) LN stations. 24 (21.1 %) patients underwent salvage radiation therapy (RT), and 44 (38.6 %) patients underwent palliative treatment. Better OS was observed in the salvage RT group (p = 0.025). The 1-year PFS and OS rates were 27.7 % and 55.2 %, respectively, with salvage RT, 14.0 % and 39.9 %, respectively, with palliative treatment, and 22.8 % and 26.8 %, respectively, with no additional treatment. Multivariate analysis showed that salvage RT (PFS, HR 0.463, p = 0.050; OS, HR 0.312, p = 0.002), palliative treatment (PFS, HR 0.436, p = 0.013; OS, HR 0.553, p = 0.050), and simultaneous distant metastasis (PFS, HR 2.335, p = 0.005; OS, HR 1.726, p = 0.054) affected clinical outcomes.

CONCLUSION

Many cases of regional LN recurrence are confined to the locoregional area of patients, and appropriate treatment can improve the prognosis of these patients.

[Stereotactic radiotherapy for localized primary lung tumours of stage T1-T2]

The historical treatment for stage I non-small cell lung cancer is surgical. Parenchymal amputation is not always possible due to cardiopulmonary comorbidities and stereotactic radiotherapy is one of the alternatives to an invasive procedure. The excellent results observed for inoperable tumors raised the question of this treatment in operable patients. This article presents the data in these two situations and the future perspectives.