Combination of novel systemic agents and radiotherapy for solid tumors - Part II: An AIRO (Italian association of radiotherapy and clinical oncology) overview focused on treatment toxicity

Non-stereotactic radiotherapy in older cancer patients

Old or very old oncological patients represent a heterogeneous and frail population due to concomitant comorbidities. Whether radiotherapy alone or in combination with novel cancer drugs may provide a clear benefit in this setting of patients is still a matter of debate.

The aim of our review is to analyze the evaluation process and the different therapeutic possibilities in older cancer patients, focusing on the different and most disparate applications of radiotherapy. We reviewed the most recent literature on radiotherapy in older patients providing clinical evidence of treatment related toxicity, tolerance and outcomes using standard fractionated and/or hypofractionated irradiation alone or in combination with chemotherapy, targeted and immunotherapy.

In older cancer patients unfit for systemic therapy or surgery, radiotherapy represents a valid therapeutic approach, both with curative and palliative intents, ensuring excellent patient compliance in terms of local toxicity and adherence to therapy.

Hypofractionated radiotherapy combined with targeted therapy or immunotherapy: Dutch survey on current practice, knowledge and challenges

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Radiotherapy referral during targeted therapy or immunotherapy occurs regularly.

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There is a knowledge gap regarding the implications of combined therapy.

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There is no consensus on expected toxicity of combined therapy.

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Multidisciplinary protocols regarding combined therapy are often not available.

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The application of radiotherapy treatment adaptations varies widely when combined with different systemic treatments.

Introduction

With the introduction of tyrosine kinase inhibitors and systemic antibodies, including immune checkpoint inhibitors, the survival of advanced-stage cancer patients has improved for many tumor types. These patients are increasingly referred for radiotherapy, but it is unclear whether radiotherapy combined with these drugs is safe. No international guidelines exist on whether or how to combine these drugs with radiotherapy. Therefore, we investigated the current clinical practice in the Netherlands regarding hypofractionated radiotherapy in patients using targeted drugs and immunotherapy.

Materials and methods

We sent a survey to all 21 Dutch radiotherapy institutes. Dedicated radiation oncologists, medical oncologists and pulmonologists were asked to fill out the survey. The questions explored their familiarity with the combination of targeted drugs and immunotherapy with radiotherapy, the encountered clinical difficulties and factors influencing treatment decisions.

Results

The survey was filled out by 54 respondents from 19 different institutes. The median annual number of patients per radiation oncologist referred for radiotherapy when using targeted drugs or immunotherapy was 10 and 15, respectively. Despite this high number, only 11% of the radiation oncologists stated that they had sufficient information (resources) for adequate treatment decision making. Among all physicians, 44% stated that there was insufficient knowledge within their institute regarding this topic. Only 17% stated that there was a multidisciplinary protocol available. The application of radiotherapy treatment adaptations (technique, dose, fractionation, field size) varied widely. Generally, there seemed to be no consensus regarding the expected toxicity of combined drug-radiotherapy treatments and the expected risk of tumor flare upon temporary drug discontinuation.

Conclusion

There is no consensus amongst involved medical specialties on expected toxicity. Consequently, it is necessary to perform clinical studies examining the safety of combined drug-radiotherapy treatments, to add radiotherapy to phase I-III clinical trials for new drugs and to incorporate outcomes into multidisciplinary, evidence-based guidelines.

Pyrotinib treatment enhances the radiosensitivity in HER2-positive brain metastatic breast cancer patients

Brain metastasis is a common cause of death in HER2-positive breast cancer patients. Currently, it is mainly treated by whole-brain radiotherapy. Pyrotinib is an irreversible pan-ErbB inhibitor, which has demonstrated promising tumor-suppressing activity and acceptable tolerance in previous phase trials. In the present study, we evaluated the efficacy of pyrotinib on HER2-positive brain metastatic breast cancer patients treated with whole-brain radiotherapy. A total of 20 such patients were separated into pyrotinib plus capecitabine and capecitabine-only groups in a 1:1 ratio. All patients met either the primary or secondary endpoints. Oral admission of pyrotinib together with radiotherapy can significantly increase the overall response rate, progression-free survival, time to progression and duration of response of HER2+ brain metastatic breast cancer patients, without causing extra adverse events. In addition, pyrotinib can enhance the radiosensitivity of in-vitro cultured HER2+ breast cancer cell lines. The outcome of our study suggests that pyrotinib might be an effective medication to enhance the tumor radiosensitivity of HER2-positive brain metastatic breast cancer patients.

Thoracic re-irradiation with 3D-conformal or more advanced techniques: A systematic review of treatment safety by the Re-irradiation Study Group of the Italian Association of Radiation and Oncology AIRO

Re-irradiation (re-RT) is a treatment modality that has been actively investigated in recurrent lung cancer or in lung metastases appeared in previously irradiated areas. A literature search, according PRISMA recommendations and a meta-analysis technique were performed with the aims to identify possible factors related to the toxicity incidence and severity of ≥ G3 acute toxicity. 1243 patients and 36 studies, met inclusion criteria. Our results, showed that there was no difference in ≥ G3 acute (10,5%) toxicity rate with respect to different radiation techniques, cumulative dose and re-irradiation total dose and fractionation. Factors eventually related to severe toxicity were described. The frequent lack of a sufficient description of the treatment's intent, the heterogeneity in technique and radiotherapy regimen, makes balancing risk and benefit of re-RT based on published data even more difficult.

Outcome and toxicity of hypofractionated image-guided SABR for spinal oligometastases

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Hypofractionated stereotactic ablative radiotherapy (SABR) in patients with spinal oligometastases.

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High rates of efficacy and minimal toxicity.

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Oligometastatic patients with metachronous spinal metastases seem to benefit the most.

Background

To investigate progression free survival (PFS), local control (LC) and overall survival (OS) outcomes for patients treated with spine hypofractionated stereotactic ablative radiotherapy (SABR) and to evaluate possible predictors of rapid progression in view of a correct patient selection for this potentially curative SABR.

Materials and methods

A cohort of 59 patients with spinal metastases were treated with SABR. Patient selection criteria were the following: histologically proven diagnosis of a solid tumor, a World Health Organization (WHO) score ≤ 2, life expectancy > 6 months, Spinal Instability Neoplastic Score (SINS) ≤ 12 points and presenting with radically treated oligometastatic disease (≤5 lesions) or stable polymetastatic disease with an oligoprogressive lesion.

Results

From March 2015 to June 2019, 59 patients were treated with Linac-based SABR to 64 spinal metastases with a median follow-up of 55 months. SABR was standard delivered every other day in 3 to 10 fractions with median prescription dose of 27 Gy (range 21–49 Gy).

The 1-,2- and 5-year PFS was 98%, 85% and 75% for all patients. OS at 5 years for all patients was 92%. Metachronous lesions (p < 0.01; HR = 7.1) and oligometastatic (vs. oligoprogressive) lesions (p = 0.02; HR = 0.3) were associated with higher PFS in uni- and multivariate Cox regression analysis. No significant predictors in multivariate analysis were demonstrated for rapid progressors.

Vertebral compression fractures developed de novo in 6.3% (4/64) of cases. The median time to fracture was 11 months (range 7–15) after treatment. No other adverse events ≥ 3 grade were observed.

Conclusions

Tumor control and toxicity after high-dose hypofractionated SABR was evaluated in patients with spinal oligometastases. High rates of efficacy and minimal toxicity were demonstrated. Oligometastatic patients with metachronous spinal metastases seem to benefit the most from SABR.

Stereotactic body radiation therapy and radiofrequency ablation for the treatment of liver metastases: How and when?

Limited liver metastases represent a clinical challenge. Surgical approach is the most frequently reported treatment option, however, some patients are not eligible for surgical interventions. Relatively recent technologic advances have permitted the safe use of ablative techniques employed in the cure of hepatic metastases. Among these, radiofrequency ablation (RFA) and stereotactic body radiotherapy (SBRT) have emerged as valid treatments in a significant proportion of patients with intrahepatic oligometastatic disease. This review offers an up-to-date of current available literature on this issue focusing on the use and outcomes of RFA and SBRT, according to the PICO (Population, Intervention, Comparison and Outcomes) criteria.