Clinical applications of stereotactic radiation therapy for oligometastatic cancer patients: a disease-oriented approach

Stereotactic body radiotherapy for mediastinal lymph node with CyberKnife®: Efficacy and toxicity

PUPRPOSE

Stereotactic body radiotherapy is more and more used for treatment of oligometastatic mediastinal lymph nodes. The objective of this single-centre study was to evaluate its efficacy in patients with either a locoregional recurrence of a pulmonary or oesophageal cancer or with distant metastases of extrathoracic tumours.

PATIENTS AND METHODS

Patients with oligometastatic mediastinal lymph nodes treated with CyberKnife from June 2010 to September 2020 were screened. The primary endpoint was to assess local progression free survival and induced toxicity. Secondary endpoints were overall survival and progression free survival. The delay before introduction of systemic treatment in the subgroup of patients who did not receive systemic therapy for previous progression was also evaluated.

RESULTS

Fifty patients were included: 15 with a locoregional progression of a thoracic primary tumour (87% pulmonary) and 35 with mediastinal metastasis of especially renal tumour (29%). Median follow-up was 27 months (6-110 months). Local progression free survival at 6, 12 and 18 months was respectively 94, 88 and 72%. The rate of local progression was significantly lower in patients who received 36Gy in six fractions (66% of the cohort) versus other treatment schemes. Two grade 1 acute oesophagitis and one late grade 2 pulmonary fibrosis were described. Overall survival at 12, 18 and 24 months was respectively 94, 85 and 82%. Median progression free survival was 13 months. Twenty-one patients were treated by stereotactic body irradiation alone without previous history of systemic treatment. Among this subgroup, 11 patients (52%) received a systemic treatment following stereotactic body radiotherapy with a median introduction time of 17 months (5-52 months) and 24% did not progress.

CONCLUSION

Stereotactic body irradiation as treatment of oligometastatic mediastinal lymph nodes is a well-tolerated targeted irradiation that leads to a high control rate and delay the introduction of systemic therapy in selected patients.

Oligometastatic disease from differentiated thyroid cancer: best treatment schemes

PURPOSE OF REVIEW

Patients with slowly progressive and/or symptomatic oligometastatic radioactive iodine refractory (RAIR) differentiated thyroid carcinomas (DTCs) are candidates to receive locoregional treatment to delay the start of systemic therapy with multikinase inhibitors. Information provided by the recent literature has not been extensively reviewed in previous published works, thus we aim to bridge this gap.

RECENT FINDINGS

We present for each metastatic site the different locoregional treatment options, contraindications and potential adverse events. Some techniques can be combined together, whereas others are discouraged in certain situations, requiring a high level of expertise and multidisciplinarity in the treatment algorithm.

SUMMARY

Different techniques of radiation therapy and interventional radiology allow to control the metastatic spread. However, as no clinical trials are available to compare the treatment schemes in terms of safety and potential impact on the prognosis, the most appropriate option for each patient should be selected within a multidisciplinary decision making, taking into account the clinical conditions and the pattern/rapidity of metastatic disease.

Management of single pulmonary metastases from colorectal cancer: State of the art

Colorectal cancer (CRC) is one of the most common causes of death from cancer. Lung seeding occurs in approximately 10% of patients surgically treated for primary CRC with radical intent: the lung is the most common site of metastases after the liver. While surgical treatment of liver metastases is widely accepted to affect long-term outcomes, more controversial and not standardized is the therapy for CRC patients developing lung metastases. Experience suggests the potential curative role of pulmonary metastasectomy, especially in oligometastatic disease. However, the optimal strategy of care and the definition of prognostic factors after treatment still need to be defined. This review focused on the uncommon scenario of single pulmonary metastases from CRC. We explored pertinent literature and provide an overview of the epidemiology, clinical characteristics and imaging of single pulmonary metastases from CRC. Additionally, we identified the best available evidence for overall management. In particular, we analyzed the role and results of locoregional approaches (surgery, radiotherapy or ablative procedures) and their integration with systemic therapy.

Solitary prostate cancer liver metastasis: an exceptional indication for liver resection

INTRODUCTION

Prostatic cancer metastases (PCM) are usually systemic. Isolated PCM liver metastases (PCLM) are very rare. The treatment of PCM consists of hormono- and chemotherapy eventually combined with stereotactic radiation.

PATIENT AND DISCUSSION

A case of a 67-year old man presenting with a solitary, metachronous PCLM undergoing a left extended hepatectomy due to resistance to hormono- and chemotherapy is reported. He died of recurrent systemic disease 31 months later.

CONCLUSIONS

The very rare indication and possible role of liver resection in the treatment of PCLM is discussed.

Current Management of Bone Metastases from Differentiated Thyroid Cancer

Simple Summary

Patients with bone metastases (BMs) from differentiated thyroid carcinoma (DTC) can live longer than those with BMs from other cancers. BMs from DTC create destructive lesions and easily cause intractable pain and neurological symptoms, including paralysis. These symptoms related to BMs affect mortality directly and indirectly by hampering the application of systemic therapies. Therefore, long-term local control of BMs in patients with DTC is desired, especially in patients with single or a small number of metastases. Local treatments for BMs have recently become advanced and sophisticated in surgery, radiotherapy, and percutaneous procedures. These therapies, either alone or in combination with other treatments, can effectively improve, or prevent the deterioration of, the performance status and quality of life of patients with DTC-BM. Among local therapies, complete surgical resection and stereotactic radiosurgery are the mainstay for achieving long-term control of DTC-BM.

Abstract

After the lung, the skeleton is the second most common site of distant metastases in differentiated thyroid carcinoma (DTC). Patients with osteolytic bone metastases (BMs) from thyroid carcinoma often have significantly reduced performance status and quality of life. Recent advancements in cancer therapy have improved overall survival in multiple cancer subtypes, including thyroid cancer. Therefore, long-term local control of thyroid BMs is desired, especially in patients with a single metastasis or oligometastases. Here, we reviewed the current management options for DTC-BMs and especially focused on local treatments for long-term local tumor control from an orthopedic tumor surgeon’s point of view. Metastasectomy and stereotactic radiosurgery can be performed either alone or in combination with radioiodine therapy and kinase inhibitors to cure skeletal lesions in selected patients. Percutaneous procedures have been developed in recent years, and they can also have a curative role in small BMs. Recent advancements in local therapies have the potential to provide not only long-term local tumor control but also a better prognosis.

Bone metastases from differentiated thyroid carcinoma: current knowledge and open issues

Bone represents the second most common site of distant metastases in differentiated thyroid cancer (DTC). The clinical course of DTC patients with bone metastases (BM) is quite heterogeneous, but generally associated with low survival rates. Skeletal-related events might be a serious complication of BM, resulting in high morbidity and impaired quality of life. To achieve disease control and symptoms relief, multimodal treatment is generally required: radioiodine therapy, local procedures-including surgery, radiotherapy and percutaneous techniques-and systemic therapies, such as kinase inhibitors and antiresorptive drugs. The management of DTC with BM is challenging: a careful evaluation and a personalized approach are essential to improve patients' outcomes. To date, prospective studies focusing on the main clinical aspects of DTC with BM are scarce; available analyses mainly include cohorts assembled over multiple decades, small samples sizes and data about BM not always separated from those regarding other distant metastases. The aim of this review is to summarize the most recent evidences and the unsolved questions regarding BM in DTC, analyzing several key issues: pathophysiology, prognostic factors, role of anatomic and functional imaging, and clinical management.

Stereotactic body radiotherapy for adrenal oligometastasis in lung cancer patients

OBJECTIVE

To report our experience on stereotactic body radiotherapy (SBRT) in adrenal metastases from lung cancer.

METHODS

37 oligometastatic lung cancer patients with 38 adrenal metastases submitted to SBRT were retrospectively analyzed. SBRT was delivered by volumetric modulated arc therapy (VMAT) or helical tomotherapy (HT). Primary study end point was local recurrence-free survival (LR-FS) and secondary end points were distant-progression free survival (d-PFS) and overall survival (OS).

RESULTS

Median age was 67 years and primary tumor was non-small-cell lung cancer in 27 (73%) and small-cell lung cancer in 10 (27%) patients. Adrenal metastases were in the left side in 66% cases. Median prescribed dose was 30 Gy in 5 fractions for a median biologically equivalent dose (α/β ratio 10  Gy, BED10) of 48 Gy. Most patients (62%) were submitted to SBRT alone, while the others (38%) received chemo-, immune- or target- therapies. Median follow-up was 10.5 months, median OS 16 months and median d-PFS 3 months. 27 (70%) patients obtained a local control with a median LR-FS of 32 months. LR-FS was significantly related to BED10 with a better LC with BED10 ≥72 Gy, 1- and 2 year LR-FS rates were 54.1±11.6% and 45±12.7% vs 100 and 100% for BED ≤59.5 Gy and BED ≥72 Gy, respectively (p = 0.05). There was no severe toxicity.

CONCLUSION

SBRT was effective and safe in lung cancer adrenal metastases. A dose-response relationship was found between BED10 >72 Gy and better local control. No significant toxicity was registered thanks to the respect of dose constraints and suspension of chemo- and target-therapies.

ADVANCES IN KNOWLEDGE

SBRT with a BED10 >72 Gy is an effective treatment for adrenal oligometastatic lung cancer patients.

Modern evidence and future prospects of external body radiation therapy for lung oligometastases of breast cancer

After Hellman and Weichselbaum defined "Oligometastasis" in 1995, several local therapies for lung oligometastases including surgical resection and external body radiation therapy were reported that improved local control (LC) and progression-free survival, overall survival, and quality of life. This suggests that oligometastases is a potentially curable state. Modern advances in radiation therapy such as stereotactic body radiation therapy (SBRT) in which high dose coverage of target lesion without exposure of normal organ is possible, and are widely used to treat solitary or a limited number of primary lung cancer and metastases. Several reports showed that SBRT was a useful treatment method for lung oligometastases, and the LC rate of SBRT was 80-90% in 2 years and less invasive than surgical resection. SBRT is a safe and effective especially for small and peripheral lung metastases. However, if the metastatic lesion is big or centrally located, careful treatment is necessary to prevent radiation pneumonitis. After SBRT, it is sometimes difficult to differentiate local recurrence and pulmonary injury, especially in the early phase. However, it is important to detect local recurrence especially in patients who require further local therapy such as surgical resection and re-irradiation or systemic therapy. The diagnosis can be improved by determining the natural course after SBRT and local recurrence with computed tomography imaging and ¹⁸F-fluorodeoxyglucose positron emission tomography, respectively. Moreover, radiation therapy may have both local and systemic effects that are related to the enhancement of immune-response after radiation. Currently, several trials evaluating the benefits of SBRT for oligometastatic breast cancer are underway. However, the adaption of SBRT for lung metastases including other treatment strategies should be carefully discussed by the radiation oncologist and a multi-disciplinary team comprising a breast surgeon, medical oncologist, diagnostic radiologist, and radiation oncologist, among others.

Role of radiotherapy in the treatment of metastatic head and neck cancer

In metastatic or locally advanced head and neck tumors that present in frail patients or after chemotherapy progression, radiotherapy is normally used as a palliative treatment, with a high rate of symptom palliation and improvement in quality of life. However, there is controversy about what the optimal regimen is. Moreover, despite the poor prognosis of metastatic head and neck cancer, different retrospective studies have shown that a minority of patients with oligometastatic disease experience prolonged disease-free survival after adding curative radiotherapy treatment to the metastatic disease and/or primary tumor. Different retrospective studies have identified clinical prognostic factors that may be used to select candidate patients with metastatic head and neck cancer for a radical approach with radiotherapy. The purpose of this manuscript is to review the role of radiotherapy in metastatic and locally advanced head and neck tumors.

Oligometastatic cancer in elderly patients: the "blitzkrieg" radiotherapy approach : SBRT in oligometastatic elderly patients

AIMS

To retrospectively evaluate the outcome of stereotactic body radiation therapy (SBRT) in the treatment of elderly patients affected by isolated body metastasis from different primitive tumors.

METHODS

70 patients with isolated body metastasis were treated. Median age at diagnosis was 75 years (IQR 69-80). The most common SBRT fractionation scheme was 5 × 7 Gy (total dose 35 Gy). The primary endpoints were Local Control (LC) and Toxicity. Secondary endpoints were Overall Survival (OS) and Disease-Specific Survival (DSS). Response to radiotherapy was assessed according to RECIST criteria v1.1. Toxicity was registered according to Common Terminology Criteria for Adverse Events (CTCAE) v 4.0. We performed survival analysis with the Kaplan-Meier method. The correlation between time actuarial incidence and clinical parameters was studied.

RESULTS

Median follow-up was 26.5 months. 44 patients (62.8%) were alive at the time of analysis, while 22 (31.4%) died because of the disease. Local control at 2 and 3 years was 87%. The 2-year OS and DSS were 84 and 71%, respectively, while the 3-year values were 57 and 62%. PFS at 2 and 3 years was 41 and 25%, respectively. On univariate analysis, KPS ≥ 90 is statistically correlated with improved OS and DSS (p < 0.05). Acute toxicity of grade ≥ 2 occurred in 4 (5.7%) patients, while late toxicity ≥ 2 was recorded in 6 (8.6%) patients.

CONCLUSIONS

Ablative Radiotherapy represents a safe, effective, and minimally invasive treatment modality for elderly oligometastatic patients who are judged unfit for systemic therapy.

Oligometastatic breast cancer treated with hypofractionated stereotactic radiotherapy: Some patients survive longer than a decade

BACKGROUND

The clinical state of oligometastases describes metastases limited in number and extent, amenable to metastasis-directed therapy. We sought to analyze long-term outcomes and characterize potential prognostic factors, in women with breast cancer (BC) oligometastases treated with hypofractionated stereotactic radiation (HSRT) therapy on a prospective phase II protocol.

METHODS

Forty-eight women with 1-5 extracranial BC oligometastases received HSRT to all radiographically apparent sites of disease. Various dose-fractionation schedules were used. Most (n = 27) received 10 daily fractions, typically ≥50 Gy (n = 17).

RESULTS

BC patients with bone-only oligometastases (BO, n = 12) vs. all other patients (non-BO; n = 36) were significantly younger, more likely to present with oligometastases at the time of primary BC diagnosis (i.e., synchronous), and significantly more likely to have had hormone receptor-positive disease. The 5-year and 10-year overall survival (OS) rates after HSRT were 83% and 75%, respectively, for BO patients vs. 31% and 17%, respectively, for non-BO patients (p = 0.002). BO patients experienced a significantly (p = 0.018) greater freedom from widespread metastases (FFWM). Among non-BO patients, net oligometastatic GTV >25 cc (reflecting disease burden) was a significant factor for freedom from local recurrence (p = 0.047) and FFWM (p = 0.028). The number of oligometastatic lesions (p = 0.007) and organs (p = 0.001) involved were also significant factors for FFWM in non-BO patients.

CONCLUSIONS

Some patients with BC oligometastases treated with HSRT can survive >10 years. Tumor burden (volume and number of lesions) appears to impact risk of recurrence. Further research is needed to help better identify BC patients most likely to benefit from metastasis-directed radiotherapy.

Radiotherapy for oligometastatic cancer: a survey among radiation oncologists of Lombardy (AIRO-Lombardy), Italy

AIMS

To evaluate the use of radiotherapy (RT) for oligometastatic cancer (OMC) among radiation oncologists in Lombardy, Italy.

METHODS AND STUDY DESIGN

A survey with 12 items regarding data of 2016 was sent to all 34 Lombardy RT centers. The survey included six general items and six specific items regarding patient/disease/treatment characteristics.

RESULTS

Thirteen centers answered the survey (38%). All centers responded to general items and 12 centers submitted patient/disease/treatment data. General items The majority of centers (8/13) consider OMC if metastases number is less than 5. The most commonly prescribed dose/fraction is 5-10 Gy (8/13) using schedules of 3-5 fractions (11/13). Patient data items A total of 15.681 patients were treated in 2016 with external beam RT in 12 responding centers, and 1.087 patients were treated for OMC (7%). Primary tumor included lung, prostate, breast, colorectal and other malignancies in 33%, 21%, 12%, 9% and 25% of all OMC patients, respectively. Brain, lymph node, lung, bone, liver and others were the most common treated sites (24%, 24%, 22%, 17%, 8% and 5%, respectively). One and more than one metastasis were treated in 75 and 25% of patients, respectively. The vast majority of patients (95%) were treated with image-guided intensity-modulated RT or stereotactic RT.

CONCLUSIONS

Seven percent of all RT patients in Lombardy are treated for OMC. Extreme hypofractionation and high-precision RT are commonly employed. The initiative of multicenter and multidisciplinary collaboration has been undertaken in order to prepare the platform for prospective and/or observational studies in OMC.

Treatment of Liver Metastases Using an Internal Target Volume Method for Stereotactic Body Radiotherapy

The prognosis of patients with metastatic cancers has improved in the past decades due to effective chemotherapy and oligometastatic surgery. For inoperable patients, local ablation therapies, such as stereotactic body radiotherapy (SBRT), can provide effective local tumor control with minimal toxicity. Because of its high precision and accuracy, SBRT delivers a higher radiation dose per fraction, is more effective, and targets smaller irradiation volumes than does conventional radiotherapy. In addition, steep dose gradients from target lesions to surrounding normal tissues are achieved using SBRT; thus, SBRT provides more effective tumor control and exhibits fewer side effects than conventional radiotherapy. The use of SBRT is prevalent for treating intracranial lesions (known as stereotactic radiosurgery); however, it is now also used for treating spinal and adrenal metastases. Because of advancements in image-guided assistance and respiratory motion management, several studies have investigated the use of SBRT for treating lung or liver tumors, which move as a patient breathes. The results of these studies have suggested that SBRT favorably controls tumors in the case of moving lesions. Four-dimensional computed tomography (4D-CT) with an abdominal compressor (AC) is clinically convenient for effective respiratory motion management. Because this method is noninvasive and allows free breathing, its use reduces complications. Furthermore, patients consider this method convenient. Moreover, it is considered more efficient than other methods of respiratory motion management by physicians and therapists. The use of 4D-CT with an AC for treating pulmonary lesions has also been widely investigated, and the technique is gaining acceptance for treating hepatic lesions. However, the protocols for using 4D-CT with an AC for treating hepatic lesions are different from those used for treating pulmonary lesions. In this article, we describe a new protocol for SBRT with 4D-CT and an AC for treating liver metastases.

Stereotactic Ablative Radiation Therapy Induces Systemic Differences in Peripheral Blood Immunophenotype Dependent on Irradiated Site

PURPOSE

Despite the strong interest in combining stereotactic ablative radiation therapy (SAR) with immunotherapy, limited data characterizing the systemic immune response after SAR are available. We hypothesized that the systemic immune response to SAR would differ by irradiated site owing to inherent differences in the microenvironment of various organs.

METHODS AND MATERIALS

Patients receiving SAR to any organ underwent prospective blood banking before and 1 to 2 weeks after SAR. Peripheral blood mononuclear cells (PBMCs) and serum were isolated. PBMCs were stained with fluorophore-conjugated antibodies against T and natural killer (NK) cell markers. Cells were interrogated by flow cytometry, and the results were analyzed using FlowJo software. Serum cytokine and chemokine levels were measured using Luminex. We analyzed the changes from before to after therapy using paired t tests or 1-way analysis of variance (ANOVA) with Bonferroni's post-test.

RESULTS

A total of 31 patients had evaluable PBMCs for flow cytometry and 37 had evaluable serum samples for Luminex analysis. The total number of NK cells and cytotoxic (CD56^dimCD16⁺) NK cells decreased (P = .02) and T-cell immunoglobulin- and mucin domain-containing molecule-3-positive (TIM3⁺) NK cells increased (P = .04) after SAR to parenchymal sites (lung and liver) but not to bone or brain. The total memory CD4⁺ T cells, activated inducible co-stimulator-positive and CD25⁺CD4⁺ memory T cells, and activated CD25⁺CD8⁺ memory T cells increased after SAR to parenchymal sites but not bone or brain. The circulating levels of tumor necrosis factor-α (P = .04) and multiple chemokines, including RANTES (P = .04), decreased after SAR to parenchymal sites but not bone or brain.

CONCLUSIONS

Our data suggest SAR to parenchymal sites induces systemic immune changes, including a decrease in total and cytotoxic NK cells, an increase in TIM3⁺ NK cells, and an increase in activated memory CD4⁺ and CD8⁺ T cells. SAR to nonparenchymal sites did not induce these changes. By comparing the immune response after radiation to different organs, our data suggest SAR induces systemic immunologic changes that are dependent on the irradiated site.

Local High-Dose Radiotherapy Induces Systemic Immunomodulating Effects of Potential Therapeutic Relevance in Oligometastatic Breast Cancer

Local irradiation of cancer through radiotherapy can induce spontaneous regression of non-directly irradiated lesions, suggesting the involvement of systemic antitumor immune responses. In oligometastatic breast cancer (BC) patients, the use of stereotactic body radiotherapy (SBRT) favors the local control of treated lesions and may contribute to break local tolerance and release tumor-associated antigens (TAAs), improving host antitumor immunity. We performed a detailed immunomonitoring of BC patients undergoing SBRT to verify its ability to “switch on” the anti-tumor immunity both systemically, in peripheral blood, and locally, employing in vitro BC models. Twenty-one BC patients with ≤6 metastases were treated with 3 daily doses of 10 Gy with SBRT. Blood samples for immune profiling were collected before and after treatment. One month after treatment a third of patients displayed the boosting or even the de novo appearance of polyfunctional CD4⁺ and CD8⁺ T cell responses against known BC TAAs (survivin, mammaglobin-A, HER2), through intracellular staining in flow cytometry. Half of patients showed increased numbers of activated natural killer (NK) cells, measured with multispectral flow cytometry, immediately after the first dose of SBRT. Interestingly, high levels of activated NK cells at diagnosis correlated with a longer progression-free survival. BC in vitro models, treated with the same SBRT modality, showed enhanced expression of MHC class-I and class-II, major histocompatibility complex class I-related chain A/B, and Fas molecules, and increased release of pro-inflammatory cytokines, such as IL-1β and TNF-α. Consistently, we noticed enhanced production of perforin by CD4⁺ T cells when patients’ lymphocytes were cultured in the presence of irradiated BC cell line, compared to untreated targets. Besides immunogenic effects, SBRT also enhanced the percentages of circulating regulatory T cells, and increased indoleamine 2,3 dioxygenase and PD-L1 expression in BC in vitro models. These results suggest that SBRT may boost host antitumor immune responses also in an advanced disease setting such as oligometastatic BC, by inducing immunomodulating effects both locally and systemically. However, the concomitant induction of immunosuppressive pathways suggests that a combination with immunotherapy could further enhance the in situ vaccination ability of radiotherapy, possibly further improving the curative potential of SBRT in this subset of patients.

[Hypofractionated stereotactic body radiation therapy for adrenal metastases]

Adrenal glands are a common site for metastatic spread since they represent the fourth metastatic site of solid tumors. Interest in local ablative treatments of oligometastases is growing since literature suggests better progression-free survival, quality of life and potentially overall survival in selected patients. Surgery remains the first treatment of adrenal oligometastases because results are good, with a long enough follow-up. However, stereotactic radiotherapy appears to be comparable to surgery and could be proposed to elderly, unfit, inoperable patients, or even to patients whose systemic treatment should not be suspended for too long. This article aims to present a review of published studies to date on stereotactic radiotherapy of adrenal metastases and to propose a treatment protocol.

[When is a nonsurgical approach possible for metastatic primary tumors and lymph node metastases of the urinary bladder and prostate?]

For metastatic carcinomas of the urinary bladder and prostate, systemic therapy is of primary importance. Due to technological advances in radiation oncology such as stereotactic radiotherapy, intensity-modulated radiotherapy, interstitial radiotherapy, and the combination of radiotherapy and chemotherapy, pelvic irradiation can nowadays be carried out effectively and without the risk of major side effects. New data from other tumor entities and retrospective analyses suggest that the use of these technologies can lead to a clinical benefit in terms of improvement in quality of life, local control, and overall survival. For the time being, the decision to administer radiotherapy to the pelvic region should be made on an individual basis. Retrospective analyses of data from prostate carcinomas in particular are currently being planned. This review article introduces potential indications which are supported with real patient examples and discusses future developments giving an overview of the literature and referring to data from prospective randomized trials.

Pulmonary Manifestations of Solid Non-Pulmonary Malignancies

The lungs are a common site of metastatic disease. Pulmonary metastases develop due to local blood flow and cellular or biochemical properties of tumor cells. Metastases develop from any type of malignancy and may occur via hematogenous, lymphatic, aerogenous, and/or direct spread. Metastatic disease may present with symptoms indistinguishable from primary lung cancer, including dyspnea, hemoptysis, and chest pain. Radiographically, these may present as parenchymal lung disease, mediastinal lymphadenopathy, airway obstruction, or pleural and vascular disease. No part of the thorax is spared from metastatic potential. This review highlights complications of non-pulmonary solid malignancies based on sites of anatomic metastases.

[Reappraisal role of locoregional radiation therapy in metastatic cancers]

Recent innovations in oncology area helped to improve the prognosis of certain cancers including metastatic ones with a decrease in mortality. Recommendations describe the treatment of metastatic cancer as systemic therapy or complementary care and the role of locoregional treatment in the treatment plan only occurs in a palliative context. Currently, in the clinical practice, out of "the evidence based medicine", an early locoregional therapy (surgery or radiation therapy) can be proposed in several cases of metastatic cancers. The aim of the present review is to describe the role of the primary tumor radiation therapy in metastatic disease. In metastatic breast, prostate, cervix, rectal or nasopharyngeal cancers, locoregional treatment including radiation therapy can, in some cases, be discussed and decided in MDT. Ongoing clinical trials in these locations should soon precise the benefit of this locoregional treatment. It will also be important to define the specific criteria in order to select patients who could benefit from this treatment.

What do radiation oncologists require for future advancements in lung SBRT?

Stereotactic Body Radiotherapy (SBRT) is a well established therapeutic option for patients affected with peripheral early stage non-small cell lung cancer (NSCLC), given the positive clinical evidence accumulated so far on its efficacy and safety. SBRT is regarded as the best choice for inoperable patients, and could also be offered as an alternative to surgery to selected operable patients. More recently, its use for lung metastases progressively increased, and SBRT is now regarded as a low toxic and highly effective local therapy for lung oligometastases from different primary tumors, especially colorectal cancer. Improved planning and delivery techniques have facilitated over the years its use on large and/or centrally located primary tumors, and multiple nodules. Given the successful applications and the current wide dissemination of this technique, clinicians are now faced with an increasingly complex and multi-variable decision process. Some clinically relevant factors are still uncertain, and strategies are needed to reduce the risk of both local and distant failures. Secondly, aspects related to target delineation, dose prescription, image guidance and treatment planning still need to be fully addressed; this may hamper, at least for now, the standardization of SBRT procedures through different Institutions making any kind of direct outcomes comparison difficult. We here aim to provide a perspective on the current role of lung SBRT and its critical aspects, highlighting the potential future developments.

Radiotherapy and immune checkpoints inhibitors for advanced melanoma

INTRODUCTION

The therapeutic landscape of metastatic melanoma drastically changed after the introduction of targeted therapies and immunotherapy, in particular immune checkpoints inhibitors (ICI). In recent years, positive effects on the immune system associated to radiotherapy (RT) were discovered, and radiation has been tested in combination with ICI in both pre-clinical and clinical studies (many of them still ongoing). We here summarize the rationale and the preliminary clinical results of this approach.

MATERIALS AND METHODS

In the first part of this review article, redacted with narrative non-systematic methodology, we describe the clinical results of immune checkpoints blockade in melanoma as well as the biological basis for the combination of ICI with RT; in the second part, we systematically review scientific publications reporting on the clinical results of the combination of ICI and RT for advanced melanoma.

RESULTS

The biological and mechanistic rationale behind the combination of ICI and radiation is well supported by several preclinical findings. Retrospective observational series and few prospective trials support the potential synergistic effect between radiation and ICI for metastatic melanoma.

CONCLUSION

RT may potentiate anti-melanoma activity of ICI by enhancing response on both target and non-target lesions. Several prospective trials are ongoing with the aim of further exploring this combination in the clinical setting, hopefully confirming initial observations and opening a new therapeutic window for advanced melanoma patients.