Once-Weekly, High-Dose Stereotactic Body Radiotherapy for Lung Cancer: 6-Year Analysis of 60 Early-Stage, 42 Locally Advanced, and 7 Metastatic Lung Cancers

Stereotactic body radiation therapy in unresectable stage III non-small cell lung cancer: A systematic review

In unresectable stage III non-small cell lung cancer (NSCLC), the standard of care for most fit patients is concurrent chemotherapy with normofractionated radiotherapy (NFRT), followed by durvalumab consolidation. Nevertheless, almost half of patients will present locoregional or metastatic intrathoracic relapse. Improving locoregional control thus remains an important objective. For this purpose, stereotactic body radiotherapy (SBRT) may be a relevant treatment modality. We performed a systematic review of the literature that evaluate the efficacy and safety of SBRT in this situation, either instead of or in addition to NFRT. Among 1788 unique reports, 18 met the inclusion criteria. They included 447 patients and were mainly prospective (n = 10, including 5 phase 2 trials). In none, maintenance durvalumab was administered. Most reported SBRT boost after NFRT (n = 8), or definitive tumor and nodal SBRT (n = 7). Median OS varied from 10 to 52 months, due to the heterogeneity of the included populations and according to treatment regimen. The rate of severe side effects was low, with <5 % grade 5 toxicity, and mainly observed when mediastinal SBRT was performed without dose constraints to the proximal bronchovascular tree. It was suggested that a biologically effective dose higher than 112.3 Gy may increase locoregional control. SBRT for selected stage III NSCLC bears potential to improve loco-regional tumor control, but at present, this should only be done in prospective clinical trials.

Relationship between Dose Prescription Methods and Local Control Rate in Stereotactic Body Radiotherapy for Early Stage Non-Small-Cell Lung Cancer: Systematic Review and Meta-Analysis

Variations in dose prescription methods in stereotactic body radiotherapy (SBRT) for early stage non-small-cell lung cancer (ES-NSCLC) make it difficult to properly compare the outcomes of published studies. We conducted a comprehensive search of the published literature to summarize the outcomes by discerning the relationship between local control (LC) and dose prescription sites. We systematically searched PubMed to identify observational studies reporting LC after SBRT for peripheral ES-NSCLC. The correlations between LC and four types of biologically effective doses (BED) were evaluated, which were calculated from nominal, central, and peripheral prescription points and, from those, the average BED. To evaluate information on SBRT for peripheral ES-NSCLC, 188 studies were analyzed. The number of relevant articles increased over time. The use of an inhomogeneity correction was mentioned in less than half of the articles, even among the most recent. To evaluate the relationship between the four BEDs and LC, 33 studies were analyzed. Univariate meta-regression revealed that only the central BED significantly correlated with the 3-year LC of SBRT for ES-NSCLC (p = 0.03). As a limitation, tumor volume, which might affect the results of this study, could not be considered due to a lack of data. In conclusion, the central dose prescription is appropriate for evaluating the correlation between the dose and LC of SBRT for ES-NSCLC. The standardization of SBRT dose prescriptions is desirable.

Stereotactic Body Radiation Therapy for the Treatment of Locally Recurrent and Oligoprogressive Non-Small Cell Lung Cancer: A Single Institution Experience

Objectives

To investigate the efficacy and safety of lung stereotactic body radiation therapy (SBRT) for non-small cell lung cancer (NSCLC) including oligorecurrent and oligoprogressive disease.

Methods

Single-institution retrospective analysis of 60 NSCLC patients with 62 discrete lesions treated with SBRT between 2008 and 2017. Patients were stratified into three groups, including early stage, locally recurrent, and oligoprogressive disease. Group 1 included early stage local disease with no prior local therapy. Group 2 included locally recurrent disease after local treatment of a primary lesion, and group 3 included regional or well-controlled distant metastatic disease receiving SBRT for a treatment naive lung lesion (oligoprogressive disease). Patient/tumor characteristics and adverse effects were recorded. Local failure free survival (LFFS), progression free survival (PFS), and overall survival (OS) were estimated using the Kaplan Meier method.

Results

At median follow-up of 34 months, 67% of the study population remained alive. The estimated 3-year LFFS for group 1, group 2, and group 3 patients was 95% (95% CI: 86%-100%), 82%(62% - 100%), and 83% (58-100%), respectively. The estimated 3-year PFS was 59% (42-83%), 40% (21%-78%), and 33% (12%-95%), and the estimated 3-year OS was 58% (41-82%), 60% (37-96%), and 58% (31-100%)), respectively for each group. When adjusted for age and size of lesion, no significant difference in OS, LFFS, and PFS emerged between groups (p > 0.05). No patients experienced grade 3 to 5 toxicity. Eighteen patients (29%) experienced grade 1 to 2 toxicity. The most common toxicities reported were cough and fatigue.

Conclusions

Our data demonstrates control rates in group 1 patients comparable to historical controls. Our study also reveals comparable clinical results for SBRT in the treatment of NSCLC by demonstrating similar rates of LFFS and OS in group 2 and group 3 patients with locally recurrent and treatment naïve lung lesion with well-controlled distant metastatic disease.

Stereotactic radiotherapy for lung oligometastases

30-60% of cancer patients develop lung metastases, mostly from primary tumors in the colon-rectum, lung, head and neck area, breast and kidney. Nowadays, stereotactic radiotherapy (SRT ) is considered the ideal modality for treating pulmonary metastases. When lung metastases are suspected, complete disease staging includes a total body computed tomography (CT ) and/or positron emission tomography-computed tomography (PET -CT ) scan. PET -CT has higher specificity and sensitivity than a CT scan when investigating mediastinal lymph nodes, diagnosing a solitary lung lesion and detecting distant metastases. For treatment planning, a multi-detector planning CT scan of the entire chest is usually performed, with or without intravenous contrast media or esophageal lumen opacification, especially when central lesions have to be irradiated. Respiratory management is recommended in lung SRT, taking the breath cycle into account in planning and delivery. For contouring, co-registration and/or matching planning CT and diagnostic images (as provided by contrast enhanced CT or PET-CT ) are useful, particularly for central tumors. Doses and fractionation schedules are heterogeneous, ranging from 33 to 60 Gy in 3-6 fractions. Independently of fractionation schedule, a BED10 > 100 Gy is recommended for high local control rates. Single fraction SRT (ranges 15-30 Gy) is occasionally administered, particularly for small lesions. SRT provides tumor control rates of up to 91% at 3 years, with limited toxicities. The present overview focuses on technical and clinical aspects related to treatment planning, dose constraints, outcome and toxicity of SRT for lung metastases.

Comparison of stereotactic body radiotherapy and radiofrequency ablation for early-stage non-small cell lung cancer: a systematic review and meta-analysis

Background

Stereotactic body radiation therapy (SBRT) and radiofrequency ablation (RFA) are recommended for patients with inoperable early-stage non-small cell lung cancer (NSCLC), with both offering promising results. However, it is largely unknown which of these two treatment modalities provides superior benefits for patients. Therefore, this systematic review and meta-analysis compared clinical outcomes and safety between SBRT and RFA in patients with inoperable early-stage NSCLC.

Methods

Eligible studies published between 2001 and 2020 were obtained through a comprehensive search of the PubMed, Medline, Embase, and Cochrane Library databases. Original English-language studies on the treatment of early-stage NSCLC with SBRT or RFA were included. Local control (LC) rates, overall survival (OS) rates, and adverse events were obtained by pooled analyses.

Results

Eighty-seven SBRT studies (12,811 patients) and 18 RFA studies (1,535 patients) met the eligibility criteria. For SBRT, the LC rates (with 95% confidence intervals) at 1, 2, 3, and 5 years were 98% (97-98%), 95% (95-96%), 92% (91-93%), and 92% (91-93%), respectively, which were significantly higher than those for RFA [75% (69-82%), 31% (22-39%), 67% (58-76%), and 41% (30-52%), respectively] (P<0.01). There were no significant differences in short-term OS between SBRT and RFA [1-year OS rate: 87% (86-88%) versus 89% (88-91%), P=0.07; 2-year OS rate: 71% (69-72%) versus 69% (64-74%), P=0.42]. Regarding long-term OS, the 3- and 5-year OS rates for SBRT were 58% (56-59%) and 39% (37-40%), respectively, which were significantly (P<0.01) superior to those for RFA [48% (45-51%) and 21% (19-23%), respectively]. The most common complication of SBRT was radiation pneumonitis (grade ≥2), making up 9.1% of patients treated with SBRT, while pneumothorax was the most common complication of RFA, making up 27.2% of patients treated with RFA.

Discussion

Compared with RFA, SBRT has superior LC and long-term OS rates but similar short-term OS rates. Prospective randomized trials with large sample sizes comparing the efficacy of SBRT and RFA are warranted.

Local Control After Stereotactic Body Radiation Therapy for Stage I Non-Small Cell Lung Cancer

PURPOSE

Numerous dose and fractionation schedules have been used to treat medically inoperable stage I non-small cell lung cancer (NSCLC) with stereotactic body radiation therapy (SBRT) or stereotactic ablative radiation therapy. We evaluated published experiences with SBRT to determine local control (LC) rates as a function of SBRT dose.

METHODS AND MATERIALS

One hundred sixty published articles reporting LC rates after SBRT for stage I NSCLC were identified. Quality of the series was assessed by evaluating the number of patients in the study, homogeneity of the dose regimen, length of follow-up time, and reporting of LC. Clinical data including 1, 2, 3, and 5-year tumor control probabilities for stages T1, T2, and combined T1 and T2 as a function of the biological effective dose were fitted to the linear quadratic, universal survival curve, and regrowth models.

RESULTS

Forty-six studies met inclusion criteria. As measured by the goodness of fit χ2/ndf, with ndf as the number of degrees of freedom, none of the models were ideal fits for the data. Of the 3 models, the regrowth model provides the best fit to the clinical data. For the regrowth model, the fitting yielded an α-to-β ratio of approximately 25 Gy for T1 tumors, 19 Gy for T2 tumors, and 21 Gy for T1 and T2 combined. To achieve the maximal LC rate, the predicted physical dose schemes when prescribed at the periphery of the planning target volume are 43 ± 1 Gy in 3 fractions, 47 ± 1 Gy in 4 fractions, and 50 ± 1 Gy in 5 fractions for combined T1 and T2 tumors.

CONCLUSIONS

Early-stage NSCLC is radioresponsive when treated with SBRT or stereotactic ablative radiation therapy. A steep dose-response relationship exists with high rates of durable LC when physical doses of 43-50 Gy are delivered in 3 to 5 fractions.

A single institutional experience with central lung stereotactic body radiation therapy demonstrating encouraging results with increased inter-fraction time

Background

Stereotactic body radiation therapy (SBRT) is an effective treatment modality for non-small cell lung cancer (NSCLC); however, there are concerns regarding potential toxicity for centrally located tumors.

Methods

This retrospective study considered patients with SBRT for central lung NSCLC (defined as a tumor within 2 cm of any mediastinal critical structure). The institutional protocol was that patients with central tumors received SBRT less frequently than daily—generally once or twice weekly.

Results

A total of 115 patients with 148 lesions were treated with SBRT to a median 45 [5–60] Gy in 4 [1–5] fractions over a median 5.3 [0–18] days. Many patients treated with this method presented with advanced disease: 58 treatments involved nodal targets, and 42 had stage 3 disease. 52% of patients had chronic obstructive pulmonary disease (COPD), and only 49% had a biopsy, often due to concerns regarding other medical comorbidities. Rates of prior chemotherapy, thoracic surgery, and thoracic radiotherapy were 32%, 21%, and 49%, respectively. Via the Kaplan-Meier method, 2-year overall survival was 65%, and 2-year local control was 77%. Two-year local-progression free survival was 53%, and 2-year progression-survival was 48%. Treatments for stage 3 disease had an impressive 82% 2-year local control that was comparable to early stage treatments. Patients with stage 3 disease had a 2-year overall survival of 59%, which trended towards decreased overall survival compared to early stage patients. There were 13 grade 1 (9%) and 14 grade 2 (9%) toxicities. There were no reported grade ≥3 acute or late toxicities and only 3 cases of pneumonitis.

Conclusions

Our series demonstrates encouraging local control with low rates of toxicity for central lung SBRT, including many stage 3 patients. This may be the result of the relatively large inter-fraction interval. This interval may allow for greater tumor effects (such as reoxygenation) and improved tolerance from normal tissues.

Systematic review of stereotactic body radiotherapy in stage III non-small cell lung cancer

Despite adequate treatment, 50% of stage III locally advanced inoperable non-small cell lung cancer (NSCLC) patients have a locoregional relapse. Local control on early stages on the contrary, is as high as 85-90% with stereotactic body radiotherapy (SBRT). The addition of SBRT to conventional chemoradiation or its use in monotherapy in stage III NSCLC is a novel strategy to decrease local failure that has been explored by various authors. This is a systematic review of studies using SBRT in inoperable stage III NSCLC. Search results obtained 141 articles of which only 6 original studies were pointed as relevant. Three of these studies were prospective, of which 2 were phase I dose-scalation studies and remaining 3 were retrospective. In summary, SBRT outcomes on 134 patients were included. Median dose in the SBRT treatment was 22.5 Gy in 2 to 7 fractions. Obtained global toxicity was 3.7% grade 5 and 14.17% grade 3. Dose-escalation studies proposed a 2 fraction SBRT schedule of 20-24 Gy, obtaining a 78% local control rate at 1 year and an OS of 67%. Initial improvement in local control with this innovative therapeutic strategy has led to ongoing phase II and III clinical trials that will evaluate the efficiency of SBRT in stage III NSCLC clinical scenario.

Early stage lung cancer survival after wedge resection and stereotactic body radiation

BACKGROUND

The comparative effectiveness of stereotactic body radiation therapy (SBRT) and wedge resection in the treatment of early stage lung cancer is still under debate. This meta-analysis compares the 5-year overall survival (OS) of wedge resection and SBRT in patients with stage I non-small cell lung cancer (NSCLC).

METHODS

Original research articles published between 1995 and 2017 were identified through the National Library of Medicine and National Institutes of Health PubMed database and through the reference lists of reviewed articles. Data were processed and analyzed in R (version 3.4.2) and a summary estimate that accounted for the sample size of each study was calculated. The combined percent survival was calculated using random effect models. Funnel plots were used to assess publication bias. Heterogeneity was tested using the Q statistic and the I2 statistic.

RESULTS

There were 16 studies totaling 1,984 patients with stage I NSCLC treated with wedge resection. The meta-estimate was 74% (95% CI, 66-81%), with significant heterogeneity across studies (Q =172.46, P<0.0001; I2=91.30%). Thirty-six studies including 3,309 patients with stage I NSCLC treated with SBRT/SABR produced a meta-estimate of 44% (95% CI, 38-50%), with significant heterogeneity (Q =423.55, P<0.0001; I2=91.74%). Two articles directly comparing stage I NSCLC patients treated with wedge resection to patients treated with SBRT both reported higher 5-year OS after wedge resection.

CONCLUSIONS

SBRT is a treatment option reserved to medically inoperable patients, but could be an alternative to surgery in medically operable patients who prefer a less invasive treatment. More standardized methods for data collection and reporting are necessary to allow better comparisons across published studies.

Partial stereotactic ablative boost radiotherapy in bulky non-small cell lung cancer: a retrospective study

Purpose

Bulky non-small cell lung cancer (NSCLC) is difficult to achieve effective local control by conventionally fractionated radiotherapy (CRT). The present work aims to evaluate the safety and efficacy of partial stereotactic ablative boost radiotherapy (P-SABR) in bulky NSCLC.

Patients and methods

From December 2012 through August 2017, 30 patients with bulky NSCLC treated with P-SABR technique were analyzed. The P-SABR plan consisted of one partial SABR plan (5-9 Gy/f, 3-6 fractions) to gross tumor boost (GTVb), followed by one CRT plan to the planning target volume (PTV). GTVb was the max volume receiving SABR to guarantee the dose of organs-at-risks (OARs) falloff to about 3 Gy/f. The total dose of PTV margin was planned to above 60 Gy. The simply CRT plans were created using the same planning parameters as the original plan, with the goal to achieve comparable OARs doses and PTV margin dose to the P-SABR plan. Dosimetric variables were acquired in both P-SABR and compared CRT plans. Toxicity, local control, and survival were also evaluated.

Results

Median follow-up in survivors was 10.3 months (range=2.3-39.4 months). Eleven patients (36.7%) had partial response (PR) and ten patients (33.3%) had stable disease (SD). Two-year overall survival was 55.6%. Two-year local control rate was 85.7%. No severe acute side effects >CTCAE Grade III were observed. Compared to the simply CRT plan, P-SABR plans achieved similar doses to the OARs and Dmin, but increased dose at the isocenter, Dmean, Dmax, and biological equivalent dose (BED) significantly (P<0.05). BED in the tumor center could reach 107.3 Gy (93.2-132 Gy). Patients with B90≥65% achieved a higher local control rate than those with B90<65% (P=0.010).

Conclusion

This retrospective study suggests that P-SABR is feasible and well tolerated in bulky NSCLC. Local control rate is encouraging, especially for the B90≥65% group, which may due to the ability of P-SABR to optimize BED with equivalent toxicity.

Comparison of the Effectiveness of Radiofrequency Ablation With Stereotactic Body Radiation Therapy in Inoperable Stage I Non-Small Cell Lung Cancer: A Systemic Review and Pooled Analysis

PURPOSE

To performed a systematic review and pooled analysis to compare clinical outcomes of stereotactic body radiation therapy (SBRT) and radiofrequency ablation (RFA) for the treatment of medically inoperable stage I non-small cell lung cancer.

METHODS AND MATERIALS

A comprehensive literature search for published trials from 2001 to 2012 was undertaken. Pooled analyses were performed to obtain overall survival (OS) and local tumor control rates (LCRs) and adverse events. Regression analysis was conducted considering each study's proportions of stage IA and age.

RESULTS

Thirty-one studies on SBRT (2767 patients) and 13 studies on RFA (328 patients) were eligible. The LCR (95% confidence interval) at 1, 2, 3, and 5 years for RFA was 77% (70%-85%), 48% (37%-58%), 55% (47%-62%), and 42% (30%-54%) respectively, which was significantly lower than that for SBRT: 97% (96%-98%), 92% (91%-94%), 88% (86%-90%), and 86% (85%-88%) (P<.001). These differences remained significant after correcting for stage IA and age (P<.001 at 1 year, 2 years, and 3 years; P=.04 at 5 years). The effect of RFA was not different from that of SBRT on OS (P>.05). The most frequent complication of RFA was pneumothorax, occurring in 31% of patients, whereas that for SBRT (grade ≥3) was radiation pneumonitis, occurring in 2% of patients.

CONCLUSIONS

Compared with RFA, SBRT seems to have a higher LCR but similar OS. More studies with larger sample sizes are warranted to validate such findings.

Stereotactic Ablative Body Radiotherapy for Lung Metastases: Where is the Evidence and What are We Doing With It?

This review provides an overview of the use of stereotactic ablative body radiotherapy (SABR) for pulmonary metastases. The local control rates after SABR are generally >90%. Whether this also translates into a significant improvement in overall survival is the subject of ongoing studies. New exciting opportunities including the integration of SABR with targeted and immune therapies as well as some competing treatment strategies are discussed.

Tumor control probability modeling for stereotactic body radiation therapy of early-stage lung cancer using multiple bio-physical models

This work is to analyze pooled clinical data using different radiobiological models and to understand the relationship between biologically effective dose (BED) and tumor control probability (TCP) for stereotactic body radiotherapy (SBRT) of early-stage non-small cell lung cancer (NSCLC). The clinical data of 1-, 2-, 3-, and 5-year actuarial or Kaplan-Meier TCP from 46 selected studies were collected for SBRT of NSCLC in the literature. The TCP data were separated for Stage T1 and T2 tumors if possible, otherwise collected for combined stages. BED was calculated at isocenters using six radiobiological models. For each model, the independent model parameters were determined from a fit to the TCP data using the least chi-square (χ²) method with either one set of parameters regardless of tumor stages or two sets for T1 and T2 tumors separately. The fits to the clinic data yield consistent results of large α/β ratios of about 20Gy for all models investigated. The regrowth model that accounts for the tumor repopulation and heterogeneity leads to a better fit to the data, compared to other 5 models where the fits were indistinguishable between the models. The models based on the fitting parameters predict that the T2 tumors require about additional 1Gy physical dose at isocenters per fraction (⩽5 fractions) to achieve the optimal TCP when compared to the T1 tumors. In conclusion, this systematic analysis of a large set of published clinical data using different radiobiological models shows that local TCP for SBRT of early-stage NSCLC has strong dependence on BED with large α/β ratios of about 20Gy. The six models predict that a BED (calculated with α/β of 20) of 90Gy is sufficient to achieve TCP⩾95%. Among the models considered, the regrowth model leads to a better fit to the clinical data.

Long-term results of a prospective phase II trial of medically inoperable stage I NSCLC treated with SBRT - the Nordic experience

BACKGROUND

Presentation of long term results of a phase II multicenter Nordic trial of medically inoperable stage I non-small cell lung cancer (NSCLC) treated with stereotactic body radiotherapy (SBRT).

MATERIAL AND METHODS

We report the extended outcome, focusing on long-term effects, of a prospective cohort of 57 evaluable patients with peripherally located T1N0M0 (72%) and T2N0M0 (28%) NSCLC, treated with SBRT 15 Gy × 3, prescribed to the 67% isodose line encompassing the PTV. The patients were inoperable due to chronic obstructive pulmonary disease (65%), cardiovascular disease (25%) or other illnesses (3%) or refused surgery (7%). Median Karnofsky score pre-treatment was 80% (70-100%). Late effects were defined as occurring > 36 months.

RESULTS

Thirty-eight patients (67%) were relapse free during their entire follow-up. Local control rate at four and five years were 79% (CI 95% 64-95%) and local relapses occurred at 10-76 months post-treatment. Seven local failures were noted, four occurring ≤ 36 months (all T2a-tumors; two isolated and two in combination with out-of-field relapses) and three occurring > 36 months (T1b-tumors n = 3). Thirteen patients had out-of-field failure only as first presentation of recurrence. Overall survival rate and lung cancer-specific survival rate at five years were 30% and 74%, respectively. Toxicity throughout the entire observation period was acceptable without any grade 5 toxicities. Seventeen grade 3-4 toxicities were noted, three presenting > 36 months (rib fracture, dyspnea and ventricle tachycardia). Median follow-up was 41.5 months (3.4-113.0) for the entire cohort and 59.3 months (36.4-113.0) for the 34 patients (60%) with a follow-up of > 36 months.

CONCLUSION

Throughout the observation period local control was excellent and toxicity limited with no increase in late presenting local relapses or late treatment-related morbidity. This further supports SBRT as an efficient local treatment modality even in a medically impaired patient cohort.

Stereotactic body radiotherapy for early-stage non-small cell lung cancer: clinical outcomes from a National Patient Registry

Objectives

Stereotactic body radiotherapy (SBRT) is a definitive local treatment option for patients with stage I non-small cell lung cancer (NSCLC) who are not surgical candidates and patients who refuse surgery. The purpose of this study was to assess the impact of SBRT on T1–T2 NSCLC from a national registry, reflecting practices and outcomes in a real-world setting.

Methods

The RSSearch® Patient Registry was screened for T1–T2N0M0 NSCLC patients treated from May 2004 to May 2013 with SBRT. Descriptive analyses were used for patient, tumor, and treatment characteristics. Overall survival (OS) and local control (LC) were calculated using the Kaplan-Meier method.

Results

In total, 723 patients with 517 T1 and 224 T2 lesions were treated with SBRT. Median follow-up was 12 months (1–87 months) with a median age of 76 years. Median SBRT dose was 54 Gy (range 10–80 Gy) delivered in a median of 3 fractions (range 1–5), and median biological equivalent dose (BED₁₀) was 151.2 Gy (range 20–240 Gy). Median OS was 30 and 26 months for T1 and T2 tumors, respectively (p = 0.019). LC was associated with higher BED₁₀ for T2 tumors, but not in T1 tumors at a median follow-up of 17 months. Seventeen-month LC for T2 tumors treated with BED₁₀ < 105 Gy, BED₁₀ 105-149, and BED₁₀ ≥ 150 Gy was 43, 74, and 95 %, respectively (p = 0.011). Local failure rates for T2 tumors treated with BED₁₀ < 105 Gy, 105–149 Gy, and ≥150 Gy were 32, 21, and 8 % (p = 0.029), respectively. Median OS for patients with T2 tumors treated with BED₁₀ < 105 Gy was 17 vs. 32 months for T2 tumors treated with BED₁₀ 105–149 Gy (p = 0.062).

Conclusion

SBRT for T1–T2 NSCLC is feasible and effective in the community setting. OS was greater for patients with T1 lesions compared to T2 lesions. An improvement in LC was observed in patients with T2 lesions treated with BED₁₀ > 105 Gy.

Hypofractionated stereotactic body radiation therapy for elderly patients with stage IIB-IV nonsmall cell lung cancer who are ineligible for or refuse other treatment modalities

Objective

In elderly patients with stage IIB–IV nonsmall cell lung cancer who cannot tolerate chemotherapy, conventionally fractionated radiotherapy is the treatment of choice. We present our experience with hypofractionated stereotactic body radiation therapy (SBRT) in the treatment of this patient population.

Methods

Thirty-three patients with a median age of 80 years treated with fractionated SBRT were retrospectively analyzed. Most patients were smokers and had preexisting lung disease and either refused treatment or were ineligible. A median prescribed dose of 40 Gy was delivered to the prescription isodose line over a median of five treatments. The majority of patients (70%) did not receive chemotherapy.

Results

With a median follow-up of 9 months (range: 4–40 months), the actuarial median overall survival (OS) and progression-free survival were 12 months for both. One year actuarial survival outcomes were 75%, 58%, 44%, and 48% for local control, regional control, progression-free survival, and OS, respectively. Increased volume of disease was a statistically significant predictor of worse OS. Three patients developed a grade 1 cough that peaked 3 weeks after treatment and resolved within 1 month. One patient developed grade 1 tracheal mucositis and three patients developed grade 1 pneumonitis. Both resolved 6 weeks after treatment. Three patients died within the first month of treatment, but the cause of death did not appear to be related to the treatment.

Conclusion

Hypofractionated SBRT is a relatively safe and convenient treatment option for elderly patients with inoperable stage IIB–IV nonsmall cell lung cancer. However, given the small sample size and the heterogeneity of the patient population, larger studies are needed before adopting this treatment option into clinical practice.

Clinical outcome of hypofractionated breath-hold image-guided SABR of primary lung tumors and lung metastases

Background

Stereotactic Ablative RadioTherapy (SABR) of lung tumors/metastases has been shown to be an effective treatment modality with low toxicity. Outcome and toxicity were retrospectively evaluated in a unique single-institution cohort treated with intensity-modulated image-guided breath-hold SABR (igSABR) without external immobilization. The dose–response relationship is analyzed based on Biologically Equivalent Dose (BED).

Patients and methods

50 lesions in 43 patients with primary NSCLC (n = 27) or lung-metastases of various primaries (n = 16) were consecutively treated with igSABR with Active-Breathing-Coordinator (ABC®) and repeat-breath-hold cone-beam-CT. After an initial dose-finding/-escalation period, 5x12 Gy for peripheral lesions and single doses of 5 Gy to varying dose levels for central lesions were applied. Overall-survival (OS), progression-free-survival (PFS), progression pattern, local control (LC) and toxicity were analyzed.

Results

The median BED2 was 83 Gy. 12 lesions were treated with a BED2 of <80 Gy, and 38 lesions with a BED2 of >80 Gy. Median follow-up was 15 months. Actuarial 1- and 2-year OS were 67% and 43%; respectively. Cause of death was non-disease-related in 27%. Actuarial 1- and 2-year PFS was 42% and 28%. Progression site was predominantly distant. Actuarial 1- and 2 year LC was 90% and 85%. LC showed a trend for a correlation to BED2 (p = 0.1167). Pneumonitis requiring conservative treatment occurred in 23%.

Conclusion

Intensity-modulated breath-hold igSABR results in high LC-rates and low toxicity in this unfavorable patient cohort with inoperable lung tumors or metastases. A BED2 of <80 Gy was associated with reduced local control.

Stereotactic radiotherapy (SABR) for the treatment of primary non-small cell lung cancer; systematic review and comparison with a surgical cohort

BACKGROUND AND PURPOSE

To assess the efficacy of stereotactic ablative radiotherapy (SABR) for the treatment of non-small cell lung cancer (NSCLC) through a systematic review of all relevant publications from 2006 to the present compared to controls treated with surgery. In the absence of Grade I evidence, the objective outcome data should form the basis for planning future studies and commissioning SABR services.

MATERIALS AND METHODS

Standard systematic review methodology extracting patient and disease characteristics, treatment and outcome data from published articles reporting patient data from populations of 20 or more Stage I NSCLC patients treated with SABR with a median follow up of minimum of 1 year. The individual outcome measures were corrected for stage and summary weighted outcome data were compared to outcome data from a large International Association for the Study of Lung Cancer (IASLC) cohort matched for stage of disease with survival as the principal endpoint and local control (local progression free survival - local PFS) as the secondary endpoint.

RESULTS

Forty-five reports containing 3771 patients treated with SABR for NSCLC were identified that fulfilled the selection criteria; both survival and staging data were reported in 3171 patients. The 2 year survival of the 3201 patients with localized stage I NSCLC treated with SABR was 70% (95% CI: 67-72%) with a 2 year local control of 91% (95% CI: 90-93%). This was compared to a 68% (95% CI: 66-70) 2 year survival of 2038 stage I patients treated with surgery. There was no survival or local PFS difference with different radiotherapy technologies used for SABR.

CONCLUSIONS

Systematic review of a large cohort of patients with stage I NSCLC treated with SABR suggests that survival outcome in the short and medium term is equivalent to surgery for this population of patients regardless of co-morbidity. As selection bias cannot be assessed from the published reports and treatment related morbidity data are limited, a direct comparison between the two treatment approaches should be a priority. In the meantime, SABR can be offered to stage I patients with NSCLC as an alternative to surgery.

Dose escalation with stereotactic body radiation therapy boost for locally advanced non small cell lung cancer

INTRODUCTION

Low survival outcomes have been reported for the treatment of locally advanced non small cell lung cancer (LA-NSCLC) with the standard of care treatment of concurrent chemoradiation (cCRT). We present our experience of dose escalation using stereotactic body radiosurgery (SBRT) following conventional cCRT for patients with LA-NSCLC.

METHODS

Sixteen patients with a median age of 67.5 treated with fractionated SBRT from 2010 to 2012 were retrospectively analyzed. Nine (56%) of the patients had stage IIIB, 6 (38%) has stage IIIA, and 1 (6%) had recurrent disease. Majority of the patients (63%) presented with N2 disease. All patients had a PET CT for treatment planning. Patients received conventional cCRT to a median dose of 50.40 Gy (range 45-60) followed by an SBRT boost with an average dose of 25 Gy (range 20-30) given over 5 fractions.

RESULTS

With a median follow-up of 14 months (range, 1-14 months), 1-year overall survival (OS), progression free survival (PFS), local control (LC), regional control (RC), and distant control (DC) rates were, 78%, 42%, 76%, 79%, and 71%, respectively. Median times to disease progression and regional failure were 10 months and 18 months, respectively. On univariate analysis, advanced age and nodal status were worse prognostic factors of PFS (p < 0.05). Four patients developed radiation pneumonitis and one developed hemoptysis. Treatment was interrupted in one patient who required hospitalization due to arrhythmias and pneumonia.

CONCLUSION

Risk adaptive dose escalation with SBRT following external beam radiotherapy is possible and generally tolerated treatment option for patients with LA-NSCLC.

Is high-dose stereotactic body radiotherapy (SBRT) for stage I non-small cell lung cancer (NSCLC) overkill? A systematic review

BACKGROUND AND PURPOSE

For stereotactic body radiotherapy (SBRT), typically a scheme of 60 Gy in 3-8 fractions is applied, producing local tumour control rates around 90%. The dose specification is in one point only and ignores possible underdosages at the edge of the planning target volume (PTV). We investigated the doses at the edge of the PTV and correlated this with local tumour control with the aim to shed light on the radiation dose needed to eradicate stage I NSCLC.

MATERIALS AND METHODS

Published data on the freedom from local progression (FFLP) data from SBRT and accelerated high-dose conventional radiotherapy series for stage I NSCLC with a follow up of at least 30 months were included. The EQD(2,T) was calculated from the dose at the periphery of the PTV.

RESULTS

Fifteen studies for SBRT (1076 patients) showed a median FFLP of 88.0±10.4% with a median EQD(2,T) of 76.9±17.4 Gy. The median FFLP was 87.6±6.0% for the accelerated schedules with an EQD(2,T) of 86.9±39.1 Gy, respectively. No significant relation was found between FFLP and the EQD(2,T) (p=0.23).

CONCLUSIONS

Several fractionated and accelerated schedules with equal biological doses achieve the same tumour control rates as SBRT. Lower, but more uniform doses to the whole PTV may be sufficient to achieve similar control rates, with the possibility to deliver SBRT in adapted schedules, beneficial to centrally located tumours in the vicinity of critical structures like the oesophagus and great vessels.

Results of stereotactic radiotherapy for stage I non-small-cell lung cancer: is there a need for image guidance and highly sophisticated devices?

SUMMARY In stage I non-small-cell lung cancer, stereotactic body radiation therapy achieves a local control of 90%, by accurate dose delivery with stereotactic beam navigation and/or image-guided techniques, and extremely dose-escalated hypofractionated radiotherapy. Three-to-ten fractions over 1–2 weeks or one single fraction as radiosurgery are used. A broad spectrum of different techniques have also been introduced, some encouraged by electric companies, and heavily commercialized by institutions and physicians. Although a direct comparison of these techniques has been carried out only in technical and not within clinical trials; clinical data from the few prospective Phase I and II trials and the majority of retrospective evaluations have not shown superiority of either technique. Based on personal experiences, there are nearly no limitations for the use of very simple and cheap techniques, and the broad and increasing disposition of dedicated systems is questionable.

Stereotactic body radiation therapy and 3-dimensional conformal radiotherapy for stage I non-small cell lung cancer: A pooled analysis of biological equivalent dose and local control

PURPOSE

To determine the relationship between tumor control probability (TCP) and biological effective dose (BED) for radiation therapy in medically inoperable stage I non-small cell lung cancer (NSCLC).

METHODS AND MATERIALS

Forty-two studies on 3-dimensional conformal radiation therapy (3D-CRT) and SBRT for stage I NSCLC were reviewed for tumor control (TC), defined as crude local control ≥ 2 years, as a function of BED. For each dose-fractionation schedule, BED was calculated at isocenter using the linear quadratic (LQ) and universal survival curve (USC) models. A scatter plot of TC versus BED was generated and fitted to the standard TCP equation for both models.

RESULTS

A total of 2696 patients were included in this study (SBRT: 1640; 3D-CRT: 1056). Daily fraction size was 1.2-4 Gy (total dose: 48-102.9) with 3D-CRT and 6-26 (total dose: 20-66) with SBRT. Median BED was 118.6 Gy (range, 68.5-320.3) and 95.6 Gy (range, 46.1-178.1) for the LQ and USC models, respectively. According to the LQ model, BED to achieve 50% TC (TCD50) was 61 Gy (95% confidence interval, 50.2-71.1). TCP as a function of BED was sigmoidal, with TCP ≥ 90% achieved with BED ≥ 159 Gy and 124 Gy for the LQ and USC models, respectively.

CONCLUSIONS

Dose-escalation beyond a BED 159 by LQ model likely translates into clinically insignificant gain in TCP but may result in clinically significant toxicity. When delivered with SBRT, BED of 159 Gy corresponds to a total dose of 53 Gy in 3 fractions at the isocenter.

Comorbidity-adjusted survival in early stage lung cancer patients treated with hypofractionated proton therapy

Objective. To determine the influence of comorbidity on survival in early-stage lung cancer patients treated with proton radiotherapy, using the Charlson Comorbidity Index. Study Design and Setting. Fifty-four non-small-cell lung cancer patients, treated prospectively in a phase II clinical trial with hypofractionated proton therapy, were analyzed retrospectively to assess their burden of comorbid disease as expressed by Charlson Comorbidity Index. Using the Charlson Comorbidity Index method, a predicted survival curve based on comorbidity was formulated and compared to the observed mortality from causes other than lung cancer in the study population. Results. The study population had an average age score of 2.8 and an average Charlson Comorbidity Index of 4.7. Predicted survival was calculated to be 67% and 50% at 2 and 4 years, respectively. Actual comorbidity-specific survival at 2 and 4 years was 64% and 45%, respectively. The observed survival fell within the 95% confidence intervals of the predicted survival at all time points up to 5 years. Conclusion. Predicted mortality from concurrent disease, based on Charlson Comorbidity Index, correlated well with observed comorbidity-specific mortality. This helps substantiate the accuracy of the data coding in cause of death and strengthens previously reported disease-specific survival rates.

Stereotactic radiotherapy for pulmonary oligometastases: a systematic review

INTRODUCTION

Hypofractionated stereotactic body radiotherapy (SBRT) is an emerging noninvasive technique for the treatment of oligometastatic cancer. The use of small numbers of large doses, should in theory, achieve high rates of local control. The aim of this literature review is to critically assess the use of SBRT for the treatment of pulmonary metastases as judged by its effect on local control, survival, and toxicity.

METHODS

A systematic literature search was performed. Both single fraction stereotactic radiosurgery (SRS) and hypofractionated radiotherapy (SBRT) were considered individually. Thirteen institutions reported results regarding SBRT and seven institutions regarding SRS (a total of 29 publications). Outcomes, techniques, radiobiology, and the scientific rigor of the reported studies were analyzed.

RESULTS

A wide range of techniques, doses, and dose fractionation schedules were found. Three hundred thirty-four patients with 564 targets were reported in the SBRT series. The 2-year weighted local control was 77.9%. The corresponding 2-year weighted overall survival was 53.7%, with a 4% rate of grade 3 or higher radiation toxicities. One hundred fifty-four patients with 174 targets were treated in the SRS series. The 2-year weighted local control was 78.6%. The corresponding weighted 2-year overall survival was 50.3%, with 2.6% rate of grade 3 or higher toxicities.

CONCLUSION

There was insufficient evidence to recommend a consensus view for optimal tumor parameters, dose fractionation, and technical delivery of treatment. This indicates the need for further prospective studies. However, high local control rates that could potentially lead to a survival benefit justifies the consideration of stereotactic radiotherapy for patients with limited pulmonary oligometastases.

Systemic review of the patterns of failure following stereotactic body radiation therapy in early-stage non-small-cell lung cancer: clinical implications

PURPOSE

To analyze the patterns of failure, the toxicity profile, and the factors influencing efficacy of stereotactic body radiation (SBRT) for early-stage non-small-cell lung cancer (NSCLC).

METHODS AND MATERIALS

A search was based on PubMed electronic databases. All searches were conducted in May, 2009.

RESULTS

The local control ranged from 80% to 100% in most studies with adequate isocentric or peripheral biologically effective dose (BED). Recurrences were associated with increased tumor size. The main pattern of failure after SBRT was distant metastasis. Grades 3-5 toxicity occurred mostly in centrally located tumors, and adjuvant chemotherapy may further decrease all recurrences; possibly translating to a survival benefit in large or centrally located tumors where high BED cannot be safely reached.

CONCLUSION

SBRT is an excellent treatment option for early-stage, and mostly medically inoperable, NSCLC. BED at both the isocenter and the tumor periphery is very important for optimal tumor control; higher doses are required for large (T2) lesions; SBRT for centrally located tumors can be feasible with a much less aggressive dose regimen than 60-66Gy/3 fractions and adjacent critical structures excluded from the target volume; chemotherapy may optimize the clinical outcome in large or centrally located lesions.

Comparação entre os volumes pulmonares irradiados com técnica bidimensional e tridimensional conformada na radioterapia de pacientes com tumores de pulmão localmente avançados

OBJETIVO: Comparar e quantificar os volumes pulmonares irradiados utilizando planejamentos bidimensional (2D) e tridimensional (3D) conformado na radioterapia de tumores de pulmão. MATERIAIS E MÉTODOS: Em 27 pacientes portadores de câncer de pulmão foi feito planejamento 3D e outro correspondente em 2D. As doses prescritas variaram de 45 a 66 Gy. Foram avaliadas as doses no volume alvo planejado (PTV), volume tumoral macroscópico (GTV) e pulmões (volume de pulmão que recebe 20 Gy ou 30 Gy - V20 e V30, respectivamente, e dose média). Os órgãos de risco adjacentes (medula espinhal, esôfago e coração) receberam doses abaixo dos limites de tolerância. RESULTADOS: O GTV variou de 10,5 a 1.290,0 cm³ (média de 189,65 cm³). Nos planejamentos 2D foi utilizado, em média, um total de 59,33 campos, e nos planejamentos 3D, 75,65 campos. Em todas as situações analisadas houve significante (p < 0,05) preservação dos volumes pulmonares com o planejamento 3D, com diminuição de cerca de 15% dos volumes irradiados. O pulmão sem tumor foi mais beneficiado. CONCLUSÃO: A radioterapia 3D permitiu maior preservação dos pulmões, tanto para tumores iniciais quanto avançados. A radioterapia 3D deve ser utilizada nos pacientes com tumores de pulmão, mesmo que volumosos.

Practical considerations arising from the implementation of lung stereotactic body radiation therapy (SBRT) at a comprehensive cancer center

INTRODUCTION

With the anticipation of improved outcomes, especially for patients with early-stage non-small cell lung cancer, stereotactic body radiation therapy (SBRT) has been rapidly introduced into the thoracic radiation oncology community. Although at first glance lung SBRT might seem methodologically similar to conventional radiotherapy, there are important differences in its execution that require particular consideration. The objective of this paper is to highlight these and other issues to contribute to the safe and effective diffusion of lung SBRT. We discuss practical challenges that have been encountered in the implementation of lung SBRT at a single, large institution and emphasize the importance of a systematic approach to the design of lung SBRT services.

METHODS

Specific technical and clinical components that were identified as being important during the development of lung SBRT at Princess Margaret Hospital are described. The clinical system that evolved from these is outlined.

RESULTS

Using this clinical framework the practical topics addressed include: patient assessment, simulation and treatment planning, tumor and organ at risk delineation, trial set up before treatment, on-line image-guidance, and patient follow-up.

CONCLUSIONS

The potential gain in therapeutic ratio that is theoretically possible with lung SBRT can only be realized if the tumor is adequately irradiated and normal tissue spared. A discussion of the component parts of lung SBRT is presented. It is a complex process and specific challenges need to be overcome to effect the satisfactory transition of lung SBRT into routine practice.