Stereotactic Radiosurgery for Early Stage Non-Small Cell Lung Cancer: Rationale, Patient Selection, Results, and Complications

Efficacy and safety of stereotactic radiosurgery for pulmonary metastases from osteosarcoma: Experience in 73 patients

Osteosarcoma pulmonary metastases are typically treated with resection and/or chemotherapy. We hypothesize that stereotactic radiosurgery (SRS) can be an alternative to surgery that can achieve high rates of local control with limited toxicity. From January 2005 to December 2013, 73 patients who developed pulmonary metastasis during period of adjuvant chemotherapy or follow-up were analyzed. 33 patients were treated by stereotactic radiosurgery using the body gamma-knife system. A total dose of 50 Gy was delivered at 5 Gy/fraction to the 50% isodose line covering the planning target volume, whereas a total dose of 70 Gy was delivered at 7 Gy/fraction to the gross target volume. The other 40 patients were treated by surgical resection. Four-year progression-free survival rate, four-year survival rate, median time of PRPFS (post-relapse progress-free survival) and PROS (post-relapse overall survival) in SRS group were parallel to that in surgical group. Patients tolerated gamma knife radiosurgery well. Our study demonstrates that SRS is well-tolerated with excellent local control and less complications. SRS should be considered as a potential option in patients with pulmonary metastases from osteosarcoma, especially in those who are medically inoperable, refuse surgery.

The impact of cine EPID image acquisition frame rate on markerless soft-tissue tracking

PURPOSE

Although reduction of the cine electronic portal imaging device (EPID) acquisition frame rate through multiple frame averaging may reduce hardware memory burden and decrease image noise, it can hinder the continuity of soft-tissue motion leading to poor autotracking results. The impact of motion blurring and image noise on the tracking performance was investigated.

METHODS

Phantom and patient images were acquired at a frame rate of 12.87 Hz with an amorphous silicon portal imager (AS1000, Varian Medical Systems, Palo Alto, CA). The maximum frame rate of 12.87 Hz is imposed by the EPID. Low frame rate images were obtained by continuous frame averaging. A previously validated tracking algorithm was employed for autotracking. The difference between the programmed and autotracked positions of a Las Vegas phantom moving in the superior-inferior direction defined the tracking error (δ). Motion blurring was assessed by measuring the area change of the circle with the greatest depth. Additionally, lung tumors on 1747 frames acquired at 11 field angles from four radiotherapy patients are manually and automatically tracked with varying frame averaging. δ was defined by the position difference of the two tracking methods. Image noise was defined as the standard deviation of the background intensity. Motion blurring and image noise are correlated with δ using Pearson correlation coefficient (R).

RESULTS

For both phantom and patient studies, the autotracking errors increased at frame rates lower than 4.29 Hz. Above 4.29 Hz, changes in errors were negligible withδ < 1.60 mm. Motion blurring and image noise were observed to increase and decrease with frame averaging, respectively. Motion blurring and tracking errors were significantly correlated for the phantom (R = 0.94) and patient studies (R = 0.72). Moderate to poor correlation was found between image noise and tracking error with R -0.58 and -0.19 for both studies, respectively.

CONCLUSIONS

Cine EPID image acquisition at the frame rate of at least 4.29 Hz is recommended. Motion blurring in the images with frame rates below 4.29 Hz can significantly reduce the accuracy of autotracking.

Stereotactic radiosurgery, a potential alternative treatment for pulmonary metastases from osteosarcoma

Stereotactic radiosurgery (SRS), such as body gamma knife, was reported to achieve excellent rates of local disease control with limited toxicity in many cases of primary or secondary pulmonary tumor, except osteosarcoma. To confirm the value of SRS in pulmonary metastases from osteosarcoma, we reviewed the experience from our institution (Department of Oncology, Affiliated Sixth People's Hospital, Shanghai) and compared the efficiency of SRS with that of surgical resection. From January 2005 to December 2012, we carried out a retrospective investigation of 58 patients (age, 8-59 years; mean, 25.2 years) who were diagnosed with non-metastatic osteosarcoma of the extremity and later developed pulmonary metastasis during the period of adjuvant chemotherapy or follow-up. Among them, 27 patients were treated by SRS using the body gamma-knife system. A total dose of 50 Gy was delivered at 5 Gy/fraction to the 50% isodose line covering the planning target volume, whereas a total dose of 70 Gy was delivered at 7 Gy/fraction to the gross target volume. The other 31 patients were treated by surgical resection. Two-year progression-free survival rate, two-year survival rate, median time of PRPFS (post-relapse progress-free survival) and PROS (post-relapse overall survival) in SRS group were parallel to that in surgical group. All 27 patients tolerated gamma knife radiosurgery well while only 9 patients had grades 1-2 pneumonitis. We believe SRS, compared with surgical resection, is effective and safe in treating pulmonary metastasis from osteosarcoma, especially for those patients who were medically unfit for a resection or who refused surgery.

Trial Watch: Anticancer radioimmunotherapy

Radiotherapy has extensively been employed as a curative or palliative intervention against cancer throughout the last century, with a varying degree of success. For a long time, the antineoplastic activity of X- and γ-rays was entirely ascribed to their capacity of damaging macromolecules, in particular DNA, and hence triggering the (apoptotic) demise of malignant cells. However, accumulating evidence indicates that (at least part of) the clinical potential of radiotherapy stems from cancer cell-extrinsic mechanisms, including the normalization of tumor vasculature as well as short- and long-range bystander effects. Local bystander effects involve either the direct transmission of lethal signals between cells connected by gap junctions or the production of diffusible cytotoxic mediators, including reactive oxygen species, nitric oxide and cytokines. Conversely, long-range bystander effects, also known as out-of-field or abscopal effects, presumably reflect the elicitation of tumor-specific adaptive immune responses. Ionizing rays have indeed been shown to promote the immunogenic demise of malignant cells, a process that relies on the spatiotemporally defined emanation of specific damage-associated molecular patterns (DAMPs). Thus, irradiation reportedly improves the clinical efficacy of other treatment modalities such as surgery (both in neo-adjuvant and adjuvant settings) or chemotherapy. Moreover, at least under some circumstances, radiotherapy may potentiate anticancer immune responses as elicited by various immunotherapeutic agents, including (but presumably not limited to) immunomodulatory monoclonal antibodies, cancer-specific vaccines, dendritic cell-based interventions and Toll-like receptor agonists. Here, we review the rationale of using radiotherapy, alone or combined with immunomodulatory agents, as a means to elicit or boost anticancer immune responses, and present recent clinical trials investigating the therapeutic potential of this approach in cancer patients.

Stereotactic body radiotherapy in patients with stage I non-small-cell lung cancer aged 75 years and older: retrospective results from a multicenter consortium

BACKGROUND

This study was a retrospective analysis of elderly patients treated with stereotactic body radiotherapy (SBRT) in the setting of a multi-institutional consortium.

PATIENTS AND METHODS

Three institutions pooled data on patients aged ≥ 75 years who received SBRT for stage I non-small-cell lung cancer (NSCLC). Forty-seven tumors in 46 patients were analyzed in patients aged 75 to 92 years (median, 82 years). Treatment was delivered during 2007 to 2009, with a median follow-up of 12.4 months. All patients underwent staging positron emission tomography-computed tomography (PET-CT), and 87% of tumors were confirmed by biopsy results. Total doses were 35 to 60 Gy, mainly in 3 to 5 fractions. All tumors were treated using a linear accelerator, with 96% of patients receiving 3-dimensional (3D) conformal RT and 4% undergoing intensity modulated RT (IMRT).

RESULTS

At the time of analysis, the local failure rate was 2% (1 of 47). The regional failure rate was 9% (4 of 47). The distant failure rate was 6% (3 of 47). The combined failure rate was 15% (7 of 47) because 1 patient experienced both regional and distant failure. Among 20 tumors with any acute toxicity, there were no ≥ grade 3 toxicities. Pneumonitis (n = 10) grades 1 (n = 3) and 2 (n = 2) was seen in 15% and 10% of patients, respectively; these data were missing for 25% of patients.

CONCLUSION

SBRT in patients aged ≥ 75 years with stage I NSCLC proved tolerable, with toxicity rates comparable to those in younger patients. Excellent rates of local, regional, and distant control were achieved at a median follow-up of 12.4 months. This patient population represents a rapidly growing segment of the early lung cancer population, and SBRT appears to be a safe and effective treatment option for patients who are not optimal candidates for surgery.

Stereotactic body radiotherapy for medically inoperable lung cancer: prospective, single-center study of 108 consecutive patients

PURPOSE

To present the results of stereotactic body radiotherapy (SBRT) for medically inoperable patients with Stage I non-small-cell lung cancer (NSCLC) and contrast outcomes in patients with and without a pathologic diagnosis.

METHODS AND MATERIALS

Between December 2004 and October 2008, 108 patients (114 tumors) underwent treatment according to the prospective research ethics board-approved SBRT protocols at our cancer center. Of the 108 patients, 88 (81.5%) had undergone pretreatment whole-body [18F]-fluorodeoxyglucose positron emission tomography/computed tomography. A pathologic diagnosis was unavailable for 33 (28.9%) of the 114 lesions. The SBRT schedules included 48 Gy in 4 fractions or 54-60 Gy in 3 fractions for peripheral lesions and 50-60 Gy in 8-10 fractions for central lesions. Toxicity and radiologic response were assessed at the 3-6-month follow-up visits using conventional criteria.

RESULTS

The mean tumor diameter was 2.4-cm (range, 0.9-5.7). The median follow-up was 19.1 months (range, 1-55.7). The estimated local control rate at 1 and 4 years was 92% (95% confidence interval [CI], 86-97%) and 89% (95% CI, 81-96%). The cause-specific survival rate at 1 and 4 years was 92% (95% CI, 87-98%) and 77% (95% CI, 64-89%), respectively. No statistically significant difference was found in the local, regional, and distant control between patients with and without pathologically confirmed NSCLC. The most common acute toxicity was Grade 1 or 2 fatigue (53 of 108 patients). No toxicities of Grade 4 or greater were identified.

CONCLUSIONS

Lung SBRT for early-stage NSCLC resulted in excellent local control and cause-specific survival with minimal toxicity. The disease-specific outcomes were comparable for patients with and without a pathologic diagnosis. SBRT can be considered an option for selected patients with proven or presumed early-stage NSCLC.

Lung cancer in chronic obstructive pulmonary disease: enhancing surgical options and outcomes

Patients with chronic obstructive pulmonary disease (COPD) are at increased risk for both the development of primary lung cancer, as well as poor outcome after lung cancer diagnosis and treatment. Because of existing impairments in lung function, patients with COPD often do not meet traditional criteria for tolerance of definitive surgical lung cancer therapy. Emerging information regarding the physiology of lung resection in COPD indicates that postoperative decrements in lung function may be less than anticipated by traditional prediction tools. In patients with COPD, more inclusive consideration for surgical resection with curative intent may be appropriate as limited surgical resections or nonsurgical therapeutic options provide inferior survival. Furthermore, optimizing perioperative COPD medical care according to clinical practice guidelines including smoking cessation can potentially minimize morbidity and improve functional status in this often severely impaired patient population.

Coil spring fiducial markers placed safely using navigation bronchoscopy in inoperable patients allows accurate delivery of CyberKnife stereotactic radiosurgery

OBJECTIVES

CyberKnife stereotactic body radiosurgery is a potentially curative option for medically inoperable Stage I lung cancer. Fiducial marker placement in or near the tumor is required. Transthoracic placement using computed tomography guidance has been associated with a high risk of iatrogenic pneumothorax. Electromagnetic navigation bronchoscopy offers a safer method of placing markers; however, previous studies using linear markers have shown at least a 10% dislocation rate. We describe the use of coil-spring fiducial markers placed under moderate sedation in an outpatient bronchoscopy suite.

METHODS

A total of 52 consecutive nonoperative patients with isolated lung tumors underwent fiducial placement using electromagnetic navigation bronchoscopy. Of the 52 patients, 4 received 17 linear fiducial markers, and 49 patients with 56 tumors received 217 coil-spring fiducial markers. The procedures were considered successful if the fiducial markers had been placed in or near the tumors and had remained in place without migration, allowing radiosurgery without the need for additional fiducial markers.

RESULTS

A total of 234 fiducial markers were successfully deployed in 52 patients with 60 tumors (mean diameter 23.7 mm). Of these 60 tumors, 35 (58%) were adjacent to the pleura. At CyberKnife planning, 8 (47%) of 17 linear fiducial markers and 215 (99%) of 217 coil-spring fiducial markers (P = .0001) were still in place. Of the 4 patients with linear fiducial markers, 2 required additional fiducial placements; none of the patients with coil fiducial markers required additional procedures. Three pneumothoraces (5.8%) occurred in peripheral lesions (2 were treated with a pig-tail chest tube and 1 with observation only).

CONCLUSIONS

Deployment of coil spring fiducial markers using navigation bronchoscopy can safely be performed with the patient under moderate sedation with almost no migration and a 5.8% rate of pneumothorax.