Intraoperative brachytherapy using Gelfoam radioactive plaque implants for resected stage III non-small cell lung cancer with positive margin: a pilot study

Salvage resection plus cesium-131 brachytherapy durably controls post-SRS recurrent brain metastases

BACKGROUND

Salvage of recurrent previously irradiated brain metastases (rBrM) is a significant challenge. Resection without adjuvant re-irradiation is associated with a high local failure rate, while reirradiation only partially reduces failure but is associated with greater radiation necrosis risk. Salvage resection plus Cs131 brachytherapy may offer dosimetric and biologic advantages including improved local control versus observation, with reduced normal brain dose versus re-irradiation, however data are limited.

METHODS

A prospective registry of consecutive patients with post-stereotactic radiosurgery (SRS) rBrM undergoing resection plus implantation of collagen-matrix embedded Cs131 seeds (GammaTile, GT Medical Technologies) prescribed to 60 Gy at 5 mm from the cavity was analyzed.

RESULTS

Twenty patients underwent 24 operations with Cs131 implantation in 25 tumor cavities. Median maximum preoperative diameter was 3.0 cm (range 1.1-6.3). Gross- or near-total resection was achieved in 80% of lesions. A median of 16 Cs131 seeds (range 6-30), with a median air-kerma strength of 3.5 U/seed were implanted. There was one postoperative wound dehiscence. With median follow-up of 1.6 years for survivors, two tumors recurred (one in-field, one marginal) resulting in 8.4% 1-year progression incidence (95%CI = 0.0-19.9). Radiographic seed settling was identified in 7/25 cavities (28%) 1.9-11.7 months post-implantation, with 1 case of distant migration (4%), without clinical sequelae. There were 8 cases of radiation necrosis, of which 4 were symptomatic.

CONCLUSIONS

With > 1.5 years of follow-up, intraoperative brachytherapy with commercially available Cs131 implants was associated with favorable local control and toxicity profiles. Weak correlation between preoperative tumor geometry and implanted tiles highlights a need to optimize planning criteria.

Clinical implications of positive margins following non-small cell lung cancer surgery

Positive margins following pulmonary resection of non-small cell lung cancer (NSCLC) occur in approximately 5-15% of patients undergoing a curative procedure. The presence of positive margins negatively impacts long-term outcomes by setting the stage for local and potentially distant disease recurrence. Despite major clinical ramifications, there are very few dedicated reports that examine the implications of positive margins following surgery for NSCLC. Furthermore, published series are typically retrospective studies from single institutions. In this review we analyze published data with special consideration of four pertinent questions: (i) what are the long term outcomes of a positive margin following pulmonary resection?, (ii) is intraoperative margin assessment by frozen section reliable?, (iii) what is the optimal distance of the tumor margin to the surgical margin?, and (iv) should adjuvant chemotherapy and/or radiation therapy be used in the setting of a positive surgical margin?

American Brachytherapy Society consensus guidelines for thoracic brachytherapy for lung cancer

PURPOSE

To update brachytherapy recommendations for pretreatment evaluation, treatment, and dosimetric issues for thoracic brachytherapy for lung cancer.

METHODS AND MATERIALS

Members of the American Brachytherapy Society with expertise in thoracic brachytherapy updated recommendations for thoracic brachytherapy based on literature review and clinical experience.

RESULTS

The American Brachytherapy Society consensus guidelines recommend the use of endobronchial brachytherapy for disease palliation in patients with central obstructing lesions, particularly in patients who have previously received external beam radiotherapy. The use of interstitial implants after incomplete resection may improve outcomes and provide enhanced palliation. Early reports support the use of CT-guided intratumoral volume implants within clinical studies. The use of brachytherapy routinely after sublobar resection is not generally recommended, unless within the confines of a clinical trial or a registry.

CONCLUSIONS

American Brachytherapy Society recommendations for thoracic brachytherapy are provided. Practitioners are encouraged to follow these guidelines and to develop further clinical trials to examine this treatment modality to increase the evidence base for its use.

Radiation therapy for early stage lung cancer

Radiation therapy for early stage lung cancer is a promising modality. It has been traditionally used in patients not considered candidates for standard surgical resection. However, its role has been changing rapidly since the introduction of new and advanced technology, especially in tumor tracking, image guidance, and radiation delivery. Stereotactic radiation therapy is one such advancement that has shown excellent local control rates and promising survival in early stage lung cancer. In addition, the toxicity profiles are quite favorable. In addition to stereotactic radiation, advances in brachytherapy techniques have enabled high local control rates in operable patients who receive sublobar resections due to compromised pulmonary function. Isotopes that have been used include iodine-125, palladium-103, and cesium-131. In this review article, the role of radiation therapy in treatment of lung cancer, patient selection, outcomes, toxicity and recent technological advancements are discussed. The radiation therapy techniques described in this article are also being used in the management of locally advanced lung cancers.

Monte Carlo calculated doses to treatment volumes and organs at risk for permanent implant lung brachytherapy

Iodine-125 ((125)I) and Caesium-131 ((131)Cs) brachytherapy have been used with sublobar resection to treat stage I non-small cell lung cancer and other radionuclides, (169)Yb and (103)Pd, are considered for these treatments. This work investigates the dosimetry of permanent implant lung brachytherapy for a range of source energies and various implant sites in the lung. Monte Carlo calculated doses are calculated in a patient CT-derived computational phantom using the EGsnrc user-code BrachyDose. Calculations are performed for (103)Pd, (125)I, (131)Cs seeds and 50 and 100 keV point sources for 17 implant positions. Doses to treatment volumes, ipsilateral lung, aorta, and heart are determined and compared to those determined using the TG-43 approach. Considerable variation with source energy and differences between model-based and TG-43 doses are found for both treatment volumes and organs. Doses to the heart and aorta generally increase with increasing source energy. TG-43 underestimates the dose to the heart and aorta for all implants except those nearest to these organs where the dose is overestimated. Results suggest that model-based dose calculations are crucial for selecting prescription doses, comparing clinical endpoints, and studying radiobiological effects for permanent implant lung brachytherapy.

Combined Modality Treatment of Non-Small-Cell Lung Cancer

Among all nonmetastatic non-small-cell lung cancer (NSCLC) patients, the best survival rates are observed in patients who undergo surgery. Nevertheless, 5-year survival rates vary between 20% and 60% depending on the stage of the disease. Several combined modality treatments have been investigated to improve outcome in localized NSCLC. These include local treatment, systemic before local treatment, concomitant systemic and local treatments, and systemic after local treatment. Preoperative irradiation was shown to be of no benefit on local recurrence rates or overall survival. Even doses of radiation >/=40 grays (Gy) were associated with lower survival rates. Postoperative irradiation did not influence survival in stage III disease and seemed to be deleterious in stages I and II disease. Modern radiotherapy techniques might be of interest in this setting but have been insufficiently tested. The early phase III studies of preoperative chemotherapy versus primary surgery in stage III NSCLC showed a tremendous difference in favor of chemotherapy. A larger study did not confirm these results but suggested that preoperative chemotherapy might have a greater effect in stages I and II of the disease. In locally advanced disease, chemotherapy followed by radiotherapy was shown to increase survival when compared with radiotherapy alone. Studies comparing concurrent chemoradiation with radiotherapy only were in favor of the concomitant schedule, which improved local control. Promising results have been reported with chemoradiation followed by surgery in stage IIIa and even stage IIIb disease. Randomized studies of postoperative chemotherapy demonstrated a 5% improvement in 5-year survival over adjuvant-free treatment. Postoperative chemoradiation showed no advantage over postoperative radiotherapy. Several trials that are ongoing or whose accrual was recently completed should further define the role of perioperative chemotherapy in resectable NSCLC and of trimodality treatments in advanced disease. Targeted agents are being developed in the postoperative setting. New schedules of chemoradiation with higher therapeutic indexes are also being investigated in nonresectable stage III NSCLC.

Intraoperative seed placement for thoracic malignancy-A review of technique, indications, and published literature

PURPOSE

This review examines the role of permanent radioactive seed implantation in thoracic malignancy. This technique can be used intraoperatively to provide additional highly localized radiation therapy in cases where optimal oncologic margins are unattainable or to palliate unresectable disease.

METHODS AND MATERIALS

Relevant trials were identified through a systematic literature search using Pubmed.

RESULTS

The intraoperative placement of brachytherapy seeds has been described after sublobar resection for non-small-cell lung cancer (NSCLC), where surgical margins are close or microscopically positive and in the presence of macroscopic residual disease. This brachytherapy technique is currently the focus of a randomized prospective trial in the USA in patients unfit for lobectomy for early-stage NSCLC.

CONCLUSIONS

This review summarizes the methods of brachytherapy seed placement and the published experience of brachytherapy implants within the thorax, also examining radiation safety and postoperative dosimetry. This technique has the potential to improve local control with optimal sparing of normal tissue owing to its highly conformal radiotherapy delivery.

Role of Sublobar Resection (Segmentectomy and Wedge Resection) in the Surgical Management of Non–Small Cell Lung Cancer

Segmentectomy demands a thorough knowledge of the three-dimensional bronchovascular anatomy of the lung. This anatomic detail makes segmentectomy significantly more challenging than lobectomy. Several principles must be applied when performing segmental lung resection: (1) the surgeon should avoid dissection in a poorly developed fissure, (2) use the transected bronchus as the base of the segmental resection during the division of the lung parenchymal in the intersegmental plane, (3) consider the use of endostapler division of the pulmonary parenchyma to reduce the air leak complications related to "finger fracture" dissection of the intersegmental plane, and (4) consider the use of adjuvant iodine 125 brachytherapy as a means of reducing local recurrence following sublobar resection. Increasing evidence supports the use of anatomic segmentectomy in the treatment of primary lung cancer for appropriately selected patients. This resection approach seems most appropriate in the management of the small (<2 cm in diameter) peripheral stage I NSCLC in which a generous margin of resection can be obtained. Accurate intraoperative nodal staging is important to estimate the relative use of these approaches compared with more aggressive resection and to determine the need for adjuvant systemic therapy if metastatic lymphadenopathy is identified. Future investigations comparing the results of sublobar resection with lobectomy will more clearly define the role of segmentectomy among good-risk patients with clinical stage I NSCLC. At the present time, it seems that sublobar resection is an appropriate therapy for the management of stage I NSCLC identified in the elderly patient, those individuals with significant cardiopulmonary dysfunction, and for the management of peripheral solitary metastatic disease to the lung. Because the primary disadvantage of sublobar resection is that of local recurrence, intraoperative adjuvant iodine 125 brachytherapy may be considered to minimize this local recurrence risk.

Fibrin glue system for adjuvant brachytherapy of brain tumors with 188Re and 186Re-labeled microspheres

Brain tumors such as glioblastoma reappear in their original location in almost 50% of cases. To prevent this recurrence, we developed a radiopharmaceutical system that consists of a gel applied immediately after surgical resection of a brain tumor to deliver local radiation booster doses. The gel, which strongly adheres to tissue in the treatment area, consists of fibrin glue containing the beta-emitters rhenium-188 and rhenium-186 in microsphere-bound form. Such microspheres can be prepared by short (2 h or less) neutron activation even in low neutron flux reactors, yielding a mixture of the two beta-emitters rhenium-188 (E(max)=2.1 MeV, half life=17 h) and rhenium-186 (E(max)=1.1 MeV, half life=90.6h). The dosimetry of this rhenium-188/rhenium-186 fibrin glue system was determined using gafchromic film measurements. The treatment efficacy of the radioactive fibrin glue was measured in a 9L-glioblastoma rat model. All animals receiving the non-radioactive fibrin glue died within 17+/-3 days, whereas 60% of the treated animals survived 36 days, the final length of the experiment. Control animals that were treated with the same amount of radioactive fibrin glue, but had not received a previous tumor cell injection, showed no toxic effects over one year. The beta-radiation emitting rhenium-188/rhenium-186-based gel thus provides an effective method of delivering high doses of local radiation to tumor tissue, particularly to wet areas where high adhesive strength and long-term radiation (with or without drug) delivery are needed.

Sublobar Resections for Lung Cancer

Sublobar resection has been utilized as an alternative to lobectomy for the treatment of early-stage lung cancer in patients with compromised preoperative pulmonary function. Early data have suggested higher rates of local recurrence and increased late mortality for sublobar resection as compared with lobectomy. Subsequent studies have been mixed with respect to outcomes. Here we review the existing literature comparing sublobar resection to lobectomy with respect to oncologic and pulmonary outcomes. We also discuss the effect of adjuvant intraoperative brachytherapy to sublobar resection and summarize ongoing clinical trials that compare sublobar resection to sublobar resection plus adjuvant brachytherapy in the treatment of early-stage lung cancer. Finally, based on the current evidence, we provide recommendations as to when sublobar resection might be considered in the treatment of lung cancer.

Intraoperative 125I Vicryl mesh brachytherapy after sublobar resection for high-risk stage I nonsmall cell lung cancer

PURPOSE

To assess the feasibility and outcomes of (125)I Vicryl mesh brachytherapy after sublobar resection in stage I non small cell lung cancer (NSCLC) patients with poor pulmonary function.

METHODS AND MATERIALS

Between January 1997 and July 2004, patients with poor cardiopulmonary reserve who had stage IA and IB (T1-2 N0 M0) NSCLC and a forced expiratory volume in 1s (FEV(1)) of > micro=0.6L were considered for limited surgical resection either by an open or video-assisted thoracoscopic procedure and for a subsequent (125)I Vicryl mesh brachytherapy implant. Mediastinal and hilar lymph node staging was performed routinely in all patients. After clear margins were obtained grossly and on frozen section, a single-plane (125)I implant was designed to encompass a plane consisting of the staple line and a 2-cm margin of surrounding visceral pleura. The implant was introduced through the surgical incision and sutured to the visceral pleura. A prescribed dose of 100-120 y was delivered to a volume within 0.5 cm rom the plane of the implant. Follow-up orthogonal films or CTs were obtained for dosimetric analysis. Kaplan-Meier analyses were used to estimate the local control, locoregional control, and overall survival rates.

RESULTS

Of the 110 patients, 65 had stage IA and 45 had stage IB NSCLC. The mean preoperative FEV(1) was 47% of the predicted volume. With a median follow-up of 11 months (range 1-68 months), there were four recurrences within the radiation volume. The estimated 5-year local (in-field) control, locoregional control, and overall survival rates were 90%, 61%, and 18%, respectively.

CONCLUSION

Vicryl mesh brachytherapy after sublobar resection for high-risk stage I NSCLC patients is a feasible procedure, which results in an excellent local (in-field) control rate.

Placement of 125I implants with the da Vinci robotic system after video-assisted thoracoscopic wedge resection: A feasibility study

PURPOSE

To evaluate the feasibility of using the da Vinci robotic system for radioactive seed placement in the wedge resection margin of pigs' lungs.

METHODS AND MATERIALS

Video-assisted thoracoscopic wedge resection was performed in the upper and lower lobes in pigs. Dummy (125)I seeds embedded in absorbable sutures were sewn into the resection margin with the aid of the da Vinci robotic system without complications. In the "loop technique," the seeds were placed in a cylindrical pattern; in the "longitudinal," they were above and lateral to the resection margin. Orthogonal radiographs were taken in the operating room. For dose calculation, Variseed 66.7 (Build 11312) software was used.

RESULTS

With looping seed placement, in the coronal view, the dose at 1 cm from the source was 97.0 Gy; in the lateral view it was 107.3 Gy. For longitudinal seed placement, the numbers were 89.5 Gy and 70.0 Gy, respectively.

CONCLUSION

Robotic technology allows direct placement of radioactive seeds into the resection margin by endoscopic surgery. It overcomes the technical difficulties of manipulating in the narrow chest cavity. With the advent of robotic technology, new options in the treatment of lung cancer, as well as other malignant tumors, will become available.

Contemporary role of modern brachytherapy techniques in the management of malignant thoracic tumors

Sole brachytherapy for carcinoma of the lung is most often performed using high-dose-rate (HDR) remote afterloading equipment, which delivers the treatment within the tracheobronchial tree in an outpatient setting. It provides excellent, rapid palliation in advanced stages, and can also be used selectively for curative intent in early stages. In better-performance patients, fractionated external beam radiation therapy (EBRT) is preferred to brachytherapy as an initial treatment because it appears to provide a modest gain in survival, and more sustained palliation. In patients with centrally located tumors and limited extent of disease, the combination of external and endoluminal irradiation enables curative treatment options. Intraoperative brachytherapy may complement standard adjuvant treatment in incompletely resected, unresectable, or medically inoperable patients, and has the potential to improve local control in selected cases. Due to the rarity of the disease, the role of endoluminal brachytherapy in the treatment regimen of tracheal neoplasms is not yet clearly defined. The risk of fatal bleeding after endoluminal brachytherapy appears to be correlated with tumor localization and fraction size, but in the majority of cases fatal bleeds are caused by progression of local disease. The use of a distanceable applicator provides a central positioning of the source, prevents the delivery of high-contact doses to the mucosa, and may reduce toxicity. The standard technique for interstitial brachytherapy after breast-conserving surgery and adjuvant EBRT is the use of low-dose-rate (LDR) brachytherapy, but it may also be applied by means of pulsed-dose-rate (PDR) or HDR techniques. Prospective trials comparing different boost techniques and indications are needed to define more precisely the subgroup of patients who are most suitable for interstitial brachytherapy. Reirradiation of chest wall local recurrences using brachytherapy molds is effective and provides a high local control rate with acceptable toxicity.

Intraoperative 125I brachytherapy for high-risk stage I non-small cell lung carcinoma

PURPOSE

Preliminary assessment of feasibility, efficacy, acute and chronic side effects associated with permanent intraoperative placement of 125I vicryl mesh brachytherapy in a select group of high-risk Stage I NSCLC who have undergone video-assisted thoracoscopic resection (VATR).

METHODS AND MATERIALS

From January 8, 1997 to March 16, 1998, 23 patients with Stage I NSCLC at high risk for conventional surgery due to cardiopulmonary compromise underwent combined VATR and intraoperative placement of 125I seeds embedded in vicryl mesh. Seeds embedded in vicryl suture were attached with surgical clips to a sheet of vicryl mesh, and thoracoscopically inserted over the target area (tumor bed and staple line) with nonabsorbable suture or surgical clips. A total dose of 100-120 Gy prescribed to the periphery of the target area (defined as the staple line and tumor bed with a 1-cm margin) was delivered.

RESULTS

The mean target area covered was 48 cm2 (range 40-72) and mean total activity was 22 mCi (range 17.2-28.2). The median length of postoperative stay was 7 days. The median follow-up was 11 months (range 2-20). Postoperative CT scans of the chest revealed no dislodgement of the seeds and no local recurrence in any patient. Three patients developed distant metastasis (1 died 6 months postoperatively; the other 2 are currently alive with disease). One patient developed an ipsilateral recurrence in the right lower lobe after having had a right upper lobe resection. There were 3 postoperative deaths due to medical comorbid conditions or surgical complications (1 in the immediate postoperative period). Pulmonary function testing performed 3 months after implantation revealed no significant difference between preoperative and postoperative values: mean preoperative FVC was 2.3 L (range 1.31-3.0) and postoperative FVC was 2.2 L (range 1.1-3.9), p = 0.42; mean preoperative FEV1 was 1.2 L (range 0.71-2.2), and postoperative FEV1 was 1.5 L (range 0.8-2.9), p = 0.28.

CONCLUSION

Review of early data suggests that intraoperative 125I vicryl mesh brachytherapy in high-risk Stage I NSCLC is potentially effective and well tolerated, with no significant decline in measurable pulmonary function studies and no increase in postoperative complications. Longer follow-up is needed to determine ultimate local control and survival.

Intraoperative brachytherapy following thoracoscopic wedge resection of stage I lung cancer

STUDY OBJECTIVES

Local recurrence is high when sublobar resection is chosen as primary management of stage I non-small cell lung carcinoma. Postoperative external-beam radiotherapy may reduce this local recurrence problem. A technique of intraoperative brachyradiotherapy following thoracoscopic wedge resection is described as an alternative to adjuvant external-beam radiotherapy for high-risk patients who are not candidates for pulmonary lobectomy.

PATIENTS

Fourteen patients with significant impairment in cardiopulmonary function having small peripheral solitary pulmonary nodules underwent video-assisted thoracoscopic (VATS) wedge resection and were found to have non-small cell cancer. Surgical margins were pathologically clear and mediastinal nodes were benign-stage I (T1NO).

INTERVENTIONS

A custom polyglyconate mesh (Vicryl) containing 125I seeds was applied to pulmonary resection margins following wedge resection of peripheral lung cancers. A total dose of 100 to 120 Gy at 1 cm was applied to the target area.

RESULTS

All patients had histologically clear surgical margins. Postoperative dosimetry confirmed adequate resection margin coverage. There was neither operative mortality nor morbidity related to the VATS wedge resection or the brachytherapy implants. Implants did not migrate, and there were no cases of significant radiation pneumonitis or local recurrence at mean follow-up of 7 months (range, 2 to 12 months).

CONCLUSIONS

Intraoperative brachytherapy appears to be a safe and efficient alternative to external-beam radiation therapy when adjuvant radiotherapy is considered following therapeutic wedge resection of stage I (T1NO) lung cancers. The impact on local recurrence, disease-free interval, and survival will require additional follow-up.