The current state of intraoperative interstitial brachytherapy in lung cancer

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.

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.

Robot-assisted minimally invasive lung brachytherapy

BACKGROUND

This paper presents a novel alternative for the treatment of lung cancer. The method consists of accessing the lung through small incisions in a minimally invasive manner in order to insert radioactive seeds directly into the lung using a robotic surgical system.

METHODS

An experimental test-bed to evaluate the feasibility of this approach has been developed. It consists of two surgical robotic systems, a device specifically designed to robotically implant radioactive seeds, needle tracking software, ultrasound imaging, electromagnetic tracking, and a surgical box that mimics a patient's thorax. A detailed comparison has been performed between currently available access options and robot-assisted minimally invasive access.

RESULTS

The results show insignificant differences in accuracy between the methods, with the exception of a significant improvement when electromagnetic (EM) guidance was added to the non-robotic techniques. The navigation system reduced the number of attempts for all seed delivery methods. Significant reductions in time were achieved in the minimally invasive procedures by the addition of EM guidance.

CONCLUSIONS

The performance achieved when using robotic systems and image guidance for minimally-invasive brachytherapy is clinically comparable to that achieved in an open surgery procedure, while reducing the invasiveness of the procedure, improving ergonomic conditions for the clinician and reducing radiation exposure.

Pemetrexed Alone and in Combination with Platinum Compounds in the Management of Malignant Mesothelioma

Malignant pleural mesothelioma is an aggressive but rare malignancy with a dismal prognosis. It is traditionally resistant to chemotherapy. Antifolate agents have recently shown promising data in the treatment of this malignancy. Pemetrexed is a multitargeted antifolate inhibitor of thymidylate synthase and other folate-dependent enzymes that has emerged as one of the most active agents in this disease. Several phase I/II trials of pemetrexed as a single agent or in combination with a platinum drug have demonstrated considerable activity in mesothelioma. In a recently published phase III randomized study, pemetrexed/cisplatin showed a significant improvement in survival, response rate, and quality of life compared with single-agent cisplatin. In addition, several trials reported that folic acid and vitamin B12 supplementation significantly reduced the toxicity observed with the use of pemetrexed without affecting the efficacy of the drug.

Toxicity of photodynamic therapy after combined external beam radiotherapy and intraluminal brachytherapy for carcinoma of the upper aerodigestive tract

BACKGROUND AND OBJECTIVE

To describe the toxicity of photodynamic therapy (PDT) in patients with carcinoma of the upper aerodigestive tract who received prior treatment with external beam irradiation and intraluminal brachytherapy (IB).

STUDY DESIGN/MATERIALS AND METHODS

Hospital records of PDT patients were reviewed. Three patients who received prior treatment with external beam irradiation and IB were identified. Two patients had esophageal carcinoma treated with combined chemotherapy and external beam irradiation (55.8 and 50.4 Gy) followed by IB (12 Gy and 35 Gy at 1 cm). These patients then received PDT for treatment of recurrence (2 mg/kg Photofrin injection and 2 light applications: 630 nm, 150--200 J/cm, 200--400 mW/cm). One patient had non-small cell lung cancer treated with external beam irradiation (60 Gy) followed by IB (36.1 Gy at 1 cm) and then received PDT for recurrence (1 mg/kg Photofrin injection and one light application: 630 nm, 150 J/cm, 200 mW/cm).

RESULTS

One patient with esophagus cancer had formation of a tracheoesophageal fistula, which required stent placement. The other esophageal cancer patient developed quadriplegia due to an epidural abscess arising from a fistula with the diseased portion of the esophagus. The lung cancer patient had massive hemoptysis after the procedure and died 2 days later. Autopsy showed necrotizing arteritis of the right pulmonary artery.

CONCLUSION

Patients with upper aerodigestive tract carcinoma who have received treatment with both external beam irradiation and IB seem to be at higher risk for complications when treated with PDT.

Endoscopic evaluation of centrally located early squamous cell carcinoma of the lung

BACKGROUND

Lung-sparing treatment recently has become a choice in the treatment of patients with early hilar lung carcinoma. To select the method of treatment, it is important to evaluate the histologic extent of the tumor using endoscopy.

METHODS

A total of 46 patients who underwent surgery for an endoscopically evaluated early lung carcinoma of the tracheobronchial tree were analyzed. Initial surgery was performed in 16 patients and in 30 patients surgery was performed after preoperative laser therapy. The endoscopic findings were classified into three types: superficial, nodular, and polypoid. In the resected lung, the greatest tumor dimension, the depth of mural invasion, the presence of microscopic blood and lymph vessel invasion, and metastases to the dissected lymph nodes were examined.

RESULTS

The mean greatest tumor dimensions were 14.6 +/- 7.3 mm (mean +/- standard deviation) in the nodular group, 23.3 +/- 12.8 mm in the superficial group, and 19.0 +/- 9.2 mm in the polypoid group. The greatest tumor dimension in the superficial group was significantly larger than that in the nodular group (P < 0.01). Preoperative endoscopic diagnosis of early hilar lung carcinoma was correct histologically in 34 of 46 cases (74.0%). Hilar lymph node metastases (N1), extrabronchial invasion, and extension to the peripheral bronchus were recognized in 12 cases. Complete disappearance of the tumor due to preoperative laser therapy was confirmed in eight patients. Lymph node metastasis was not found when the greatest tumor dimension measured < 8 mm. The overall absolute 5-year survival rate was 76.0% for all patients, 87.1% for the surgery alone group, and 70.0% for the surgery after preoperative laser therapy group.

CONCLUSIONS

Curative treatment of early hilar lung carcinoma is possible using photodynamic therapy alone when the tumor size is < or = 8 mm and the lesion does not extend to the peripheral bronchus.

Predictive factors in radiotherapy for non-small cell lung cancer: present status

PURPOSE

To evaluate the predictive factors for radiation response in non-small cell lung cancer (NSCLC) and the role of such factors in guiding high dose radiation therapy.

METHODS

The first International Workshop on Prognostic and Predictive Factors in Lung Cancer was organized by the Hellenic Cooperative Oncology Group and held in Athens, Greece under the auspices of the International Association for the Study of Lung Cancer. Presentations at this meeting provided the outline of this report, which has also been supplemented with available data from the current literature.

RESULTS

The predictive factors for both the natural history and the therapy outcome of NSCLC are grouped as follows: (1) tumor related factors (anatomic factors); the extent of tumor (tumor stage) is one of most important prognostic factors affecting the therapy outcome. Tumor size (T stage), anatomical structures involved (T4 vs. T3 lesion), and the presence of regional lymph node metastasis have a significant impact on both prognosis and response to appropriate therapy; (2) host-related factors (clinical factors) that are important in therapy response include performance status, weight loss of more than 10% of body weight in the previous 6 months, and associated co-morbidities, i.e. pulmonary and cardiac diseases; (3) technical factors of radiation therapy which play a decisive role in successful outcome. The target volume should be defined accurately using modern imaging studies. The radiation dose fractionation schedule, in terms of the dose intensity and total dose, should be high enough to provide local tumor control in the majority of patients. Three-dimensional (3-D) conformal planning is an essential tool in dose escalation studies to determine the maximum tolerated dose of radiation; (4) biological/radiobiological/metabolic factors. Biologic markers resulting from genetic lesions in lung cancer are grouped as follows: (a) oncogene amplification and overexpression (aberrant gene expression) and mutated tumor suppressor genes -- ras gene, myc gene, HER-2/neu and survivin gene, p53 and mutated beta-tubulin gene; (b) tumor biologic/radiobiologic factors -- tumor cell proliferation kinetics, hypoxia, intrinsic cellular radiosensitivity, gamma factor, and DNA content; (c) enzymes and hormones: neuron-specific enolase, serum lactate dehydrogenase, and enhanced glucose metabolic rate supported by increased glucose transporter protein. The surviving fraction of tumor cells at 2.0 Gy of radiation (SF2) as a measure of intrinsic tumor cell radiosensitivity, potential doubling time (T(Pot)) as a measure of the rate of tumor cell proliferation and gamma factor representing the slope of the survival curve at 50% survival rate are being investigated as potential predictors for therapy response. Enhanced glucose utilization, a hallmark of malignant transformation, is being studied as a potential monitor for therapy response by using PET-FDG.

CONCLUSION

Current data indicate that there is a dose-response relationship between radiation dose and local tumor control, and also between local tumor control and survival in stage III NSCLC. Therapeutic factors, i.e. total radiation dose, fractionation schedule and dose intensity, and use of 3-D conformal radiation to secure the optimum therapeutic ratio are important for improved local tumor control and survival. Future research should be directed towards radiation dose escalation using 3-D conformal therapy to determine the maximum tolerated dose (MTD) of radiation in chemo-radiotherapy, and the use of this MTD for improved local tumor control and survival. Radiobiological, molecular, and metabolic markers may have potential for monitoring tumor response and optimizing radiation therapy.

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.

Percutaneous brachytherapy for small-sized non-small cell lung cancer

A patient with a small-sized pulmonary adenocarcinoma was successfully treated by percutaneous high dose rate interstitial brachytherapy alone. The patient, who had an adenocarcinoma with 12-mm diameter in the lingular lobe of left lung, was judged to be inoperable because of poor pulmonary function due to emphysema and extensive pleural adhesion. The tumor was punctured with a 21-gauge fine applicator needle followed by the introduction of an iridium 192 (192Ir) radioactive source through the applicator needle using a remote afterloader. The tumor was irradiated for 225.1 s in one fraction. The tumor was in the inside of the iso-dose line of 40 Gy. The delivered doses calculated at nine reference points, which were 12.5 mm distant from the center of the tumor, distributed between 19.225 and 32.169 Gy, with a mean of 24.8 Gy. No apparent side effect including pneumothorax and hemoptysis was observed. The tumor shrank and showed no increment of the size for about 2 years.

Clinical indications for brachytherapy

Brachytherapy, or placing radioactive sources either temporarily or permanently into or near a malignant tumor, is a long-established cancer treatment method. During the past 25 years, brachytherapy has become safer and more versatile than earlier radium therapy, and its indications have increased dramatically during this period. One estimate is that at least 5-10% of all patients needing radiation therapy require brachytherapy. The site-specific clinical indications and methods for brachytherapy implementation are described.

Review of the curative role of radiotherapy in the treatment of non-small cell lung cancer

The present paper is a comprehensive review of available data concerning the role of radiotherapy as an intended curative treatment in patients with non-small cell lung cancer (NSCL). The following issues are reviewed (1) optimal dose, (2) optimal fractionation, (3) optimal treatment planning, (4) clinical results in terms of single treatment and combined treatment with either surgery or chemotherapy. In resectable NSCLC high dose radiotherapy to small localized tumours gives a 5-year survival rate of 7-38%. It is concluded that this treatment modality is appropriate for certain selected patients who refuse to have surgery, who have medical contradications for surgery, or who are of old age. It is discussed whether the treatment should be split course, continuous, hypo-og hyperfraction. A total dose of 55 Gy must be given. CT scanning should be mandatory for optimal planning and therapy. The literature does not give a conclusive answer to whether preoperative or postoperative radiotherapy is indicated. The data indicate that patients with Stage III NSCLC will benefit from a combined treatment modality in terms of chemotherapy based on high dose cisplatinum and radiotherapy. The main conclusion of the review is that many areas with randomized controlled trials are needed in order to answer the critical issue of the role of radiotherapy in the treatment of NSCLS.

Absorbable mesh in placement of temporary implants

PURPOSE

To evaluate absorbable mesh for the suturing of afterloading catheters in patients with tumors involving the chest wall.

METHODS AND MATERIALS

Patients underwent thoracotomy and resection of tumor; a layer of absorbable mesh was then sutured to the tumor bed. Nylon flexiguide afterloading catheters were sutured into the mesh at about 1.5 cm distance from each other. A second layer of mesh was then sutured on top of the catheters. The chest wall was closed. Orthogonal radiographs and CT scans of the area of implants were done to verify catheter position in each patient on day 1 and on the last day of implant. Computer dosimetry by digitization of dummy sources was performed on each set of radiographs. The same seed for both sets of films was chosen as the origin of digitization. All seed coordinates were compared directly to offset for any rotation of the patient during the two sets of films. The distances were calculated from all seed positions to the origin, then tabulated and compared.

RESULTS

The distances agreed within a few millimeters (7-8 mm). The differences may be attributed to the patient's breathing and to the localization uncertainty. The resulting dose alteration was negligible.

CONCLUSION

This technique appears to provide adequate anchorage of catheters with resulting constant seed position and dose distribution in areas of scant tissues or in surgical beds of considerable size.

Iodine125 interstitial brachytherapy in the treatment of carcinoma of the lung

In a prospective study, 14 patients with primary non-oat cell lung carcinoma were treated with intraoperative Iodine125 (I125) implantation of the lung tumor via lateral thoracotomy or median sternotomy. Staging mediastinal node dissection was performed in each case. Patients were selected when wedge or segmental resections were not technically feasible, such that lobectomy or completion pneumonectomy would have been required or pulmonary function studies were poor. Doses ranged from 8,000 cGy at the periphery to 20,000 cGy at the center. With a minimum 12 month follow-up, mean and median survivals were 16.7 and 15.1 months, respectively. Local control was achieved in 10 of 14 patients (71%) with all local failures occurring in pathologic stage III patients. When separated according to tumor size, local control was obtained in six of seven tumors of less than 3 cm and four of five tumors of 3-5 cm. Both cases with masses greater than 5 cm failed locally. There was one operative mortality and two postoperative complications. All other patients were discharged within one week of surgery. There was no radiation pneumonitis. I125 lung brachytherapy is an excellent alternative treatment for T1 and T2 tumors when medical conditions preclude curative resection.

Induction chemotherapy for non-small cell lung cancer with clinically evident mediastinal node metastases: the role of postoperative radiotherapy

Survival for clinical Stage IIIa (T1-3, N2) non-small cell lung cancer is very poor because of poor local disease control and systemic spread. To address these shortcomings, we initiated a treatment program with induction chemotherapy, surgery, and postoperative radiation reserved for patients with residual disease at thoracotomy. Between 1984 and 1986, 41 patients with clinically evident N2 disease were treated with induction chemotherapy followed by resection and the selective use of intraoperative brachytherapy. All patients with tumor in the resection specimen received two cycles of chemotherapy and 15 patients received radiation therapy. With a median follow-up of 5.4 years, overall survival is 27% at 3 years, and 12% at 5 years. Despite the adverse selection process median survival is 19 months for patients receiving postoperative radiation therapy, and 22 months for the more favorable patients not requiring radiation therapy, supporting the selective use of postoperative radiation in this setting. In summary, this treatment has yielded good median survival and long-term survival for some of the patients. However, the ultimate value of this approach can only be determined by prospective trials which compare it to standard therapy.

Intraoperative plus external beam irradiation in nonresectable lung cancer: assessment of local response and therapy-related side effects

Since 1987, 24 patients with inoperable non-small-cell lung cancer (NSCLC), stage T1-3 N0-2 M0, have undergone lymph node dissection and intraoperative radiation therapy (IORT) to the primary with 10-20 Gy. Patient selection criteria were nonresectability based on severe cardiorespiratory impairment, no radiological evidence of distant metastases and a Karnofsky performance status of greater than 80. In 18 patients the IORT procedure was followed by an external beam radiation series (EBR) including the tumor with 46 Gy and the regional lymph nodes with 46/56 Gy. The tumor response was assessed by CAT-scan volumetry before the institution of IORT, 4 weeks later, before the onset of EBR, 8 weeks after the combined treatment course and on a 3 months basis thereafter. Prospectively, MRI of the thorax with/without Gadolinium-DTPA was performed to examine contrast enhancement and signal behavior of the tumor, in an attempt to differentiate residual disease compared to therapy-related collateral damage. So far, 18 patients have completed the combined treatment course with a median follow-up of 11 months (range 4.5 to 25 months). The overall local response rate (CR and PR) was 88.2%. In detail, 11 complete responses, 6 partial responses and one minimal response were observed. The overall and recurrence-free survival at 25 months was 49.6% and 83.3%, respectively.

Role of brachytherapy in the management of pulmonary and mediastinal malignancies

Brachytherapy, the permanent or temporary implantation of radioactive sources, has been performed in limited numbers of patients with lung cancer over the last 50 years. Because of renewed interest in this modality, we reviewed our experience with 103 patients treated over a 7-year period. The mean age of this group was 55.5 years (range, 1 to 84 years). Primary lung cancer accounted for 82 patients (79.6%); metastatic lesions to the lung, 13 (12.6%); and mediastinal malignancies, 8 (7.8%). Indications for brachytherapy included mediastinal and chest wall invasion in 42 patients (40.8%), unresectable tumors and mediastinal adenopathy in 30 (29.1%), medical contraindications to extensive pulmonary resection in 20 (19.4%), and irradiation of excised lymph node beds in 11 (10.7%). Seeds labeled with radioactive iodine 125 alone were used in 65 patients (63.1%), afterloading catheters containing iridium 192 sources in 25 (24.3%), and both in 13 (12.6%). There were no operative deaths. With a mean follow-up of 18.6 months, the mean and median survivals for the entire group were 17.3 and 14.0 months, respectively. The 1-year, 2-year, and 3-year survivals for the entire group were 67.9%, 38.7%, and 27.8%, respectively. In summary, brachytherapy offers a useful surgical approach in patients in whom unresectable pulmonary or mediastinal malignancies are found at the time of thoracotomy or in patients previously treated with other modalities for whom limited therapeutic alternatives exist.

Radiation therapy for medically inoperable stage I and II non-small cell lung cancer

The published results of primary radiation therapy for early stage NSCLC, indicate that it is a reasonable alternative in patients with medical contraindications or who refuse surgery, resulting in acceptable morbidity, local control, and survival rates. There is no conclusive evidence that EMI is of benefit. Consequently treatment with involved field alone, may be considered when there is no evidence of hilar involvement, or when it is necessary to limit the volume of lung tissue irradiated. Although the data are not conclusive, there is evidence to suggest that the total dose of radiation delivered to the primary should be sufficient to eradicate gross disease (60 Gy or higher). Such does result in high response rates particularly for T1 tumors. There is also an indication that complete responders have better survival than other patients, suggesting that radiotherapeutic strategies to enhance tumor eradication may improve survival.