Manuel Santos

Non-melanoma skin cancer treated with HDR Valencia applicator: clinical outcomes.

Purpose Radiotherapy (RT) has played a significant role in treating non melanoma skin cancer (NMSC). High-dose-rate brachytherapy (HDR-BT) approaches have a paramount relevance due to their adaptability, patient protection, and variable dose fractionation schedules. Several innovative applicators have been introduced to the brachytherapy community. The Valencia applicator is a new superficial device that improves the dose distribution compared with the Leipzig applicator. The purpose of this work is to assess the tumor control, cosmesis, and toxicity in patients with NMSC treated with the Valencia applicator and a new regimen of hypofractionation. Material and methods From January 2008 to March 2010, 32 patients with 45 NMSC lesions were treated with the Valencia applicator in the Hospital La Fe. The gross tumor volume was visually assessed, but the tumor depth was evaluated using ultrasound imaging. All lesions for the selected cases were limited to 4 mm depth. The prescription dose was 42 Gy in 6 or 7 fractions (biologically effective dose [BED] ≈ 70 Gy), delivered twice a week. Results Ninety-eight percent of the lesions were locally controlled at 47 months from treatment. Ninety-three percent of patients were out at least 36 months from treatment. The treatment was well tolerated in all cases. The highest skin toxicity was grade 1 RTOG/EORTC, having resolved with topical treatment at 4 weeks in all but one case which required 2 months. There were no grade 2 or higher late adverse events. Conclusions In patients with superficial basal cell carcinoma lesions less than 25 mm in maximum diameter, HDRBT treatment with the Valencia applicator using a hypofractionated regimen provides excellent results, for both cosmetic and local control at a minimum of 3 years follow-up. Moreover, the shorter hypofractionated regimen facilitates compliance, which is very relevant for the elderly patients in our series. Valencia applicators offer a simple, safe, quick, and attractive nonsurgical treatment option.

Intraoperative radiotherapy for recurrent and/or residual colorectal cancer

Intraoperative radiotherapy (IORT) is an attractive boosting modality in the combined treatment of recurrent and/or residual colorectal cancer. Twenty seven patients treated with IORT are analysed. Residual disease following resection of the primary tumor was treated in 11 cases (group I). Localized recurrent disease without previous radiotherapy was treated in 11 cases (group II). IORT was used in five additional patients with local recurrences in previously irradiated areas (group III). The treatment program consisted of maximal tumor resection, IORT (10-30 Gy) to the area of residual disease and external beam radiotherapy (46-50 Gy). The median follow-up time for the entire series of patients is 11 months. Local tumor control rates are 90% in group I, 63% in group II and 60% in group III. Toxicity and complications related to IORT observed in this initial experience have been pelvic pain (29%) and lower extremity neuropathy (3%). These early clinical results suggest that the IORT combined with surgery and external beam radiotherapy is feasible in primary and recurrent disease. Local control rates obtained in patients not suitable for curative surgery are encouraging.

Intraoperative radiotherapy during lung cancer surgery: Technical description and early clinical results

A phase I-II study of intraoperative radiotherapy (IORT) for Stage III lung cancer was performed in 34 patients during a period of 58 months. Loco-regional treatment included tumor resection if technically feasible, IORT boost of electron beams using moderate single doses (10-15 Gy) to tumor bearing areas and external photon beam irradiation (46-50 Gy in 5 weeks) using conventional fields. Indications for this study were unresectable hiliar tumors (14, 41%), and mediastinal, hiliar and/or chest wall residual disease following resection (20, 59%). Thirty-four procedures, with 40 IORT fields, have been analyzed to describe the relevant technical aspects and the toxicity. IORT was delivered using acrylic transparent cones of different diameters. Surgical approach consisted in a lateral thoracotomy in all patients (21 right side and 13 left side). Tissues included within the IORT field were: tumor or residual tumor tissues (34, 100%), collapsed lung parenchyma and main bronchus not surgically manipulated (14, 41%), bronchial stump and vascular suture following resection (19, 55%), mediastinal structures (20, 58%), and brachial plexus (1, 3%). The bronchial suture was covered with pleural or pericardial flap after IORT in 10 cases (29%). Life threatening toxicity related to IORT consisted in broncho-pleural fistula (1, 3%) and massive hemoptysis (1, 3%). Other reversible toxic events were acute pneumonitis (12, 85%) and esophagitis (10, 50%). Long term asymptomatic lung fibrosis was detected in 11 cases (32%). Median survival time for the entire group has been 12 months. With a median follow-up time of 12 months the freedom from thoracic recurrence rate is 30% (65% in cases with tumor resection). Projected actuarial survival rates at 4 years were 28% for resected group and 7% for unresected cases. This experience supports IORT as a feasible alternative modality to be used in the management of locally advanced lung cancer. Tolerance of thoracic organs to moderate doses of IORT appeared to be adequate and local control is achieved in certain patients. These results deserve further investigation and confirmation trials.

Exclusive MRI-based tandem and colpostats reconstruction in gynaecological brachytherapy treatment planning

PURPOSE According to the GYN GEC-ESTRO Recommendations, MRI is needed with the modality of T2 weighted. CT-MR compatible tandem plus colpostats (T/C) (Nucletron) is widely used in cervical brachytherapy. The major challenge of MRI is the lack of dummy catheters. Therefore, an additional imaging modality is usually required. One disadvantage of sliced-based reconstruction is that resolution in longitudinal directions can be affected by the slice thickness. The aim of this study is to present a modified T/C applicator in which the catheter visibility is significantly improved. METHODS AND MATERIALS A modification to the existing T/C applicator has been made available, increasing the catheter entrance diameter. It allows a greater dummy catheter diameter, and consequently it can be filled with more material per unit length. Visibility was studied with different materials. RESULTS The catheter filled with saline water plus iodine compound was clearly seen in both axial and longitudinal acquisitions. To avoid uncertainties introduced by the slice thickness, a simple procedure is presented using longitudinal acquisitions. CONCLUSIONS The modified applicator plus catheter allows a powerful signal in T2 weighted MRI, using a very simple and accessible material. Also, a method is proposed to solve the problem of the uncertainty derived from slice thickness using few longitudinal acquisitions.

Intraoperative and external beam radiotherapy in advanced resectable gastric cancer: Technical description and preliminary results

Twenty-two patients with resectable gastric cancer treated with intraoperative radiotherapy and external beam irradiation, in a Phase I-II oriented study, were analyzed. Tumor Stages were III & IV in 18 cases (82%). Tumor histology was described as diffuse undifferentiated type in 14 cases (63%). Following surgical resection of the primary tumor, IORT 15 Gy was delivered in the celiac axis area, using high energy electron beams ranging from 9 to 20 MeV. External beam irradiation fields covered the draining nodal areas of the upper abdomen and the gastric bed. There were no postoperative deaths. Reversible postoperative complications were recorded in 14 patients (63%). Long term complications observed were vertebral collapse and liver hemangiomas. First sites of recurrence have been: hepatic hilum (three cases), peritoneum combined with central axis nodes (two cases), liver metastasis (one case), and lung metastasis (one case). Survival data shows a follow-up period ranging from 1+ to 33+ months, with a median survival time for the entire group of 13+ months. At the time of this report, 16 patients (72%) are still alive and six have died (four from progressive malignant disease and two from intercurrent disease). From this preliminary data, it can be concluded that a combined approach with surgical resection, intraoperative radiotherapy, and external beam irradiation is feasible in advanced gastric carcinoma, and is not limited by toxicity or any complications observed. Despite this intense loco-regional therapeutic approach, the upper abdominal failure rate has been demonstrated in 22% of the cases.

Intraoperative radiation therapy in malignant glioma: early clinical results.

Intraoperative radiation therapy (IORT) with high energy electron beams is a treatment modality that has been included in multimodal programs in oncology to improve local tumor control. From August 1991 to December 1993, 17 patients with primary (8) or recurrent (9) high grade malignant gliomas, anaplastic astrocytoma (4), anaplastic oligodendroglioma (6) and glioblastoma multiforme (7), underwent surgical resection and a single dose of 10-20 Gy intraoperative radiation therapy was delivered in tumor bed. Fourteen patients received either pre-operative (8) or post-operative (6) external beam radiation therapy. Primary gliomas: 18-months actuarial survival rate has been 56% (range: 1-21+ months) and the median survival time has not yet been achieved. Four patients developed tumor progression (median time to tumor progression: 9 months). Recurrent gliomas: 18-months actuarial survival rate and median survival time has been 47% and 13 months (range: 6-32+ months) respectively. The median time to tumor progression was 11 months. No IORT related mortality has been observed. IORT is an attractive, tolerable and feasible treatment modality as antitumoral intensification procedure in high grade malignant gliomas.

Postoperative radical radiotherapy with concurrent weekly intra-arterial cis-platinum for treatment of malignant glioma: a pilot study

Twelve patients with histologically proven malignant glioma have been treated with a combination of intra-arterial (IA) cis-platinum (CDDP) and radical radiation therapy (RT). Chemotherapy consisted of intracarotid (IC) CDDP, 40-60 mg/m2, weekly, repeated for 3-5 treatments. Radiation therapy consisted of whole-brain irradiation 5000 cGy in 5 weeks, plus a cone-down boost (1000 cGy in one week) to the primary tumour lesion. Ocular toxicity derived from IC chemotherapy was observed in 3 out of 41 procedures analyzed (7%). Results in tumour response assessed by computed tomography (CT) showed 5 complete remissions, 6 partial remissions and one patient was not evaluable. The median survival time for the entire group was 10 months. Median survival time in patients with complete response is 17 months, and 10 months in patients with partial response. Four patients are still alive with a follow-up ranging from 6+ to 27+ months.

Stereotactic radiosurgery of the foramen magnum region and upper neck lesions: Technique modification

A modification of the stereotactic radiosurgical procedure to permit treatment of lesions in the foramen magnum and upper cervical regions is described. The modification consists of placing the frontal pins of the stereotactic head ring in the zigoma bone, with no changes in the position of the occipital pins, so the final BRW head ring is oblique to the orbito-meatal plane. In this new position there is room enough in the posterior part of the guide for the support scrubs. This is unhampered by the patients shoulders and the lesion is far enough to permit setting the axial coordinate sufficiently above the head ring plane.

General Rationale and Historical Perspective of Intraoperative Irradiation

Most of the major advances in clinical applications of radiation therapy in the treatment of cancer have been because of differences in dose distribution between tumor and normal tissue. For most tumor types, the likelihood of achieving local tumor control improves if increasing irradiation doses can be delivered to the tumor mass. However, in many clinical situations, the dose that can be delivered safely to the tumor volume is limited by the normal tissues that are in close proximity to the tumor.

I-125 seed calibration using the SeedSelectron® afterloader: a practical solution to fulfill AAPM-ESTRO recommendations

Purpose SeedSelectron® v1.26b (Nucletron BV, The Netherlands) is an afterloader system used in prostate interstitial permanent brachytherapy with I-125 selectSeed seeds. It contains a diode array to assay all implanted seeds. Only one or two seeds can be extracted during the surgical procedure and assayed using a well chamber to check the manufacturer air-kerma strength (SK) and to calibrate the diode array. Therefore, it is not feasible to assay 5–10% seeds as required by the AAPM-ESTRO. In this study, we present a practical solution of the SeedSelectron® users to fulfill the AAPM- ESTRO recommendations. Material and methods The method is based on: a) the SourceCheck® well ionization chamber (PTW, Germany) provided with a PTW insert; b) n = 10 selectSeed from the same batch and class as the seeds for the implant; c) the Nucletron insert to accommodate the n = 10 seeds on the SourceCheck® and to measure their averaged SK. Results for 56 implants have been studied comparing the SK value from the manufacturer with the one obtained with the n = 10 seeds using the Nucletron insert prior to the implant and with the SK of just one seed measured with the PTW insert during the implant. Results We are faced with SK deviation for individual seeds up to 7.8%. However, in the majority of cases SK is in agreement with the manufacturer value. With the method proposed using the Nucletron insert, the large deviations of SK are reduced and for 56 implants studied no deviation outside the range of the class were found. Conclusions The new Nucletron insert and the proposed procedure allow to evaluate the SK of the n = 10 seeds prior to the implant, fulfilling the AAPM-ESTRO recommendations. It has been adopted by Nucletron to be extended to seedSelectron® users under request.