Reconstruction and navigation system for intraoperative brachytherapy using the flab technique for colorectal tumor bed irradiation.

PURPOSE: To present the development of a new navigation and reconstruction system based on an electromagnetic free-hand tracker and on CT imaging for treatment planning of intraoperative high-dose-rate brachytherapy (IORT-HDRB) in the sacral region. Our aim is to improve accuracy and to enable individualized treatment planning and dose documentation to be performed for IORT-HDRB using a flab technique. METHODS AND MATERIALS: The material consists of an electromagnetic 3D tracker system, a PC workstation with Microsoft Windows NT 4.0 operating system, and a recognition program for continuous speech. In addition, we designed an external reference system constructed of titanium and Perspex, which is positioned in the pelvis, and a special digitizer pen for reconstruction of the flab geometry. The flab design incorporates a series of silicon 10-mm-diameter spherical pellets. Measurements were made with a pelvic phantom in order to study the accuracy of the system. The reconstruction results are stored and can be exported via network or floppy to our different treatment planning systems. RESULTS: Our results for the reconstruction of a flab with six catheters and a total of 100 spherical pellets give mean errors in the range (2.5 +/- 0.6) mm to (3.5 +/- 0.8) mm depending on the positions of the pelvic phantom and transmitter relative to the operation table. These errors are calculated by comparing the reconstruction results of our system with those using a CT-based reconstruction of the flab geometry. For the accuracy of the navigation system for the pelvic phantom, we obtained mean errors in the range (2.2 +/- 0.7) mm to (3. 1 +/- 1.0) mm. CONCLUSIONS: The new system we have developed enables navigation and reconstruction within the surgical environment with a clinically acceptable level of accuracy. It offers the possibility of individualized treatment planning and effective documentation of the 3D dose distribution in IORT-HDRB using a flab technique.

[Preoperative irradiation and interstitial radiotherapy-hyperthermia boost in breast tumors > or = 3 cm. The Düsseldorf experience]. / Präoperative Bestrahlung mit interstitiellem Radio-hyperthermie-Boost bei Mammatumoren > or = 3 cm. Düsseldorfer Ergebnisse.

AIM: The aim of this protocol was to investigate breast conservation rates with and without flap-supported surgery after preoperative chemotherapy, radiotherapy and hyperthermia. PATIENTS AND METHODS: One hundred and fifty-eight patients with stage IIA-IV breast cancers were initially treated with chemotherapy, radiotherapy and hyperthermia. Radiation treatment consisted of an interstitial boost of 10 Gy 192Ir-afterloading therapy and a course of external beam radiotherapy of 50 Gy, using 5 x 2 Gy/week. Local hyperthermia with 43.5-44.5 degrees C over 60 minutes was delivered immediately before interstitial radiotherapy. RESULTS: One hundred and forty-two patients underwent salvage surgery. A breast-conserving approach was possible in 74 patients (52%). Fifty-three patients (37%) underwent flap-supported surgery. After a median follow-up of 20 months, one patient developed isolated local recurrence. In 14 cases, locoregional recurrences occurred in combination with distant metastases. CONCLUSION: In about 50%, breast conservation was achieved by chemotherapy, radiotherapy and hyperthermia. The low isolated local recurrence rate of 0.6% (1/158) has to be substantiated by further follow-up.

Cyclophosphamide, mitoxantrone, fluorouracil versus conventional CMF as adjuvant treatment in node-positive breast cancer patients. A Hellenic Cooperative Oncology Group Study.

362 evaluable node-positive patients with stage II breast cancer were randomized, receiving either 6 cycles of conventional CMF or 6 cycles of the combination of cyclophosphamide (500 mg/m2), mitoxantrone (Novantrone 10 mg/m2), and fluorouracil (500 mg/m2; CNF). After a median follow-up of 51 months, 64 (36%) patients relapsed in the CMF group and 60 (33%) in the CNF group (p=0.8276). By Cox multivariate analysis, tumor size, menopausal status and number of involved nodes were retained as independently significant variables. Toxicities were remarkably similar in both groups. It appears that after a median follow-up of 51 months there is no significant difference in relapse-free survival between node-positive patients with breast cancer who received either 6 cycles of the conventional CMF or the CNF combination as adjuvant treatment.

Intraarterial 5-FU-infusion and simultaneous radiotherapy as palliative treatment of recurrent rectal cancer.

Palliative treatment of recurrent rectal cancer remains to be a challenge. From 1989 to 1991 13 patients with recurrent rectal cancer were treated with intraarterial infusion of 5-Fluorouracil and simultaneous radiotherapy in a palliative intent. Seven patients had received postoperative adjuvant radiotherapy with 56 to 60 Gy. Three patients had been treated with systemic chemotherapy. Radiotherapy of the recurrence was performed with 19.8 to 30.6 Gy in the pre-irradiated patients and with 50.4 to 59.4 Gy in the others. One complete remission, three partial remissions and nine minor responses were observed. Three patients had complete pain relief after the treatment, in the remaining patients major pain reduction was achieved. Palliation lasted from three to twelve months (median: five months). Our results indicate that locoregional chemo- and radiotherapy are a effective modality in recurrent rectal cancer.