Kaoru Okajima

Radiation therapy for T1,2 glottic carcinoma: impact of overall treatment time on local control

PURPOSE Local control probabilities of T1,2 glottic laryngeal cancer were evaluated in relation to dose and fractionation of radiation therapy (RT). MATERIALS AND METHODS Between 1975 and 1993, 96 T1N0M0 glottic cancers and 32 T2N0M0 glottic cancers were treated with definitive RT. Total RT dose was 60-66 Gy/2 Gy for most of the T1 and T2 tumors, although 10 T2 tumors were treated with hyperfractionation (72-74.4 Gy/1.2 Gy bid). Of the 128 patients, 90 T1 glottic tumors and 30 T2 glottic tumors were followed for > 2 years after treatment. Multivariate analyses using the Cox proportional hazards model and a logistic regression analysis were performed to evaluate the significance of prognostic variables on local control. RESULTS The 5-year local control probability for T1 tumors was 85%, whereas that for T2 tumors was 71%. Multivariate analyses demonstrated that only overall treatment time (OTT) was a significant variable for local control. Total RT dose, normalized total doses at a fraction size of 2 Gy, and fraction size were not significant. Local control probability of T1 tumors with an OTT of 42-49 days was significantly higher than that of tumors with an OTT of > 49 days (P < 0.02). Only a 1-week interruption of RT, due to holidays, significantly reduced the 5-year local control probability of T1 glottic tumors from 89 to 74% (P < 0.05). CONCLUSIONS These results indicate that OTT is a significant prognostic factor for local control of T1 glottic tumors.

Esophageal cancer treated with radiotherapy: Impact of total treatment time and fractionation

PURPOSE Local control rate and survival rate of esophageal cancer treated with radical radiation therapy (RT) were analyzed with special respect to total treatment time and fractionation. METHODS AND MATERIALS Between 1979 and 1992, 88 patients with Stages I-III esophageal cancer were treated radically with RT at Kyoto University Hospital and Wakayama Red Cross Hospital. Of the 88 patients, 52 patients were treated with conventional fractionation (1.7-2.0 Gy/day, five times/week), and the remaining 36 patients were treated with accelerated hyperfractionation (AHF). In 1989, we started AHF regimen for esophageal cancer. Daily fractionations were 2.0 Gy and 1.2 Gy (field-in-field), or 1.5 Gy and 1.5 Gy at 5- to 6-h interval. Most of the patients treated with AHF received the total radiation dose of 64-68 Gy. Twenty-seven patients were treated with intraluminal brachytherapy (IBT) as boost therapy following external RT. Fourteen patients were treated with IBT following AHF. RESULTS The median of treatment time of AHF was approximately 2 weeks shorter than that of conventional fractionation. Local control rate at 1 year were 47% for AHF, which was significantly higher than that for conventional fractionation (22%, p < 0.05). The improvement of local control by AHF was responsible for a trend to an improved cause-specific survival (p = 0.07). Local control rates at 1 year were plotted as a function of total treatment time. The slope of the linear regression line was -2.3 +/- 0.5% per day (p < 0.025) for patients treated with external RT alone, indicating a 2.3% per day loss in local control. Pretreatment and treatment parameters were evaluated in a multivariate analysis for the end point of local control. T stage (T1, 2 vs. T3, 4; p = 0.003) and fractionation schedule (p = 0.03) were independent of prognostic significance. Patients could tolerate the AHF well, although esophageal stenosis was noted frequently as a late toxicity. CONCLUSION Accelerated hyperfractionation was the most important treatment-related variable in this patient population. Total treatment time may have a significant impact on the treatment outcome for esophageal cancer.

CT simulator: A new 3-D planning and simulating system for radiotherapy: Part 2. clinical application

We have performed radiotherapy treatment planning (RTP) with a new system called CT simulator in 72 patients. With the system, RTP is performed with the patient lying on the CT couch within a short period of time. All the CT images scanned were immediately transported to the multi-image monitors and to the treatment planning device. Radiotherapy treatment planning could be performed not only at the beam center but also at any CT slice. Using a laser-beam field projector, field outlines were drawn over the patients skin. In clinical use, the system was useful for cases in which a target lies adjacent to dose limiting organs, cases with a complicated target shape, cases with complicated dose distribution curves, and cases treated with tangential fields. This system enables us to make optimum use of CT information and to make accurate 3-dimensional treatment planning programs.

Reproducibility of geometric distortion in magnetic resonance imaging based on phantom studies

BACKGROUND AND PURPOSE Image distortion is one of the major drawbacks of magnetic resonance (MR) imaging for use in radiotherapy treatment planning (RTTP). In this study, the reproducibility of MR imaging distortion was evaluated by repeated phantom measurements. MATERIALS AND METHODS A grid-pattern acrylic phantom was scanned with a 0.2-Tesla permanent magnetic unit. We repeated a series of scans three times to evaluate the reproducibility of the distortion. In each series, co-ordinates at 432 intersections of the grid were measured for both T1- and T2-weighted spin-echo (SE) pulse sequences. Positional displacements and their variations at the intersections were calculated. RESULTS Averages of the displacements were distributed between 1.58 and 1.74 mm, and maximum values (MAX) between 12.6 and 15.0 mm. Within 120 mm of the image center, the average values ranged from 0.73 to 0.80 mm, and from 3.4 to 5.0 mm for MAX. The absolute values of the positional variations among three series were distributed between 0.41 and 0.88 mm for average values, and between 1.4 and 4.5 mm for MAX. CONCLUSIONS The positional variations were mostly within 3 pixels, and most of the positional displacements within the radius of 120 mm of the image center were 2 mm or less. Therefore, it will be possible to use this MR system in RTTP under limited situations, although careful applications are required for RTTP of the body. The development of a computer program to correct image distortion is expected.

Use of a CT simulator in radiotherapy treatment planning for breast conserving therapy

A CT simulator (CT-S) is a real-time, CT-linked, 3-D treatment planning system, which consists of a CT scanner, a multi-image display, a treatment planning device with real-time visual optimization, and a laser beam projector. This system was clinically evaluated in 339 Stage 0, I and II breast cancers in 337 patients who received breast conserving therapy. Following quadrantectomy or wide excision with complete axillary dissection, a total of 50 Gy was delivered to the ipsilateral breast using 60Co gamma-rays. In patients with involved surgical margins, boost electron irradiation was also given. Treatment planning could be accomplished within 40-50 min using the CT-S. The parameters for the tangential portals could be optimized for each patient, and the wedge filters and the electron energy for boost irradiation could be appropriately selected. The incidence of moist desquamation and depigmentation at the areola was slightly decreased with the use of wedge filters. During the follow-up for 2-71 months (median, 22 months), local recurrence and symptomatic radiation pneumonitis occurred in one patient each. The CT-S appears to be useful for the individualized optimization of tangential irradiation fields in breast conserving therapy.

Transcatheter arterial embolization for malignant osseous and soft tissue sarcomas. II. Clinical results

AbstractPurpose: To evaluate the clinical effects of transcatheter arterial embolization (TAE) on malignant bone and soft tissue tumors. Methods: TAE was performed in 10 patients with primary bone and soft tissue sarcomas and in 31 patients with metastatic bone tumors. The embolized arteries were the internal iliac artery in 30 cases, the intercostal artery in six cases, the lumbar artery in five cases, the suprascapular artery in three cases, and the iliolumbar artery, the internal pudendal artery, and the lateral sacral artery in one case each. The embolized material was gelatin sponge particles. The chemotherapeutic drugs were usually 20–40 mg of doxorubicin for primary and metastatic tumors and 50–100 mg of cisplatin only for primary tumors. In addition, 50–60 Gy of 10-MV radiotherapy with or without radiofrequency (RF)-capacitive hyperthermia in four sessions was administered before TAE for primary tumors only. Results: Even though the pain score increased immediately after TAE, 30 of 38 (79%) patients with pain (8 of 9 with primary tumors, and 22 of 29 with metastases) achieved pain control after TAE. A necrotic low-density area shown by computed tomography (CT) after TAE was found in 31 of 41 (76%) tumors [8 of 10 (80%) with primary tumors, and 23 of 31 (74%) with metastatic tumors]. The tumor size decreased in 14 of 25 (56%) primary and metastatic tumors after 3 months. Osteosclerotic changes appeared in two cases of metastatic tumors after 6 months. In five tumors resected after TAE, large areas of necrosis within the tumor were confirmed histologically. Transient local pain and numbness appeared after TAE, but were relieved by drug treatment within 1 week. No severe complications except a case of gluteal muscle necrosis were encountered after TAE. The 1-year survival rate of the patients with primary tumors was 38.1%, and the median survival was 18 months. The longest survival was 84 months. The 1-year survival rate of the patients with metastatic bone tumors was 38.9%; the median survival was 12 months. The longest survival was 24 months. Conclusion: TAE could be an effective treatment for pain control and local control of malignant bone and soft-tissue tumors.

Three-dimensional treatment planning for maxillary cancer using a CT simulator

PURPOSE The results of three-dimensional treatment planning using a computed tomography simulator were evaluated in patients with maxillary cancer. METHODS AND MATERIALS Treatment planning was done in 25 patients using an x-ray simulator and plain x-ray films (1979-1982, group 1) in 34 patients using an x-ray simulator and computed tomography films (1983-1987, group 2), in 24 patients using a computed tomography simulator (1988-1992, group 3). The number of patients with Stage IV disease increased in the order of group 1 to group 3. RESULTS The average radiation field was smallest in group 3 (66.5 cm2) followed by group 2 (67.4 cm2) and group 1 (72.9 cm2). A radiation dose of more than 30 Gy to the lens of the effected side was delivered to 13% of group 3, 44% of group 2, and 44% of group 1. The dose to the lens on the uneffected side was zero in 56% of group 1, 74% of group 2, and 96% of group 3. A long-term decrease in visual activity on the effected side occurred in 11% of group 3, 32% of group 2, and 44% of group 1. However, a significant increase in survival was only noted between groups 1 and 2, because the three population of patients were different. CONCLUSION The three-dimensional treatment planning results in a better treatment than two-dimensional treatment planning as measured by complication rates and field sizes.

Laser projection system for radiotherapy and CT-guided biopsy

We devised a laser projection system combined with a CT scanner and radiotherapy treatment planning computer (CT stimulator). The irradiation field can be projected over a range of 180 degrees on the skin of a patient lying on the CT couch. For CT-guided biopsy, the system can project the skin entry point and needle direction.

Treatment outcomes and dose-volume histogram analysis of simultaneous integrated boost method for malignant gliomas using intensity-modulated radiotherapy

BackgroundThe aim of this article is to report the treatment outcomes, toxicities, and dosimetric feasibility of our simultaneous-boost intensity-modulated radiotherapy (SIB-IMRT) protocol.MethodsThirteen patients with malignant gliomas treated between December 2000 and September 2004 were enrolled in this study. Two planning target volumes (PTVs) were defined in the present study. Our IMRT regimen delivered 70 Gy/28 fractions (fr)/daily; 2.5 Gy to the gross tumor volume (GTV) with a 0.5-cm margin, defined as the PTV-G, and 56 Gy/28 fr/daily, with 2.0 Gy to the surrounding edema, defined as the planning target volume annulus (PTV-a). Eleven of the 13 patients received one or two courses of nimustine hydrochloride (ACNU) (100 mg/m2) and vincristine (1.2 mg/body) and interferon-β (3 × 106 units) three times weekly during the period of radiotherapy. Adjuvant chemotherapy, ACNU (100 mg/m2) and vincristine (1.2 mg/body), was repeated every 6 weeks and interferon-β was repeated every 2 weeks. The treatment outcomes, toxicity, and dosimetric feasibility were assessed.ResultsAll the patients experienced tumor recurrence. The median progression-free survival times for patients with grade III tumors and glioblastome were 7.5 and 8.0 months, respectively. The 1-year and 2-year overall survival rates for all the patients were 77% and 31%, respectively. Four patients experienced acute grade 1/2 toxicities during the treatment. No late toxicity related to radiotherapy has been seen. Analyses with dose-volume histograms confirmed excellent conformity of dose distributions in the two target volumes, PTV-G and PTV-a, with the sparing of organs at risk.ConclusionOur IMRT regimen did not prevent tumor progression. However, the ability of IMRT to deliver highly conformative doses to two contiguous targets, GTV and the surrounding edema, justifies its application to malignant gliomas.

Neoadjuvant Chemotherapy by Transcatheter Arterial Infusion Method for Uterine Cervical Cancer

PURPOSE The effects of transcatheter intraarterial infusion of anticancer drugs on the prognosis of cervical cancer were retrospectively studied. MATERIALS AND METHODS Two or three sessions of transcatheter arterial infusion therapy were performed in 97 patients with primary uterine cervical cancer. The number of patients in stage I, II, III, or IV were 15, 37, 34, and 11, respectively. The drugs infused were cisplatin (60-70 mg/m2), doxorubicin hydrochloride (30-40 mg/m2), mitomycin (15 mg/m2), and 5-fluorouracil (500 mg/body). They were infused via the bilateral internal iliac arteries. Seventy-five patients of the 97 (78%) underwent radical hysterectomy after arterial infusion: stage I (14 of 15), stage II (31 of 37), stage III (25 of 34), and stage IV (5 of 11). Three stage II and nine stage III patients received radical radiation therapy. The other 10 patients (one with stage I, three with stage II, and six with stage IV) did not receive an operation and radiation therapy after arterial infusion because of their distant metastases at the time of operation. Thirty-eight patients of 75 (51%) received postoperative radiation therapy. RESULTS The complete histologic response rates (no active cancer cells) after arterial infusion were four of 14, four of 31, six of 25, and one of five for stages I, II, III, and IV. The histologic response rates, which showed no parametrial invasion after arterial infusion, were 12 of 14, 24 of 31, and 15 of 25 for stages I, II, and III. The histologic response rates, which demonstrated no lymph node metastases after arterial infusion, were 12 of 14, 24 of 31, and 19 of 25 for stages I, II, and III. The overall 5-year survival rates of the patients with stages I, II, and III were 93.3%, 58.7%, and 69.7%, respectively. The 5-year survival rates of the operated patients with stages I, II, and III were 100%, 60.5%, and 63.6%, respectively. The 5-year survival rates of the irradiated patients with stage III was 87.5%. Leukocytopenia and thrombocytopenia occurred as an acute complication in 75% and 79% of the patients, respectively. As a late complication, ileus occurred in 7%. CONCLUSION Arterial infusion may improve the prognosis of patients with cervical cancer without increasing the incidence of late complications.