Kazuma Toda

QUALITY OF LIFE OF ORAL CANCER PATIENTS AFTER LOW-DOSE-RATE INTERSTITIAL BRACHYTHERAPY

PURPOSE To assess the quality of life (QOL) of oral cancer patients treated with low-dose-rate interstitial brachytherapy (LDR-BT) alone. METHODS AND MATERIALS Between June 2005 and July 2006, a total of 56 patients with oral cancer were enrolled in this prospective study. QOL was assessed by means of the core questionnaire and head and neck questionnaire module of the European Organization for Research and Treatment of Cancer (EORTC Quality of Life Questionnaire-Core 30 [QLQ-C30] and QLQ Head and Neck 35 [H&N35]). The questionnaires were distributed to the patients before the start of treatment and 3 months, 6 months, and 12 months after the start of LDR-BT. RESULTS It was possible to analyze the results for 20 of the initial 56 patients because they did not experience metastasis or recurrence during this study. No functions or symptoms asked about in the QLQ-C30 deteriorated during the first year. The emotional function score steadily and significantly increased. No symptoms in the QLQ-H&N35 significantly deteriorated. The scores for pain, trouble with social eating, and weight loss on the QLQ-H&N35 steadily and significantly decreased. Age, gender, and LDR-BT source had no effect on the change in QOL during the first year, but T-stage significantly affected the change in global health status, tumor site affected the changes in swallowing, sensory problems, sticky saliva, and complications affected the changes in pain, swallowing, and mouth opening. CONCLUSIONS QOL of oral cancer patients treated with LDR-BT is high. However, tumor stage, tumor site, and complications affected the changes in a few functions and symptoms during the first year.

Radiation-induced cancer after radiotherapy for non-Hodgkin's lymphoma of the head and neck: a retrospective study

Backgroundsurvivors of non-Hodgkins lymphoma (NHL) are well known to be at an increased risk of second malignancies. In this study, we evaluated the incidence and clinical features of head and neck cancer (HNC) occurring after radiotherapy (RT) for NHL.Materials and methodsWe investigated the clinical records of 322 patients who had received RT for early-stage NHL of the head and neck at our institute between 1952 and 2000.ResultsThere were 4 patients with a second HNC developing in the irradiated field, consisting of 2 patients with gum cancer, 1 case with tongue cancer and 1 case with maxillary sinus cancer. The pathological diagnosis in all the 4 patients was squamous cell carcinoma (SCC). Two of the patients (one with gum cancer and one with maxillary sinus cancer) died of the second HNC, while the remaining 2 patients are still living at the time of writing after therapy for the second HNC, with neither recurrence of the second tumor nor relapse of the primary tumor. The ratio of the observed to the expected number (O/E ratio) of a second HNC was calculated to be 12.7 (95%CI, 4.07–35.0), and the absolute excess risk (AER) per 10,000 person-years was 13.3. The median interval between the RT and the diagnosis of the second HNC was 17.0 years (range, 8.7 to 22.7 years).ConlusionThe risk of HNC significantly increased after RT for early-stage NHL. These results suggest that second HNC can be regarded as one of the late complications of RT for NHL of the head and neck.

Radiotherapy doses at special reference points correlate with the outcome of cervical cancer therapy

PURPOSE The authors analyzed the correlation between radiotherapy doses at reference points on the uterine edge and the rectal wall and both pelvic control and late rectal complications of cervical cancer therapy. METHODS AND MATERIALS Between 1997 and 2005, 57 patients with Stages IB-IVA cancer of uterine cervix were treated with a combination of external beam radiotherapy and high-dose-rate intracavitary brachytherapy. Their high-dose-rate intracavitary brachytherapy was planned by dose-point optimization at six dose points located on the edge of uterus by computed tomography. A rectal reference point located on the anterior wall of the rectum by computed tomography was also used. The pelvic control rate and the rate of late rectal complications were calculated according to the biologically effective dose (BED) at each point and several clinical parameters. RESULTS The overall 3-year pelvic control rate was 69.4%. The patients with a BED >80 Gy10 at the point on the edge of the uterine cervix had better pelvic control (78.4% at 3 years) than the patients with a BED < or =80 Gy10 (54.4% at 3 years), and the difference was significant. The difference in the BED (Gy3) at the rectal reference point between the patients with Grade 0-1 late rectal complications (median, 114 Gy) and the patients who developed Grade > or =2 late rectal complications (median, 178 Gy) was significant. Chemotherapy was a borderline significant parameter in regard to correlation with pelvic control and late rectal complications, but there were no correlations with other dosimetric or clinical parameters. CONCLUSIONS The radiotherapy dose at the reference point on the edge of the cervix affected pelvic control more than the clinical parameters, and the dose at the rectal reference point was more strongly correlated with the occurrence of late rectal complications.

Repeat Brachytherapy for Patients With Residual or Recurrent Tumors of Oral Cavity

PURPOSE To analyze data from patients receiving repeat brachytherapy (re-BT) for the treatment of residual or recurrent tumor in the oral cavity. METHODS AND MATERIALS Between January 2003 and December 2007, 62 patients who had undergone definitive BT as an initial treatment of oral cancer subsequently underwent re-BT for the treatment of residual or recurrent tumors at the diagnostic radiology and oncology department (Tokyo Medical and Dental University Hospital). Re-BT was performed 0.9-73 months (median, 5.7) after the initial BT. Au-198 grains were used as the re-BT source in all 62 patients, and an area of 0.8-6.3 cm(2) (median, 3.1) was permanently irradiated with 60-110 Gy (median, 83) according to the system of Paterson-Parker. RESULTS The 2-year local control and overall survival rate was 53% and 66%, respectively, and local control significantly affected overall survival. Both local control and overall survival were affected by the initial tumor characteristics and the macroscopic appearance of the residual or recurrent tumor. Grade 3 or 4 complications were seen in 5 patients. The incidence of mandibular and mucosal complications was significantly related to a biologic effective dose of α/β of 3 Gy to the surface of the gingiva and mucosa, respectively. CONCLUSION Re-BT using Au-198 grains for the treatment of residual or recurrent tumor after definitive BT in the oral cavity is effective and well tolerated.

Electron Therapy for Orbital and Periorbital Lesions Using Customized Lead Eye Shields

Purpose: To establish the protective efficacy against late complications of electron therapy using customized lead eye shields in cases with orbital and periorbital lesions. Methods: Between 1982 and 2006, 16 patients with 22 orbital and periorbital lesions were treated by electron therapy. Customized lead eye shields were prepared and placed in the respective patients’ eyes during each fraction of electron therapy. The toxicity and local control rates were analyzed. Results: The preparation period for the customized lead eye shields was 2 days. The shields could be used throughout the treatment period in all the patients. No evidence of radiation cataract was observed in 15 of the 16 patients. None of the patients developed corneal ulceration or evidence of lead poisoning. Conclusion: Customized lead eye shields could be made relatively quickly, and electron therapy for orbital and periorbital lesions could be undertaken safely without any late complication.

Estimation of whole-body radiation exposure from brachytherapy for oral cancer using a Monte Carlo simulation

Abstract Early stage oral cancer can be cured with oral brachytherapy, but whole-body radiation exposure status has not been previously studied. Recently, the International Commission on Radiological Protection Committee (ICRP) recommended the use of ICRP phantoms to estimate radiation exposure from external and internal radiation sources. In this study, we used a Monte Carlo simulation with ICRP phantoms to estimate whole-body exposure from oral brachytherapy. We used a Particle and Heavy Ion Transport code System (PHITS) to model oral brachytherapy with 192Ir hairpins and 198Au grains and to perform a Monte Carlo simulation on the ICRP adult reference computational phantoms. To confirm the simulations, we also computed local dose distributions from these small sources, and compared them with the results from Oncentra manual Low Dose Rate Treatment Planning (mLDR) software which is used in day-to-day clinical practice. We successfully obtained data on absorbed dose for each organ in males and females. Sex-averaged equivalent doses were 0.547 and 0.710 Sv with 192Ir hairpins and 198Au grains, respectively. Simulation with PHITS was reliable when compared with an alternative computational technique using mLDR software. We concluded that the absorbed dose for each organ and whole-body exposure from oral brachytherapy can be estimated with Monte Carlo simulation using PHITS on ICRP reference phantoms. Effective doses for patients with oral cancer were obtained.