Radiotherapy has played an important role in the treatment of head and neck squamous cell cancers. In this several decades, new radiotherapy methods, such as conformal radiotherapy, chemoradiation and hyperfractionated radiotherapy has been introduced. Literatures about these methods and the experience of our institute are discussed in this paper. New trial is not necessary for such tumors as early stage laryngeal cancer or lingual cancer, in which 85-90% of local control rates has been obtained by conventional radiotherapy or brachytherapy.
Three dimensional conformal radiotherapy (3DRT), which can not only escalate the dose delivered to the target volume but also reduce the dose to the adjacent normal tissue, may be a good indication to the nasopharyngeal cancer or early stage tumor in the oral cavity or mesopharynx.
Although a lot of regime of chemoradiation are used mainly to advanced cancer, their usefulness has not been established yet. High dose cispaltin based intravenous induction chemotherapy followed by radiotherapy and/or operation is mainly used in the locoreginal advanced cancer. Low dose cisplatin besed daily concomitant chemoradiation is also used in the locoreginal advanced cancer. Intraarterial chemotherapy followed by radiation and/or operation is used to the locally advanced cancer. Usefulness of these regime must be evaluated carefully.
The efficacy of hyperfractionated radiotherapy in advanced head and neck cancer is proved in Europe and United States. Because the number of the stuff engaging in radiotherapy is small in our country, institutions in which hyperfractionated radiotherapy can be done are limited.

View full abstract

The diagnosis of mediastinal disease using conventional chest radiographs is based on the recognition of abnormal lung-mediastinal interfaces resulting from the abnormal contours of ajacent or underlining mediastinal structures.
The increasing use of degital radiography has improved visualization to the point that many lung-mediastinal interfaces previously not imaged are now routinely demonstrated. This permits earlier and more accurate diagnosis of pathologic conditions. Radiation oncologists frequently use chest radiography for follow-up study, are forced to detect new mediastinal abnomalities. Thus, if subtle mediastinal abnomaliteis is to be detected, a detailed understanding of normal lung-mediastinal interfaces is necessary. Familiarity with these lung-mediastinal interfaces willfaciliitate accurate interpretation of chest radiographs in both normal and pathologic conditions.
It is important that their lung-mediastinal interfaces, at least the right paratracheal stripe, right paraesophageal line and left paraspinal line are checked in every chest radiographs at routine work.
In this discussion, I will review the mediastinal contours and interfaces most useful in thedetection of mediastinal disease, its applications.

View full abstract

In the field of radiotherapy for the uterine cervical cancer in Europe and USA, the effectiveness of brachytherapy using Ra-source was already established in 1913. The standard technique of brachytherapy combined with the external irradiation for the cervicalcancer had been established at the end of the 1930's. In Europe and USA, the irradiated dose was revised to be recorded with the actually irradiated dose (R-unit) at the point A and B, not with the oldfashioned mgh-unit in 1938. But it was in the second half of the 1950's that the modern brachytherapy technique developed by Manchester-group in 1938 was introduced to Japan by theradiation oncologists (Dr. Tazaki, E et al). And still in Japan the standard treatment strategy for the cervical cancer in stage I and II is the ‘radical hysterectomy’, in spite of almost the same treatment results. That is probably because the radiotherapy has been performed mainly by the gynecologists before and during the Second World War.

View full abstract

Using dose measurements of electron beams in ionization chambers for small fields, the average energy of electron beams determined with large fields was examined to ascertain the smallest size of field to which applicability could be achieved. Simple and accurate methods of dose measurements of electron beams generally applicable for very small fields were also examined. In large fields, PDDs measured with ionization chambers agreed well (within 2%) with PDDs measured using either film methods and semiconductor detectors. As such, the energy dependency of electron beams in film and semiconductor detectors was considered to be disregardable. The PDD of irradiated fields less than 4 cm in diameter achieved with smallelectron cones were measurable with either film methods or semiconductor detectors.
We introduced the concept of “output factor”(OPF), which is analogous to field factor (FA), to the dose measurements of electron beams. We found that measurements of the OPF of electron beams (6-18 MeV) in JARP ionization chambers in irradiated fields of greater than 6 cm in diameter, with semiconductor detectors in irradiated fields from 3 cm in diameter to 5 cm in diameter, and using film methods in very small irradiated fields of approximately 2 cm in diameter are both convenient and very accurate.

View full abstract

Purpose: Late radiation damages associated with high-dose rate intraluminal brachytherapy (HDR-IBT) and external radiotherapy (RT) were analyzed using the linearquadratic (LQ) model.
Materials and Methods: Normalized total dose at a fraction size of 2 Gy (NTD-2 Gy) was calculated using the LQ model. The α/β ratio for the central nervous system was assumed to be 1 Gy or 2 Gy, while the α/β ratio for the other tissues was assumed to be 3 Gy.
Results: NTD-2 Gy at the esophageal mucosa was 142 Gy when HDR-IBT (12 Gy/2 fractions) were given using a centering device of 10 mm in diameter following external RT of 60 Gy/30 fractions. When the same dose-fractionation was given using a centering device of 20 mm, NTD-2 Gy decreased to 110 Gy. The adverse effect of external RT treating of only one field each day was evaluated. NTD-2 Gy of several critical organs increased 4-5% when only one field was treated each day compared to that when two fields for parallel-opposed fields were treated each day.
Conclusion: Calculations of NTD-2 Gy were easy to perform, and NTD-2 Gy is very comprehensive for radiation oncologists. NTD-2 Gy provides a good clue for comparing different fractionations of HDR-IBT and external RT.

View full abstract

Purpose: To compare results of treatment performed (a) with and (b) without teampractice in supraglottic laryngeal cancer patients, including local control rate and preservation of voice.
Materials and Methods: In April 1991, the first author joined the Kurume University hospital. Since then, radiation oncologists, radiologists and otolaryngologists have worked in close collaboration to treat head and neck cancer patients. We examined all cancer patients together and discussed and determined the choice of treatment modalities as a team. In group A (period, Jan. 1978 to Mar. 1991), 125 supraglottic laryngeal cancer patients were treated before team practice. Among them, only 6 (9.1%) T1 and T2 patients were treated with radical radiotherapy. In group B (period, Apr. 1991 to Mar. 1997), 74 patients were treated with team practice, of which 22 (73.3%) T1 and T2 patients were treated with radical radiation. All 199 patients had histologically proven invasive squamous cell carcinoma. Follow-up period was at least 2 years.
Results: Local control rate of T1 and T2 cancer improved from 75.3% for group A patients to 87.7% for group B patients. Larynx preservation rate improved significantly from 49.4% to 85.6%(P<0.01). Five-year overall, cause-specific and relapse-free survival rate for all stages I to IV patients improved significantly from group A to group B: from 52.8% to 68.8%, from 67.0% to 86.1% and from 51.7% to 81.2%, respectively.
Conclusion: Team practice provides effective results in improved local control and preservation of natural voice for patients with supraglottic carcinoma.

View full abstract

We have constructed and are operating a multi-institutional radiotherapy database ROGAD (Radiation Oncology Greater Area Database) since 1992. One of it's purpose is “to optimize individual radiotherapy plans”. We developed “Radiation oncology learning system combined with ROGAD” which conforms to that purpose. Several medical doctors evaluated our system. According to those evaluations, we are now confident that our system is able to contribute to improvement of radiotherapy results.
Our final target is to generate a good cyclic relationship among three components (1) radiotherapy results according to “Radiation oncology learning system combined with ROGAD.”, (2) The growth of ROGAD and (3) radiation oncology learning system.

View full abstract

The results of external radiation therapy used on 109 superficial esophageal carcinoma patients in 9 institutions in Japan were analyzed retrospectively. All patients had histologically proven squamous cell carcinoma. The survival rates at one, two, and five years were 88%, 73%, and 45% respectively. Of the 64 patients who had died, only 19 died of esophageal cancer. Cause-specific survival rates at one, two and five years were 96%, 89%, and 75%, respectively. Sex was the only significant prognostic factor (worse in women). Although the difference wasnot significant, the survival of patients with a tumor invading the submucosa and with an elevated type of growth was poorer than the other patients. Severe late injury such as esophageal ulcer, perforation, and bleeding was not observed. External radiation therapy alone is effective for treating superficial esophageal carcinoma. However, further investigation is needed toestablish a standard treatment protocol.

View full abstract

Purpose: To evaluate the results of conventional radiotherapy for pituitary adenomas assessed with computed tomography (CT) or magnetic resonance imaging (MRI). Endpoints include tumor control, normalization of hormone levels in functioning adenomas, and hypopituitarism after radiotherapy as an adverse effect.
Materials and Methods: Forty-two patients were treated with radiotherapy from 1982 to 1995 at Niigata University Hospital. Forty patients were irradiated after surgery because of residual adenomas in 33 patients and tumor regrowth in 7 patients. One patient was treated with radiotherapy alone, and the remaining 1 patient was treated with preoperative radiotherapy.Tumor size and extension were evaluated using CT or MRI, and all tumors were macroadenomas. They consisted of 18 non-functioning and 24 functioning adenomas (growth hormone (GH)-secreting: 11, prolactinomas: 7, concomitant GH and prolactin (PRL)-secreting: 5, gonadotropin-secreting: 1). Treatment was given in 200 cGy daily fraction size and a total dose of 50 Gy was given to most patients. Sixteen patients with GH-and/or PRL-secreting adenomas received bromocriptine. Tumor progression was determined by increase in tumor size as shown by CT or MRI. Hypopituitarism after radiotherapy was evaluated using the functions of corticotropin (ACTH), thyrotropin (TSH), and gonadotropin. Median follow-up time from the end of radiotherapy was 103 months.
Results: Tumor progression occurred in 2 out of 42 patients and 10-year progression-free rate for all patients was 93.7%. Normalization of GH levels was obtained in 12 of 16 GH-secreting adenomas with a mean time of 27 months after radiotherapy, and 9 of 12 PRL-secreting adenomas achieved normalization of PRL levels with a mean time of 34 months. One gonadotropin-secreting adenoma achieved normalization of gonadotropin level at 21 months after radiotherapy. The incidence of hypopituitarism after radiotherapy increased with time, and cumulative risk of deficiencies of ACTH, TSH, and gonadotropin at 10 years were 48.6%, 22.8%, and 75.1%, respectively.
Conclusions: Conventional radiotherapy was effective in preventing tumor growth of pituitary adenomas. But the effect of reducing hormone levels in functioning adenomas appeared to require several years after radiotherapy in most cases. Because hypopituitarism occurs in the late period after radiotherapy, long-term follow-up is necessary and mandatory.

View full abstract

Background and Objective: Cases of radiation therapy for benign diseases have diminished in number because of recent alternative methods and knowledge about radiation carcinogenesis. In contrast to this tendency, our cases of benign diseases have recently increased. The facts made us reconsider today's radiation therapy of benign diseases.
Patients and methods: We reviewed 349 patients who were diagnosed as having benign tumors or non-neoplastic conditions and treated by radiation therapy in the past sixteen years. Analyzed items were the annual transition of treatment number, sorts of diseases, patients' age and sex, and the goal of therapy.
Results: Of all radiation therapy patients, benign diseases account for 9.26%. The annual percentages were 0.5%, 6.0%, 11.2% and 13.7% at intervals of five years ince 1982. The majority was 246 post-operative irradiation for keloids (71%) and 41 pituitary adenomas (12%). Compared with malignant tumors, benign disease patients were statistically younger and femaledominant. Applications of radiation therapy in keloids and pituitary adenomas had definite goals, but were unclear in other rare diseases.
Interpretation: Benign diseases should be treated by radiation therapy as the second or third option, provided the patients have serious symptoms and their diseases do not respond to other modalities. It seems to be widely accepted that favorite cases such as keloids and pituitary adenomas are treated by radiation therapy. But, optimal radiation therapies for other rare benign diseases have not been established. Therefore, the building of databases on radiation therapy on benign diseases should be pursued. Since benign disease patients were young and female-dominant and had many remaining years, their carcinogenicity potential should beconsidered.

View full abstract

We report a patient who suffered from prolonged loss of taste acuity after irradiation and recovered lately.
An electric gustometry was used for the evaluation of quantitative local taste acuity and amodified LENT SOMA scale was used for the evaluation of subjective total taste acuity.
A sixty three years old male patient having lower gingiva cancer suffered from loss of taste acuity with a duration of more than 4 and a half years after radiation therapy to the oral cavity. And he recovered from the loss of taste acuity after the healing of mandibular bone sequestration due to osteoradionecrosis.
This indicates that intra-oral diseases can delay recovery from loss of taste acuity after oralcavity irradiation.

View full abstract