Masao Hoshina

The efficacy of radiation therapy for a malignant melanoma in the mucosa of the upper jaw: an analytic study

An analysis has been made of the effect of radiation therapy in 28 patients with a malignant melanoma (Stage I: 18 cases; Stage II: 10 cases) in the mucosa of the upper jaw. Treatment had been provided by one of the following methods: intraoral mold (10 cases), interstitial brachytherapy (two cases), intraoral electron therapy (nine cases), or external irradiation (seven cases). The results have shown that the survival rate for all 28 patients was 25%, and that the survival rate for stage I patients treated by intraoral electron or brachytherapy was 47%. The primary tumor control rate in percentages was 79% (22/28) in all 28 radiotherapy patients; 92% (11/12) for tumors treated by a mold or an interstitial implant; 67% (6/9) for tumors treated by an intraoral cone; and 71% (5/7) for tumors treated by external irradiation with or without surgery. A neck metastasis that was found in 19 patients was treated by surgery, radiotherapy, and/or immunochemotherapy, and the result was successful in nine patients. The major factor in the failure of treatment was a distant, metastatic dissemination. This analysis revealed that radiotherapy has achieved similar or better results than surgery and may be advocated for the management of a localized malignant melanoma in the mucosa of the upper jaw.

FACTORS AFFECTING MANDIBULAR COMPLICATIONS IN LOW DOSE RATE BRACHYTHERAPY FOR ORAL TONGUE CARCINOMA WITH SPECIAL REFERENCE TO SPACER

PURPOSE To evaluate the efficacy of a spacer in the prevention of mandibular complications in low dose rate (LDR) brachytherapy (BRT) for oral tongue carcinoma. METHODS AND MATERIALS A retrospective analysis was conducted using 103 patients with T1 or T2 tongue carcinoma treated by a single plane implantation of iridium (192Ir) pins between 1979-1994. Of these patients, 60 were treated by BRT alone, and the rest were combined with external irradiation (Ext) and/or chemotherapy (CHT). Forty-eight and 55 patients were given BRT with and without a spacer, respectively. Spacers were individually made of acrylic resin according to a prosthetic technique so as to obtain the thickness of 7-10 mm at the lingual part of the implanted side. Variables, including a spacer, which may be associated with the development of osteoradionecrosis (ORN) of the mandible, were analyzed by the Cox proportional hazards regression analysis. RESULTS Our spacer reduced about 50% of the absorbed dose at the lingual side surface of the lower gingiva (LSG) to that in the absence of a spacer. Absolute incidence of ORN was 2.1% (1 of 48) and 40.0% (22 of 55), with and without a spacer, respectively, and the difference was statistically significant by univariate analysis (p = 0.0004). It was revealed by the Cox analysis that the spacer (p = 0.0247), combined CHT (p = 0.0295), and combined Ext (p = 0.0279) were significant independent factors associated with the development of ORN. The spacer was shown to be a significant factor by univariate analysis (p = 0.0037), but not by multivariate analysis when analysis was restricted to the patients who did not receive CHT. The absorbed dose, dose rate, and biological effective dose (BED) reflecting early or late response were estimated at the LSG, and prognosticators associated with the incidence of ORN were also determined by the Cox analysis. Particularly, BED for late response by BRT, the total absorbed dose, and any BED by Ext plus BRT were highly significant factors in the whole population. Essentially similar results were obtained in the patients without receiving CHT. CONCLUSIONS It was clarified that our spacer effectively prevents mandibular complications in LDR BRT by 192Ir for oral tongue carcinoma. Furthermore, introduction of a spacer provided novel information concerning the development of ORN, where BED particularly for late response given by BRT, the total absorbed dose, and any BED by Ext plus BRT could be good prognostic factors only when estimated at the LSG.

Usefulness of 198Au grain implants in the treatment of oral and oropharyngeal cancer

A series of 177 patients with squamous cell carcinoma of the oral cavity and oropharynx were treated with 198Au grain (gold grain) implants. Sites of the lesion included the tongue, mouth floor, buccal mucosa and oropharynx, especially the soft palate and faucial arch. Three-fourths of the patients were treated in combination with prior external beam irradiation. A permanent implant dose (total decay) of 80-90 Gy was given in the form of gold grains alone and in combination with an external dose of no more than 30 Gy, and 60-70 Gy, total decay, was given after an external dose greater than 30 Gy. The 2-year recurrence-free rate was 86.2% in the case of T1N0, 72.6% in T2N0 and 72.2% in T3N0. The difference in the results of implant therapy alone and combined therapy was not significant. Late complications were minimal after grain implantation alone, and when used in combination, less than 70 mCi of grain activity after a 40 Gy external dose did not seem to be a serious hazard with respect to bone damage except in the case of cancer of the mouth floor. Gold grain implants were useful and easily applied under local anesthesia to early or superficial lesions at sites where a rigid linear source could not be used. Exposure of the radiology staff was only 5-10 mrad in the case of the usual 10-15 (50-75 mCi) implant grains.

Chromosome aberration frequencies produced by a 70-MeV proton beam

The effectiveness of a 70-MeV proton beam in the induction of chromosome aberrations was studied. We employed peripheral lymphocytes and analyzed the frequencies of dicentrics and rings after irradiation at doses ranging from 0.1 to 8.0 Gy at various depths within a Lucite phantom. The frequency of chromosome aberrations after irradiation with an unmodulated proton beam at 5 mm showed a dose-response relationship similar to that of 60Co gamma rays. However, irradiation at greater depths with the spread-out Bragg peak induced higher aberration frequencies at doses lower than those with gamma rays. Furthermore, the distribution curve of chromosome aberration frequencies as a function of depth was found to be slightly different from the physically measured depth-dose curve. With the spread-out Bragg peak the biological effects were more marked at greater depths, resulting in a distribution of relative biological effectiveness values. The results obtained from chromosome aberration analysis may not be related directly to those for the relationship between dose and cell killing. Slight differences in values for relative biological effectiveness due to the change of dose and site of proton beam irradiation may not be important for practical proton beam therapy, but may be important in the prevention of late radiation injuries.

External and interstitial radiotherapy in the treatment of oropharyngeal squamous cell carcinoma

The records of 165 patients with squamous cell carcinoma of the oropharynx treated at our hospital with external and/or interstitial radiotherapy between 1971 and 1990 were reviewed to evaluate the treatment results, focusing on primary control and complications. All cancers were restaged according to the UICC 1987 TNM staging system. Of these 165 patients, 11% were in Stage I, 55% in Stage II, 24% in Stage III and 8.5% in Stage IV. Local control and complications were analysed in 140 patients. The remaining 25 patients died of intercurrent or metastatic disease during the first 2 years following treatment and were excluded from the analysis. 70 patients were treated by interstitial implant using permanent implant seeds (Rn-222 in eight patients, Au-198 in 62 patients) with or without external radiation. 56 other patients received external irradiation alone and another 14 patients received pre-operative external irradiation plus surgery. 2-year recurrence-free rates were 73% (100% for T1, 76% for T2, 36% for T3 tumours) in the patients who received interstitial implant with or without external radiation and 36% (67% for T1, 48% for T2, 13% for T3 tumours) in the patients treated by external irradiation alone. The incidence of soft-tissue or bone complications requiring long-term treatment was 14%. Based on these findings, it is believed that an interstitial implant using Au-198 grains combined with external beam irradiation is a useful treatment modality for small lesions of the oropharynx.

Brachytherapy for non-metastatic squamous cell carcinoma of the buccal mucosa : an analysis of forty-five cases treated with permanent implants

An analysis has been undertaken of 45 patients with non-metastatic squamous cell carcinoma of the buccal mucosa treated by permanent 198Au or 222Rn implants and in most cases supplementary external irradiation. Eight patients had T1, 30 had T2, and 7 T3 disease. Of the lesions 21 were located in the buccal mucosal surface, 14 in the retromolar region, and 10 in the bucco-alveolar sulci. Seven of the 45 (16%) died of the disease and the actuarial 5-year survival rate was 81%. No obvious differences were noted in survival rate between different stages of the disease or between different subsites of the primary lesion. There were 6 local recurrences occurring from 3 to 33 months after treatment, and only one of these was salvageable by further radiation therapy. Neck node metastasis occurred in 11 cases from 2 to 34 months after treatment, and 8 of these cases responded successfully to a radical neck dissection or radiotherapy.

Squamous Cell Carcinoma of the Maxillary Sinus and the Oral Part of the Upper Jaw: Comparison of treatment results

The treatment results were compared in 77 patients with maxillary sinus squamous cell carcinoma (MC) and 53 patients with squamous cell carcinoma arising from the oral part of the upper jaw (OC). Both sets of patients received radiotherapy alone, or radiotherapy combined with surgery and/or chemotherapy. Computerized tomography was useful for the definition of the treatment volume. Intraarterial chemotherapy was given in 89 of 130 patients and in these patients the total radiation dose was reduced by about 10 Gy. No difference was found in the 5-year survival rate between the MC (65%) and the OC (66%) groups. The cumulative incidence of local failure was higher in MC (36%) than in OC (26%), whereas the ultimate incidence of neck node metastasis was higher in OC (43%) than in MC patients (18%). Half of the inoperable patients (9/18) were older than 80 years and had contraindications to anaesthesia and major surgery. The local recurrence rate was high in the inoperable MC patients (6/8). Contralateral sinus cancers occurred in 4 patients in the MC group.

Maintained Salivary Function after Brachytherapy in Patients with Head and Neck Carcinomas Evaluation Using Quantitative Salivary Gland Scintigraphy

The purpose of this study was to determine whether or not salivary gland dysfunction occurs within the first three months after brachytherapy in patients with head and neck carcinoma. Of the 20 patients with head and neck squamous cell carcinoma included in this study, 11 were treated with brachytherapy and the remaining 9 patients received external irradiation. All the patients underwent a salivary gland scintigraphy before and after radiotherapy. The scintigraphic parameters of each major salivary gland were then compared before and after the radiotherapy. In the brachytherapy group, none of the scintigraphic functional parameters showed a significant change before and after the radiotherapy. In contrast, all of the parameters with the exception of the uptake ratio (UR) of the submandibular glands significantly decreased after external irradiation. This observation was to be expected owing to the different irradiation doses administered by the two techniques. The scintigraphic technique used to evaluate salivary gland function should be used in future intensity-modulated radiation therapy salivary-gland-sparing studies in order to evaluate both the acute and chronic effects of irradiation in head and neck cancer patients.

A comparative study of dose distribution of a high-energy electron beam and chromosome aberration frequencies.

Electron beam therapy is usually employed for the treatment of tumours located at or near the surface of the body, because the electron beam gives a high dose near the surface, but falls off rapidly with increasing depth beyond the level of the 80% depth dose. Isodose curves for radiotherapy have been obtained using physical methods, but have rarely been investigated on the basis of living human cells. In the present study, lymphocyte chromosome analysis was employed as a biological dosemeter for comparison with the isodose curve measured physically. The peripheral blood was exposed to a 14 MeV electron beam in a plastic tube set in a specially made test-tube stand immersed in a water tank. The chromosome aberration frequencies induced by irradiation of about 95% of peak dose at a depth of 31 mm were found to be higher in value than those induced at a depth of 17 mm where the peak dose had been determined physically. Three gray of irradiation given to whole blood in the presence of contrast medium gave rise to a slight enhancement of radiation-induced chromosome aberration frequencies in the lymphocytes exposed at a depth of 17 mm, but a slight decrease at 31 mm.

PROGNOSTIC FACTORS IN HEAD AND NECK NON-HODGKIN'S LYMPHOMA WITH SPECIAL REFERENCE TO SERUM LACTIC DEHYDROGENASE AND SERUM COPPER

An analysis of prognostic variables was performed in a retrospective study of 121 patients with Ann Arbor stage I-II head and neck non-Hodgkins lymphoma admitted from 1973 to 1988. The overall actuarial 5-year survival rate was 58.8% and the minimum follow-up 15 months. Nine clinical and laboratory parameters were studied, including serum lactic dehydrogenase (LDH) and serum copper (SCL), and subjected to univariate and multivariate analyses. In univariate analysis, histology and LDH were found to be significant prognostic variables. Evaluation by Coxs multivariate proportional hazard model revealed histology, SCL and sex to be of prognostic significance.