Relationship between cell kinetics and radiation-induced arrest of proliferating cells in G2: relevance to efficacy of radiotherapy

Monitoring the radiation-induced G2-arrest with flow cytometry disclosed the relationship between the pattern of accumulation in G2 and the cell kinetics (Tc), as assessed with semi-continuous labelling. A close relationship between these two parameters was observed in a murine mammary tumour after high dose-rate irradiation and in human cervix tumours (xenografted and in patients) after low dose-rate irradiation. In inoperable tumours of the oral cavity, a G2-arrest, observed in the first two weeks of fractionated therapy, was found to predict a local cure. Consequently, it was concluded that the cells accumulated in G2 were not doomed cells. This process of radiation-induced synchronization might be exploited in fractionation schemes of which treatment intervals are adjusted to the Tc-related timing of the radiation-induced G2-arrest.

[Thermoradiotherapy of the late stages of cancer of the oral mucosa and oropharynx]

Local UHF-hyperthermia (915 MHz) of cancer of the oral mucosa at advanced stages ensures higher immediate cure rates (48.9 +/- 7.5%) as compared to radiotherapy (26.8 +/- 6.9%). 30-min. hyperthermia before irradiation turned out more effective than 60-min. hyperthermia. Hyperthermia was attended by side-effects (fatigue and sweating, vertigo and pain in the zone of heating). Hyperthermia was not tolerated by 10.7% of patients. Fixed metal prostheses and crowns in the zone of planned hyperthermia should be removed.

The role of combined composite resection and irradiation in the management of carcinoma of the oral cavity and oropharynx

Squamous cell carcinoma of the oral cavity and oropharynx can invade the mandible requiring an "en bloc" or composite resection. With this procedure alone, reported local control rates for advanced stage tumors have been suboptimal suggesting the need for adjuvant therapy. The treatment records of 35 patients were reviewed who were treated with composite resection alone, composite resection plus radiotherapy, or composite resection as a salvage procedure for a primary treatment failure. Combined irradiation and composite resection resulted in a higher local control than patients receiving composite resection alone (72% vs. 43%). There was no difference in complication rates between these two treatment groups. Composite resection as a salvage procedure resulted in local control in 38% of patients through this was associated with a 64% rate of complications. This data and a review of the literature suggest that tumors of the oral cavity and oropharynx with extension to the mandible requiring composite resection probably represent a category of tumors with a high risk of local recurrence and may benefit from adjuvant irradiation.

[Pre- and postoperative radiotherapy of oral carcinoma of a locally advanced stage. An analysis of the results and complications]

The combination of radiotherapy and surgery in the treatment of advanced oral carcinoma (T3 and T4 lesions) yields good possibilities of recovery; whether radiotherapy should be given before or after surgery is still debated. Fifty patients with advanced oral carcinomas were analyzed: 24 of them were irradiated before and 26 after surgery; doses ranged from 40 to 56 Gy for the first group of patients, and from 50 to 68 Gy for the second one. The disease-free survival 48 months after the diagnosis was 36% in patients who received preoperative irradiation, and 53.6% in patients who received postoperative radiotherapy; the latter allowed local control of the disease to be significantly improved (chi 2 3.99, 0.01 less than p less than 0.05). The quality of survival was worse in the group receiving preoperative irradiation, because of radiation-induced surgical complications, which were especially observed in patients with diffuse disease. Our findings suggest that postoperative radiotherapy may be advisable if the tumor is resectable, since tolerance and local control rate were acceptable. On the contrary, nearly inoperable masses and massive neck diseases often require preoperative irradiation.

Radiotherapy of carcinoma of the buccal mucosa

A retrospective study of 399 cases of buccal cancer, presenting to the Tata Memorial Hospital, Bombay, during January to December 1984 was undertaken to define the efficacy of various treatment modalities in different clinical stages. Analysis of treatment technique and response was carried out in 185 cases that completed adequate therapy. Sixty percent of patients with stage I and II disease (21/35) received radiation therapy alone as the primary modality of treatment. Patients (150) with stage III or IV disease received palliative irradiation (57 cases), radical surgery (54 cases), or a combination of both (39 cases). The 2-year disease-free survival (DFS) rates were 48% for radiotherapy and 46% for surgery in the early stages and 5% and 33%, respectively, for advanced stages. Radiotherapy with a modified technique is recommended for the early-stage cancers and preoperative irradiation with adjuvant chemotherapy or hyperthermia for the advanced stages.

[The results of radiotherapy in advanced oral carcinomas. The effect of altered therapeutic strategies]

During the period from 1968 through 1984, 197 patients with advanced carcinomas of the oral cavity have been irradiated. The authors investigate the influence of a standardized chemotherapy as initial therapy measure on the subsequent radiotherapy and the therapy results. Whereas 4.2% of patients were submitted to this treatment between 1968 and 1975, 64.5% of patients received a chemotherapy during 1976 and 1984. The remission rate following to cytostatic therapy was 71%; most of them were partial remissions. The influence of chemotherapy manifested itself by an increase of macroscopically radical tumor resections, especially in stage IV, but also by an increased number of radiotherapy interruptions in case of strong mucosal reactions. An increase of the median survival time from 20 to 30.5 months was connected with the intensified therapy. Further on, this difference vanished, and the five-year survival rates were identical.

[Role fo ultrasound in the study of latero-cervical metastases]

In patients undergoing radiotherapy (RT) for malignant neoplasies of the head and neck the availability of a diagnostic method permitting frequent, easy checkups of the latero-cervical lymph nodes would be extremely useful. This is especially so because clinical examination is often hindered by the post-actinic fibrosis of the tissues. Among the methods presently available for this purpose (CAT, NMR, lymphoscintigraphy, xerography, ultrasound) echotomography appears to be the most indicated as it is least invasive, can easily be repeated and is not difficult to perform. The refining of ultrasound techniques would, as reported in the literature, make it possible today to evaluate the effects of RT on latero-cervical metastases both during and some time after treatment. The authors, therefore evaluated the advantages and limitations of the method examining 33 patients undergoing RT for latero-cervical metastases due to head and neck carcinoma. Each patient underwent ultrasound examination prior to, during and at the end of the RT treatment cycle. Once treatment had been terminated 18 underwent latero-cervical neck dissection. Upon termination of the radiation treatment three distinct types of ultrasound behaviour were identified: complete response; partial response; minimal or negligible response. For those patients undergoing surgery this response was compared to lymph node chain histology while, for the others, it was compared to the ultrasound findings of subsequent examinations. The results obtained appear to indicate that a systematic scheduling of ultrasound checkups offers a reliable evaluation of how metastatic adenopathies respond to RT. At times such response can only be completed several months after treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Minor salivary gland tumors of the lip and buccal mucosa

Between 1944 and 1985, 50 patients with minor salivary gland tumors of the lip and buccal mucosa were treated at M.D. Anderson Cancer Center: 19 with lip and 31 with buccal mucosa tumors. The male-to-female ratios were 2.8:1 for lip and 1:2.9 for the buccal mucosa tumors. Patient age at presentation ranged from 18 to 98 years with a median of 55 years. Treatment consisted of surgery alone for 28 patients, radiotherapy in 9 patients, and combined therapy for 13. Adenoid cystic carcinoma was the predominant histologic type, accounting for 21 (42%) tumors. Risk for recurrence was influenced by histology, the presence of perineural invasion, and the location of the primary tumor. Six patients developed recurrent disease; all six had adenoid cystic carcinoma. The therapeutic approach and the rationale for combined treatment of these neoplasms are discussed.

[Therapy for angiomas of the oromaxillofacial region]

The AA, describe the treatment of the hemangiomas of the oral and maxillofacial district, on the light of the last acquisitions.

Afterloaded radiation carrier for carcinoma of the palate. A clinical report

Although every brachytherapy procedure is individualized, similar factors must be considered for each patient. Dental prostheses with modification may be useful in brachytherapy for managing selected patients with malignancies of the oral cavity. The prosthesis described in this article allowed an irregular surface to be treated with a relatively uniform radiation dose, while minimizing radiation exposure to uninvolved tissues and medical personnel. Whereas uniformity of dose is usually desirable in brachytherapy, it assumed even greater importance for this patient because of previous RT.

Comparison between predicted and actual dose distribution in interstitial therapy of the oral cavity

During the period 1985-1986, 10 patients with lesions of the floor of the mouth or of the mobile part of the tongue were treated by interstitial curietherapie with iridium-192. In the patients treated with the looping technique essential differences were found between the predicted source configuration and that actually achieved, resulting in a disagreement between precalculated and actual dose distribution. To avoid this undesirable situation, a simple oral cavity applicator was constructed which guarantees parallelism and equidistance between the implanted needles. It was found that the use of this applicator resulted in an almost complete agreement between forecast and actual dose distribution.

Local prostaglandin E2 in patients with oral malignancies undergoing chemo- and radiotherapy

Patients undergoing chemo- and/or radiotherapy for malignancies were often found to develop annoying inflammation of the oral mucosa. As prostaglandins are known to be cytoprotective. Prostaglandin E2 was given to 10 patients who received combined radio- and chemotherapy for oral neoplasms. Patients receiving PGE2 reported substantially less intense pain then those in the control group. Our statistically significant results indicate that topical treatment of side effects produced by combined radio- and chemotherapy of oral neoplasms with PGE2 holds promise and is clearly superior to conventional treatment modalities.

Mandibulotomy and radical radiotherapy: compatible or not?

The mandibular swing, as an approach to upper aerodigestive tract malignancies, has been gaining popularity in recent years. Little has been reported in the literature as to the feasibility of this procedure in subjects having received radical preoperative radiotherapy. The preliminary results of a retrospective analysis of 23 subjects, 70% of whom received radical preoperative radiotherapy, is presented. There was no statistically significant difference between the complication rates in the irradiated and nonirradiated subject populations. All subjects, ultimately, were orally rehabilitated.

[Treatment of head and neck cancer with twice-a-day fractionation]

Fifty patients with locally advanced head and neck cancer were treated with twice-a-day fractionation (1.0-1.5 Gy 2 times daily, 5 days per week). These patients consist of 12 cases of thyroid cancer, 23 of hypopharynx cancer, 7 of cancer of the oral cavity, 6 of oropharynx cancer and 2 of other sites. Total delivered dose was 21-73 Gy in 10-74 days. In respect of thyroid cancer, 2 cases of 3 with papillo-follicular carcinoma, 1 of 1 with small cell carcinoma and 3 of 8 with giant cell carcinoma were locally controlled. Patients of hypopharyngeal carcinoma treated with multifractionated radiotherapy combined with or without surgery revealed good prognosis (91% of T1 + T2, 100% of T3 + T4 at 2 years). Patients with cancer of the oral cavity or oropharynx, however, had poor prognosis.

[Hyperthermia in combined radiotherapy of cancer of the mouth mucosa]

Combined treatment of patients with cancer of the oral mucosa using a dynamic course of irradiation in combination with local hyperthermia was proposed. Altogether 55 patients were treated, of them in 51 (92.7%) complete tumor regression was achieved. The short-term results were indicative of the efficacy of the above method.

Reirradiation of tumors in cats and dogs

Fifty-one cats and dogs with tumor recurrence after irradiation were treated with a second course of radiotherapy, using either teletherapy or brachytherapy. Eighty-six percent of the tumors had partial or complete response at 2 months after reirradiation. Tumor response was significantly (P = 0.041) affected when the interval between the 2 courses of irradiation was greater than 5 months. The estimated local tumor control rate was 38% at 1 year after reirradiation. Of all the factors examined, complete response at 2 months, reirradiation field size less than or equal to 10 cm2, and reirradiation dose greater than 40 gray emerged as predictors of local tumor control. The estimated overall survival rate was 47% at 2 years. Tumor location had a significant (P = 0.001) influence on overall survival; animals with cutaneous tumors had the longest survival times, and those with oral tumors had the shortest survival times. The other significant (P = 0.001) factor affecting overall survival time was the field size of the reirradiated site. Estimated survival time after reirradiation was 41% at 1 year. Favorable prognostic indicators were complete response at 2 months and location of tumor; animals with skin tumors had a favorable prognosis. The acute effects of reirradiation on normal tissues were acceptable, but 12% of the animals had severe delayed complications. Significant risk of complications after reirradiation was associated with squamous cell carcinoma (P = 0.015) and reirradiated field size greater than 30 cm2 (P = 0.056). When the interval between irradiations was greater than 5 months, the risk of complications was significantly (P = 0.022) lower.(ABSTRACT TRUNCATED AT 250 WORDS)

Microwave hyperthermia in the treatment of spontaneous canine tumours: an analysis of treatment parameters and tumour response

Fifty-one spontaneous canine tumours were treated with combined radiation and hyperthermia in a pilot study designed to investigate the feasibility and efficacy of the combined modality treatment in the dog. The tumours varied in site and histological type: 35 were in the oral cavity and included squamous cell carcinoma, melanoma and various 'sarcomas'. All animals received radiation (36-40 Gy in four weekly fractions) and post-irradiation hyperthermia (prescription -44 degrees C for 30 min) on one or two occasions. The microwave hyperthermia system was technically satisfactory in elevating tumour temperature to 44 degrees C or above in 95 per cent of treatments. However, thermal gradients of the order of 3-5 degrees C were frequently measured across the tumour, and rarely did all peripheral points achieve the target of 44 degrees C for 30 min. The overall tumour response rate (CR + PR) was 87.7 per cent with 60.7 per cent of tumours achieving complete regression. Smaller lesions showed a significantly greater response rate (P = 0.004) and those lesions which received two thermal treatments show an increased response (P = 0.0095). Fifty-one per cent of tumours showed significant necrosis following hyperthermia. Normal tissue necrosis was seen in three patients; in two cases this was attributed to hyperthermia. Local tumour control rate and necrosis was not correlated with measured minimum, mean or maximum thermal doses.

Reactive changes in the mandible in the presence of squamous cell carcinoma

A series of 80 mandibles, which were removed as part of composite resections for primary intraoral squamous cell carcinoma, was examined. Of these, 58 were nonirradiated and 22 were previously irradiated. Several changes were observed in the nonirradiated mandible in response to invading tumor. Deposition of new bone was obvious on the periosteal and endosteal surfaces. Osteoclastic resorption of bone was prominent and there was replacement of hemopoietic marrow by fibrous tissue. By contrast, it was found in the irradiated specimens that osteoblastic activity was absent but that osteoclastic activity persisted. The hemopoietic marrow was replaced by fibrous tissue. The lack of osteoblastic activity was interpreted as being due to irradiation. The extent of these changes and their relationship to the invading tumor have implications for both surgeon and pathologist.

[Results of radiotherapy of carcinomas of the retromolar trigone observed at the Varese Regional Hospital]

Retromolar Trigone Carcinomas (RTC) are generally diagnosed at an advanced stage in spite of their accessible location. From December 1979 to January 1987 we examined 23 patients with RTC at the Varese Regional Hospital--three women and 20 men, with an average age of 62.9 years. 21/23 patients were heavy cigarette smokers and consumed more than 1 l of alcohol per day. The patients were classified as 1 T1, 9 T2, 9 T3 and 4 T4 on the basis of TNM classification of malignant tumors. At the beginning of the treatment 12 patients had latero-cervical metastatic nodes. Fifteen patients underwent radiotherapy with 60Co with doses ranging from 60 to 70 Gy. The patients without evident metastatic cervical nodes were also irradiated with doses of at least 45 Gy as a precautionary measure. The percentage of cumulative survival of these patients amounts to 41.1% after 3 years, while for relapse-free patients pcs amounts to 40.7% after 3 years. In view of our results, we do not consider radiotherapy alone an effective treatment as a local cure for RTC. We intend to set up a new therapeutic protocol which incorporates surgery with radiotherapy and includes chemotherapy as necessary on the basis of T volume and of the presence of loco-regional metastatic nodes.