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Biomedical subjects

G H Fletcher

Publications and source records attributed to G H Fletcher.

At least 109 records · Page 6Linked to original sources
PubMed1977

The significance of residual disease after external irradiation of squamous-cell carcinoma of the oropharynx.

366 patients with squamous-cell carcinoma of the oropharynx treated by external irradiation were studied to see whether residual disease at the end of treatment influences control. The frequency of recurrence was found to be significantly greater when residual disease was present. When the total dose was determined by the degree of regression of the primary lesion during treatment rather than the initial tumor volume, recurrence was significantly more frequent. Forcing the dose beyond a level suitable for the original volume of disease failed to prevent recurrence in patients with residual disease, most likely due to the hypoxic state of the remaining tumor cells.

Carcinoma, Squamous Cell↗
PubMed1977

Preirradiation celiotomy and extended field irradiation for invasive carcinoma of the cervix.

Epidermoid carcinoma of the cervix was treated in 120 patients by means of exploratory celiotomy (with semitherapeutic excision of involved lymph nodes) followed by irradiation. The size of the field used for irradiation was determined by the presence and site of lymph involvement. Of 64 patients, metastatic cancer in pelvic nodes was found in 40, and in common iliac or aortic nodes in 24. Of the 2 groups, 8 and 3 patients, respectively, survived for 2 years or more. Irradiation to extended fields (using 5500 rads at 850 rads per week) controlled the cancer satisfactorily within the treated area, but the incidence of bowel complications was high. Recurrent carcinoma usually appeared as distant metastases outside the treatment area which suggests that patients with bulky primary lesions and positive nodes actually already have systemic disease as treatment is started. A safe yet effective dosage level for radiation therapy to extended fields has not yet been established.

Carcinoma, Squamous Cell↗
PubMed1976

Results in irradiation of the in situ carcinomas of the vocal cords.

From 1952 through 1973, 79 patients with the diagnosis of in situ carcinoma and seven with the diagnosis of leukoplakia and/or atypical hyperplasia were treated with irradiation. The staging system was the same as for the invasive squamous carcinomas. The irradiation techniques were also identical to those used for invasive squamous cell carcinomas. The failure rate for the T1 lesions was 11% and 26% for the T2 lesions--in the same range as the failure rates observed for the invasive squamous carcinomas. Only two of the 12 failures were on the initially involved cord. These two facts suggest that most of the failures were not recurrences but were new disease developing on the dysplastic epithelium. There was a delay in the appearance of failure for the in situ carcinomas as compared with that for the invasive squamous cell carcinomas of the supraglottic larynx. Seventy-six percent of the patients have a normal voice.

Adult↗
PubMed1976

Time, dose, and tumor volume relationships in irradiation of squamous cell carcinomas of the base of the tongue.

Between January 1954 and August 1971, 174 patients with squamous cell carcinoma of the base of the tongue were treated with megavoltage external beam using conventional treatment times. Since the cumulative recurrence rate was 90% by 2 years, patients surviving 2 years without primary recurrences are considered to have no evidence of disease (NED) at the primary site. The primary control rate for T1 lesions is over 90% for doses of 6000 rads in 6 weeks to 6500 rads in 6 1/2 weeks. The control rate for T2 and T3 lesions is in excess of 80% with 7500 rads in 7 1/2 weeks. The slope of a hand-drawn exclusion line for T2 and T3 lesions is 0.38. For T4 lesions no significant pattern of dose, time, and primary control could be elicited. Of the 15 mandibular necroses, only six ultimately required mandibular resection. There was a signficant relationship (p = 0.03) between the development of mandibular necroses and extension of the primary onto the mucosa covering the mandible. A plot of ret dose versus area suggested a direct relationship between the portal area (volume irradiated) and the development of mandibular necroses.

Carcinoma, Squamous Cell↗
PubMed1976

Fast neutron radiotherapy for locally advanced pelvic cancer.

Between March 1973 and May 1975, 82 patients with locally advanced pelvic tumors were treated with 50 MeVdleads to Be neutrons. Seventy-nine have been included for analysis. The clinical material included 51 patients with gynecologic cancers, 15 with colorectal adenocarcinomas, and 13 with prostatic adenocarcinomas. Three treatment approaches have been used: 1) neutrons only--160 rad mu gamma twice weekly, 2) neutron boost following 25 MV photon irradiation--160 rad mu gamma twice weekly, and 3) mixed beam--photons (200 rads) three times weekly and neutrons (65 rad mu gamma) twice weekly. The preliminary results with the mixed beam are superior to those obtained with neutrons only or a neutron boost. However, the cancer and have been treated to slightly higher equivalent doses than those treated with neutrons only. The superior results with the mixed beam may be related to a better volume distribution and/or five-times weekly fractionation.

Adenocarcinoma↗
PubMed1976

Clinical studies with adjunctive surgery and irradiation therapy in the treatment of carcinoma of the cervix.

The majority of patients with cancer of the cervix are treated adequately by irradiation alone, and surgery is not necessary. A role for operation developsin certain patients with Stage I-II cancer of the cervix, who are prone to develop central recurrence if treated by irradiation alone. In these patients the primary lesion is massive. The vasculature to the center of these bulky or barrel-shaped cancer is insufficient, and a population of the cancer cells, perhaps related to anoxia, is more resistant to irradiation. The postirradiation conservative hysterectomy was incorporated into the treatment plan for 212 selected patients and the number of local recurrences was reduced. Incomplete cure of the peripheral component of the disease is another mechanism of treatment failure. This may occur, even though the primary lesion is cured. Patients with cervical cancers greater than 5 cm diameter have a high incidence of node metastasis, regardless of clinical stage. In those patients with positive nodes, the standard portals for external irradiation were expanded to include nodes at higher levels. The site of metastases was established by pretreatment laparotomy and the irradiation portals were then extended to include the involved nodes. Survival rates were not improved, because recurrences were not prevented, and death from treatment complications were high.

Adenocarcinoma↗
PubMed1976

Advanced squamous cell carcinoma of the oral cavity and oropharynx treated with irradiation and surgery.

One hundred and sixteen patients with advanced squamous cell carcinoma of the oral cavity and oropharynx were treated with irradiation and surgery. Failures were correlated with respect to tumor factors and treatment. Associated with failures are: (a) cut-through of disease at the primary site, (b) connective tissue involvement in the neck, (c) insufficient dose or use of a wedge pair, and (d) failure to give elective treatment to the neck. There is no significant difference in control in the pre- vs. the postoperative group. Combined treatment is indicated in those patients with a high risk of failure if treated by either modality alone.

Carcinoma, Squamous Cell↗
PubMed1976

Osteonecrosis in patients treated with definitive radiotherapy for squamous cell carcinomas of the oral cavity and naso-and oropharynx.

A group of 381 patients with squamous cell carcinoma of the oral cavity and naso-and oropharynx treated with definitive radiotherapy were analyzed with respect to the incidence and precipitating factors of mandibular osteonecrosis. Elective dental extraction prior to therapy increased the incidence, and dental conservation decreased it. Spontaneous osteonecrosis did not occur with doses less than 6,000 rads in 6 weeks, and was uncommon (1.8%) at doses under 7,000 rads in 7 weeks. At doses over 7,000 rads, osteonecrosis developed in 9%. The incidence was greater in patients with tumors near bone (9.4%) than in those with tumors not next to bone (2.1%).

Carcinoma, Squamous Cell↗
PubMed1976

Results of irradiation in squamous cell carcinomas of the glossopalatine sulcus.

Eighty-one patients with squamous cell carcinoma of the glossopalatine sulcus received definitive megavoltage irradiation at M.D. Anderson Hospital and Tumor Institute. Such tumores have a specific natural history and spread pattern. Almost all T2 and T3 lesions are controlled with 7,000 rads/7 wk.-7,500 rads/7 1/2 wk. The time-dose data for control of these lesions by radiotherapy indicate the importance of precise treatment. Complications are found to be dose related.

Adult↗
PubMed1976

Irradiation of endometrial cancer in patients with medical contraindication to surgery or with unresectable lesions.

In 124 medically inoperable patients with endometrial cancer, the five and ten year actuarial survival rates were 68% and 57%. In 26 patients with technically unresectable endometrial cancer, 26% actuarial survival rates at both five and ten years were seen. Pelvic control at death was 89% in Stage Ia, 78% in Stage Ib, 82% in Stage II, and 62% in Stage III. Sophisticated intracavitary therapy alone or in conjunction with external irradiation appears to give better uterine control rates than does external irradiation alone.

Adult↗
PubMed1976

Experience with twice-a-day fractionation in clinical radiotherapy.

Theoretical reasons have led to the treatment of 24 patients with advanced, rapidly growing squamous cell carcinomas of the head and neck, and 17 patients with inflammatory carcinoma of the breast with twice-a-day fractionation. After initial reduction in dose in both series, acute reactions and sequelae are similar to those in conventionally treated patients. The relative control rates are better than would be expected from conventional irradiation.

Breast Neoplasms↗
PubMed1976

Volume and time factors in interstitial gamma-ray therapy.

The two suppositions which have dictated time-dose and volume relationships in interstitial gamma ray implantation have been examined in the light of recent publications. The first of these assumptions, that total dose reduction is required when the dose rate exceeds 6,000-7,000 rads in seven days, does not appear to be substantiated by clinical experiences. It appears that total dose is the critical treatment parameter and that dose rate may be increased by a factor of two or three without requiring alteration of the total dose. Although the second classical assumption, "volume increase requires dose decrease," has been shown throughout radiation therapy experience to be generally correct, it should not be applied rigidly to interstitial gamma-ray therapy. In fact, recent experiences seem to indicate that compensation with respect to volume is not an absolute necessity. Larger lesions require, if anything, higher doses than small ones. To obtain a high percentage of controlled, lesions there must be no dose reduction, regardless of increased volume treated.

Animals↗
PubMed1976

Combination of conservative surgery and irradiation for cancer of the breast.

In patients with relatively advanced local or axillary disease, or both, a simple mastectomy followed by irradiation gives the best local and regional control rates. From the existing data, one can state unreservedly that women with early breast cancer take no chance on their life by having a treatment method which preserves the breast. In conjunction with the wedge excision, even if the axilla is clinically negative, a dissection of the low and central axilla brings enough information to decide on elective chemotherapy.

Breast Neoplasms↗
PubMed1976

Squamous cell carcinoma of the oral tongue and floor of mouth. Evaluation of interstitial radium therapy.

From January, 1965, to December, 1972, 46 patients with squamous cell carcinoma of the floor of the mouth and 102 patients with squamous cell carcinoma of the oral tongue were treated at M.D. Anderson Hospital and Tumor Institute by interstitial irradiation alone or in combination with external irradiation. Through the years the combination of radiation therapy modalities has been adjusted in an attempt to improve local control, keeping complications to a minimum. In this paper we analyze local control, causes of failure and complications as related to the primary size (T stage) and radiation therapy techniques employed.

Carcinoma, Squamous Cell↗
PubMed1976

Isoeffect exponents for the production of dose-response curves in squamous cell carcinomas treated between 4 to 8 weeks.

A scattergram diagram was made of controls and failures of treatment of squamous cell carcinoma in the tonsillar fossa on log-log paper coordinates of doses and treatment times. An exclusion line with an exponent of 0.30 was hand-drawn with all failures below the line. The same methodology has been used for the squamous cell carcinomas of the glosso-palatine sulcus and the base of the tongue. Isoeffect curves were obtained for lesions of all sites of the oropharynx with an exponent of 0.30 for the tonsillar fossa, 0.35 for the glossopalatine sulcus, and 0.38 for the base of the tongue. GHOSSEIN, using the least square method, obtained a curve with a slope of 0.33 for the squamous cell carcinomas of the supraglottic larynx. One can conclude that dose equivalents calculated from the equation D = D.T0.33 can be used as a first approximation in the squamous cell carcinomas of the upper respiratory and digestive tract treated between 4 to 8 weeks. It does not mean that a dose given in 4 weeks is clinically equivalent to a dose given in 7 weeks, derived from the isoeffect curve.

Carcinoma, Squamous Cell↗