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Biomedical subjects

W D Rider

Publications and source records attributed to W D Rider.

At least 37 records · Page 2Linked to original sources
PubMed1983

Supraglottic laryngeal carcinoma: an analysis of dose-time-volume factors in 410 patients.

Four hundred and ten patients with supraglottic laryngeal carcinoma treated with moderate dose radical radiotherapy with surgery for salvage (RRSS) were analyzed in detail to determine optimal dose-time-volume parameters to be used in the treatment of each stage of supraglottic carcinoma. In the RRSS group 41% are alive and well at 5 years, 38% died of their tumor and 21% of intercurrent disease. Presence or absence of nodal disease has a major impact on survival. Local control is approximately 70% in T1, T2N0 patients and approximately 50% in T3 and T4N0 patients. Seventeen percent of T1 and T2N0 patients failed in the initially negative neck. Ten major complications (2.4%) have been seen. Local control by irradiation was not influenced by dose or field size. Regional control in the initially negative neck was markedly increased with the use of larger irradiation field sizes. Field sizes of less than 7 X 7 cm resulted in an 18% neck failure rate as compared to 3% with larger field sizes (p = 0.00005). This particularly applied to early stage disease. As a result of the use of larger irradiation field sizes giving reduced neck failure rates, improvement in survival has been seen in early stage supraglottic patients. The results are compared with published results. There is no statistically significant dose response curve in any stage of supraglottic cancer over the dose range 1650-2300 ret. Optimal treatment factors for supraglottic cancer are discussed.

Carcinoma, Squamous Cell↗
PubMed1983

Magna-field irradiation: work in progress in bone marrow transplantation at The Princess Margaret Hospital, Toronto.

Our work with total body irradiation (TBI) for acute leukemia in relapse dates from 1959. Following reports of the Seattle experience, we treated a small number of patients in remission--lowering the dose to 500 rad given at 50 rad/min, based in part on our experience with radiation pneumonitis complicating upper HBI. We have treated 51 patients since July 1979, with an actuarial survival of 65% overall, and 85% for patients 35 years-old or less. A specially designed cobalt-60 unit is used, which allows very large fields and high exposure rates. Dose is calculated at midplane and a homogeneity of +/- 5% obtained.

Acute Disease↗
PubMed1982

Observer variation in the assessment of patients with rectal cancer.

To examine the reliability of clinical features as possible components of a clinical method of prognostic staging for patients with rectal cancer, the results obtained when two pairs of physicians interviewed and examined a consecutive series of 60 patients with unresected rectal cancer were compared. High levels of agreement between physicians were found for most items of the patient's history, on whether the lesion was palpable, on the distance of the tumor from the anus, on the location and circumferential extent of the tumor, and on whether the tumor was fixed or mobile. Although physicians elicited similar physical signs, their use of terms to describe the rectal lesions varied widely unless agreed-upon criteria were used. There was 63 per cent agreement on the use of descriptive terms among physicians using criteria and only 13 per cent agreement among physicians not using criteria. These results show that prognostically important clinical features in patients with rectal cancer can be reliably identified and are thus suitable for inclusion in methods of clinical prognostic staging for this disease.

Humans↗
PubMed1982

Seminoma of the testis: results of treatment and patterns of failure after radiation therapy.

Four hundred and forty-four patients with the histological diagnosis of pure seminoma were treated at The Princess Margaret Hospital between 1958 and 1976. Using the Walter Reed Hospital staging classification, 338 patients (76.1%) were Stage I, 86 (19.4%) were Stage II, and 20 (4.7%) were Stage III. The 5 year actuarial survival rate (5 yr Sa) for all stages was 87%, and for Stages I, II and III: 94%, 74% and 32% respectively. In Stage II the 5-year Sa was significantly worse when palpable abdominal disease was present (62%, vs 87% when it was absent, p less than .02). Prophylactic mediastinal irradiation was not used for patients with Stage II disease. None of 40 Stage II patients without palpable abdominal disease recurred in the non-irradiated mediastinum. Ten of 46 Stage II patients with palpable abdominal disease recurred in the mediastinum; 7 of the 10 were cured with mediastinal irradiation at the time of relapse. Prophylactic mediastinal irradiation appears unnecessary in Stage II patients. The Stage III category includes a subgroup of patients who were curable with radiation therapy:L 5/6 with supradiaphragmatic nodal disease without palpable abdominal or visceral disease were cured. Exploration of new treatment methods appears indicated for the salvage of patients recurring in sites other than the mediastinum or supraclavicular fossa and for patients presenting with visceral disease.

Adolescent↗
PubMed1982

Lung density as measured by computerized tomography: implications for radiotherapy.

Accurate dose calculations for radiotherapy planning require a detailed knowledge of the internal anatomy of the patient both in terms of geometry and density. Computed tomography (CT) is presently the best means of providing these data. Fifty-eight patients who had scans of the thorax for radiotherapy planning were studied. The CT numbers were converted to relative electron densities and average lung densities were obtained for every patient. A linear correlation of lung density with age was found with the mean lung density of 0.35 at an age 5 years and 0.19 at an age of 80. The effect of scanning the patient under full inspiration, full expiration or normal shallow breathing conditions was analyzed. At the age of 5 years the expiration and inspiration average lung densities were 0.36 and 0.20, while at the age of 80 years they were 0.22 and 0.16, respectively. Respiratory volume changes were linearly correlated with changes in relative electron density. Differences in lung density between expiration and inspiration scans were found to demonstrate a similar trend with age as the relationship between vital capacity and age. The dosimetric and the possible clinical implications of lung density measurements for radiotherapy are considered. In particular, dose calculations were performed using scans taken under a number of different respiratory conditions. Doses calculated for a single cobalt-60 beam can differ by more than 25% when comparing a full inspiration scan to a normal breathing scan. A similar comparison for a parallel pair distribution on the lung yields a difference of about 3% while a typical three field technique for treating cancer of the esophagus shows a difference of nearly 10%.

Adolescent↗
PubMed1982

Carcinoid heart disease: diagnosis by two-dimensional echocardiography.

We prospectively studied 14 patients with the carcinoid syndrome to determine if two-dimensional echocardiography could detect the nature and extent of valvular abnormalities. Eight of the 14 patients had definite abnormalities of the right-sided cardiac valves. The tricuspid valve had a characteristic appearance, similar to previously described pathologic findings. The leaflets appeared diffusely thickened, shortened and stiff without evidence of commissural fusion. Saline contrast studies demonstrated tricuspid regurgitation, which corresponded to the severity of the tricuspid valve involvement. The pulmonary valve could only be adequately assessed in seven of 14 patients, and morphologic abnormalities similar to those in the tricuspid valve were found. Follow-up studies have shown progression of cardiac disease in six of eight patients. We conclude that two-dimensional echocardiography can detect the characteristic cardiac abnormalities in the carcinoid syndrome and may be a useful tool for following their progression.

Adult↗
PubMed1982

Combined radical radiation therapy and chemotherapy for primary squamous cell carcinoma of the anal canal.

Radical radiation therapy (5000 rads in 20 fractions in 4 weeks) combined with iv mitomycin (10 mg/m2) and 5-FU (1000 mg/m2/24 hours for 4 days) was used to treat 13 patients with locally advanced but operable squamous cell carcinoma of the anal canal. All patients achieved local control and retained anal continence, and none developed metastases. The patients were followed from 4 to 34 months (median, 12). Severe acute gastrointestinal toxic effects were seen in three patients; the same patients had significant thrombocytopenia or leukopenia. Treatment with this combined program may allow conservative management of squamous cell carcinoma of the anal canal and should be considered as an alternative to abdominoperineal resection.

Adult↗
PubMed1981

The effects of cancer and cancer therapy on male fertility.

Multimodality treatments have increased the survival of cancer patients in recent years. With cure the quality of life also should be taken into consideration. Maintenance of the reproductive capacity is of great concern to many young patients. Until now the cause of sterility was attributed to the long-term side effects of treatment when recovery could not be predicted. Pre-treatment sperm banking is advised routinely for many of these patients. Our own observation as well as a few other reports show that cancer itself seems to have an adverse effect on fertility before any form of treatment. As assessed by semen quality the majority of our patients were subfertile when first seen. Hence, sperm banking may be a poor guarantee for future reproduction in these patients.

Adolescent↗
PubMed1981

Testicular tumours in maldescended testes.

Maldescent is known to increase the risk of cancer of the testis. However, the effect of orchiopexy on reducing tumour risk and altering tumour type or stage at diagnosis is not established. The authors review the records of patients with testicular tumours seen for seminoma (1958 to 1975) and nonseminoma (1958 to 1970). Of 646 patients, 53 (8.2%) had a history of testicular maldescent; in 42 (79%) the maldescent was unilateral and in 6 of these, the tumour developed in the normally descended testis. Twenty patients had successful orchiopexy at a median age of 14 years (range from 6 to 35 years). Tumours found in the 53 patients were seminoma (38 patients), teratoma (7 patients), embryonal carcinoma (6 patients), teratocarcinoma (1 patient) and choriocarcinoma (1 patient). Average age at the time of diagnosis of seminoma was 38 years and of nonseminoma 31 years. Average age was lower at the time of diagnosis of the tumour for those who had successful orchiopexy than for those who did not. Earlier stage nonseminomas were found in patients who had an orchiopexy. Twenty-five (66%) of the 38 seminomas occurred in testes located outside the scrotum, whereas only 6 (40%) of 15 nonseminomas occurred in a nonscotal position, suggesting that persistent maldescent favours seminoma over nonseminoma. In this retrospective review, no statement can be made about the effect of orchiopexy on tumour risk. However, this procedure appears to lead to an earlier diagnosis and may influence the type of tumour that subsequently develops.

Adolescent↗