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T Keane

Publications and source records attributed to T Keane.

At least 19 recordsLinked to original sources
PubMed2001

Squamous cell carcinoma of the oesophagus treated with radiation and 5-fluorouracil, with and without mitomycin C.

A retrospective analysis was performed of patients with squamous cell carcinoma of the oesophagus without evidence of distant metastases, who were treated with radical intent. Between 1981 and 1984, and 1989 and 1991, 98 patients were treated with radiation, 5-fluorouracil (5-FU) and mitomycin C; and between 1984 and 1989, 133 patients were treated with radiation and 5-FU without mitomycin C. Actuarial survival and local control were assessed, and prognostic factors were identified for both endpoints. The standard dose of radiation prescribed was 52 Gy to the 95% isodose in 20 fractions over 4 weeks. 5-FU was given by continuous infusion as 1 g/m2 (maximum 1.5 g)/day, for 4 days. Patients who received mitomycin C were given 10 mg/m2 (maximum 18 mg) on day 1. Survival and local relapse-free rates were estimated using the method of Kaplan and Meier, and the Cox proportional hazards model was used to evaluate possible prognostic factors, including the effect of mitomycin C administration. The median survival was 15.4 months (95% confidence interval 12.7-17.2) with 31% 2-year survival (standard error (SE) 3%), and 13% 5-year survival (SE 2%). In the multivariate analysis, lower radiation dose and younger age were the only statistically significant prognostic factors for reduced overall survival and reduced relapse-free rate respectively. There was no difference in survival (chi(2) = 0.07, 1 degree of freedom (df), P=0.79) or local relapse-free rate (chi2 = 0.39, 1 df, P = 0.53) between patients treated with or without mitomycin C. The treatment was well tolerated. Further studies are required to determine the most effective combination of radiation and chemotherapy or other radiation sensitizers for squamous cell carcinoma of the oesophagus.

Aged↗
PubMed2001

Long-term efficacy of sildenafil and tachyphylaxis effect.

PURPOSE: We observed that patients who initially responded to sildenafil frequently became resistant to it with time. We evaluated the long-term efficacy of sildenafil. MATERIALS AND METHODS: A telephone survey was conducted of patients during the first year of sildenafil usage, and another one was completed 2 years later of the same group. RESULTS: During the first survey, the etiology of impotence included post radical prostatectomy in 25, arterial insufficiency in 26, diabetes in 19, neurogenic impotence in 12, suspected venous leak in 9, proved venous leak in 7, Peyronie's disease in 6 and unspecified in 47 patients. The overall improvement rate, which was defined as the ability to initiate and maintain erections for successful intercourse, was 74%. The dose necessary to achieve this response was 100 mg. sildenafil in 15% of patients, 50 mg. in 83% and 25 mg. in 2%. During the second survey, information was collected on 82 patients and only 43 (52%) had continued treatment. Of the 69 patients who reported an initial good response 41 (59%) were still using sildenafil, and of the 43 who were still using it 16 (37%) had to increase the dose by 50 mg. to achieve an adequate result. There was no significant relationship between the need to increase the dose and frequency of treatment per month. Reduction in efficacy ranged from 15% to 50% (mean 36 +/- 12%) and the time to loss of efficacy ranged from 1 to 18 months (mean 11 +/- 5). Of the 82 patients in the second surgery, 39 (48%) stopped using sildenafil. A total of 28 (74%) patients reported a good initial response on the first survey, and 6 had spontaneous erections and no longer needed treatment. However, 14 (50%) patients discontinued sildenafil because of the loss of efficacy. In this group 10 patients had side effects, mainly headache and flushing of the face and nose, and only 2 discontinued treatment because of them. CONCLUSIONS: Our data suggest that there is a possible tachyphylaxis effect with sildenafil. Of the patients who were followed for 2 years 20% had to increase the sildenafil dose to have the same effect and 17% discontinued use due to loss of efficacy.

Adult↗
PubMed1997

Enhanced control by radiotherapy of cervical lymph node metastases arising from nasopharyngeal carcinoma compared with nodal metastases from other head and neck squamous cell carcinomas.

PURPOSE: To test the hypothesis that metastatic cervical lymph nodes arising from nasopharyngeal carcinoma (NPC) are more readily controlled with radiotherapy than comparable nodes from squamous cell carcinomas of other head and neck sites (SCC). METHODS AND MATERIALS: One hundred four NPC patients with metastatic cervical nodes (mean size of the largest node equals 4.1 cm) were randomly selected from radiation treatment files for two time periods, 1969-1976 and 1983-1988, when radiation alone was the first line treatment. Candidate controls were selected randomly from radiation treatment files of node positive squamous cell carcinomas arising from the oropharynx, hypopharynx, oral cavity or larynx who were also treated by radical radiation therapy as sole initial treatment in the 1970s and 1980s. Each NPC case was matched with a control using the size of the largest involved node as the matching criterion. The median follow-up of all 208 patients was 3 years (4.2 years in NPC cases and 1.4 years in the matched controls). For those who were alive at last follow-up, the median follow-up for both arms was 7.7 years (6.7 years in NPC cases and 10.2 years in the matched controls). Nodal control was evaluated by clinical neck examination in both arms. Nodal recurrence was defined as relapse or persistence of metastatic nodal disease from day 1 of radiotherapy treatment. RESULTS: Despite a similar mean delivered dose to involved neck nodes (52.9 Gy for the NPC group and 53.9 Gy for the matched controls), the SCC group had significantly worse nodal control with radiation when compared to the NPC group (p < 0.0001, relative risk 3.0, 95% [1.8, 5.1]). The 3-year nodal recurrence-free rate among NPC cases was 71 +/- 5%, compared to 43 +/- 5% among matched controls. CONCLUSION: The result of this study supports the hypothesis that metastatic cervical nodes from NPC are more readily controlled by irradiation than cervical nodes of similar size arising from other head and neck squamous cell carcinomas. Further study is required to explore the reasons for this apparent radiosensitivity.

Adolescent↗
PubMed1997

Surgical salvage after radiotherapy for advanced laryngopharyngeal carcinoma.

OBJECTIVE: To comment on the use of surgery after the failure of radiotherapy in patients with advanced laryngeal, oropharyngeal, and hypopharyngeal carcinomas. DESIGN: Randomized, controlled, clinical trial, with a mean follow-up period of 3.1 years. SETTING: The Princess Margaret Hospital, Toronto, Ontario. PATIENTS: Patients with advanced laryngopharyngeal carcinoma (T3 or T4 or N+). INTERVENTION: Three hundred thirty-six patients who met the eligibility criteria were enrolled in a randomized, controlled, clinical trial and treated with primary radiotherapy using either the standard fractionation regimen or the hyperfractionation regimen. One hundred eight patients with recurrent disease underwent salvage surgery and were observed prospectively, with careful documentation of surgical and tumor data, complications, recurrences, and survival. MAIN OUTCOME MEASURES: Surgical complication rate and survival. RESULTS: Of the 108 patients who underwent surgery, 29 (27%) had complications. One third of these had multiple complications. There was no statistical difference between the surgical complication rates of the 2 radiotherapy groups (16 patients [28%] in the standard fractionation radiotherapy group and 13 [25%] in the hyperfractionation radiotherapy group). Survival after surgery was statistically correlated with the TNM system for the stage of the recurrent tumor, the pathologic nodal status, and the surgical margin status. The overall 3-year survival rate, which was calculated from the date of surgery, for the group of patients who underwent surgery was 22%. CONCLUSIONS: In this patient population, the hyperfractionation regimen was not associated with a higher surgical complication rate. Using the policy of primary radiotherapy and reserving surgery for the management of failures of radiotherapy, 140 patients (71%) at highest risk (laryngeal and hypopharyngeal primary tumor sites) retained an intact larynx until the end of the study or death. Since it is the stage of the recurrent tumor that correlates with survival rather than the stage of the tumor at initial presentation, we suggest that tumors be restaged at the time of recurrence.

Adult↗
PubMed1996

The role of palliative radiotherapy in advanced head and neck cancer.

The role of radiotherapy in the palliation of patients with advanced cancer of the head and neck is not clear. Several distinctive characteristics of advanced head and neck cancer contribute to the complexities in the choice of appropriate palliative management strategies. Palliative treatment may be the appropriate management for a proportion of patients with advanced disease, but the current stage groupings of head and neck cancer are not sufficient for use in the reliable identification of such a patient group. Controversy arises because of the difficulties in distinguishing patients who should be offered conventional treatment with curative intent from those appropriate for treatment with palliative intent. A structured review of the cancer and quality of life literature identified 298 references pertaining to palliative radiotherapy in head and neck cancer, 26 of which met the criteria for inclusion in this review. An expert panel discussed the literature, and concluded that insufficient information precluded estimations of the frequency, degree of, or duration of symptomatic relief that radiation offered to those patients not cured of their disease. Moreover, the currently available literature does not address the toxicity or appropriate dose and fractionation of palliative radiotherapy in this setting. Further studies are necessary to evaluate clinical endpoints appropriate to the use of radiotherapy in the palliative management of patients with advanced head and neck cancer. Studies are also needed to refine the current clinical classification of patients, allowing the identification of patients suitable for palliative management.

Clinical Trials as Topic↗
PubMed1995

Local control of carcinoma of the tonsil by radiation therapy: an analysis of patterns of fractionation in nine institutions.

PURPOSE: To investigate the importance to outcome of treatment for squamous cell carcinomas of the tonsillar fossa, of dose per fraction, overall treatment duration, and total dose. METHODS AND MATERIALS: A collaborative retrospective study was undertaken in nine centers that used widely different dose-fractionation patterns for external beam radiation therapy. RESULTS: There were 676 eligible cases treated only with photon beams during the years 1976-1985. The probability of local control (of the tonsillar fossa primary) was influenced by both T-stage and N-stage. Significant treatment parameters were total dose and overall treatment duration, but not dose per fraction. Over the range of about 40 to 90% and for a constant overall treatment duration, local tumor control probability increased by nearly 2% for each 1 Gy increase in total dose. For a constant total dose there was a decrease in the probability of local control associated with prolongation of overall treatment duration, presumed to result from accelerated regrowth of surviving tumor clonogens during the course of treatment. If it is assumed that accelerated regrowth occurred at a constant rate and began within 9 days of the start of treatment, an average of 0.53 Gy extra dose per day's extension of treatment would be required to maintain a constant probability of local control. Correspondingly, the probability of local control from a constant dose would be lowered by an average of at least 1% for each day's extension of treatment duration. However, the data are slightly more consistent with an average delay of as long as 30 days before onset of accelerated repopulation, with a consequent increase to an average of 0.73 Gy per day for the value of the compensatory dose. The alpha/beta ratio for this tumor is high enough that the effect of fraction size on the probability of local control can be ignored; a precise estimate is not possible because the best value for beta was close to zero. After accounting for the significant variables studied (treatment time, T-stage, N-stage), the dose-response curves for tumor control were still shallow, suggesting that there are additional causes for heterogeneity of responses among these tumors. CONCLUSIONS: Total dose is important to treatment outcome: After accounting for other treatment variables, there is about a 2% per Gy increase in probability of tumor control over the ranges of control commonly achieved. Overall treatment duration is important. There is at least a 1% per day decrease in tumor control probability if delivery of a constant total dose is prolonged, requiring a compensatory increase in dose by 0.5-0.7 Gy per day to achieve a constant rate of tumor control. Fraction size is not, of itself, an important factor in the response of primary carcinoma of the tonsil. If a tumor has demonstrated a capacity for metastatic spread to lymph nodes, a higher total dose should be considered to achieve control rates at the primary site equivalent to those in node negative patients. Even after accounting for variables such as tumor stage, total dose, and overall treatment duration, there is sufficient heterogeneity in other undocumented determinants of tumor control to cause the tumor control probability curve to be a shallow function of dose.

Analysis of Variance↗
PubMed1995

Late normal tissue sequelae from radiation therapy for carcinoma of the tonsil: patterns of fractionation study of radiobiology.

PURPOSE: To evaluate the influence of dose fractionation and other factors on the development of late complications in mandibular bone, muscle, and mucosa of the oral cavity after external beam radiation therapy for carcinoma of the tonsil. METHODS AND MATERIALS: A retrospective analysis was made of the results in 676 patients treated with a spectrum of fractionation regimens in nine centers during the years 1976-1985. Only severe (Grades 3-4) late complications were analyzed. RESULTS: With more than 5 years follow-up, it was found that total dose was a factor for all three types of complications, but that in other respects, the radiobiology of late-(> 3 months) developing mucosal ulcerations was different from that for mandibular necrosis and muscle injury. Dose per fraction was a significant factor for bone and muscle (estimated alpha/beta values of 0.85 Gy and 3.1 Gy, respectively). By contrast, mucosa showed no influence on response from change in fraction size over the range of approximately 1.0-3.5 Gy. Complications in bone and muscle were not related to overall treatment duration, whereas there was a significant inverse relationship for mucosa breakdown. The rate of development of complications was fastest in mucosa and slowest in bone. The appearance of complications by 4 years after treatment was about 80% of those developing by 8 years in the mucosa, 66% in muscle, and about 50% in bone. The high alpha/beta ratio, inverse relationship with overall treatment duration, and faster development of mucosal complications suggests that they may develop as a consequence of earlier mucosal injury. As anticipated, adequate retrospective analysis of acute complications could not be made even when objective criteria such as weight loss, unplanned delays in completing treatment, or hospitalization during treatment were the measures. Field size was a significant factor for mandible complications, but not for muscle or mucosa. CONCLUSION: The radiobiological characteristics of bone and muscle were those characteristic of other late-responding tissues, whereas late sequelae in mucosa had radiobiological parameters similar to those for acute responses. Field size was a significant factor for bone complications but not for others.

Carcinoma, Squamous Cell↗
PubMed1995

Outcome following radiotherapy in verrucous carcinoma of the larynx.

PURPOSE: To evaluate the outcome of patients with verrucous carcinoma of the larynx treated at the Princess Margaret Hospital with respect to control rates with radiotherapy, the salvage of local failure, the risk of regional lymph node metastasis following radiation therapy, and the risk of anaplastic transformation following radiotherapy. METHODS AND MATERIALS: Forty-eight patients underwent primary treatment for verrucous carcinoma of the larynx in the period between January 1961 and December 1990. This represented 1.1% of cases of laryngeal cancer seen in this time period. Forty-three received radiotherapy and 5 had surgery as the primary treatment. Several radiation dose-fractionation schedules were used, the most frequent being 50 Gy in 20 fractions in 4 weeks (31 cases), while eight patients were treated with 55 Gy over 5 weeks. RESULTS: The 5-year rate of local control was 59% for the 43 patients treated with radiotherapy. Surgical salvage was universally successful in all cases where it was attempted. The five cases treated with surgery alone did not experience relapse. Only one patient died of verrucous carcinoma. He had been medically unfit for surgical intervention at the time of initial treatment and at the time of relapse. He underwent a truncated course of radiotherapy (24 Gy in 3 fractions over three weeks in 1975). There was no evidence of increased neck relapse compared to other forms of laryngeal carcinoma following radiation treatment. No evidence to support anaplastic transformation of tumors treated with radiotherapy was evident in this series. CONCLUSIONS: Local control using radiation treatment is less successful than with ordinary invasive and in situ squamous carcinomas of the larynx. Nevertheless, the treatment is effective and provides an appropriate option for laryngeal conservation, especially in advanced lesions where total laryngectomy may be the only treatment alternative. Surgical salvage of radiation failures contributes to very high rates of cure for verrucous carcinoma of the larynx. Anaplastic transformation of cases treated with radiotherapy was not observed in any case in this series.

Adult↗
PubMed1995

Radiation treatment of cervical lymph node metastases from an unknown primary: an analysis of outcome by treatment volume and other prognostic factors.

One hundred and forty-four patients with diagnosis of carcinoma involving cervical lymph nodes from an unknown primary site were seen at the Princess Margaret Hospital, Toronto between 1970 and 1986. This paper addresses the outcome of two treatment approaches using radiation treatment as potentially curative therapy. The treatment approaches compared in a retrospective analysis are radiation to the involved node regions alone (85 cases), and radiation to both the nodes and to potential primary sites in the head and neck (59 cases). The overall 5-year survival rate of the entire group of 144 cases was 41%. There was a trend to increased survival in favour of the group receiving radiation to the nodes and potential primary sites (p = 0.07), however, when differences in extent of nodal involvement were considered and adjusted for using the Cox Proportional Hazard Model, no difference in survival, or cause-specific survival was found between the two treatment groups (p = 0.18 and 0.22, respectively). A total of seven head and neck primary cancers were subsequently discovered, six in the group receiving radiation only to the nodes and one in the group receiving radiation to the nodes and primary sites. The results of this retrospective analysis need to be interpreted with caution but suggest that, for some patients with this diagnosis, radiation to the involved node region alone is adequate. A discussion of the literature is presented with attention to the effect of extent of treatment on outcome.

Carcinoma, Squamous Cell↗
PubMed1994

The role of surgery following radiotherapy failure for advanced laryngopharyngeal cancer. A prospective study.

BACKGROUND: To comment on the use of surgery following radiotherapy failure for advanced laryngopharyngeal cancer. METHODS: Of 212 participants, 88 underwent potentially curative surgical salvage following radiotherapy failure. These 88 patients were followed up prospectively for a median of 4.4 years following surgery; complications, recurrences, tumor measures, and survival were documented to facilitate a critical analysis. RESULTS: Surgical complications developed in 48% of the patients, were most prevalent following pharyngectomy (P = .03), and were not influenced by the addition of a neck dissection (P = .76). Postsurgical survival was statistically associated with the TNM stage of the recurrent tumor and the site of recurrence (local or regional vs both), but was not associated with the TNM stage of the original tumor, time to recurrence, age, sex, or primary site. The overall 5-year postsurgical survival for this cohort was 35%. Utilizing a policy of primary radiotherapy, reserving surgery for radiotherapy failures, 41% of our patients retained functional larynges without reducing their overall survival. CONCLUSIONS: We suggest that recurrent tumors be restaged, as the measures of the recurrent tumor, not the tumor at original presentation, correlate best with survival following surgical intervention for tumor recurrence.

Aged↗
PubMed1994

A procedure for estimating the dose modifying effect of chemotherapy on radiation response.

A procedure based on a logistic regression model was used to estimate the dose-modifying effect of chemotherapy on the response of normal tissues to radiation. The magnitude of this modifying effect is usually expressed as a dose-effect factor (DEF). Values > 1.0 indicate an enhancing effect of chemotherapy while values < 1.0 suggest a 'protective' effect. The DEF in the proposed procedure is expressed as a function of logistic regression coefficients, response levels and values of covariates in the model. The proposed procedure is advantageous as it allows consideration of both the response levels and the values of covariates in calculating the DEF. A plot of the DEF against the response or a covariate describes how the DEF varies with the response levels or a covariate describes how the DEF varies with the response levels or the covariate values. Confidence intervals of the DEF were obtained based on the normal approximation of the distribution of the estimated DEF and on a non-parametric Bootstrap method. An example is given to illustrate the proposed procedure.

Antineoplastic Agents↗
PubMed1989

Chronicity. Adjustment differences of Vietnam combat veterans differing in rates of psychiatric hospitalization.

The study focuses on the frequency of inpatient care for patients with Posttraumatic Stress Disorder (PTSD). This factor, termed "chronicity," is, perhaps surprisingly, largely overlooked in many PTSD studies. The significance of chronicity was addressed through administration of Minnesota Multiphasic Personality Inventory (MMPI) to Vietnam Theater and Era veterans in an inpatient psychiatry service. MMPI scores were analyzed for two main effects: combat exposure and chronicity (i.e., number of inpatient psychiatry admissions). The results replicated research showing combat exposure is associated with greater maladjustment (i.e., higher MMPI scores). Moreover, chronicity also emerged as a significantly important variable: of all groups compared, Vietnam combat veterans higher in chronicity scored higher on MMPI clinical scales, particularly on scales Paranoia, Psychasthenia, and Schizophrenia, thereby (a) empirically establishing (a) the methodological point that number of admissions must be controlled and (b) the substantive point that chronicity is important in studies of PTSD.

Adaptation, Psychological↗
PubMed1988

Low dose postoperative adjuvant radiation therapy for rectal cancer is ineffective.

Ninety-seven patients with rectal cancer which had either penetrated through the rectal wall or involved regional lymph nodes received postoperative adjuvant radiation therapy of 24 Gy in 12 fractions or 25 Gy in 10 fractions in 2 weeks. The crude pelvic recurrence rate was 48/97 (49%) and the actuarial local relapse-free rate at 5 years was 41%. The radiation doses used produced no late morbidity, but had no discernible effect on the risk of local recurrence, and may have compromised the subsequent use of radiation for symptomatic pelvic recurrence.

Adenocarcinoma↗
PubMed1987

Carcinoma of the subglottis. Results of initial radical radiation.

During the 12-year period 1971 to 1982, 23 patients with primary squamous cell carcinoma of the subglottis were treated with initial radical radiation therapy. There were 19 men and four women, with a mean age of 64 years. Five patients had T1 tumors, four had T2, three had T3, and 11 had T4. The actuarial overall and cause-specific survival rates were 26% and 61%, respectively. Local control was achieved with initial radiation therapy in 16 patients (70%). Subsequent local control was achieved in one other patient following surgery for recurrence, giving an ultimate local control figure of 74% (17 of 23 patients). All patients with T1, T2, and T3 disease achieved local control with initial treatment; however, seven of the 11 patients with T4 disease either had residual disease following radiation therapy or developed local recurrence on follow-up.

Aged↗