Search PubMed⌕ Search

Biomedical subjects

R B Keus

Publications and source records attributed to R B Keus.

42 records · Page 3Linked to original sources
PubMed1991

Local control in T3 laryngeal cancer treated with radical radiotherapy, time dose relationship: the concept of nominal standard dose and linear quadratic model.

In a retrospective study of the Dutch cooperative head and neck group 104 evaluable patients with T3NxMO squamous cell carcinoma of the larynx were treated primarily with a full course of radiotherapy. The results of treatment are presented in terms of locoregional control. The actuarial 3-year local control rate was 53%. Regional control was 77% for node positive patients and 96% for N0 patients (p = 0.01). Surgical salvage was successful in 53% of cases with a local recurrence and in 3/8 regional recurrences, resulting in an ultimate locoregional control rate of 83% for N0 patients and 68% for N+ patients. A uni- and multivariate analysis of local control rate versus total dose, nominal standard dose, and extrapolated response dose has been done. To calculate extrapolated response dose the linear quadratic equation was used, assuming an a/b of 10 and a potential doubling time of clonogenic cells of 3, 5, and 7 days. In multivariate analysis the extrapolated response dose with a potential doubling time of 5 days was the only independent prognostic factor for local control (p = 0.069) and ultimate locoregional control (p = 0.0015). Nominal standard dose showed no dose-response relationship. Based on the S-shaped dose response curve, using the LQ model, several therapeutical options are discussed.

Aged↗
PubMed1991

Progress in radiotherapy by treatment tailoring in head and neck cancer.

Radiotherapy plays a key role with surgery in the treatment of head and neck cancer. Encouraging results have recently been published indicating new ways to improve locoregional control by tailoring the radiation treatment to individual tumors. This has been reached by the following means: adapting fractionation schemes to the potential doubling time of tumors, technical developments resulting in higher doses to the primary tumor and at the same time reducing normal tissue doses, and the concomitant use of radiotherapy and chemotherapy. Fractionation studies have shown that changing the standard fractionation schedule can increase the therapeutic margin of radiotherapy. Predictive assays are now becoming available to provide guidelines for the optimal fractionation schedules in individual patients. Combined treatment with radiotherapy and chemotherapy has been widely tested and although the results have been generally disappointing, one approach remains promising, ie, the concomitant use of these two modalities, which seems to result in a modest improvement of survival. Increasing the radiation dose to the tumor together with a better shielding of normal tissues has become possible by technical developments in radiotherapy such as three-dimensional treatment planning, multileaf collimators, and quality control procedures using megavoltage imaging devices.

Antineoplastic Agents↗
PubMed1988

Results of irradiation in squamous cell carcinoma of the soft palate and uvula.

Out of a series of 235 patients presenting with tumours of the soft palate at the Institut Curie, between 1958 and 1980, 146 cases were analysed to evaluate the results of radical radiation therapy. Seventy patients (48%) had advanced T3-T4 disease and 40 patients (27%) had clinically involved metastatic nodes. All patients had a minimum follow-up of 5 years. In 103 cases, megavoltage X-ray therapy was employed. For 43 patients, presenting with small or moderately advanced tumours, a combination of megavoltage and intra-oral orthovoltage X-rays was used. The local control rate at 3 years was 92% for T1, 70% for T2, 58% for T3 and 49% for T4 lesions. Nodal failure was seen in 19 patients. In 9 of these, it was not associated with failure at the primary site, 7 out of 9 occurring marginally or outside the treatment portals. Complications were observed in 16 patients, 7 requiring surgery. The crude 3 and 5 year survival rate was 52 and 40%, respectively, and the disease-free survival 59 and 53%.

Carcinoma, Squamous Cell↗
PubMedDate not supplied

Preservation of function by radiotherapy of small primary carcinomas preceded by neck dissection for extensive nodal metastases of the head and neck.

BACKGROUND: When patients are initially seen with a small primary tumor and regional metastases, the question arises whether the primary can be managed by definitive radiotherapy while treating the neck with surgery and postoperative radiation. The advantage of this is least disturbance of the primary site, while still achieving maximal control of the neck disease. METHOD: A retrospective review was conducted over an 8-year period; of the 619 patients seen during this time, 15 were judged suitable for this approach. Small primaries were defined as T1 or T2 lesions or superficial spreading T3 tumors. Extensive neck disease was defined as at least 3 cm in size. RESULTS: There were no regional recurrences and only 3 local recurrences, 2 of which were successfully salvaged. Four patients died of distant metastases. The arguments for and against this unusual approach are discussed. CONCLUSIONS: It is concluded that, in patients conforming to our criteria, this is a sound oncologic approach.

Adult↗
PubMedDate not supplied

Supraglottic laryngectomy with postoperative radiation versus primary radiation in the management of supraglottic laryngeal cancer.

PURPOSE: The purpose of this review was to study the results of horizontal partial laryngectomy (HPL) for supraglottic laryngeal cancer (stages N0 and N+) and the effects and morbidity of postoperative radiation therapy (RT), especially after bilateral neck dissection, as opposed to primary RT. PATIENTS AND METHODS: Of a total of 89 patients, 26 were treated by HPL, 44 by primary RT, and 19 by total laryngectomy (TL). Of the HPL patients, 19 of 26 had neck dissection, 10 were bilateral. Twelve of the patients received postoperative RT, and 10 of 12 procedures were combined with neck dissection. RESULTS: When comparing the results of HPL and primary RT, the locoregional control was equivalent for the N0 patients, but HPL showed better results in locoregional control for the N+ patients (P < .0024). Postoperative RT with or without bilateral neck dissection did not show an increase in postoperative morbidity. CONCLUSION: Therefore, our data suggest that there should be no hesitation in giving postoperative RT where indicated, after performing HPL plus unilateral or bilateral neck dissection. Patients that are stage N0 should receive primary RT.

Humans↗