Biomedical subjects

Chris H J Terhaard

Publications and source records attributed to Chris H J Terhaard.

At least 19 recordsLinked to original sources

PubMed2007

Quality of life and salivary output in patients with head-and-neck cancer five years after radiotherapy.

BACKGROUND: To describe long-term changes in time of quality of life (QOL) and the relation with parotid salivary output in patients with head-and-neck cancer treated with radiotherapy. METHODS: Forty-four patients completed the EORTC-QLQ-C30(+3) and the EORTC-QLQ-H&N35 questionnaires before treatment, 6 weeks, 6 months, 12 months, and at least 3.5 years after treatment. At the same time points, stimulated bilateral parotid flow rates were measured. RESULTS: There was a deterioration of most QOL items after radiotherapy compared with baseline, with gradual improvement during 5 years follow-up. The specific xerostomia-related items showed improvement in time, but did not return to baseline. Global QOL did not alter significantly in time, although 41% of patients complained of moderate or severe xerostomia at 5 years follow-up. Five years after radiotherapy the mean cumulated parotid flow ratio returned to baseline but 20% of patients had a flow ratio <25%. The change in time of xerostomia was significantly related with the change in flow ratio (p = 0.01). CONCLUSION: Most of the xerostomia-related QOL scores improved in time after radiotherapy without altering the global QOL, which remained high. The recovery of the dry mouth feeling was significantly correlated with the recovery in parotid flow ratio.

Adult↗

PubMed2006

Intensity-modulated radiotherapy significantly reduces xerostomia compared with conventional radiotherapy.

PURPOSE: Xerostomia is a severe complication after radiotherapy for oropharyngeal cancer, as the salivary glands are in close proximity with the primary tumor. Intensity-modulated radiotherapy (IMRT) offers theoretical advantages for normal tissue sparing. A Phase II study was conducted to determine the value of IMRT for salivary output preservation compared with conventional radiotherapy (CRT). METHODS AND MATERIALS: A total of 56 patients with oropharyngeal cancer were prospectively evaluated. Of these, 30 patients were treated with IMRT and 26 with CRT. Stimulated parotid salivary flow was measured before, 6 weeks, and 6 months after treatment. A complication was defined as a stimulated parotid flow rate <25% of the preradiotherapy flow rate. RESULTS: The mean dose to the parotid glands was 48.1 Gy (SD 14 Gy) for CRT and 33.7 Gy (SD 10 Gy) for IMRT (p < 0.005). The mean parotid flow ratio 6 weeks and 6 months after treatment was respectively 41% and 64% for IMRT and respectively 11% and 18% for CRT. As a result, 6 weeks after treatment, the number of parotid flow complications was significantly lower after IMRT (55%) than after CRT (87%) (p = 0.002). The number of complications 6 months after treatment was 56% for IMRT and 81% for CRT (p = 0.04). CONCLUSIONS: IMRT significantly reduces the number of parotid flow complications for patients with oropharyngeal cancer.

Adult↗

PubMed2006

Does 4 MV perform better compared to 6 MV in the presence of air cavities in the head and neck region?

BACKGROUND AND PURPOSE: The underdose near air cavities in the head and neck region at photon energies of 4 MV and 6 MV was studied in search for clinical advantages of the 4 MV over 6 MV treatments. MATERIALS AND METHODS: The on-axis and off-axis dose distributions were measured with a parallel-plate ionization chamber and films in polystyrene phantoms containing an air cavity of appropriate size based on the results of computed tomography scans. RESULTS: Although most results are similar for both energies, the 4 MV photon beams give a somewhat smaller underdose effect and a faster re-build up than the 6 MV. For both energies a significant underdose effect was observed at the edge of the field in the larynx phantom. This proved to be true for small and large fields, for smaller and larger cavities, for one-beam as well as parallel-opposed beams. CONCLUSION: For most clinically relevant situations there is no remarkable benefit in the use of either of the two energies.

Air↗

PubMed2006

3D MR sialography protocol for postradiotherapy follow-up of the salivary duct system.

PURPOSE: To develop and evaluate an MR sialography protocol that reproducibly images the parotid and submandibular ducts over time, in 3D. Such a protocol is needed in order to investigate the possible radiation-induced changes to the salivary ducts in patients receiving radiotherapy to the head-and-neck. MATERIALS AND METHODS: MR sialography was performed on a 1.5-T MR scanner. Sequence parameters were optimized on 11 healthy volunteers. A 3D water-selective turbo spin echo (TSE) pulse sequence (TR/TE = 6000 msec/190 msec), using a two-element circular surface coil was applied twice in one MR session. In order to assess the reproducibility, the same procedure was repeated four to six months later. The quality of the MR sialograms was measured subjectively by developing a visibility scoring system and objectively by the means of contrast-to-noise ratio (CNR) of the ducts vs. fat (CNR(duct-fat)). RESULTS: High-quality, 3D MR sialographic images were obtained. The quality of the MR sialograms and the subjective visibility score of the salivary ducts were constant over time. The CNR(duct-fat) varied between volunteers (standard deviation, SD 26%) but it was relatively constant per volunteer (SD 5%). CONCLUSION: The MR sialography protocol presented in this study provides good quality 3D imaging of the major salivary ducts, submandibular duct, and the parotid duct and it can be used for the comparison of the salivary duct system of an individual over time.

Head and Neck Neoplasms↗

PubMed2005

Comparing step-and-shoot IMRT with dynamic helical tomotherapy IMRT plans for head-and-neck cancer.

PURPOSE: The goal of this planning study was to compare step-and-shoot intensity-modulated radiotherapy (IMRT) plans with helical dynamic IMRT plans for oropharynx patients on the basis of dose distribution. METHODS AND MATERIALS: Five patients with oropharynx cancer had been previously treated by step-and-shoot IMRT at the University Medical Centre Utrecht, The Netherlands, applying five fields and approximately 60-90 segments. Inverse planning was carried out using Plato, version 2.6.2. For each patient, an inverse IMRT plan was also made using Tomotherapy Hi-Art System, version 2.0, and using the same targets and optimization goals. Statistical analysis was performed by a paired t test. RESULTS: All tomotherapy plans compared favorably with the step-and-shoot plans regarding sparing of the organs at risk and keeping an equivalent target dose homogeneity. Tomotherapy plans in particular realized sharper dose gradients compared with the step-and-shoot plans. The mean dose to all parotid glands (n = 10) decreased on average 6.5 Gy (range, -4 to 14; p = 0.002). The theoretical reduction in normal tissue complication probabilities in favor of the tomotherapy plans depended on the parotid normal tissue complication probability model used (range, -3% to 32%). CONCLUSION: Helical tomotherapy IMRT plans realized sharper dose gradients compared with the clinically applied step-and shoot plans. They are expected to be able to reduce the parotid normal tissue complication probability further, keeping a similar target dose homogeneity.

Head and Neck Neoplasms↗

PubMed2005

Long-term parotid gland function after radiotherapy.

PURPOSE: Irradiation of the parotid glands causes salivary dysfunction, resulting in reduced salivary flow. Recovery can be seen with time; however, long-term prospective data are lacking. The objective of this study was to analyze the long-term parotid gland function after irradiation for head-and-neck cancer. METHODS AND MATERIALS: A total of 52 patients with head-and-neck cancer and treated with radiotherapy (RT) were prospectively evaluated. Stimulated bilateral parotid salivary flow rates were measured before RT and 6 weeks, 6 months, 12 months, and at least 3.5 years after RT completion. A complication was defined as a stimulated parotid flow rate of <25% of the pre-RT flow rate. The normal tissue complication probability model proposed by Lyman was fit to the data. Multilevel techniques were used to model the patterns of flow rates with time. RESULTS: The mean stimulated flow rate of the parotid glands before RT was 0.31 mL/min (standard deviation [SD], 0.21). This was reduced to 0.14 mL/min (SD, 0.15) at 6 weeks after RT and recovered to 0.20 mL/min (SD, 0.22) at 6 months and 0.19 mL/min (SD, 0.21) at 12 months after RT. The mean stimulated flow rate was 0.25 mL/min (SD, 0.28) 5 years after RT. The mean dose to the parotid gland resulting in a 50% complication probability increased from 34 Gy at 6 weeks to 40 Gy at 6 months, 42 Gy at 12 months, and 46 Gy at 5 years after RT. Multilevel modeling indicated that both dose and time were significantly associated with the flow ratio. CONCLUSION: Salivary output can still recover many years after RT. At 5 years after RT, we found an increase in the salivary flow rate of approximately 32% compared with at 12 months after RT.

Adult↗

PubMed2005

A comparison of mean parotid gland dose with measures of parotid gland function after radiotherapy for head-and-neck cancer: implications for future trials.

PURPOSE: To determine the most adequate parameter to measure the consequences of reducing the parotid gland dose. METHODS AND MATERIALS: One hundred eight patients treated with radiotherapy for various malignancies of the head and neck were prospectively evaluated using three methods. Parotid gland function was objectively determined by measuring stimulated parotid flow using Lashley cups and scintigraphy. To assess xerostomia-related quality of life, the head-and-neck cancer module European Organization for Research and Treatment of Cancer QLQ (Quality of Life Questionnaire) H&N35 was used. Measurements took place before radiotherapy and 6 weeks and 12 months after the completion of radiotherapy. Complication was defined for each method using cutoff values. The correlation between these complications and the mean parotid gland dose was investigated to find the best measure for parotid gland function. RESULTS: For both flow and scintigraphy data, the best definition for objective parotid gland toxicity seemed to be reduction of stimulated parotid flow to < or =25% of the preradiotherapy flow. Of all the subjective variables, only the single item dry mouth 6 weeks after radiotherapy was found to be significant. The best correlation with the mean parotid gland dose was found for the stimulated flow measurements. The predictive ability was the highest for the time point 1 year after radiotherapy. Subjective findings did not correlate with the mean parotid dose. CONCLUSIONS: Stimulated flow measurements using Lashley cups, with a complication defined as flow < or =25% of the preradiotherapy output, correlated best with the mean parotid gland dose. When reduction of the mean dose to the parotid gland is intended, the stimulated flow measurement is the best method for evaluating parotid gland function.

Head and Neck Neoplasms↗

PubMed2005

Why to start the concomitant boost in accelerated radiotherapy for advanced laryngeal cancer in week 3.

PURPOSE: We analyzed toxicity and the local control rates for advanced laryngeal cancer, treated with two accelerated fractionation schedules. The main difference between the schedules was the onset of the concomitant boost, in Week 3 or Week 4. Overall treatment time and total dose were equivalent. METHODS AND MATERIALS: In a prospective, nonrandomized study of T3, T4, and advanced T2 laryngeal cancer, concomitant boost schedules were used in 100 patients. Thirty patients received a schedule of twice daily 1.2 Gy in Weeks 1-3, followed by twice daily 1.7 Gy in Weeks 4 and 5; total dose was 70 Gy (the hyperfractionated accelerated schedule [HAS] regimen). Seventy patients were treated with 5 times 2 Gy in Weeks 1 and 2, followed by daily 1.8 Gy and 1.5 Gy (boost) in Weeks 3-5; total dose 69.5 Gy (the accelerated schedule only [ASO] regimen). Distribution of T stage was 47%, 40%, and 12% for T2, T3, and T4, respectively. In 24% of the patients, lymph nodes were positive. Pretreatment tracheotomy or stridor or both occurred in 8 patients. The distribution of prognostic factors was not significantly different between the two fractionation schedules. Acute and late toxicity was assessed. Results were estimated by the use of actuarial methods. For late toxicity and local control univariate and multivariate analyses were performed. Tumor control probability analysis was used to model cure rate differences. RESULTS: Overall acute mucositis score was equal for both schedules. Acute mucositis started and decreased significantly earlier in the HAS regimen. In all patients acute mucositis healed completely. The treatment was completed within 38 days in all patients. The regional control rate was 100% for clinical N0, and 75% for the clinical N+ patients. The 3-year local control rate was 59% and 78% for the HAS and ASO regimens, respectively (p = 0.05); the ultimate local control was 80% and 94%, respectively. In multivariate analysis, besides the fractionation schedule (relative risk [RR], 2.6 for HAS vs. ASO), pretreatment tracheotomy/stridor (RR 4.3, yes vs. no), and local tumor response 3-6 weeks after radiotherapy (RR 5.1, no vs. yes) were independent factors for local control. Tumor control probability analysis indicated that the onset of repopulation may be about 4-6 days earlier for the HAS regimen. The onset of repopulation in the HAS regimen is probably at the end of the second week or at the beginning of the third week. Severe late toxicity was observed in the HAS group and ASO group in, respectively, 11% and 16%. In multivariate analysis this toxicity related significantly to the field size and pretreatment tracheotomy/stridor. CONCLUSIONS: In our study the timing of the boost in accelerated radiotherapy for advanced laryngeal cancer was an independent factor for local control, favoring the use of a concomitant boost in Week 3. This finding may indicate that accelerated repopulation of tumor cells starts early in the treatment phase.

Adult↗

PubMed2005

Adequate margins for random setup uncertainties in head-and-neck IMRT.

PURPOSE: To investigate the effect of random setup uncertainties on the highly conformal dose distributions produced by intensity-modulated radiotherapy (IMRT) for clinical head-and-neck cancer patients and to determine adequate margins to account for those uncertainties. METHODS AND MATERIALS: We have implemented in our clinical treatment planning system the possibility of simulating normally distributed patient setup displacements, translations, and rotations. The planning CT data of 8 patients with Stage T1-T3N0M0 oropharyngeal cancer were used. The clinical target volumes of the primary tumor (CTV(primary)) and of the lymph nodes (CTV(elective)) were expanded by 0.0, 1.5, 3.0, and 5.0 mm in all directions, creating the planning target volumes (PTVs). We performed IMRT dose calculation using our class solution for each PTV margin, resulting in the conventional static plans. Then, the system recalculated the plan for each positioning displacement derived from a normal distribution with sigma = 2 mm and sigma = 4 mm (standard deviation) for translational deviations and sigma = 1 degrees for rotational deviations. The dose distributions of the 30 fractions were summed, resulting in the actual plan. The CTV dose coverage of the actual plans was compared with that of the static plans. RESULTS: Random translational deviations of sigma = 2 mm and rotational deviations of sigma = 1 degrees did not affect the CTV(primary) volume receiving 95% of the prescribed dose (V(95)) regardless of the PTV margin used. A V(95) reduction of 3% and 1% for a 0.0-mm and 1.5-mm PTV margin, respectively, was observed for sigma = 4 mm. The V(95) of the CTV(elective) contralateral was approximately 1% and 5% lower than that of the static plan for sigma = 2 mm and sigma = 4 mm, respectively, and for PTV margins <5.0 mm. An additional reduction of 1% was observed when rotational deviations were included. The same effect was observed for the CTV(elective) ipsilateral but with smaller dose differences than those for the contralateral side. The effect of the random uncertainties on the mean dose to the parotid glands was not significant. The maximal dose to the spinal cord increased by a maximum of 3 Gy. CONCLUSIONS: The margins to account for random setup uncertainties, in our clinical IMRT solution, should be 1.5 mm and 3.0 mm in the case of sigma = 2 mm and sigma = 4 mm, respectively, for the CTV(primary). Larger margins (5.0 mm), however, should be applied to the CTV(elective), if the goal of treatment is a V(95) value of at least 99%.

Head and Neck Neoplasms↗

PubMed2005

The role of radiotherapy in the treatment of malignant salivary gland tumors.

PURPOSE: We analyzed the role of primary and postoperative low linear energy transfer radiotherapy in 538 patients treated for salivary gland cancer in centers of the Dutch Head and Neck Oncology Cooperative Group, in search for prognostic factors and dose response. METHODS AND MATERIALS: The tumor was located in the parotid gland in 59%, submandibular gland in 14%, oral cavity in 23%, and elsewhere in 5%. In 386 of 498 patients surgery was combined with radiotherapy, with a median dose of 62 Gy. Median delay between surgery and radiotherapy was 6 weeks. In the postoperative radiotherapy group, adverse prognostic factors prevailed. Elective radiotherapy to the neck was given in 40%, with a median dose of 50 Gy. Primary radiotherapy (n = 40) was given for unresectable disease or M(1), with a dose range of 28-74 Gy. RESULTS: Postoperative radiotherapy improved 10-year local control significantly compared with surgery alone in T(3-4) tumors (84% vs. 18%), in patients with close (95% vs. 55%) and incomplete resection (82% vs. 44%), in bone invasion (86% vs. 54%), and perineural invasion (88% vs. 60%). Local control was not correlated with interval between surgery and radiotherapy. No dose-response relationship was shown. Postoperative radiotherapy significantly improved regional control in the pN(+) neck (86% vs. 62% for surgery alone). A rating scale for different sites, T stage, and histologic type may be applied to calculate the risk of disease in the neck at presentation, and so indicate the need for elective neck treatment. A marginal dose-response was seen, in favor of a dose > or =46 Gy. A clear dose-response relationship was shown for patients treated with primary radiotherapy. Five-year local control was 50% with a dose of 66-70 Gy. CONCLUSIONS: Postoperative radiotherapy with a dose of at least 60 Gy is indicated for patients with T(3-4) tumors, incomplete or close resection, bone invasion, perineural invasion, and pN(+). In unresectable tumors, a dose of at least 66 Gy is advisable.

Adolescent↗

PubMed2004

Treatment of stage III-IV nasopharyngeal carcinomas by external beam irradiation and local low doses of IL-2.

The therapeutic effect of intratumoural application of Interleukin-2 (IL-2) was studied in patients with stage III-IV nasopharyngeal carcinoma (NPC) that received radiotherapy. Patients with stage III-IV NPC receiving a standard treatment of 7,000 cGy external beam irradiation have a mean disease-free survival of about 1.5 years. In this paper, we describe ten of these patients who were treated with additional peritumoural and intratumoural injections with 3 x 10(4) U IL-2 on 5 days in weeks 2, 4, and 6 of the 7-weeks' irradiation period. This combined treatment group was compared with a historical group of patients treated with standard irradiation alone. Local IL-2 therapy showed a marked clinical and statistical significant improvement of disease-free survival. After 5 years, 63% of the IL-2 treated patients were disease-free versus 8% of the control patients. These results suggest that the therapeutic results of radiotherapy can be significantly improved by combining it with local IL-2 treatment. To our knowledge, this is the first clinical report showing that local IL-2 therapy is effective against an infiltrative and locally metastasizing tumour in human patients.

Adult↗

PubMed2004

Implanted gold markers for position verification during irradiation of head-and-neck cancers: a feasibility study.

PURPOSE: To assess the toxicity and reliability of the use of implanted gold markers for position verification during irradiation of head-and-neck cancer. METHODS AND MATERIALS: Ten patients with localized head-and-neck tumors received two gold markers in the parapharyngeal region. The acute and late radiation-related toxicity were scored prospectively using the Common Toxicity Criteria. The patients were immobilized during irradiation using a five-point mask. The marker location was detected in portal images taken with an a-Si flat panel imager. The intermarker distance, as well as the interfraction motion of the markers, was determined for all patients. RESULTS: No acute major complications were observed. The acute toxicity grade was not greater than normally detected. The markers were visible in all images. On average, the projected intermarker distance varied 0.8 mm (1 standard deviation). A small time trend was observed in the intermarker distance for 3 patients. For these patients, at least one marker was located in the mucosa or pharyngeal constrictor muscle. Deeper-seated gold markers did not show a time trend in the intermarker distance. The random positioning uncertainty determined using the markers was on average 1.1 and 1.4 mm (1 SD) in the craniocaudal and AP direction, respectively. CONCLUSION: The use of implanted gold markers for position verification during radiotherapy for head-and-neck cancer patients seems safe and feasible. To avoid any chance of migration, markers should be placed in deep muscular compartments.

Feasibility Studies↗

PubMed2004

Scintigraphic assessment of early and late parotid gland function after radiotherapy for head-and-neck cancer: a prospective study of dose-volume response relationships.

PURPOSE: To investigate the value of scintigraphy as an indirect measurement of parotid function after radiotherapy (RT). METHODS AND MATERIALS: Ninety-six patients with primary or postoperative RT for various malignancies in the head-and-neck region were prospectively evaluated. Parotid gland scintigraphy was performed before RT and 6 weeks and 1 year after RT. The uptake, excretion fraction of the saliva from the parotid gland to the oral cavity (SEF), and the ratios of uptake and SEF after and before treatment were calculated. CT-based treatment planning was used to derive dose-volume histograms of the parotid glands. To establish the effects of both the radiation dose and the volume of the parotid gland irradiated, the normal tissue complication probability model proposed by Lyman was fit to the data. RESULTS: The mean maximal uptake of 192 parotid glands decreased significantly from 3329 counts (ct)-/s before RT to 3084 ct/s and 3005 ct/s at 6 weeks and 1 year after RT. The SEF before treatment was 44.7%. The SEF decreased to 18.7% at 6 weeks after RT, but recovered to a SEF of 32.4% at 1 year after RT. A significant correlation was found between the uptake 1 year after RT and the mean parotid dose. The reduction in post-RT SEF correlated significantly with the mean parotid gland dose. The normal tissue complication probability model parameter TD50 was found to be 29 and 43 Gy at 6 weeks and 1 year after RT, respectively, when a complication was defined as a posttreatment SEF parotid ratio of <45%. CONCLUSIONS: The effects of radiation on parotid gland function using scintigraphy could be well established. A statistically significant correlation between the SEF ratio and the mean parotid dose was shown, with some recovery of function at 1 year after RT, comparable with the flow results. When direct flow measurements are not feasible, parotid scintigraphy appears to be a good indicator of gland function.

Adult↗

PubMed2004

Location of cervical lymph node metastases in oropharyngeal and hypopharyngeal carcinoma: implications for cranial border of elective nodal target volumes.

PURPOSE: To analyze the exact location of the most cranial metastatic cervical lymph node in patients with oropharyngeal or hypopharyngeal carcinoma. This was done to specify the cranial border of the elective nodal target volume for improvement of parotid-sparing irradiation. METHODS AND MATERIALS: The most cranial metastatic lymph node, ipsilateral and, when present, contralateral, was delineated on 58 diagnostic CT scans of patients with node-positive oropharyngeal or hypopharyngeal carcinoma. The distances from the delineated lymph node to the base of the skull were measured in all planes. RESULTS: The mean ipsilateral and contralateral distance to the base of the skull in the coronal plane was 25.6 mm (range 2.6-73.8; SD 14.7) and 34.7 mm (range 10.4-78.9; SD 14.0), respectively (p = 0.002). Ipsilateral and contralateral metastatic lymph nodes were located within 20 mm below the base of the skull in 24 patients (41%) and 3 patients (5%), respectively. CONCLUSION: Contralateral metastatic lymph nodes are more caudally located than are ipsilateral metastatic lymph nodes. In elective irradiation, lowering the cranial border of the contralateral nodal target volume with 20 mm below the base of the skull should be considered.

Carcinoma, Squamous Cell↗

PubMed2004

Level II lymph nodes and radiation-induced xerostomia.

PURPOSE: To investigate the influence of the cranial border of electively irradiated Level II lymph nodes on xerostomia in patients with oropharyngeal cancer using three-dimensional conformal and intensity-modulated radiotherapy (3D-CRT and IMRT). METHODS AND MATERIALS: The target volumes and organs at risk were delineated on the planning CT scans of 12 patients. Two elective target volumes were delineated. The first had the transverse process of the C1 atlas and the second had the transverse process of the C2 axis as cranial border of the Level II lymph nodes. 3D-CRT and IMRT planning were performed for both elective volumes, resulting in two plans per patient and technique, called the C1 and C2 plans, respectively. Irradiation of the ipsilateral elective volume up to C1 and the contralateral up to C2 was also performed for IMRT. The normal tissue complication probability (NTCP) for xerostomia 1 year after RT was calculated using the parotid mean dose. RESULTS: The average mean dose +/- standard deviation (SD) to the contralateral parotid gland was reduced from 33 +/- 5 Gy for the IMRT C1 plans to 26 +/- 4 Gy for the IMRT C2 plans and from 51 +/- 6 Gy to 49 +/- 7 Gy for the 3D-CRT C1 and C2 plans, respectively. The associated NTCP +/- SD for xerostomia was 38% +/- 10% for IMRT C1 plans and 24% +/- 6% for IMRT up to C2 on the contralateral side, regardless of which cranial border was irradiated on the ipsilateral side. For the 3D-CRT C1 and C2 plans, an NTCP value of 74% +/- 12% and 71% +/- 15% was obtained, respectively. The NTCP for xerostomia of the ipsilateral parotid gland was 53% +/- 17% and 45% +/- 20% for the IMRT C1 and C2 plans and 89% +/- 11% and 87% +/- 12% for the 3D-CRT C1 and C2 plans, respectively. CONCLUSION: Lowering the cranial border of the Level II lymph nodes from C1 to C2, in the case of bilateral elective neck irradiation, could be considered on the contralateral side when the risk of metastasis on that side is very low. This is especially true when IMRT is used, because the relative reduction of NTCP for xerostomia 1 year after RT could be up to 68% compared with conventional conformal RT up to C1.

Cervical Vertebrae↗

PubMed2004

Salivary gland carcinoma: independent prognostic factors for locoregional control, distant metastases, and overall survival: results of the Dutch head and neck oncology cooperative group.

BACKGROUND: We analyzed the records of patients with malignant salivary gland tumors, as diagnosed in centers of the Dutch Head and Neck Oncology Cooperative Group, in search of independent prognostic factors for locoregional control, distant metastases, and overall survival. METHODS: In 565 patients, we analyzed general results and looked for the potential prognostic variables of age, sex, delay, clinical and pathologic T and N stage, site (332 parotid, 76 submandibular, 129 oral cavity, 28 pharynx/larynx), pain, facial weakness, clinical and pathologic skin involvement, histologic type (WHO 1972 classification), treatment, resection margins, spill, perineural and vascular invasion, number of neck nodes, and extranodal disease. The median follow-up period was 74 months; it was 99 months for patients who were alive on the last follow-up. RESULTS: The rates of local control, regional control, distant metastasis-free and overall survival after 10 years were, respectively, 78%, 87%, 67%, and 50%. In multivariable analysis, local control was predicted by clinical T-stage, bone invasion, site, resection margin, and treatment. Regional control depended on N stage, facial nerve paralysis, and treatment. The relative risk with surgery alone, compared to surgery plus postoperative radiotherapy, was 9.7 for local recurrence and 2.3 for regional recurrence. Distant metastases were independently correlated with T and N stage, sex, perineural invasion, histologic type, and clinical skin involvement. Overall survival depended on age, sex, T and pN stage, site, skin and bone invasion. CONCLUSIONS: Several prognostic factors for locoregional control, distant metastases, and overall survival were found. Postoperative radiotherapy was found to improve locoregional control.

Adenocarcinoma↗

PubMed2003

Intrafraction motions of the larynx during radiotherapy.

PURPOSE: To quantify the intrafraction motions of the larynx during radiotherapy of laryngeal cancer. Depending on the magnitude, duration, and incidence, these motions may have clinical consequences for the choice of margins around the clinical target volume. METHODS AND MATERIALS: The intrafraction motions were analyzed for 10 patients, treated in 33 or 35 fractions. The intrafraction motions of the larynx were visualized using an a-Si flat panel imager. Images were obtained every 200 ms, resulting in a movie of images for each beam. In addition to visual analysis of all movies, the tip of the epiglottis was delineated and used as a landmark, the coordinates of which were followed in time. RESULTS: Movies were obtained during 79% of the total number of radiotherapy fractions. The total duration of swallowing was on average 0.45% (range 0.0-1.5) of the total irradiation time. Deviations of motions other than swallowing ranged between 0.3 and 11.5 mm. Some of these motions were more sudden, and others were probably related to breathing, because the frequency of these motions was 8-20/min. CONCLUSION: The incidence and total duration of swallowing is low. Therefore, it is not necessary to apply an internal margin to take into account these displacements. Other motions, however, occur more often. In 95% of the irradiation time, the tip of the epiglottis moves within a range of 7.1 mm. A margin should be applied to the clinical target volume to take into account these motions.

Deglutition↗

PubMed2003

Prognostic index for patients with parotid carcinoma: external validation using the nationwide 1985-1994 Dutch Head and Neck Oncology Cooperative Group database.

BACKGROUND: Validation of the prognostic indices for the recurrence-free interval of patients with parotid carcinoma, the development of which was described in a previous report, is needed to be confident of their generalizability and justified prospective use. METHODS: The Dutch Cooperative Group on Head and Neck Cancer database contains 231 patients with parotid carcinoma from six tertiary referral centers who were seen between 1985-1994. This database was used to validate the predictive value of the prognostic indices, PS1 (pretreatment index predicting recurrence) and PS2 (posttreatment index predicting recurrence), in patients with parotid carcinoma. Validation methods included calculation of both indices for each patient, comparison of coefficients, construction of survival curves using the published cutoff points, and calculation of concordance measure C. Wald tests for optimization of scale and weights of the contributing variables, and for possible score improvement by including other variables, were also performed. RESULTS: The 5-year disease-free rate was 62% (standard error = 4%). PS1 was calculated for 183 patients. The previously set cutoff points resulted in 5-year disease-free rates that ranged from 92% (PS1 = 1) to 42% for the least favorable group (PS1 = 4). Concordance measure C was 0.74. The postoperative score, PS2, was calculated for 171 patients. Previous cutoff points resulted in 5-year disease-free rates that ranged from 90% (PS2 = 1) to 40% (PS2 = 4). Concordance measure C was 0.71. Both PS1 and PS2 did not improve using the findings in this independent material. CONCLUSIONS: The prognostic indices performed adequately in this validation sample. This finding demonstrates that the prognosis of a parotid carcinoma patient can be quantified by using a weighted combination of the parameters of age, pain, clinical T (cT) classification, clinical N (cN) classification, skin invasion, facial nerve dysfunction, perineural growth, and involved surgical margins. A quantified prognosis, in terms of the recurrence-free interval, can be used to provide information to the patient, to perform clinical trials, and eventually to make clinical decisions. A user-friendly translation and computerized calculation of the indices should be the next step toward generalized prospective use and repetitive evaluation of the indices.

Adult↗