Intensity modulated radiation therapy planning for patients with a metal hip prosthesis based on class solutions.

PURPOSE: With the aging of the population, an increasing number of patients with metallic hip implants are referred for radiotherapy treatment. Class solutions for intensity modulated radiation therapy (IMRT) treatment planning are generally not applicable for these patients due to the required avoidance of dose delivery through prostheses. In this work a new approach for IMRT planning is presented, allowing the use of a default beam setup. METHODS AND MATERIALS: For IMRT planning, Monaco (Elekta; CMS Software, Maryland Heights, MO) was used. In addition to the target and organs at risk, so-called prosthesis avoidance volumes (PAVs) were delineated in the beam's eye view projection for beams in which the prosthesis was partially in front of the target. By putting strict constraints on these virtual organs at risk, entrance dose delivery through a prosthesis is avoided while exit dose delivery is allowed. In this way, uncertainties in the dose delivery to the target and organs at risk, as derived by the treatment planning system, are largely minimized. To show the advantages of this IMRT-PAV technique, for 2 prostate cancer patients, 1 with bilateral and the other with unilateral metallic hip prostheses, obtained IMRT plans were compared with conventional IMRT plans using a prosthesis-avoiding beam setup. RESULTS: For both IMRT techniques a similar planning target volume coverage was achieved, but with the IMRT-PAV technique the mean doses to the bladder and the rectum were reduced by up to 25%. While the IMRT-PAV technique required more time for delineation, the time for treatment planning reduced because the default beam setup could be applied. The number of segments needed for dose delivery was comparable for both techniques. CONCLUSIONS: With the new IMRT-PAV technique IMRT class solutions can safely be applied for cancer patients with metallic hip prostheses, generally yielding a reduced dose delivery to organs at risk or improved target coverage.

Early hyperbaric oxygen therapy for reducing radiotherapy side effects: early results of a randomized trial in oropharyngeal and nasopharyngeal cancer.

PURPOSE: Comparison of quality of life (QoL) and side effects in a randomized trial for early hyperbaric oxygen therapy (HBOT) after radiotherapy (RT). METHODS AND MATERIALS: From 2006, 19 patients with tumor originating from the tonsillar fossa and/or soft palate (15), base of tongue (1), and nasopharynx (3) were randomized to receive HBOT or not. HBOT consisted of 30 sessions at 2.5 ATA (15 msw) with oxygen breathing for 90 min daily, 5 days per week, applied shortly after the RT treatment was completed. As of 2005, all patients received validated questionnaires (i.e., the European Organization for Research and Treatment of Cancer [EORTC] QLQ-C30, EORTC QLQ Head and Neck Cancer Module (H&N35), Performance Status Scale): before treatment; at the start of RT treatment; after 46 Gy; at the end of RT treatment; and 2, 4, and 6 weeks and 3, 6, 12, and 18 months after follow-up. RESULTS: On all QoL items, better scores were obtained in patients treated with hyperbaric oxygen. The difference between HBOT vs. non-HBOT was significant for all parameters: EORTC H&N35 Swallowing (p = 0.011), EORTC H&N35 Dry Mouth (p = 0.009), EORTC H&N35, Sticky Saliva (p = 0.01), PSS Eating in Public (p = 0.027), and Pain in Mouth (visual analogue scale; p < 0.0001). CONCLUSIONS: Patients randomized for receiving hyperbaric oxygen after the RT had better QoL scores for swallowing, sticky saliva, xerostomia, and pain in mouth.

Results of fiberoptic endoscopic evaluation of swallowing vs. radiation dose in the swallowing muscles after radiotherapy of cancer in the oropharynx.

BACKGROUND AND PURPOSE: Dysphagia is a serious complaint but frequently underreported. This paper assesses for oropharyngeal cancer (OPC) the relationship between the dose received by the swallowing structures, and the findings of a fiberoptic endoscopic evaluation of the swallowing process (FEES). MATERIALS AND METHODS: Between 2000 and 2005, 60 of 67 OPC patients local-regionally NED for at least one year following treatment responded to three types of QoL questionnaires; i.e. Performance Status Scales, EORTC H&N35, and M.D. Anderson Dysphagia Inventory. Twenty-four patients agreed to the FEES procedure. The main swallowing muscles were delineated, with the mean dose per muscle calculated using the original 3D CT-based treatment plans. Regression analysis was performed between FEES variables and the doses in the different swallowing muscles and the dysphagia related questionnaires. RESULTS: A significant relationship was found between the results of FEES and the mean dose in the superior constrictor muscle (SCM). Some of the subjective dysphagia complaints were significantly correlated with the FEES variables in this retrospectively study. CONCLUSION: A higher dose in the SCM generally results in worsening of the findings obtained by the FEES examination.

Treatment techniques and site considerations regarding dysphagia-related quality of life in cancer of the oropharynx and nasopharynx.

PURPOSE: To assess the relationship for oropharyngeal (OP) cancer and nasopharyngeal (NP) cancer between the dose received by the swallowing structures and the dysphagia related quality of life (QoL). METHODS AND MATERIALS: Between 2000 and 2005, 85 OP and 47 NP cancer patients were treated by radiation therapy. After 46 Gy, OP cancer is boosted by intensity-modulated radiation therapy (IMRT), brachytherapy (BT), or frameless stereotactic radiation/cyberknife (CBK). After 46 Gy, the NP cancer was boosted with parallel-opposed fields or IMRT to a total dose of 70 Gy; subsequently, a second boost was given by either BT (11 Gy) or stereotactic radiation (SRT)/CBK (11.2 Gy). Sixty OP and 21 NP cancer patients responded to functional and QoL questionnaires (i.e., the Performance Status Scales, European Organization for Research and Treatment of Cancer H&N35, and M.D. Anderson Dysphagia Inventory). The swallowing muscles were delineated and the mean dose calculated using the original three-dimensional computed tomography-based treatment plans. Univariate analyses were performed using logistic regression analysis. RESULTS: Most dysphagia problems were observed in the base of tongue tumors. For OP cancer, boosting with IMRT resulted in more dysphagia as opposed to BT or SRT/CBK. For NPC patients, in contrast to the first booster dose (46-70 Gy), no additional increase of dysphagia by the second boost was observed. CONCLUSIONS: The lowest mean doses of radiation to the swallowing muscles were achieved when using BT as opposed to SRT/CBK or IMRT. For the 81 patients alive with no evidence of disease for at least 1 year, a dose-effect relationship was observed between the dose in the superior constrictor muscle and the "normalcy of diet" (Performance Status Scales) or "swallowing scale" (H&N35) scores (p < 0.01).

Intraoperative validation of CT-based lymph nodal levels, sublevels IIa and IIb: is it of clinical relevance in selective radiation therapy?

PURPOSE: The objectives of this study are to discuss the intraoperative validation of CT-based boundaries of lymph nodal levels in the neck, and in particular the clinical relevance of the delineation of sublevels IIa and IIb in case of selective radiation therapy (RT). METHODS AND MATERIALS: To validate the radiologically defined level contours, clips were positioned intraoperatively at the level boundaries defined by surgical anatomy. In 10 consecutive patients, clips were placed, at the time of a neck dissection being performed, at the most cranial border of the neck. Anterior-posterior and lateral X-ray films were obtained intraoperatively. Next, in 3 patients, neck levels were contoured on preoperative contrast-enhanced CT scans according to the international consensus guidelines. From each of these 3 patients, an intraoperative CT scan was also obtained, with clips placed at the surgical-anatomy-based level boundaries. The preoperative (CT-based) and intraoperative (surgery-defined) CT scans were matched. RESULTS: Clips placed at the most cranial part of the neck lined up at the caudal part of the transverse process of the cervical vertebra C-I. The posterior border of surgical level IIa (spinal accessory nerve [SAN]) did not match with the posterior border of CT-based level IIa (internal jugular vein [IJV]). Other surgical boundaries and CT-based contours were in good agreement. CONCLUSIONS: The cranial border of the neck, i.e., the cranial border of level IIa/IIb, corresponds to the caudal edge of the lateral process of C-I. Except for the posterior border between level IIa and level IIb, a perfect match was observed between the other surgical-clip-identified levels II-V boundaries (surgical-anatomy) and the CT-based delineation contours. It is argued that (1) because of the parotid gland overlapping part of level II, and (2) the frequent infestation of occult metastatic cells in the lymph channels around the IJV, the division of level II into radiologic sublevels IIa and IIb may not be relevant. Sparing of, for example, the ipsilateral parotid gland in selective RT can even be a treacherous undertaking with respect to regional tumor control. In contrast, the surgeon's reasoning for preserving the surgical sublevel IIb is that the morbidity associated with dissection of the supraspinal accessory nerve compartment of level II is reduced, whereas there is evidence from the surgical literature that no extra risk for regional tumor control is observed. Therefore, in selective neck dissections, the division into surgical sublevels IIa/IIb makes sense.

Optimisation of conformal radiation therapy by intensity modulation: cancer of the larynx and salivary gland function.

PURPOSE: Prevention of damage to critical normal tissues is of paramount importance for the quality of life of patients irradiated for cancers in the head and neck. The purpose of this paper was to evaluate the parotid gland sparing 3D conformal radiation therapy technique (3DCRT) in a prospective study in node negative cancer of the larynx. MATERIALS AND METHODS: Twenty-six patients with node negative squamous cell cancer of the larynx were irradiated by a 3DCRT technique (class solution) to both sides of the neck (elective dose 46 Gy to levels II, III and IV) and primary tumour (70 Gy). Dose distributions of the major salivary glands were correlated with objective (stimulated whole saliva flow, WS) and subjective (questionnaire; visual analogue scale, VAS) salivary gland function. Apart from the clinically used 3DCRT technique, in order to optimise 3DCRT dose distributions, intensity modulated (IMRT) treatment plans were generated for the same patient population. Dose-volume histograms of 3DCRT and IMRT treatment plans were analysed and compared. RESULTS: For the 26 patients irradiated with the 3DCRT class solution technique: VAS scores and questionnaires reached their nadir 3 months post-radiotherapy; WS reached its nadir 6 months post-radiotherapy. WS flow rates improved significantly, but never normalised; 2 years post-treatment WS measurements were 48% of the pre-treatment values. VAS scores deteriorated during ERT from 0 pre-treatment to 6.1 immediately post-treatment. Compared to pre-treatment, questionnaires were answered affirmative by increasing numbers of patients. For all patients, IMRT treatment plans resulted in a significant reduction of the dose delivered to the parotid glands compared to the 3DCRT-treatment technique. CONCLUSIONS: The class solution for the 3DCRT salivary gland sparing technique is inadequate for fully preserving salivary gland function, given the dose distributions (DVHs) as well as the subjective- and objective salivary gland function assessments. The results can be optimised in the future, that is a further reduction of xerostomia can be achieved, by using IMRT techniques focused at sparing major and minor salivary glands.