Xerostomia and its predictors following parotid-sparing irradiation of head-and-neck cancer

Dosimetric issues in radiation protection of radiotherapy patients

As life expectancy increases, thanks to improving general medical practices, cancer treatments for the ageing population become evermore necessary. Radiation therapy is increasingly a treatment of choice, promoted by continuing improvements in dose delivery technologies. Some techniques, collectively referred to as intensity-modulated radiation therapy, are encountering widespread acceptance and implementation, promoted by reports of superior tumour control and reduced toxicity. However, these new techniques pose new challenges in terms of radiation protection of patients, as they cause a more extensive low-dose exposure of normal tissues compared with conventional radiation therapy. The related dosimetric challenges and the methods available to tackle them are reviewed in this paper, which also emphasises the need for standard radiation protection dosimetry procedures so that information may be consistently gathered for a comparative evaluation of the different treatment modalities.

Radiation-induced xerostomia

BACKGROUND

Radiation-induced xerostomia is a frequent and usually permanent side effect of radiation therapy for head and neck cancer. We summarize recent developments in the prevention and treatment of radiation-induced xerostomia.

METHODS

The Medline database was searched for articles published within the past 10 years on the prevention and treatment of postirradiation xerostomia. Proceedings of recent important national meetings and government Web registries of clinical trials and therapeutic agents were also consulted. Priority was given to randomized controlled trials but, because of the scarcity of such trials, small open trials were included in this review. No other predetermined selection criteria were used, although articles exploring the effects of xerostomia and its treatment on quality of life were considered of special interest.

RESULTS

A variety of preventive approaches for postirradiation xerostomia exist, involving more conformal radiation delivery technology, radioprotective agents, and even preirradiation surgical techniques. Therapeutic interventions include supportive care, saliva supplementation, and the use of pro-cholinergic salivary secretagogues.

CONCLUSIONS

Radiation-induced xerostomia constitutes a significant morbidity after orofacial irradiation. Careful preventive techniques, meticulous supportive care, and new preventive and therapeutic agents may prove useful in combination.

Matched case-control study of quality of life and xerostomia after intensity-modulated radiotherapy or standard radiotherapy for head-and-neck cancer: initial report

PURPOSE

To compare quality of life (QOL) and xerostomia between head-and-neck cancer patients who received standard radiotherapy (RT) and patients matched by factors known to affect QOL who received intensity-modulated RT (IMRT).

METHODS AND MATERIALS

This was a prospective, longitudinal study of patients with head-and-neck cancer requiring bilateral neck irradiation who received IMRT at the University of Michigan and patients who received standard RT at affiliated clinics. Each patient received a validated head-and-neck cancer-related QOL questionnaire (HNQOL) consisting of four multi-item domains--Eating, Communication, Pain, and Emotion--and a validated patient-reported xerostomia questionnaire (XQ). In both questionnaires, the answers were scored 0-100, with higher scores denoting worse QOL or xerostomia. The questionnaires were given before therapy and at 1, 3, 6, 12, 18, and 24 months after the completion of therapy. Each standard RT patient was matched with several IMRT patients according to tumor site, stage, RT status (postoperative or definitive), and age. A linear mixed-effects model was fit to compare outcomes between the two treatment groups and to model trends over time. To account for matching, the differences in scores between the matched sets of patients were fit as a random intercept. Also, matching was taken into account in the model by using the standard error of the within-paired-groups differences.

RESULTS

Between 1997 and 2002, 10 patients who had received standard RT and answered the XQ and HNQOL through at least 1 year were included in the study. Each of these patients was matched with a subgroup of 2-5 patients (median, 3) who had received IMRT, had similar patient and tumor characteristics, and answered the same questionnaires. A total of 30 patients were included in the IMRT group. During the initial months after therapy, the XQ and HNQOL summary scores worsened significantly in both groups compared with the pretherapy scores. Starting at 6 months, improvements of both XQ and HNQOL scores were found over time in the IMRT patients (p = 0.01 and 0.04, respectively), compared with no trend of improvement in the standard RT patients (p = 0.5 and 0.9, respectively). The trend of improvement over time in QOL in the IMRT patients was noted in most of the HNQOL domains (Eating: p = 0.07, Pain: p = 0.05, Emotion: p = 0.04, and Communication: p = 0.13), compared with no trend of improvement in most of the domains in the standard RT patients. As the scores of the IMRT (but not the standard RT) patients improved over time, the differences between the groups in the mean XQ and HNQOL summary scores widened. At 12 months, median XQ and HNQOL scores were lower (better) in the IMRT compared with the standard RT patients by 19 and 20 points, respectively, adjusted for the pretherapy values (p = 0.2). In both groups, the pretherapy XQ and HNQOL summary scores were significantly related to the respective posttherapy scores (p = 0.02 and p < 0.01, respectively).

CONCLUSIONS

After initial posttherapy declines in both groups, xerostomia and QOL improved over time after IMRT but not after standard RT. The potential benefits gained from IMRT in xerostomia or in QOL, compared with standard RT, are best reflected late (> or = 6 months) after therapy.

Late xerostomia after intensity-modulated radiation therapy versus conventional radiotherapy

PURPOSE

To evaluate xerostomia following intensity-modulated radiation therapy (IMRT).

MATERIALS AND METHODS

An institutional review board-approved study of xerostomia was conducted in 210 head and neck cancer patients who were beyond the acute recovery phase (> 1 year) after radiation therapy. Xerostomia was evaluated with the 8-question XQ developed and validated at the University of Michigan.

RESULTS

Median XQ scores (normalized so that no xerostomia = 0 and maximum xerostomia = 100) were larynx-only group, 4 points, ipsilateral radiotherapy, 34 points; bilateral radiotherapy, 64 points; IMRT with mean contralateral parotid dose more than 26 Gy, 44 points; and IMRT with mean contralateral parotid dose 26 Gy or less, 32 points (P < 0.05 for all major comparisons).

CONCLUSION

The XQ is an excellent tool for identifying important differences in xerostomia after radiation therapy for head and neck cancer. The authors' IMRT program decreases the severity of xerostomia symptoms compared with what is typically seen after conventional radiation therapy.

Does radiation dose to the salivary glands and oral cavity predict patient-rated xerostomia and sticky saliva in head and neck cancer patients treated with curative radiotherapy?

BACKGROUND AND PURPOSE

To investigate the association between the mean salivary gland and oral cavity dose, with patient-rated moderate and severe xerostomia and sticky saliva.

PATIENTS AND METHODS

One hundred and fifty-seven patients treated with bilateral irradiation for head and neck cancer were included. The parotid and submandibular glands and the oral cavity were delineated on plannings-CT scans. At baseline and 6 and 12 months self-reported xerostomia and sticky saliva were assessed using the EORTC QLQ-H&N35 questionnaire.

RESULTS

At 6 months a significant association between the mean parotid (MD(par)) and mean submandibular dose (MD(subm)) and xerostomia was observed (OR - MD(par): 1.17; P=0.002 and OR - MD(subm): 1.08; P = 0.02). Between MD(par) and MD(subm), a significant interaction term was present. No significant association was found with the oral cavity dose. Xerostomia was reversible depending on MD(par) and MD(subm). Considering Sticky saliva, a significant association was found at 6 and 12 months with MD(subm) (OR: 1.03; P < 0.001). The P50 for sticky saliva increased with elapsing time.

CONCLUSIONS

Both MD(par) and MD(subm) influence the risk of xerostomia in irradiated patients at 6 months. This probability as a function of the mean parotid dose significantly depended on the mean dose in the submandibular glands. Sticky saliva mainly depends on MD(subm).

Intensity-modulated radiation treatment for head-and-neck squamous cell carcinoma—the University of Iowa experience

PURPOSE

To review the University of Iowa experience with intensity-modulated radiotherapy (IMRT) in the treatment of head-and-neck squamous cell carcinoma.

METHODS AND MATERIALS

From October 1999 to April 2004, 151 patients with head-and-neck squamous cell carcinoma were treated with IMRT for curative intent. One patient was lost to follow-up 2 months after treatment and therefore excluded from analysis. Of the remaining 150 patients, 99 were treated with definitive IMRT, and 51 received postoperative IMRT. Sites included were nasopharynx, 5; oropharynx, 56; larynx, 33; oral cavity, 29; hypopharynx, 8; nasal cavity/paranasal sinus, 8; and unknown primary, 11. None of the patients treated with postoperative IMRT received chemotherapy. Of 99 patients who had definitive IMRT, 68 patients received concurrent cisplatin-based chemotherapy. One patient received induction cisplatin-based chemotherapy, but no concurrent chemotherapy was given. Three clinical target volumes (CTV1, CTV2, and CTV3) were defined. The prescribed doses to CTV1, CTV2, and CTV3 in the definitive cohort were 70-74 Gy, 60 Gy, and 54 Gy, respectively. For high-risk postoperative IMRT, the prescribed doses to CTV1, CTV2, and CTV3 were 64-66 Gy, 60 Gy, and 54 Gy, respectively. For intermediate-risk postoperative IMRT, the prescribed doses to CTV1, CTV2, and CTV3 were 60 Gy, 60 Gy, and 54 Gy.

RESULTS

The median follow-up was 18 months (range, 2-60 months). All living patients were followed for at least 6 months. There were 11 local-regional failures: 7 local failures, 3 regional failures, and 1 failure both in the primary tumor and regional lymph node. There were 16 patients who failed distantly, either with distant metastasis or new lung primaries. The 2-year overall survival, local progression-free survival, locoregional progression-free survival, and distant disease-free survival rates were 85%, 94%, 92%, and 87%, respectively. The median time from treatment completion to local-regional recurrence was 4.7 months (range, 1.8 to 15.6 months). Only one marginal failure was noted in a patient who had extensive tonsil cancer with tumor extension into the orbit and cavernous sinus. Patients with oropharyngeal cancer did significantly better than patients with oral cavity and laryngeal cancer, with a 2-year local-regional control rate of 98%, compared with 78% for oral cavity cancer and 85% for laryngeal cancer (p = 0.005). There was no significant difference in local-regional control for patients who received postoperative radiation or definitive radiation (p = 0.339) and for patients who had chemotherapy or not (p = 0.402). Neither T stage nor N stage had a significant effect on local-regional control (p = 0.722 and 0.712, respectively).

CONCLUSIONS

Our results have confirmed the effectiveness of IMRT in head-and-neck cancer. It offers excellent outcomes in local-regional control and overall survival. More studies are necessary to further improve the outcomes of laryngeal cancer as well as oral cavity cancer.

Intensity-modulated radiotherapy as the boost or salvage treatment of nasopharyngeal carcinoma: The appropriate parameters in the inverse planning and the effect of patient's anatomic factors on the planning results

The current study demonstrates that the large increase in normal tissue penalty often degrades target dose uniformity without a concomitant large improvement in normal tissue dose, especially in anatomically unfavorable patients. The excessively large normal tissue penalties do not improve treatment plans for patients having unfavorable geometry.

Intensity-modulated radiation therapy use in the U.S., 2004

BACKGROUND

Intensity-modulated radiation therapy (IMRT) is a novel approach to the planning and delivery of radiation therapy. The prevalence of IMRT use among radiation oncologists in the U.S. appears to be increasing, despite limited data evaluating its risks and benefits.

METHODS

A random sample of radiation oncologists in the U.S., including a cohort of 441 physicians who were surveyed in 2002, was surveyed regarding IMRT use. IMRT users were questioned regarding their frequency of use, clinical applications, and reasons for adopting IMRT. IMRT nonusers were asked their reasons for not using IMRT, whether they planned to use it in the future, and reasons for wanting to adopt IMRT. Differences in responses between 2002 and 2004 were compared.

RESULTS

The survey was conducted between July 1, 2004 and August 31, 2004. Of 368 evaluable participants, 239 physicians (64.9%) responded. The proportion of respondents who used IMRT was 73.2% (175 physicians), compared with 32.0% in 2002. The adoption rate of IMRT among nonusers from 2002 to 2004 was 62.7% (95% confidence interval, 51.9-73.5%). Many IMRT users (81.0%) had used IMRT to deliver higher than conventional doses of radiation, predominantly in patients with genitourinary and head and neck tumors. Major reasons cited for IMRT adoption were permitting normal tissue sparing (88.0%), dose escalation (85.1%), and economic competition (62.4%). Ninety-one percent of nonusers planned to adopt IMRT in the future.

CONCLUSIONS

IMRT use among radiation oncologists in the U.S. has increased significantly since 2002. Standardized guidelines and careful, prospective analyses evaluating its risks and benefits are needed.

Dose-volume modeling of salivary function in patients with head-and-neck cancer receiving radiotherapy

PURPOSE

We investigated the factors that affect salivary function after head-and-neck radiotherapy (RT), including parotid gland dose-volume effects, potential compensation by less-irradiated gland tissue, and functional recovery over time.

METHODS AND MATERIALS

Sixty-five patients with head-and-neck tumors were enrolled in a prospective salivary function study. RT was delivered using intensity-modulated RT (n = 45), forward-planning three-dimensional conformal RT (n = 14), or three-dimensional conformal RT with an intensity-modulated RT boost (n = 6). Whole salivary flow was measured before therapy and at 6 months (n = 61) and 12 months (n = 31) after RT. A wide variety of dose-volume models to predict post-RT salivary function were tested. Xerostomia was defined according to the subjective, objective, management, analytic (SOMA) criteria as occurring when posttreatment salivary function was < 25% of the pretreatment function. Multivariate logistic regression analysis was used to assess the combined effect of dose-volume, patient-, and treatment-related factors.

RESULTS

A significant correlation was observed between the relative quality-of-life scores and relative stimulated saliva values at 6 months after RT (Spearman's correlation coefficient [R(s)] = 0.46, p < 0.001). The dose-volume factors were by far the strongest correlates with stimulated saliva flow, although other factors showed modest significance in multimetric models (chemotherapy, gender, and Karnofsky performance status). Several fitted dose-volume models provided a good mathematical description of the data. Significant noise in the salivary measurements (repeated measurement coefficient of variation was 27% in normal subjects) precluded selection of any one of the models presented solely on the basis of the objective fit criteria. Nevertheless, the mean dose-exponential model, in which each parotid gland's relative salivary gland function equaled exp(-A x mean gland dose), with A equal to 0.054/Gy (68% confidence interval 0.052-0.059), provided a good representation of the data and was incorporated into our multimetric analysis. Using that model, we estimated that a mean parotid dose of 25.8 Gy, on average, was likely to reduce a single parotid gland's flow to 25% of its pretreatment value, regardless of the treatment delivery method. Significant correlations were observed between a logistic multivariate model (incorporating the mean dose-exponential equation, gender, and Karnofsky performance status) and stimulated saliva flow at 6 months (R(s) = 0.73), stimulated saliva flow at 12 months (R(s) = 0.54), and quality-of-life score at 6 months (R(s) = 0.35) after RT.

CONCLUSION

Stimulated parotid salivary gland dose-volume models strongly correlated with both stimulated salivary function and quality-of-life scores at 6 months after RT. The mean stimulated saliva flow rates improved from 6 to 12 months after RT. Salivary function, in each gland, appeared to be lost exponentially at a rate of approximately 5%/1 Gy of mean dose. Additional research is necessary to distinguish among the models for use in treatment planning. The incidence of xerostomia was significantly decreased when the mean dose of at least one parotid gland was kept to < 25.8 Gy with conventional fractionation. However, even lower mean doses imply increased late salivary function.

Structural and functional characteristics of irradiation damage to parotid glands in the miniature pig

PURPOSE

To evaluate the effects of a solitary megadose protocol of ionizing radiation (IR) on the structure and function of the miniature pig (minipig) parotid gland.

METHODS AND MATERIALS

Fourteen minipigs were subjected to either 15 or 20 Gy to one parotid gland with a linear accelerator, whereas another four minipigs served as non-IR controls. Salivary flow rates and salivary chemistries were measured pre-IR and 4 and 16 weeks post-IR. A quantitative assessment of gland weight and acinar area and detailed serum chemistry and hematologic analyses were also performed.

RESULTS

Parotid flow rates decreased by approximately 50% either with 20 Gy at 4 weeks, or 15 Gy at 16 weeks post-IR. In the 20 Gy group, salivary flow rates were reduced by approximately 80% at 16 weeks post-IR. A significant decrease in salivary calcium and amylase and an increase of salivary potassium levels were found in both IR groups. There were also transient alterations in serum chemistry and hematology parameters post-IR. Parotid gland weights were significantly decreased (-50%) in the 15 and 20 Gy groups at 4 and 16 weeks post-IR. Additionally, the acinar cell area in glands of both IR groups was significantly reduced from that in control glands at both the 4 and 16 weeks time points.

CONCLUSION

Structural changes in salivary gland parenchyma occurred relatively early after IR, whereas the alterations in salivary output were relatively delayed. Further, reductions in salivary flow were not proportional to acinar cell area loss. Together, these findings suggest that nonparenchymal IR damage likely contributes to IR-induced salivary hypofunction.

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.

Early and Late Effects of X-Irradiation on Submandibular Gland: A Morphological Study in Mice

BACKGROUND

Radiotherapy for head and neck cancers causes permanent salivary gland dysfunction and xerostomia. The aim of this study was to determine changes in mice submandibular glands after X-irradiation.

METHODS

The submandibular glands of male C57BL/6 mice were locally X-irradiated in the head and neck region with a single dose of 7.5 or 15 Gy and analyzed morphologically and morphometrically at 1, 3, 6, 10, 40, and 90 days after irradiation.

RESULTS

Two phases of gland reaction to irradiation have been noted. The first, early phase is observed up to 10 days after irradiation. The second, late phase was observed 90 days after irradiation. Also, a dose-related effect was noticed. The most prominent morphological changes were pyknotic nuclei, vacuolization of acinar cells and lysis of acini and granular convoluted tubules. Changes were detected at 3 and 6 days after irradiation followed by tissue regeneration. Ninety days after irradiation, prominent pathological changes (vacuolization and pyknotic nuclei of acinar cells, lysis of acini and granular convoluted tubules and edema) were detected, but the most remarkable change was disseminated mononuclear infiltration. Also, a statistically significant reduction in number of acinar cells was detected in both irradiated glands.

CONCLUSIONS

Occurrence of disseminated mononuclear infiltration in gland during late post-irradiation phase makes the mouse model potentially better than the rat model for investigation of irradiation-induced salivary gland damage.

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.

Importance of the Initial Volume of Parotid Glands in Xerostomia for Patients with Head and Neck Cancers Treated with IMRT

OBJECTIVE

Our aim was to evaluate predictors of xerostomia in patients with head and neck cancers treated with intensity-modulated radiation therapy (IMRT).

METHODS

Thirty-three patients with pharyngeal cancer were evaluated for xerostomia after having been treated with IMRT. All patients were treated with whole-neck irradiation of 46-50 Gy by IMRT, followed by boost IMRT to the high-risk clinical target volume to a total dose of 56-70 Gy in 28-35 fractions (median, 68 Gy). For boost IMRT, a second computed tomography (CT-2) scan was done in the third to fourth week of IMRT. Xerostomia was scored 3-4 months after the start of IMRT.

RESULTS

The mean doses to the contralateral and ipsilateral parotid glands were 24.0 +/- 6.2 and 30.3 +/- 6.6 Gy, respectively. Among the 33 patients, xerostomia of grades 0, 1, 2 and 3 was noted in one, 18, 12 and two patients, respectively. Although the mean dose to the parotid glands was not correlated with the grade of xerostomia, the initial volume of the parotid glands was correlated with the grade of xerostomia (P = 0.04). Of 17 patients with small parotid glands (< or =38.8 ml) on initial CT (CT-1), 11 (65%) showed grade 2 or grade 3 xerostomia, whereas only three (19%) of 16 patients with larger parotid glands showed grade 2 xerostomia (P < 0.05). The mean volume of the parotid glands on CT-1 was 43.1 +/- 15.2 ml, but decreased significantly to 32.0 +/- 11.4 ml (74%) on CT-2 (P < 0.0001).

CONCLUSIONS

Initial volumes of the parotid glands are significantly correlated with the grade of xerostomia in patients treated with IMRT. The volume of the parotid glands decreased significantly during the course of IMRT.

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.

Intensity-modulated radiation therapy: emerging cancer treatment technology

The use of intensity-modulated radiation therapy (IMRT) is rapidly advancing in the field of radiation oncology. Intensity-modulated radiation therapy allows for improved dose conformality, thereby affording the potential to decrease the spectrum of normal tissue toxicities associated with IMRT. Preliminary results with IMRT are quite promising; however, the clinical data is relatively immature and overall patient numbers remain small. High-quality IMRT requires intensive physics support and detailed knowledge of three-dimensional anatomy and patterns of tumour spread. This review focuses on basic principles, and highlights the clinical implementation of IMRT in head and neck and prostate cancer.

Obstructive sleep apnea and head and neck neoplasms

OBJECTIVE

To elaborate the relationship between obstructive sleep apnea (OSA) and head and neck neoplasms (HNN).

STUDY DESIGN AND SETTING

A systematic review of the MEDLINE literature.

RESULTS

Thirty of 34 articles indexed under OSA and HNN were about neoplasms that presented first as OSA. Four of the articles were about treatment of HNN causing OSA and gave incidences varying from 8% to 92%. Quality of life surveys confirm that patients with malignant HNN have sleep problems. Xerostomia may contribute to these sleep problems, and the role of salivary mucins deserves consideration.

CONCLUSIONS

This review of the literature raises several new research questions about the clinical and biological relationships between OSA and HNN.

Proposition de sélection et délimitation des volumes cibles microscopiques péritumoraux dans les cancers de la cavité buccale et de l'oropharynx (aires ganglionnaires exclues)

This article reviews the concept of selectivity in peritumoral microscopic disease to be included in the Clinical Target Volume (CTV) for elective treatment for oral cavity and oropharyngeal squamous cell carcinoma, using the local tumoral spread. The objective of the present article is to present a procedure for the delineation of the target volumes, required for an appropriate application of 3-DCRT and IMRT for head and neck cancers. These propositions are for the delineation of microscopic peritumoral target volumes when external beam irradiation is required. CTVs are illustrated on CT sections.

Intensity-modulated radiation therapy for the treatment of oropharyngeal carcinoma: the Memorial Sloan-Kettering Cancer Center experience

PURPOSE

To review the Memorial Sloan-Kettering Cancer Center's experience in using intensity-modulated radiation therapy (IMRT) for the treatment of oropharyngeal cancer.

METHODS AND MATERIALS

Between September 1998 and June 2004, 50 patients with histologically confirmed cancer of the oropharynx underwent IMRT at our institution. There were 40 men and 10 women with a median age of 56 years (range, 28-78 years). The disease was Stage I in 1 patient (2%), Stage II in 3 patients (6%), Stage III in 7 (14%), and Stage IV in 39 (78%). Forty-eight patients (96%) received definitive treatment, and 2 (4%) were treated in the postoperative adjuvant setting. Concurrent chemotherapy was used in 43 patients (86%). Patients were treated using three different IMRT approaches: 76% dose painting, 18% concomitant boost with IMRT in both am and pm deliveries, and 6% concomitant boost with IMRT only in pm delivery. Regardless of the approach, the average prescription dose to the gross tumor planning target volume was 70 Gy, while the average dose delivered to the subclinical volume was 59.4 Gy in the dose painting group and 54 Gy in the concomitant boost group. Percutaneous endoscopic gastrostomy feeding tubes (PEGs) were placed before the beginning of treatment in 84% of the patients. Acute and late toxicity were graded according to the Radiation Therapy Oncology Group (RTOG) radiation morbidity scoring criteria. Toxicity was also evaluated using subjective criteria such as the presence of esophageal stricture, and the need for PEG usage. The local progression-free, regional progression-free, and distant metastases-free rates, and overall survival were calculated using the Kaplan-Meier method.

RESULTS

Three patients had persistent locoregional disease after treatment. The 2-year estimates of local progression-free, regional progression-free, distant metastases-free, and overall survival were 98%, 88%, 84%, and 98%, respectively. The worst acute mucositis experienced was Grade 1 in 4 patients (8%), Grade 2 in 27 (54%), and Grade 3 in 19 (38%). Xerostomia decreased with increasing time interval from the end of radiotherapy, and among the patients with at least 9 months of follow-up there was 67% Grade 0-1 and 33% Grade 2 toxicity. Of the 42 patients who required upfront PEG placement, 6 were still using PEG for nutrition at the time of this analysis. Three patients had cervical esophageal strictures, and of these, 1 was still PEG dependent 1 year after treatment. Two of these patients were treated with the IMRT concomitant boost am and pm approach, whereas the other was treated with the dose painting technique.

CONCLUSIONS

Intensity-modulated radiotherapy achieved encouraging local control rates in patients with oropharyngeal carcinoma. Treatment toxicity was acceptable even in the setting of concurrent chemotherapy. Long-term follow-up is needed to confirm these preliminary findings.

Xerostomia Following Radiotherapy of the Head and Neck Affects Vocal Function

Purpose

To investigate whether xerostomia induced by wide-field radiotherapy (RT) of the head and neck affects vocal function.

Patients and Methods

We conducted a retrospective cohort study comparing 20 patients with early glottic cancer treated by limited RT of the larynx to 20 patients receiving wide-field RT of the primary tumor site and the lymphatic system of the entire head and neck, including the salivary glands. Salivary and vocal functions, as well as responses to questionnaires on xerostomia and quality of life were compared between groups. Twenty healthy volunteers matched for age, sex, and smoking status were included as controls.

Results

The wide-field RT patients showed high xerostomia-related symptom scores and significantly lower values of whole salivary flow rate compared to the limited RT and healthy patients (P < .001). Subjective vocal dysfunction and stroboscopic abnormality were observed in the wide-field RT group (P < .05), but acoustic or aerodynamic profiles showed no significant difference among groups (P > .05). Subjective and objective salivary gland hypofunction was significantly correlated to vocal dysfunction.

Conclusion

Our results suggest that xerostomia following extensive RT of the head and neck can affect vocal function. In the treatment of head and neck malignancies, efforts to prevent post-RT xerostomia would be anticipated to contribute to the preservation of vocal function.

Implications of radiation dosimetry of the mandible in patients with carcinomas of the oral cavity and nasopharynx treated with intensity modulated radiation therapy

Intensity modulated radiation therapy (IMRT) is a newer method of delivering highly conformal, salivary gland sparing radiation treatment that is finding increasing applications in head and neck malignancies. However, the radiation dose distribution to the mandible is rarely considered with IMRT, and the potential risks of osteoradionecrosis or osseointegrated implant failure are not well characterized for this modality. In a series of 10 patients with oral cavity and nasopharyngeal cancers who previously underwent IMRT, examination of the three-dimensional mandibular dose distribution was undertaken. The findings indicate a modest potential risk of osteoradionecrosis and osseointegrated implant failure in cases where IMRT optimization constraints are not specifically aimed at sparing the mandibular bone. Significantly higher mandibular doses (P < 0.04) were received in cases of oral cavity as opposed to nasopharyngeal cancers with IMRT. Efforts to optimize IMRT to further reduce doses to the mandible should be considered, and development of software tools to integrate three-dimensional dose distributions into planning of post-radiotherapy osseointegration would be beneficial.

Intensity-modulated radiotherapy: Is xerostomia still prevalent?

Conformal radiation with intensity-modulated radiotherapy (IMRT) is a technique that potentially can minimize the dose to salivary glands and thereby decrease the incidence of xerostomia. Precise target determination and delineation is most important when using salivary gland-sparing techniques of IMRT. Reduction of xerostomia can be achieved by sparing the salivary glands on the uninvolved oral cavity and keeping the mean parotid gland dose of less than 26 to 30 Gy as a planning criterion if the treatment of disease is not compromised and parotid function preservation is desired.

11C-methionine PET, a novel method for measuring regional salivary gland function after radiotherapy of head and neck cancer

BACKGROUND AND PURPOSE

Loss of salivary gland function is a distressing side-effect of radiotherapy (RT) for head and neck cancer. The aim of this study was to develop a positron emission tomography (PET) method for measuring regional salivary gland function in the major salivary glands irradiated during RT.

PATIENTS AND METHODS

Eight head and neck cancer patients were included; two were examined before RT and six after parotid sparing RT. Patients were examined by dynamic 11C-methionine PET of the major salivary glands and parotid gland salivary flow measurements. PET data were analysed using a kinetic model of salivary gland 11C-methionine metabolism, in which salivary gland function was quantified by the net metabolic clearance of 11C-methionine, K. Functional voxel-wise images of K were calculated and matched with the CT-dose-plan for comparing regional salivary gland function with the regional radiation dose.

RESULTS

Parotid gland K correlated positively with parotid gland salivary flow, indicating that K can be used as an index of salivary gland function. K of parotid and submandibular glands was reduced dependent on the median radiation dose. In one patient, receiving a heterogeneous radiation dose to the parotid glands, regional salivary gland function was inversely correlated to the regional radiation dose.

CONCLUSIONS

Salivary gland function can be measured by dynamic 11C-methionine PET. The net metabolic clearance of 11C-methionine of salivary glands was reduced dependent on the radiation dose. Dynamic 11C-methionine PET offers a method for studying the individual response of the major salivary glands to irradiation.

A randomized phase II trial of amifostine for head and neck irradiation in lymphoma

Acute and long-term oral complications occur in patients receiving mantle radiation therapy or irradiation to the head and neck region for Hodgkin's disease or non-Hodgkin's lymphoma. While considerable data are available on the effect of radiation therapy on the oral function and quality of life of patients with squamous cell carcinoma of the head and neck, such information is lacking for similarly irradiated lymphoma patients. In this article we discuss the rationale and study design of an ongoing, randomized phase II study evaluating the role of amifostine (Ethyol; Medimmune Inc, Gaithersburg, MD) as a radiation protectant in patients receiving head and neck irradiation for lymphoma. Further investigation in this lymphoma population is needed to improve our understanding of the extent of the problem and its impact on patients' daily living and functioning. Importantly, fine-tuning the treatment and management approaches to minimize morbidity while maximizing the survival and quality of life of patients are crucial next steps.

Intensity Modulated Radiation Therapy in Head and Neck Squamous Cell Carcinoma: state of the art and future challenges

Intensity-modulated radiation therapy (IMRT) for head and neck (HN) tumors refers to a new approach to the whole treatment procedure from patient immobilization to beam delivery. Implementation of IMRT thus requires knowledge of setup uncertainties, adequate selection and delineation of target volumes based on clinical examination and optimal imaging modalities, appropriate specification and dose prescription regarding dose-volume constraints, and ad hoc quality control of both the clinical and physical aspects of the whole procedure. A large number of issues still need to be resolved and/or further refined, such as the optimal selection and delineation of the target volume in particular, with the introduction of functional imaging, and a better integration of improved dose distribution into the fractionation strategy. IMRT is associated with a potentially increased incidence of carcinogenesis, although in the HN area this risk is relative to the intrinsic risk of co-morbidity and secondary cancer associated with the patient's lifestyle. Currently, the implementation of IMRT into routine clinical practice for HN cancers may not be a straightforward matter, and should probably be restricted to selected patients and selected institutions with adequate resources and experience. This review emphasizes the above aspects and provides some recommendations for the future use of IMRT in patients with HN tumors.

Radiation-induced xerostomia in patients with head and neck cancer: pathogenesis, impact on quality of life, and management

BACKGROUND

Xerostomia is a common, debilitating complication of radiation therapy (RT) for head and neck cancer. This article reviews the pathogenesis of radiation-induced xerostomia, its impact on quality of life (QOL), and treatment options.

METHODS

Virtually all patients undergoing RT for head and neck cancers have xerostomia, which causes oral discomfort and pain, increased dental caries and oral infection, and difficulty speaking and swallowing. This significantly impairs QOL and can compromise nutritional intake and continuity of cancer therapy. The literature describing pathogenesis, impact on QOL of radiation-induced xerostomia, and preventive and interventional therapies was reviewed.

RESULTS

Current management strategies include stringent dental and oral hygiene; parotid-sparing radiation techniques to prevent or minimize xerostomia; and pharmacotherapies, such as salivary substitutes and sialogogues. Future strategies may include advanced three-dimensional intensity-modulated RT techniques, salivary gland transfer, newer sialogogues, and gene therapy.

CONCLUSIONS

New treatment approaches to xerostomia from RT for head and neck cancer may result in significant improvement in patient QOL.

Intensity-modulated radiation therapy in the treatment of head and neck cancer

Intensity-modulated radiation therapy (IMRT) is a new technical improvement of radiotherapy, in which computer-controlled treatment machines produce multiple beams of radiotherapy whose intensity is optimized to deliver a high dose of radiation to specified volumes, while reducing the dose to adjacent non-target organs. The potential benefits include the ability to deliver higher doses to the target with an improved safety than has previously been possible, and to reduce side effects and complications. Using IMRT to treat some head and neck cancers is especially attractive due to the close vicinity of the targets and many critical, dose-limiting and non-involved structures, and because of the lack of breathing-related motion. The main clinical uncertainties in the use of IMRT for head and neck cancer relate to uncertainties in the extent of radiation to the target areas. In addition, large volumes of adjacent, non-target tissue receive moderate to low radiation doses, raising concerns of increased risk of radiation-related carcinogenesis in young patients. Initial promising clinical data have emerged from IMRT treatment of several head and neck tumor sites.

Intensity modulated radiotherapy for head and neck cancer: evidence for preserved salivary gland function

BACKGROUND AND PURPOSE

To investigate the salivary gland function following intensity modulated radiotherapy (IMRT) for head and neck cancer.

PATIENTS AND METHODS

Seventeen patients with oropharyngeal (n=11) or nasopharyngeal (n=6) carcinoma located adjacent to the major salivary glands were treated with IMRT with an emphasis to spare the salivary glands from high-dose irradiation and to reduce the risk of postirradiation xerostomy. Three patients had stage 2, 4 stage III, and 10 stage IVA cancer. The total basal and stimulated saliva flow rates were measured before the treatment, and 6 and 12 months after radiotherapy.

RESULTS

The median basal saliva flow rate measured before radiation treatment was 0.13 mL/min, and at 6 and 12 months after the completion of IMRT 0.04 mL/min and 0.07 mL/min, respectively. The corresponding median stimulated saliva flow rates were 0.49 mL/min, 0.33 mL/min, and 0.45 mL, respectively. The D50 for an impaired stimulated parotid gland saliva flow rate was 25.5 Gy. Only two (12%) patients developed grade 3 and none grade 4 xerostomia during a median follow-up of 24 months (range, 12-40 months). No patients had locoregional cancer recurrence following IMRT.

CONCLUSIONS

The results suggest that much of the salivary gland function can be maintained with IMRT without jeopardizing the local control rate in the treatment of locally advanced oropharynx or nasopharynx carcinoma.

A phase II study to assess the efficacy of amifostine for submandibular/sublingual salivary sparing during the treatment of head and neck cancer with intensity modulated radiation therapy for parotid salivary sparing

Intensity modulated radiation therapy (IMRT) allows for relative parotid salivary gland sparing for patients undergoing treatment for head and neck squamous cell cancer, but is less reliable for sparing the submandibular glands. Cytoprotection with amifostine (Ethyol; Medimmune Inc, Gaithersburg, MD) has been shown to decrease rates of acute and late xerostomia in patients undergoing radiation therapy for head and neck squamous cell cancer. The addition of amifostine to IMRT may augment parotid salivary sparing, and add submandibular/sublingual, and minor salivary gland sparing resulting in greater salivary flow rates and a more physiologic saliva. Eligible patients include those slated to receive definitive IMRT for early oropharynx cancer or postoperative RT, both without chemotherapy, for more advanced cancers. These include T1, T2 and favorable T3 (favorable, exophytic), N0-2b (small volume) M0 oropharynx cancers who are to receive bilateral neck RT. Postoperative patients with nodal metastases, T3 and T4 primaries, perineural invasion, and lymphovascular invasion will be eligible. Patients will receive 30 to 33 fractions. Clinical target volume (CTV) 1 will receive 60 to 66 Gy, CTV2 will receive 60 Gy, and CTV3 will receive 54 to 57 Gy. The mean dose goal for the parotid gland is 25 Gy. Patients will receive fixed-dose amifostine 500 mg subcutaneously 30 to 60 minutes before each radiation fraction. Subjective xerostomia questionnaires will be administered. Whole mouth and individual major salivary gland stimulated and unstimulated saliva will be collected before and after therapy at 6 weeks, 6 and 12 months. Xerostomia outcomes will be correlated with salivary dose volume histogram data. Accrual has not yet begun. The results of this study will give an indication of the objective and subjective benefit of combined IMRT physical parotid salivary sparing and amifostine chemical cytoprotection for combined salivary gland sparing and reduction in the rate of xerostomia in patients undergoing IMRT for head and neck squamous cell cancer.

Radiotherapy-induced salivary dysfunction

Dry mouth (xerostomia) is one of the most common complaints following radiation therapy (RT) for head and neck cancers. Notably, RT causes irreparable damage to salivary glands that increases the risk for severe and long-term oral and pharyngeal disorders. Several strategies in the treatment of head and neck cancers have been developed to prevent RT-induced salivary dysfunction while providing definitive oncologic therapy. These include salivary-sparing RT; cytoprotectants (such as amifostine); combination therapy of high-dose-rate intraoperative RT, external beam RT, plus a cytoprotectant; salivary gland surgical transfer; and gene therapy. Future research that incorporates biologic, pharmacologic, and technologic advancements that optimize therapeutic ratios and minimizes adverse oral sequelae is warranted.

A dynamic supraclavicular field-matching technique for head-and-neck cancer patients treated with IMRT

PURPOSE

The conventional single-isocenter and half-beam (SIHB) technique for matching supraclavicular fields with head-and-neck (HN) intensity-modulated radiotherapy (IMRT) fields is subject to substantial dose inhomogeneities from imperfect accelerator jaw/MLC calibration. It also limits the isocenter location and restricts the useful field size for IMRT. We propose a dynamic field-matching technique to overcome these limitations.

METHODS AND MATERIALS

The proposed dynamic field-matching technique makes use of wedge junctions for the abutment of supraclavicular and HN IMRT fields. The supraclavicular field was shaped with a multileaf collimator (MLC), which was orientated such that the leaves traveled along the superoinferior direction. The leaves that defined the superior field border moved continuously during treatment from 1.5 cm below to 1.5 cm above the conventional match line to generate a 3-cm-wide wedge-shaped junction. The HN IMRT fields were optimized by taking into account the dose contribution from the supraclavicular field to the junction area, which generates a complementary wedge to produce a smooth junction in the abutment region. This technique was evaluated on a polystyrene phantom and 10 HN cancer patients. Treatment plans were generated for the phantom and the 10 patients. Dose profiles across the abutment region were measured in the phantom on films. For patient plans, dose profiles that passed through the center of the neck lymph nodes were calculated using the proposed technique and the SIHB technique, and dose uniformity in the abutment region was compared. Field mismatches of +/- 1 mm and +/- 2 mm because of imperfect jaw/MLC calibration were simulated, and the resulting dose inhomogeneities were studied for the two techniques with film measurements and patient plans. Three-dimensional volumetric doses were analyzed, and equivalent uniform doses (EUD) were computed. The effect of field mismatches on EUD was compared for the two match techniques.

RESULTS

For a perfect jaw/MLC calibration, dose profiles for the 10 patients in the 3-cm match zone had an average inhomogeneity range of -1.6% to +1.6% using the dynamic-matching technique and -3.7% to +3.8% according to the SIHB technique. Measurements showed that dose inhomogeneities that resulted from 1-mm and 2-mm jaw/MLC calibration errors were reduced from as large as 27% and 45% with the SIHB technique to less than 2% and 5.7% with the dynamic technique, respectively. For -1-mm, -2-mm, +1-mm, and +2-mm jaw/MLC calibration errors, respectively, treatment plans for the 10 patients yielded average dose inhomogeneities of -5.9%, -3.0%, +2.7%, and +5.8% with the dynamic technique as compared to -22.8%, -11.1%, +9.8%, and +22.1% with the SIHB technique. Calculation based on a dose-volume histogram (DVH) showed that the SIHB technique resulted in larger changes in EUD of the PTV in the junction area than did the dynamic technique.

CONCLUSION

Compared with the conventional SIHB technique, the dynamic field-matching technique provides superior dose homogeneity in the abutment region between the supraclavicular and HN IMRT fields. The dynamic feathering mechanism substantially reduces dose inhomogeneities that result from imperfect jaw/MLC calibration. In addition, isocenter location in the dynamic field-matching technique can be chosen for reproducible patient setup and for adequate IMRT field size rather than being dictated by the match position. It also allows angling of the supraclavicular field to reduce the volume of healthy lung irradiated, which is impractical with the SIHB technique. In principle, this technique should be applicable to any treatment site that requires the abutment of static and intensity-modulated fields.

The stable nitroxide tempol facilitates salivary gland protection during head and neck irradiation in a mouse model

PURPOSE

Radiotherapy is commonly used to treat a majority of patients with head and neck cancers. The long-term radiation-induced reduction of saliva output significantly contributes to the posttreatment morbidity experienced by these patients. The purpose of this study was to test the ability of the stable-free radical Tempol (4-hydroxy-2,2,6,6-tetramethylpiperidine-N-oxyl), an established radioprotector, to prevent radiation-induced salivary hypofunction in mice.

EXPERIMENTAL DESIGN

The heads of C3H mice were exposed to a range of single radiation doses with or without an i.p. injection of 275 mg/kg Tempol 10 min before treatment. Salivary gland output was assessed 8 weeks postirradiation.

RESULTS

Radiation caused a dose-dependent reduction in salivary flow in this model. Tempol treatment alone significantly reduced radiation-induced salivary hypofunction. The combination of Tempol with mouth/nose shielding showed essentially complete radiation protection at 15 Gy and approximately 75% protection at 17.5 Gy.

CONCLUSIONS

This study demonstrates for the first time that significant radioprotection of the salivary glands is possible with Tempol in C3H mice.

Simultaneous integrated boost intensity-modulated radiotherapy for locally advanced head-and-neck squamous cell carcinomas: II—clinical results

PURPOSE

To perform a Phase I radiation dose-escalation trial to determine the maximal tolerable dose (MTD) deliverable to the gross tumor volume (GTV) using an accelerated fractionation with simultaneous integrated boost intensity-modulated radiotherapy regimen with parotid gland sparing as the sole therapy in the treatment of locally advanced head-and-neck squamous cell carcinoma. The primary objective was the definition of the MTD using established criteria of quantifying acute dose-limiting toxicity (DLT). Secondary objectives included analysis of failure patterns, tumor control rates, and toxicity.

METHODS AND MATERIALS

Between July 1999 and June 2002, eligible patients with bulky Stage II to Stage IVB head-and-neck squamous cell carcinoma, excluding laryngeal primaries, were enrolled. Intensity-modulated radiotherapy was delivered with 6-MV photons using a "sliding-window" technique. Enrollment of 6 patients for each dose level was planned; if DLTs were seen in >2 of 6 patients, the previous dose was to be expanded by an additional 6 patients to confirm that dose level as the MTD. All schedules administered a total of 30 fractions, but with escalating doses per fraction (2.27, 2.36, and 2.46 Gy) to achieve a total dose to the GTV of 68.1, 70.8, and 73.8 Gy, respectively. The remaining target tissues were constrained to receive the same dose in all patients regardless of the GTV dose level. The clinical target volume, defined as tissue within 1 cm around the GTV (at high risk of subclinical disease), received 60 Gy in 30 fractions of 2.0 Gy. The electively irradiated target volume, defined as the clinically uninvolved lymph node-bearing tissues, received 54 Gy in 30 fractions of 1.8 Gy. The parotid glands were spared to the degree possible without compromising target coverage. Acute toxicity was scored weekly using National Cancer Institute Common Toxicity Criteria. DLT was defined as any Grade 4 acute toxicity or any acute toxicity requiring either a dose reduction or a treatment break of >5 treatment days.

RESULTS

Of 18 men and 2 women (average age, 57 years; range, 37-80 years), 17 presented with oropharyngeal primary tumors, and 1 each with squamous cell carcinoma of the oral cavity, nasopharynx, and hypopharynx. None of the 6 patients at dose level 1, and 2 of the 6 patients initially enrolled at dose level 2, developed DLT. Both patients treated at dose level 3 required a 3-day treatment break and dose reduction after rapid development of Grade 3 toxicity (by Day 15). Six additional confirmatory patients subsequently enrolled at dose level 2 completed treatment without DLT. At least 50% of the total parotid gland volume received <30 Gy in 14 patients (average, 54% of volume), with an average mean dose of 32 Gy. In contrast, >/=50% of the distal parotid gland volume received <25 Gy in 15 patients (average, 63% of volume), with an average mean dose of 24 Gy. With a median follow-up of 20 months from the date of enrollment and 28 months for surviving patients, the actuarial 2-year local control (primary site), regional control (nodal sites), and distant control rate was 76.3%, 66.7%, and 71.8%, respectively.

CONCLUSION

Dose level 2, 70.8 Gy in 30 fractions of 2.36 Gy, was defined as the MTD deliverable to the GTV using this accelerated fractionation with simultaneous integrated boost intensity-modulated radiotherapy regimen with parotid gland sparing as the sole treatment for locally advanced head-and-neck squamous cell carcinoma. Adequate parotid sparing was achievable in most cases. Early toxicity, tumor control, and survival rates compared favorably with the outcomes after other accelerated regimens.

Intensity-modulated radiotherapy for early-stage nasopharyngeal carcinoma: a prospective study on disease control and preservation of salivary function

BACKGROUND

Xerostomia is a uniform complication after radiotherapy (RT) for nasopharyngeal carcinoma (NPC). Dosimetric studies suggested that intensity-modulated RT (IMRT) can spare part of the parotid glands from high-dose radiation. Disease control and salivary function after IMRT for early-stage NPC was studied prospectively.

METHODS

Thirty-three patients with T1,N0-N1,M0 NPC were treated with IMRT from 2000 to 2002. The prescribed dose was 68-70 grays (Gy) in 34 fractions to gross tumor volume, 64-68 Gy to the planning target volume, and 70 Gy to enlarged cervical lymph nodes. Nineteen patients had stimulated whole salivary (SWS) flow assessment and stimulated parotid salivary (SPS) flow assessment at baseline and at 2 months, 6 months, 12 months, 18 months, and 24 months after the completion of IMRT.

RESULTS

At a median follow-up of 2 years, only 1 neck failure was observed. The 2-year and 3-year local control, distant metastases-free, and overall survival rates all were 100%. The lymph node control and progression-free survival rates were 100% at 2 years and 92.3% at 3 years, respectively. The average mean dose to the parotid gland was 38.8 Gy. The SWS and SPS flow showed continuous recovery: 60% and 47.1% of patients recovered at least 25% of their baseline SPS flow and SWS flow, respectively, at 1 year after completion of IMRT, and the proportions rose to 85.7% and 71.4%, respectively, by 2 years. The pH and buffering capacity of saliva also improved with time.

CONCLUSIONS

Parotid-sparing IMRT achieved good locoregional control, and there was continuous recovery of salivary flow, pH, and buffering capacity in the first 2 years after IMRT in patients with NPC.

A dose-volume-based tool for evaluating and ranking IMRT treatment plans

External beam radiotherapy is commonly used for patients with cancer. While tumor shrinkage and palliation are frequently achieved, local control and cure remain elusive for many cancers. With regard to local control, the fundamental problem is that radiotherapy‐induced normal tissue injury limits the dose that can be delivered to the tumor. While intensity‐modulated radiation therapy (IMRT) allows for the delivery of higher tumor doses and the sparing of proximal critical structures, multiple competing plans can be generated based on dosimetric and/or biological constraints that need to be considered/compared. In this work, an IMRT treatment plan evaluation and ranking tool, based on dosimetric criteria, is presented. The treatment plan with the highest uncomplicated target conformity index (TCI+) is ranked at the top. The TCI+ is a dose‐volume‐based index that considers both a target conformity index (TCI) and a normal tissue‐sparing index (NTSI). TCI+ is designed to assist in the process of judging the merit of a clinical treatment plan. To demonstrate the utility of this tool, several competing lung and prostate IMRT treatment plans are compared. Results show that the plan with the highest TCI+ values accomplished the competing goals of tumor coverage and critical structures sparing best, among rival treatment plans for both treatment sites. The study demonstrates, first, that dose‐volume‐based indices, which summarize complex dose distributions through a single index, can be used to automatically select the optimal plan among competing plans, and second, that this dose‐volume‐based index may be appropriate for ranking IMRT dose distributions.

PACS numbers: 87.53.‐j, 87.53.Tf

Les contraintes aux organes à risque en radiothérapie par modulation d'intensité des cancers ORL

Constraint definitions in intensity modulated radiation therapy is a key point factor during the treatment planning process. In literature some data are available about dose constraints and volumes according to the tissue architectures. Following ICRU recommendations, organs at risk organized in a parallel structure could receive an acceptably small proportion of high dose component. Mean dose and dose volume histogram is a most convenient tool for incorporating such constraints. Organs described as a serial structure are supposed to receive less than the given maximum dose, directly linked to the occurrence of complications. Dmax is the best way to describe such events. These constraints are new tools in radiation therapy, available for optimizing the dose distribution in target volume, sparing the organs at risk to protect the organ function or at least decreasing the late functional damages like xerostomia. It is necessary to define with accuracy gross target volumes and clinical target volume with available radio-anatomical guidelines before introducing current constraints on each volume in the inverse dosimetry. The management of these constraints remains under the responsibility of the clinicians. A permanent compromise has to be chosen between homogeneity of the dose distribution in the target volume and the probability of preserving functions of organs at risk.

Are neck nodal volumes drawn on CT slices covered by standard three-field technique?

PURPOSE

Several definitions have been proposed in the past few years on how to contour the various neck nodal levels on CT slices. However, whether the resulting nodal volumes would have been covered by standard techniques is unknown. The purpose of this study was to clarify this issue.

METHODS AND MATERIALS

Eight patients (N0-N1) with head-and-neck cancer from various primary sites referred to us for definitive radiotherapy were included in this study. Two observers contoured the level Ib-V neck nodal volumes on planning CT according to seven reported definitions. Each observer also drew blocks on digitally reconstructed radiographs for the initial (on-cord) phase of a standard three-field technique (parallel opposed lateral fields and AP supraclavicular field) for three different clinical settings: "medium" larynx (to cover upper, mid, and low jugular nodes), "big" larynx (same as for medium, plus posterior cervical nodes), and "tonsil" (same as for big plus retropharyngeal nodes). Fields blocks were concentrically reduced 5 mm in all directions as a surrogate for the clinical target volume to planning target volume expansion. A plan was created for each of the clinical settings, delivering 2 Gy to the International Commission on Radiation Units and Measurements reference point. The coverage of the nodal levels according to the various definitions was investigated throughout the analysis of the volume receiving 50%, 80%, and 95% of the prescribed dose (V(50), V(80), and V(95), respectively) and dose covering at least 95% of the volume (D(95)) values extracted from their cumulative dose-volume histograms in the three clinical settings.

RESULTS

The V(50) coverage of levels III and IV was adequate for all definitions and trials. For level V, about 3-5% of the volume was outside the 50% isodose of those trials that targeted the posterior cervical chain. Coverage of level Ib was highly dependent on the definition, with up to 21% of the volume outside the standard tonsillar fields. For level II, although the 50% isodose from the tonsillar fields seemed to encompass all definitions, this was not the case for the laryngeal trials. Overall, we found 20-30% of the volumes to be outside the 95% isodose, with larger percentages for levels II and V. Similarly the D(95) results showed all volumes to be underdosed; only about 45% and 65% of levels II and V, on average, received 95% of the prescription dose.

CONCLUSION

Within three different clinical settings, we showed that the current definitions provide nodal neck volumes that often fall outside the 50% and 95% isodose lines of the standard three-field technique. Because these volumes are routinely used to define nodal neck volumes for intensity-modulated radiotherapy, the dose-volume objectives of intensity-modulated radiotherapy may not be consistent with those traditionally achieved by the standard three-field technique.

Radiothérapie conformationnelle avec modulation d'intensité des cancers des voies aérodigestives supérieures avec irradiation bilatérale du cou : résultats préliminaires

PURPOSE

To report preliminary results of a prospective study of intensity-modulated radiotherapy (IMRT) for head and neck squamous cell carcinoma (HNC) with bilateral irradiation of the neck.

PATIENTS AND METHODS

At the Alexis Vautrin Cancer Center, 23 patients have been treated with IMRT for HNC since January 2002-August 2003. The first 10 patients with a minimum follow-up of 3 months were analyzed. All tumors were oropharyngeal. There were four females and six males, with a mean age of 50 years (range 39-66). Stages were I-II in eight and III-IV in two. CTV1 was microscopic disease and N0 neck (prescribed dose : 50 Gy) and CTV2 was macroscopic disease and the volume at risk (prescribed dose: 66-70 Gy). PTV were CTV + 5 mm. Patient's immobilization consisted of a five-point head neck shoulder thermoplastic mask. Set-up verifications were done by semi-automatically matching portal images and digitized reconstructed radiographs. IMRT used dynamic multileaf collimation. Five patients (group A) received 50 Gy IMRT (two post-operative and three with a brachytherapy boost with a mean dose: 27.5 Gy), and five patients (group B) received 66-70 Gy IMRT (four post-operative). Acute and late normal tissue effects were graded according to the RTOG-EORTC radiation morbidity scoring criteria.

RESULTS

With a median follow-up of 7.4 months (range 3-18.5), no patient died or had loco-regional relapse. The displacements were <4 mm in 98% cases. CTV1 and 2 received 95% of the prescribed dose in 100% of the volume. On average the mean dose to the contralateral parotid was 25.5 Gy for group A vs. 31 Gy for group B (P = 0.09). Mean doses <26 Gy were obtained in three of five patients in group A vs. zero of five patients in group B (P = 0.04). Acute skin toxicities were grade 1 in five patients, grade 2 in four and grade 3 in one. Acute mucositis cases were grade 1 in three patients, grade 2 in five and localized grade 3 in two. At 3 months, 50% of the patients had a grade 0-1 late xerostomia.

CONCLUSION

The 26 Gy dose limit constraint to the contralateral parotid was easier to satisfy when IMRT was prescribed at a maximum dose of 50 Gy. Acute toxicity is low. The displacements in the mask indicate that it is possible to define the PTV as CTV + 4 mm. This reduction should decrease the mean dose to the parotids. At 3 months, a 50% rate of grade 0-1 late xerostomia encourages the hope of a very low rate at 2 years.

Recurrences near base of skull after IMRT for head-and-neck cancer: implications for target delineation in high neck and for parotid gland sparing

PURPOSE

Locoregional (LR) failures near the base of the skull, and their relationships to the targets in the high neck, were examined in a series of patients who underwent intensity-modulated radiotherapy (IMRT) for head-and-neck cancer.

METHODS AND MATERIALS

Between 1994 and 2002, 133 patients with non-nasopharyngeal head-and-neck squamous cell carcinoma completed a course of curative, parotid-sparing RT. Treatment was delivered until 1996 with conformal three-dimensional techniques and thereafter with multisegmental static IMRT. Of the 133 patients, 80 had oropharyngeal, 27 oral cavity, 12 hypopharyngeal, 11 laryngeal, and 3 unknown primary cancer. The AJCC stage was I in 1, II in 6, III in 26, IVA in 83, and IVB in 12; cancer was recurrent in 5. Sixty patients received primary and 73 postoperative IMRT. 86% of patients (n = 115) had ipsilateral neck metastasis. In all patients, the contralateral neck was clinically node negative but was judged to be at high risk of subclinical disease. Delineation of the superior-most extent of the nodal targets was consistent and corresponded with Rouviere's observations. In the contralateral clinically node-negative neck, the uppermost Level II nodal target was the subdigastric (SD) nodes. To ensure coverage, the uppermost clinical target volume was delineated at the axial CT image in which the posterior belly of the digastric muscle crossed the jugular vein. In the ipsilateral neck, which was node positive in most patients, the uppermost Level II clinical target volume was delineated through the base of the skull. The uppermost retropharyngeal (RP) nodal target was delineated at the level of the top of the C1 vertebral body, accommodating Rouviere's description of the location of the lateral RP nodes. The dose prescription was 70 Gy for the primary planning target volumes (PTVs); 64 Gy and 60 Gy for PTV of the postoperative beds with and without extracapsular extension, respectively; and 50-54 Gy for PTVs of nonoperated subclinical disease, at 1.8-2.0 Gy fractions. In-field or marginal recurrences were defined as those occurring when >95% or 20-95% of the recurrence volume, respectively, had received >95% of the prescribed dose.

RESULTS

At a median follow-up of 32 months (range, 6-107 months), 21 patients (16%) had locoregional recurrence. Seventeen recurrences were in-field and four were marginal. The most prevalent nodal recurrence was in Level II bilaterally, where all failures were in-field. In-field failures were observed in the ipsilateral high neck cranial to the SD nodes (all in initially node-positive neck). No recurrences occurred in the contralateral high neck, cranial to the SD nodes, which was not included in the targets. The 95% confidence interval for the risk of recurrence in that region was 0-2.7%. Three RP nodal failures were observed; two were marginal, occurring ipsilateral and contralateral to the primary tumors, and centered cranial to the top of C1. After these recurrences, the RP nodal clinical target volumes were delineated bilaterally through the base of skull, without subsequent RP recurrence. These target delineation guidelines allowed the achievement of a mean contralateral parotid dose of < or =26 Gy (found previously to preserve salivary output significantly) in 82% of the patients. The 3-year actuarial LR recurrence-free survival rate of primary and postoperative IMRT patients was similar (81% and 84%, respectively). Oropharyngeal cancer patients had the greatest LR recurrence-free survival rate (94%, p <0.001). No statistically significant differences were found in the dose delivered to the PTVs or the in-field recurrence volume between patients who had or did not have LR failure.

CONCLUSION

These results suggest that when the contralateral node-negative side of the neck has a high risk of subclinical metastasis, it is adequate to include the SD nodes as the cranial-most Level II nodal target in non-nasopharyngeal head-and-neck cancer. In the node-positive side of the neck, this nodal level should be delineated more cranially. The RP nodal targets should be delineated more cranially. The RP nodal targets should be delineated bilaterally and should extend to the base of the skull, rather than to the top of C1. These guidelines allowed substantial sparing of the contralateral parotid gland. The results of this series validate a consensus for target delineation adopted recently by cooperative radiotherapy groups.

A comparison of forward and inverse treatment planning for intensity-modulated radiotherapy of head and neck cancer

BACKGROUND AND PURPOSE

To compare intensity-modulated treatment plans of patients with head and neck cancer generated by forward and inverse planning.

MATERIALS AND METHODS

Ten intensity-modulated treatment plans, planned and treated with a step&shoot technique using a forward planning approach, were retrospectively re-planned with an inverse planning algorithm. For this purpose, two strategies were applied. First, inverse planning was performed with the same beam directions as forward planning. In addition, nine equidistant, coplanar incidences were used. The main objective of the optimisation process was the sparing of the parotid glands beside an adequate treatment of the planning target volume (PTV). Inverse planning was performed both with pencil beam and Monte Carlo dose computation to investigate the influence of dose computation on the result of the optimisation.

RESULTS

In most cases, both inverse planning strategies managed to improve the treatment plans distinctly due to a better target coverage, a better sparing of the parotid glands or both. A reduction of the mean dose by 3-11Gy for at least one of the parotid glands could be achieved for most of the patients. For three patients, inverse planning allowed to spare a parotid gland that had to be sacrificed by forward planning. Inverse planning increased the number of segments compared to forward planning by a factor of about 3; from 9-15 to 27-46. No significant differences for PTV and parotid glands between both inverse planning approaches were found. Also, the use of Monte Carlo instead of pencil beam dose computation did not influence the results significantly.

CONCLUSION

The results demonstrate the potential of inverse planning to improve intensity-modulated treatment plans for head and neck cases compared to forward planning while retaining clinical utility in terms of treatment time and quality assurance.

Preservation of oral health-related quality of life and salivary flow rates after inverse-planned intensity- modulated radiotherapy (IMRT) for head-and-neck cancer

PURPOSE

To assess whether comprehensive bilateral neck intensity-modulated radiotherapy (IMRT) for head-and-neck cancer results in preserving of oral health-related quality of life and sparing of salivary flow in the first year after therapy.

METHODS AND MATERIALS

Twenty-three patients with head-and-neck cancer (primary sites: nasopharynx [5], oral cavity [12], oropharynx [3], and all others [3]) were accrued to a Phase I-II trial. Inverse planning was carried out with the following treatment goals: at least 1 spared parotid gland (defined as the volume of parotid gland outside the planning target volume [PTV]) to receive a median dose of less than 20 Gy; spinal cord, maximum 45 Gy; PTV(1) to receive a median dose of 50 Gy; PTV(2) to receive a median dose of 60 Gy (postoperative setting, n = 15) or 66-70 Gy (definitive radiotherapy setting, n = 8). Treatment was delivered with 6 and 15 MV photons using a "step-and-shoot" technique on a Varian 2300 EX linac with 120-leaf Millenium MLC. Unstimulated and stimulated whole-mouth salivary flow rates were measured, and patients completed the University of Washington instrument (UWQOL) and a separate xerostomia questionnaire (XQOL) in follow-up.

RESULTS

Early functional outcome end point data are available at the 1-, 3-, and 12-month follow-up time points for 22, 22, and 18 patients, respectively. The combined mean parotid dose was 30.0 Gy (95% confidence interval: 26.9-33.1). The differences from baseline in mean overall UWQOL scores at 1, 3, and 12 months postradiotherapy were -0.24, 0.32, and 4.28, not significantly different from zero (p = 0.89, p = 0.87, p = 0.13). None of the UWQOL individual domain scores related to oral health (pain, eating-chewing, eating-swallowing, and speech) at 1, 3, or 12 months were significantly different from baseline. Both unstimulated and stimulated whole-mouth flow was variably preserved. Unstimulated salivary flow at 1 and 12 months was inversely correlated with combined mean parotid dose (p = 0.014, p = 0.0007), whereas stimulated salivary flow rates at 3 and 12 months were also correlated with combined mean parotid dose (p = 0.025, p = 0.0016). Combined maximum parotid dose was correlated with unstimulated flow rate at 12 months (p = 0.02, r = -0.56) and stimulated flow rate at 1 and 12 months (p = 0.036, r = -0.45; p = 0.0042, r = -0.66). The proportion of patients reporting total XQOL scores of 0 or 1 (no or mild xerostomia) did not diminish significantly from baseline at 1, 3, or 12 months (p = 0.72, p = 0.51, p = 1.0). Unstimulated and stimulated flow at 1 month was inversely correlated with total XQOL score at 12 months (p = 0.025, p = 0.029).

CONCLUSIONS

Oral health-related quality of life (HRQOL) was highly preserved in the initial 12 months after IMRT, as assessed with separate, validated instruments for xerostomia-specific quality of life and oral HRQOL. In general, patients with better-preserved unstimulated salivary flow rates tended to report lower xerostomia scores. Whole-mouth salivary flow rates post IMRT were inversely correlated with combined mean parotid doses. Longer follow-up is required to assess to what extent HRQOL is favorably maintained.

Intensity-modulated radiotherapy: Examples of its utility in head and neck cancer

Intensity-modulated radiotherapy (IMRT) has been available at Peter MaCallum Cancer Centre (PMCC) since November 2000. The present report illustrates two cases of our early experience with IMRT. Case 1 is a 66-year-old man with a T(1)N(2)M(0) nasopharyngeal carcinoma treated with chemo-radiotherapy using parotid-sparing IMRT. Fourteen months following treatment he remains in complete remission, with salivary function assessed using a xerostomia-specific quality of life questionnaire, having returned to near pretreatment levels by 12 months. Case 2 is a 70-year-old man with a T(4)N(0)M(0) base of tongue squamous cell carcinoma treated with chemo-radiotherapy after refusing radical surgery. He had received subtotal nodal irradiation to 36 Gy in 1994 for Hodgkins disease stage IIA. A radical dose was still achievable despite previous irradiation without exceeding unacceptable spinal cord dose with IMRT. He remains in complete remission 14 months from his initial presentation without evidence of neurological toxicity. Intensity-modulated radiotherapy allows sparing of critical normal structures in the head and neck without compromising dose to the tumour. It is, therefore, desirable for several clinical applications and essential in some, if unacceptable compromises are not to be made.

Serious adverse effects of amifostine during radiotherapy in head and neck cancer patients

BACKGROUND AND PURPOSE

Amifostine has been shown to protect against xerostomia induced by radiotherapy for head and neck cancer, but its impact on the therapeutic index is unknown. This is the first report focusing on amifostine related adverse effects leading to discontinuation of amifostine treatment.

PATIENTS AND METHODS

Thirty-nine patients from two centers irradiated for head and neck cancer received i.v.-infusions of amifostine prior to each radiation fraction. In a phase III study, two daily amifostine doses, 200 mg/m(2) (n = 21) and 340 mg/m(2) (n = 18), were compared for protection against radiation induced toxicity. Total radiation dose was 60-70Gy (2Gy per fraction), nine patients received concurrent chemotherapy with cisplatin/5-FU. amifostine was usually discontinued after >1 episode of serious toxicity during subsequent treatment sessions.

RESULTS

In 16/39 patients (41%) amifostine was discontinued due to severe adverse effects, which led to discontinuation of the phase III study. In four of 16 patients radiotherapy was delayed due to amifostine related adverse effects for 1-3 days. Discontinuation occurred more often in patients receiving chemotherapy. The results led to a literature review for amifostine treatment during radiotherapy in head and neck cancer patients. Regarding our series and published series using an amifostine schedule comparable to ours, total discontinuation rate was 27% (57/214). Discontinuation was significantly influenced by chemotherapy (P = 0.007) but not by amifostine dose (P = 0.156).

CONCLUSION

Daily i.v. administration of amifostine during radiotherapy in head and neck cancer is associated with a high rate of serious adverse effects leading to discontinuation of amifostine treatment and sometimes delay of radiotherapy.

Evaluation of salivary gland function after treatment of head-and-neck tumors with intensity-modulated radiotherapy by quantitative pertechnetate scintigraphy

PURPOSE

To evaluate salivary gland function after inversely planned stereotactic intensity-modulated radiotherapy (IMRT) for tumors of the head-and-neck region using quantitative pertechnetate scintigraphy.

METHODS AND MATERIALS

Since January 2000, 18 patients undergoing IMRT for cancer of the head and neck underwent pre- and posttherapeutic scintigraphy to examine salivary gland function. The mean dose to the primary planning target volume was 61.5 Gy (range 50.4-73.2), and the median follow-up was 23 months. In all cases, the parotid glands were directly adjacent to the planning target volume. The treatment planning goal was for at least one parotid gland to receive a mean dose of <26 Gy. Two quantitative parameters (change in maximal uptake and change in the relative excretion rate before and after IMRT) characterizing the change in salivary gland function after radiotherapy were determined. These parameters were compared with respect to the dose thresholds of 26 and 30 Gy for the mean dose. In addition, dose-response curves were calculated.

RESULTS

Using IMRT, it was possible in 16 patients to reduce the dose for at least one parotid gland to < or =26 Gy. In 7 patients, protection of both parotid glands was possible. No recurrent disease adjacent to the protected parotid glands was observed. Using the Radiation Therapy Oncology Group/European Organization for the Research and Treatment of Cancer scoring system, only 3 patients had Grade 2 xerostomia. No greater toxicity was seen for the salivary glands. The change in the relative excretion rate was significantly greater, if the parotid glands received a mean dose of > or =26 Gy or > or =30 Gy. For the change in maximal uptake, a statistically significant difference was seen only for the parotid glands and a dose threshold of 30 Gy. For the end point of a reduction in the parotid excretion rate of >50% and 75%, the dose-response curves yielded a dose at 50% complication probability of 34.8 +/- 3.6 and 40.8 +/- 5.3 Gy, respectively.

CONCLUSION

Using IMRT, it is possible to protect the parotid glands and reduce the incidence and severity of xerostomia in patients. Doses <26-30 Gy significantly preserve salivary gland function. The results support the hypothesis that application of IMRT does not lead to increased local failure rates.

Rotterdam and Brussels CT-based neck nodal delineation compared with the surgical levels as defined by the American Academy of Otolaryngology-Head and Neck Surgery

PURPOSE/OBJECTIVE

Rotterdam and Brussels have independently published guidelines for the definition and delineation of CT-based neck nodal Levels I-VI. This paper first reports on the adequacy of contouring of the Rotterdam delineation protocol. Rotterdam and Brussels differed slightly in translating the original surgical level definitions as proposed by the 2002 American Academy of Otolaryngology-Head and Neck Surgery (AAO-HNS) to CT guidelines. To adapt to the surgical level definitions to come to a unifying concept, adjustments of both CT-based classifications are proposed.

METHODS AND MATERIALS

The clinical neck nodal target volumes of patients irradiated in Rotterdam by three-dimensional conformal radiotherapy (3D-CRT) between December 1998 and March 2001 were reviewed. Thirty-four patients with N0 and 27 patients with N+ disease with primary tumors located in the oral cavity (n = 1) oropharynx (n = 24), hypopharynx (n = 7), and larynx (n = 29) were evaluated. Seven patients underwent unilateral (3 N0 patients, 4 N+ patients) and 54 underwent bilateral (31 N0 patients, 23 N+ patients) irradiation of the neck. In 11 N+ patients, 3D-CRT of the neck was followed by unilateral neck dissection. The dose to the primary and nonresected N+ necks was 70 Gy and to the N0 neck was 46 Gy. Neck levels were analyzed for adequacy of contouring, dose distribution, and patterns of relapse. The mean dose and the percentage of the volume receiving a minimum of 95% (V95) or >107% (V107) of the prescribed dose was computed.

RESULTS

In 4 patients treated with bilateral 3D-CRT, contouring was not in concordance with the guidelines of the protocol. The V95 and V107 in the 81 adequately contoured N0 necks (63 irradiated N0 necks from 33 N0 patients, 18 irradiated N0 necks from 24 N+ patients) was 95.6% and 6.3%, respectively. For the 26 N+ necks (15 N+ necks from 13 N+ RT-only patients, 11 N+ necks from 11 preoperatively irradiated patients), the V95 and V107 was 94.6% and 6.7%, respectively. With a median follow-up of 29 months, in 4 (8.6%) of 46 patients treated by 3D-CRT only, regional relapse was found. An actuarial regional and locoregional relapse-free survival and disease-free survival rate at 3 years of 90%, 78%, and 68%, respectively, was observed. All regional relapses were observed in the N0 necks of patients with supraglottic laryngeal carcinoma. Taking the surgical 2002 AAO-HNS classification as a reference, adjustments are proposed for the Rotterdam and Brussels delineation protocols to arrive at a unified CT-based neck nodal classification.

CONCLUSION

Adequate dose coverage for the Rotterdam CT-based contours of the neck nodal levels was found. In the RT-only patients, only four failures were observed: one regional and three locoregional relapses. As a next step in optimizing the current Rotterdam and Brussels CT-based delineation protocols, adaptations are proposed to resolve the discrepancies compared with the 2002 AAO-HNS surgical classification.