Parotid gland-sparing 3-dimensional conformal radiotherapy results in less severe dry mouth in nasopharyngeal cancer patients: a dosimetric and clinical comparison with conventional radiotherapy

Long-term outcomes of interventions for radiation-induced xerostomia: A review

Xerostomia, or dry mouth, is a significant problem affecting quality of life in patients treated with radiation therapy for head and neck cancer. Strategies for reduction of xerostomia burden vary widely, with options including: sialagogue medications, saliva substitutes, acupuncture, vitamins, hyperbaric oxygen, submandibular gland transfer, and acupuncture or associated treatments. In this review, we sought to evaluate long-term outcomes of patients treated with various interventions for radiation-induced xerostomia. A literature search was performed using the terms "xerostomia" and "radiation" or "radiotherapy"; all prospective clinical trials were evaluated, and only studies that reported 1 year follow up were included. The search results yielded 2193 studies, 1977 of which were in English. Of those, 304 were clinical trials or clinical studies. After abstract review, 23 trials were included in the review evaluating the following treatment modalities: pilocarpine (three); cevimeline (one); amifostine (eleven); submandibular gland transfer (five); acupuncture like transcutaneous electrical nerve stimulation (ALTENS) (one); hyperbaric oxygen (one); and acupuncture (one). Pilocarpine, cevimeline, and amifostine have been shown in some studies to improve xerostomia outcomes, at the cost of toxicity. ALTENS has similar efficacy with fewer side effects. Submandibular gland transfer is effective but requires an elective surgery, and thus may not always be appropriate or practical. The use of intensity-modulated radiation therapy, in addition to dose de-escalation in select patients, may result in fewer patients with late xerostomia, reducing the need for additional interventions.

Proton change of parotid glands after gustatory stimulation examined by magnetic resonance imaging

The aim of this study was to investigate proton changes of the parotid gland after gustatory stimulation by semi-quantitative parameters and an empirical mathematical model (EMM) using high-temporal-resolution, double-echo, echo-planar imaging (EPI). Approved by a local institutional review board, this study examined 20 parotid glands from 10 healthy volunteers (male:female = 6: 4; age ± standard deviation =35.1 ± 14.1 years) with written informed consent obtained. All participants underwent 1.5-T, double-echo EPI with gustatory stimulation. Semi-quantitative parameters, including maximal drop ratio (MDR), time to peak (TTP), drop slope (DS), recovery slope (RS) and recovery ratio (RR), were calculated. The effect of temporal resolution on parotid functional parameters was evaluated. An EMM comprising an output function ( Sot=Aoe-kot+B) and an input function ( Sint=Ain1-e-kint) was also applied to fit all dynamic curves. Kruskal-Wallis test, Wilcoxon test, linear regression analysis and goodness of fit were used for statistical analysis. p < 0.05 was considered to be statistically significant. The signal intensity dropped significantly after gustatory stimulation on the proton density (PD) image (p < 0.01). MDR was 8.26% in the PD image. MDR and RR were negatively associated with time interval, whereas DS and TTP were significantly positively associated with time interval (all p < 0.05). EMM parametric values derived from PD-time curves of parotid glands were 12.04 ± 6.81%, 6.43 ± 4.23 min^-1 , 88.73 ± 6.18%, 8.41 ± 4.86 min^-1 and 1.09 ± 1.35 for A_o , k_o , B, A_in and k_in , respectively. Semi-quantitative functional parameters and EMM parameters using high-temporal-resolution, double-echo EPI allow the quantification of parotid proton changes after gustatory stimulation.

A comparison of weekly versus 3-weekly cisplatin during concurrent chemoradiotherapy for locoregionally advanced nasopharyngeal carcinoma using intensity modulated radiation therapy: a matched study

Purpose: To compare the long-term survival outcomes and acute toxicity between locoregionally advanced nasopharyngeal carcinoma (NPC) patients who received either weekly or 3-weekly cisplatin during concurrent chemoradiotherapy (CCRT).

Methods: Between November 2008 and August 2011, 241 biopsy-proved NPC patients receiving concurrent cisplatin with intensity modulated radiotherapy (IMRT) were included. 90 patients treated with 4-7 weeks of 30-40 mg/m² cisplatin weekly were matched with 90 patients who received two or three cycles of 80 mg/m² cisplatin three-weekly by sex, age, T stage, N stage, Karnosky performance score (KPS). IMRT was presented to the nasopharyngeal gross target volume at 66-72 Gy/30-32 fractions and those involved neck area at 60-66 Gy/30-32 fractions.

Results: The median follow-up time was 69 months (range, 2-91 months), and the 5-year overall survival (OS), disease-free survival (DFS), locoregional relapse-free survival (LRFS), and distant metastasis-free survival (DMFS) rates were 85.6% vs. 90.0% (P = 0.207), 85.6% vs. 92.6% (P = 0.152), 94.4% vs. 96.7% (P = 0.411), and 88.9% vs. 95.6% (P = 0.107) for the group treated weekly and 3-weekly cisplatin, respectively. No statistically significant survival differences were found between the two treatment groups in both univariate and multivariate analyses. The similar incidence of acute toxicities was observed between two groups.

Conclusions: Concurrent cisplatin-based chemotherapy administered weekly or three-weekly in combination with IMRT leads to similar acute toxicities and long-term survival outcomes in locoregionally advanced NPC patients.

Dynamic MRI follow-up of radiation encephalopathy in the temporal lobe following nasopharyngeal carcinoma radiotherapy

The natural course of radiation encephalopathy following nasopharyngeal carcinoma (NPC) radiotherapy remains poorly understood. The present study aimed to investigate the magnetic resonance imaging (MRI) characteristics and evolution of radiation encephalopathy. A series of 162 follow-up MRI examinations from 68 NPC patients with radiation encephalopathy in the temporal lobes were analyzed retrospectively. Each component of radiation encephalopathy was defined as follows: i) contrast enhanced lesions were enhanced lesions on contrast enhanced T1-weighted images (T1WI); ii) white matter lesions were lesions of homogeneous hyperintensity on T2-weighted images (T2WI) and hypointensity on T1WI; iii) cysts were round or oval well-defined lesions of hyperintensity on T2WI; iv) hemosiderin deposition were nodular or annular hypointense lesions with lower hypointense than normal white matter on both T1WI and T2WI; v) gray matter lesions were defined as disruption or erosion of hyperintensity in the cortex on T2WI. Contrast enhanced lesions, white matter lesions, gray matter lesions, cysts and hemosiderin deposition were detected in 105 (100.0%), 98 (93.3%), 94 (89.5%), 2 (1.7%) and 2 (1.7%) cases of the 105 initial diagnosed temporal lobe lesions. Contrast enhanced lesions were the most commonly observed, followed by white matter lesions, gray matter lesions, temporal lobe atrophy, cysts and hemosiderin deposition. In addition, 12 new lesions were identified during the follow-up, 4 of which presented as solid enhanced nodular lesions. Importantly, in 11 of the 117 (9.4%) affected temporal lobes, solid enhanced nodular lesions were observed to be the only initial abnormalities to occur. For those enhanced nodular lesions measuring <0.8 cm, no necrosis could be detected. On the contrary, all the contrast enhanced lesions measuring >2.0 cm exhibited a necrotic core. To the best of our knowledge, the present study revealed for the first time solid enhanced nodular lesions as the earliest MRI abnormalities of radiation encephalopathy following NPC radiotherapy.

IMRT vs. 2D-radiotherapy or 3D-conformal radiotherapy of nasopharyngeal carcinoma : Survival outcome in a Korean multi-institutional retrospective study (KROG 11-06)

OBJECTIVE

We compared treatment outcomes of two-dimensional radiotherapy (2D-RT), three-dimensional conformal radiotherapy (3D-CRT), and intensity-modulated radiotherapy (IMRT) in patients with nasopharyngeal carcinoma (NPC).

PATIENTS AND METHODS

In total, 1237 patients with cT1-4N0-3M0 NPC were retrospectively analyzed. Of these, 350, 390, and 497 were treated with 2D-RT, 3D-CRT, and IMRT, respectively.

RESULTS

3D-CRT and IMRT showed better 5-year overall survival (OS) rates (73.6 and 76.7 %, respectively) than did 2D-RT (5-year OS of 59.7 %, all p < 0.001). In T3-4 subgroup, IMRT was associated with a significantly better 5-year OS than was 2D-RT (70.7 vs. 50.4 %, respectively; p ≤ 0.001) and 3D-CRT (70.7 vs. 57.8 %, respectively; p = 0.011); however, the difference between the 2D-RT and 3D-CRT groups did not reach statistical significance (p = 0.063). In multivariate analyses of all patients, IMRT was a predictive factor for OS when compared with 2D-RT or 3D-CRT, as was 3D-CRT when compared with 2D-RT.

CONCLUSION

Our study showed that 3D-CRT and IMRT were associated with a better local progression-free survival and OS than was 2D-RT in NPC. IMRT was significantly superior in terms of OS for advanced primary tumors (T3-4).

The management of head and neck tumors with high technology radiation therapy

Squamous cell carcinoma is responsible for 90% of the head and neck cancers affecting over 600,000 people worldwide. Radiation therapy, surgery and chemotherapy are the most important treatment modalities in head and neck squamous cell carcinoma. The aim of this review is to summarize the recent innovations in head and neck radiation therapy, which intends to appreciate the cutting-edge intensity-modulated radiation therapy strategies to mitigate long-term toxicities and evaluate promising technologies in the field as adaptive treatment, dose painting and proton therapy.

Evolution of treatment for nasopharyngeal cancer--success and setback in the intensity-modulated radiotherapy era

BACKGROUND AND PURPOSE

To assess the therapeutic gains and setbacks as we evolved from the 2-dimensional radiotherapy (2DRT) to conformal 3-dimensional (3DRT) and to intensity-modulated (IMRT) era.

MATERIALS AND METHODS

1593 consecutive patients from 1994 to 2010 were retrospectively analyzed. Evolving changes in the different era included advances in staging investigation, radiotherapy technique, dose escalation, and use of chemotherapy.

RESULTS

The 3DRT era achieved significant improvement in local failure-free rate (L-FFR), disease-specific survival (DSS) and overall survival (OS). Neurological damage and bone/soft tissue necrosis were significantly reduced. However, the improvement in distant failure-free rate (D-FFR) was insignificant, and more hearing impairment occurred due to chemotherapy. Significantly higher D-FFR was achieved in the IMRT era, but L-FFR did not show further improvement. 5-Year DSS increased from 78% in the 2DRT, to 81% in the 3DRT, and 85% in the IMRT era, while the corresponding neurological toxicity rate decreased from 7.4% to 3.5% and 1.8%.

CONCLUSIONS

Significant improvement in survival and reduction of serious toxicity was achieved as we evolved from 2DRT to 3DRT and IMRT era; the therapeutic ratio for all T-categories improved with more conformal techniques. Improvements in tumor control were attributed not only to advances in RT technique, but also to better imaging and increasing use of potent chemotherapy. However, it should also be noted that hearing impairment significantly increased due to chemotherapy, L-FFR reached a plateau in the 3DRT era, and it is worrisome that the result for T4 remained unsatisfactory. Besides exploring for more potent chemotherapy and innovative methods, the guideline on dose constraint should be re-visited to optimize the therapeutic ratio.

Parotid perfusion in nasopharyngeal carcinoma patients in early-to-intermediate stage after low-dose intensity-modulated radiotherapy: evaluated by fat-saturated dynamic contrast-enhanced magnetic resonance imaging

PURPOSE

To investigate parotid perfusion in early-to-intermediate stage after parotid-sparing radiation dose using fat-saturated DCE-MRI, and to verify whether the perfusion alteration was related to radiation dose and the PSV.

METHODS AND MATERIALS

Thirty-two parotid glands from 16 consecutive patients with pathologically proven nasopharyngeal carcinoma treated by IMRT were examined. The parotid glands received a radiation dose of 28.9±3.9Gy with a PSV of 43.1%±13.9%. Perfusion parameters were calculated using time-shifted Brix model from fat-saturated DCE-MRI data before (pre-RT) and in early-to-intermediate stage after (post-RT) IMRT. Paired t-test was used to evaluate perfusion changes, while Pearson's correlation test was used to examine perfusion dependency on radiation dose and PSV. For multiple comparisons Bonferroni correction was applied.

RESULTS

Successful fat saturation was achieved in 29 of 32 parotid glands. Compared with pre-RT, the post-RT parotid glands showed significantly higher A, peak enhancement, and wash-in slope, plus a lower Kel, suggesting a mixed effect of increased vascular permeability and acinar loss. Linear regression showed that peak enhancement was positively associated with radiation dose in post-RT parotid glands. Kel and slope were negatively associated with PSV, while time-to-peak was positively associated with PSV significantly.

CONCLUSIONS

Our results suggest that time-shifted Brix model is feasible for quantifying parotid perfusion using DCE-MRI. The perfusion alterations in early-to-intermediate stage after IMRT might be related to a mixed effect of increased vascular permeability and acinar loss with dose and PSV dependencies.

Prognostic value of quality of life measured after treatment on subsequent survival in patients with nasopharyngeal carcinoma

PURPOSE

Pretreatment quality of life (QoL) has been used to predict survival in cancer patients. In this study, we examined the prognostic value of QoL measured after treatment on subsequent survival in patients with nasopharyngeal carcinoma (NPC).

METHODS

We enrolled 273 patients with NPC who had been curatively treated for more than 1 year. The EORTC QLQ-C30 and H&N35 questionnaires were completed 1 year after radiotherapy. The predictability of QoL variables on disease-specific survival (DSS) and overall survival (OS) was analyzed using Cox's proportional hazards models.

RESULTS

Twenty-nine (10.6%) patients developed locoregional relapse and 27 (9.9%) had distant metastasis after the QoL survey with subsequent 5-year DSS and OS rates of 87.9% and 84.0 %, respectively. Based on the QLQ-C30, scales of physical functioning, fatigue, and appetite loss significantly predicted DSS and OS (p < 0.05). In the H&N35, only sexuality was significantly correlated with DSS and OS (p < 0.05). An increment of 10 points in physical functioning (HR: 0.69; 95% CI: 0.48-0.90; p = 0.004) or a decline of 10 points in fatigue problems (HR: 1.40; 95% CI: 1.19-1.61; p = 0.0002), appetite loss (HR: 1.21; 95% CI: 1.03-1.40; p = 0.02), and sexuality (HR: 1.14; 95% CI: 1.02-1.25; p = 0.019) was associated with better OS.

CONCLUSION

Some QoL variables measured after the treatment provide prognostic value on subsequent survival in patients with NPC.

Xerostomia and salivary hypofunction in vulnerable elders: prevalence and etiology

OBJECTIVE

The goal of this article is to review existing research on the prevalence and etiology of dry mouth in the vulnerable elders and identify knowledge gaps.

STUDY DESIGN

Vulnerable elders (VE) are persons aged >65 years who have any or all of the following: limited mobility, limited resources, or complex health status. A systematic search was conducted of PubMed sources from 1989 to May 2010. Evidence was evaluated on the prevalence and etiology of xerostomia and salivary gland hypofunction (SGH) in VE.

RESULTS

The search identified 1,422 publications. The inclusion/exclusion criteria yielded 348 articles, 80 of which are cited herein.

CONCLUSIONS

Research has showed a high prevalence of xerostomia and SGH in VE. Common etiologies include medications, poor general health, female gender, and age. Gaps still exist in the evaluation of dry mouth in VE. Nonetheless, oral dryness will remain an important health issue as life expectancy increases.

Recurrence of nasopharyngeal carcinoma in the parotid region after parotid-gland-sparing radiotherapy

This study reported our experience of the clinical characteristics of periparotid recurrence of nasopharyngeal carcinoma (NPC) after parotid-gland-sparing radiotherapy. We retrospectively reviewed the charts of 296 patients with NPC who underwent parotid-gland-sparing radiotherapy at the Tri-Service General Hospital from 1998 to 2008. Eighty-three patients underwent three-dimensional conformal radiotherapy, and 205 patients underwent intensity-modulated radiotherapy; parotid glands were spared bilaterally in all patients. None of these patients had undergone previous radiotherapy or surgical treatment of the head and neck. Disease recurred in a spared parotid gland in three patients (1.04%). Two of these patients had undergone three-dimensional conformal radiotherapy and the third underwent intensity-modulated radiotherapy. All three patients had undergone parotidectomy. Adjuvant radiotherapy or concurrent chemoradiation was administered. One patient died of metastatic disease 26 months after diagnosis of recurrence; the others were well with no evidence of disease at 63 and 6 months after initial recurrence. Periparotid recurrence is an uncommon pattern of locoregional failure after parotid-gland-sparing radiotherapy for NPC. Early diagnosis and aggressive therapy for patients with periparotid recurrence may improve outcomes.

Quality of life for head and neck cancer patients treated by combined modality therapy: the therapeutic benefit of technological advances in radiotherapy

PURPOSE

To evaluate quality of life (QoL) in patients with head and neck squamous cell carcinoma (HNSCC) treated by combined modality therapy, with a focus on the therapeutic benefits of QoL that result from technological advances in radiotherapy (RT).

METHODS

A cross-sectional survey of QoL using the EORTC QLQ-C30 and QLQ-H&N35 questionnaires was performed for 307 HNSCC survivors. One hundred and thirty-five patients were treated by two-dimensional RT (2DRT), 90 by three-dimensional conformal RT (3DCRT), and 82 by intensity-modulated RT (IMRT). The effect size between groups was calculated using Cohen's D coefficient.

RESULTS

Those who had a higher annual family income or were treated by more advanced RT techniques had better QoL outcomes. Compared with 2DRT, the impact of 3DCRT was small (Cohen's D: 0.02-0.40) on all QoL scales. For IMRT, the impact was small on most scales and moderate (Cohen's D: 0.55-0.60) on opening mouth, dry mouth, and sticky saliva. Compared with 3DCRT, the impact of IMRT was small (Cohen's D: 0.03-0.29) on all scales.

CONCLUSION

Advances in RT provided a positive effect on QoL outcome, especially on swallowing-related QoL scales, for patients with HNSCC treated by combined modality therapy.

A systematic review of salivary gland hypofunction and xerostomia induced by cancer therapies: prevalence, severity and impact on quality of life

PURPOSE

This systematic review aimed to assess the literature for prevalence, severity, and impact on quality of life of salivary gland hypofunction and xerostomia induced by cancer therapies.

METHODS

The electronic databases of MEDLINE/PubMed and EMBASE were searched for articles published in English since the 1989 NIH Development Consensus Conference on the Oral Complications of Cancer Therapies until 2008 inclusive. Two independent reviewers extracted information regarding study design, study population, interventions, outcome measures, results and conclusions for each article.

RESULTS

The inclusion criteria were met by 184 articles covering salivary gland hypofunction and xerostomia induced by conventional, 3D conformal radiotherapy or intensity-modulated radiotherapy in head and neck cancer patients, cancer chemotherapy, total body irradiation/hematopoietic stem cell transplantation, radioactive iodine treatment, and immunotherapy.

CONCLUSIONS

Salivary gland hypofunction and xerostomia are induced by radiotherapy in the head and neck region depending on the cumulative radiation dose to the gland tissue. Treatment focus should be on optimized/new approaches to further reduce the dose to the parotids, and particularly submandibular and minor salivary glands, as these glands are major contributors to moistening of oral tissues. Other cancer treatments also induce salivary gland hypofunction, although to a lesser severity, and in the case of chemotherapy and immunotherapy, the adverse effect is temporary. Fields of sparse literature included pediatric cancer populations, cancer chemotherapy, radioactive iodine treatment, total body irradiation/hematopoietic stem cell transplantation, and immunotherapy.

Quality of life and survival outcome for patients with nasopharyngeal carcinoma receiving three-dimensional conformal radiotherapy vs. intensity-modulated radiotherapy-a longitudinal study

PURPOSE

To investigate the changes of quality of life (QoL) and survival outcomes for patients with nasopharyngeal carcinoma (NPC) treated by three-dimensional conformal radiotherapy (3D-CRT) vs. intensity-modulated radiotherapy (IMRT).

METHODS AND MATERIALS

Two hundred and three newly diagnosed NPC patients, who were curatively treated by 3D-CRT (n = 93) or IMRT (n = 110) between March 2002 and July 2004, were analyzed. The distributions of clinical stage according to American Joint Committee on Cancer 1997 were I: 15 (7.4%), II: 78 (38.4%), III: 74 (36.5%), and IV: 36 (17.7%). QoL was longitudinally assessed by the European Organization for Research and Treatment of Cancer (EORTC) QLQ-C30 and the EORTC QLQ-H&N35 questionnaires at the five time points: before RT, during RT (36 Gy), and 3 months, 12 months, and 24 months after RT.

RESULTS

The 3-year locoregional control, metastasis-free survival, and overall survival rates were 84.8%, 76.7%, and 81.7% for the 3D-CRT group, respectively, compared with 84.2%, 82.6%, and 85.4% for the IMRT group (p value > 0.05). A general trend of maximal deterioration in most QoL scales was observed during RT, followed by a gradual recovery thereafter. There was no significant difference in most scales between the two groups at each time point. The exception was that patients treated by IMRT had a both statistically and clinically significant improvement in global QoL, fatigue, taste/smell, dry mouth, and feeling ill at the time point of 3 months after RT.

CONCLUSIONS

The potential advantage of IMRT over 3D-CRT in treating NPC patients might occur in QoL outcome during the recovery phase of acute toxicity.

Unilateral versus bilateral irradiation in squamous cell head and neck cancer in relation to patient-rated xerostomia and sticky saliva

BACKGROUND AND PURPOSE

To investigate the association between radiation technique with patient-rated moderate and severe xerostomia and sticky saliva.

MATERIALS AND METHODS

One hundred and fifty patients treated with bilateral or unilateral irradiation for head and neck cancer were included. The salivary glands and the oral cavity were delineated on plannings-CT scans. Xerostomia and sticky saliva were assessed using the EORTC QLQ-H&N35 questionnaire at baseline and 6 and 12 months.

RESULTS

At 6 months a significant association between radiation technique and the mean parotid dose (MD(parb)) and xerostomia was observed (Odds ratio (OR)-technique: 2.55; p=0.04 and OR-MD(parb): 1.04; p=0.009). Considering the individual salivary glands, only the mean dose in the contralateral parotid gland (MD(parcl)) is associated with xerostomia (OR: 1.04; p<0.0001). Moreover, the threshold dose for a 50% probability (P50) on xerostomia increased from 21 Gy with bilateral to 44 Gy for unilateral irradiation.

CONCLUSIONS

Both technique and MD(parb) influence the risk of xerostomia in irradiated patients. Of all individual salivary glands, only MD(parcl) is of utmost importance for xerostomia. The shift in the P50 observed for xerostomia suggests that sparing of the contralateral parotid gland is compensated by hyperfunction of the contralateral parotid gland.

Intensity-modulated or conformal radiotherapy improves the quality of life of patients with nasopharyngeal carcinoma: comparisons of four radiotherapy techniques

BACKGROUND

It was reported previously that the dosimetric superiority of conformal radiotherapy (RT), either 3-dimensional conformal RT (3D-CRT) or intensity-modulated RT (IMRT), over conventional 2D-RT translated into clinical benefits for patients with nasopharyngeal carcinoma (NPC). In this study, the authors compared quality-of-life (QOL) outcomes of NPC survivors who received treatment with 1 of 4 different RT techniques at a single institute during different periods.

METHODS

The authors analyzed QOL data of from 237 patients with NPC who were cancer free for 2 or 3 years when their QOL was assessed. The study population included 152 patients who received conventional RT (2D-RT, 61 patients; 2D-RT plus 3D-CRT boost, 91 patients) and 85 patients who received conformal RT (3D-CRT, 33 patients; IMRT, 52 patients). The European Organization for the Research and Treatment of Cancer (EORTC) Core QOL questionnaire and the EORTC Head and Neck QOL questionnaire were completed.

RESULTS

Compared with patients who received with conventional RT, patients who received conformal RT had both statistically (P < .05) and clinically (a difference in mean scores >or=10 points) significant improvements in the scales of global QOL, pain, appetite loss, senses, speech, social eating, teeth, opening mouth, xerostomia, sticky saliva, and feeling ill. No significant difference was observed in any of the scales that compared 2D-RT with 2D-RT plus 3D-CRT boost or that compared 3D-CRT with IMRT. Survivors who received conformal RT had a 2.01-fold higher probability (odds ratio [OR], 2.01; 95% confidence interval [95% CI], 1.19-3.68) of reporting good global QOL and a 2.70-fold lower probability (OR, 0.37; 95% CI, 0.20-0.66) of reporting a high level of xerostomia than survivors who received conventional RT.

CONCLUSIONS

Conformal RT substantially improved head and neck-related symptoms and broad aspects of QOL for survivors of NPC.

Factors influencing the parotid function in nasopharyngeal carcinoma treated with parotid-sparing radiotherapy

BACKGROUND

To evaluate the factors influencing post-irradiation parotid gland function in nasopharyngeal cancer treated with parotid-sparing radiotherapy.

METHODS

This study consisted of 45 patients with nasopharyngeal cancer treated with radiotherapy including 3D conformal radiotherapy, intensity-modulated radiotherapy and high-dose-rate brachytherapy. The mean follow-up time was 37.5 months (range: 15-50 months). Objective parotid gland function was assessed by series sialoscintigraphy pre-irradiation and post-irradiation at 1, 6, 12 and 18 months. Subjective salivary function was recorded by the LENT/SOMA system. Wilcoxon signed-rank test was used to compare the secretion ratio (SR) of parotid gland before and after treatment. Mann-Whitney rank-sum test was used to determine the factors influencing the post-irradiated SR. Chi-square test was used to compare the correlation between subjective grading of xerostomia and objective grading of parotid glands.

RESULTS

There was a significant difference between the pre-irradiation and post-irradiation parotid gland's SR at 1 (0.30 versus 0.01, P < 0.05) and 6 months (0.03 versus 0.08, P < 0.05). However, there was no significant difference compared with the pre-irradiation SR at 12 (0.30 versus 0.20, P > 0.05) and 18 months (0.30 versus 0.18, P > 0.05). There was significant correlation between subjective and objective salivary function (P = 0.024) at 12 months after radiotherapy. The factor that impacted the preservation of parotid function was mean dose to the parotid gland >38.0 Gy (P < 0.05).

CONCLUSIONS

Our results demonstrated that parotid function could recover 1 year after treatment with parotid-sparing radiotherapy in patients with nasopharyngeal cancer. The most important factor that influenced parotid function was the mean dose to the parotid gland.

Intensity-modulated radiotherapy significantly reduces xerostomia compared with conventional radiotherapy

PURPOSE

Xerostomia is a severe complication after radiotherapy for oropharyngeal cancer, as the salivary glands are in close proximity with the primary tumor. Intensity-modulated radiotherapy (IMRT) offers theoretical advantages for normal tissue sparing. A Phase II study was conducted to determine the value of IMRT for salivary output preservation compared with conventional radiotherapy (CRT).

METHODS AND MATERIALS

A total of 56 patients with oropharyngeal cancer were prospectively evaluated. Of these, 30 patients were treated with IMRT and 26 with CRT. Stimulated parotid salivary flow was measured before, 6 weeks, and 6 months after treatment. A complication was defined as a stimulated parotid flow rate <25% of the preradiotherapy flow rate.

RESULTS

The mean dose to the parotid glands was 48.1 Gy (SD 14 Gy) for CRT and 33.7 Gy (SD 10 Gy) for IMRT (p < 0.005). The mean parotid flow ratio 6 weeks and 6 months after treatment was respectively 41% and 64% for IMRT and respectively 11% and 18% for CRT. As a result, 6 weeks after treatment, the number of parotid flow complications was significantly lower after IMRT (55%) than after CRT (87%) (p = 0.002). The number of complications 6 months after treatment was 56% for IMRT and 81% for CRT (p = 0.04).

CONCLUSIONS

IMRT significantly reduces the number of parotid flow complications for patients with oropharyngeal cancer.

Grading xerostomia by physicians or by patients after intensity-modulated radiotherapy of head-and-neck cancer

PURPOSE

To assess observer-based vs. patient self-reported scoring of xerostomia after intensity-modulated radiotherapy (IMRT) of head-and-neck (HN) cancer.

METHODS

A total of 38 patients who had received IMRT for HN cancer underwent xerostomia evaluations 6 to 24 months after completion of therapy using three methods each time: (1) Grading by 3 observers according to the Radiotherapy Oncology Group/European Organization for Research and Therapy of Cancer (RTOG/EORTC) system; (2) patient self-reported validated xerostomia questionnaire (XQ); and (3) major salivary gland flow measurements.

RESULTS

The interobserver agreement regarding the RTOG/EORTC grades was moderate: kappa-coefficient 0.54 (95% CI=0.31-0.76). The correlations between the average RTOG/EORTC grades and the salivary flow rates were not statistically significant. A trend for significant correlation was observed between these grades and the percent (relative to the pretherapy) nonstimulated salivary flow rates (p=0.07), but not with the percent stimulated flow rates. Better correlations were found between grading made more than the median time (15 min) after the last liquid sipping and the nonstimulated (but not the stimulated) flows compared with grading made shortly after sipping. In contrast, significant correlations were found between the XQ scores and the nonstimulated (p<0.005) and the stimulated (p<0.005) salivary flow rates, as well as with the percentages of the corresponding pretherapy values (p=0.002 and 0.038, respectively). No significant correlation was found between the RTOG/EORTC grades and the XQ scores. The observer-based grades underestimated the severity of xerostomia compared with the patient self-reported scores.

CONCLUSIONS

Patient self-reported, rather than physician-assessed scores, should be the main end points in evaluating xerostomia.

Sparing of the submandibular glands by intensity modulated radiotherapy in the treatment of head and neck cancer

BACKGROUND AND PURPOSE

The submandibular glands produce most of the unstimulated saliva output and are the key in prevention of radiation-related xerostomia. We investigated whether sparing of the submandibular function is feasible with intensity modulated radiotherapy (IMRT).

PATIENTS AND METHODS

Thirty-six patients diagnosed with head and neck cancer were treated with IMRT and had at least one parotid gland excluded from the planning target volume. In a subset, of these patients (n=18) where the risk of cancer recurrence in the contralateral submandibular region was judged low, the contralateral submandibular gland was spared from full-dose irradiation. The total unstimulated and stimulated salivary flow rates and adverse effects were monitored.

RESULTS

Twelve months following IMRT mean unstimulated saliva flow was 60% of the baseline value among patients who had one submandibular gland spared and 25% among those who did not (P=0.006). Patients whose contralateral submandibular was spared reported less grade two or three xerostomia (4 vs. 11; P=0.018), and used less saliva substitutes. No cancer recurrences were detected at the vicinity of the spared glands during a median follow-up time of 31 months.

CONCLUSIONS

Submandibular gland sparing with IMRT is safe in selected patients treated for head and neck cancer. It is effective in prevention of radiation-associated xerostomia.

Influence of connective tissue diseases on the expression of radiation side effects: a systematic review

BACKGROUND AND PURPOSE

Patient related co-factors may increase the risk of radiation morbidity. Connective tissue diseases (CTD) are among the co-morbidities that are relatively well studied and have been shown to be of potential clinical relevance for radiotherapy. The aim of this systematic review is to quantify the contribution of CTD to the risk of radiation related side effects.

PATIENTS AND METHODS

Relevant publications reporting the outcome of radiotherapy in patients with CTD were retrieved according to a standardized query and evaluated for their methodology and quality of reporting, using defined quality criteria. A quantitative estimate of the relative risk of developing side effects in patients with CTD was derived from the observed proportions of responders in patients with or without CTD. Risk estimates were synthesized across studies.

RESULTS

Eight studies which include data of 9-209 patients who had CTD and were treated with radiotherapy were identified and reviewed. Three of these studies included data suited for further quantitative analysis. The test of the uni-directional hypothesis that patients with CTD had an increased risk of late effects after radiotherapy reached statistical significance, the one-tailed P-value being 0.03. The pooled relative risk was 2.0 with 95% confidence interval (0.99, 4.1).

CONCLUSIONS

CTD is associated with an increased risk of late radiation induced normal tissue reaction. The literature published to date provides some support for this assertion although most of the reports are plagued by methodological weaknesses, thus calling for a large coordinated study.