Intensity-modulated radiotherapy: Is xerostomia still prevalent?

Modeling of Xerostomia After Radiotherapy for Head and Neck Cancer: A Registry Study

Aim

Data from a local quality registry are used to model the risk of late xerostomia after radiotherapy for head and neck cancer (HNC), based on dosimetric- and clinical variables. Strengths and weaknesses of using quality registry data are explored.

Methods

HNC patients treated with radiotherapy at the Karolinska University hospital are entered into a quality registry at routine follow up, recording morbidity according to a modified RTOG/LENT-SOMA scale. Other recorded parameters are performance status, age, gender, tumor location, tumor stage, smoking status, chemotherapy and radiotherapy data, including prescribed dose and organ-at-risk (OAR) dose. Most patients are entered at several time points, but at variable times after treatment. Xerostomia was modeled based on follow-up data from January 2014 to October 2018, resulting in 753 patients. Two endpoints were considered: maximum grade ≥2 (XER_G≥2) or grade ≥3 (XER_G≥3) late xerostomia. Univariate Cox regression was used to select variables for two multivariate models for each endpoint, one based on the mean dose to the total parotid volume (D_tot) and one based on the mean dose to the contralateral parotid (D_contra). Cox regression allows the estimation of the risk of xerostomia at different time points; models were presented visually as nomograms estimating the risk at 9, 12, and 24 months respectively.

Results

The toxicity rates were 366/753 (49%) for XER_G≥2 and 40/753 (5.3%) for XER_G≥3. The multivariate models included several variables for XER_G≥2, and dose, concomitant chemotherapy and age were included for XER_G≥3. Induction chemotherapy and an increased number of fractions per week were associated with a lower risk of XER_G≥2. However, since the causality of these relationships have limited support from previous studies, alternative models without these variables were also presented. The models based on the mean dose to the total parotid volume and the contralateral parotid alone were very similar.

Conclusion

Late xerostomia after radiotherapy can be modeled with reasonable predictive power based on registry data; models are presented for different endpoints highly relevant in clinical practice. However, the risk of modeling indirect relationships, given the unavoidably heterogeneous registry data, needs to be carefully considered in the interpretation of the results.

Prognostic nomogram of xerostomia for patients with nasopharyngeal carcinoma after intensity-modulated radiotherapy

Xerostomia is a common radiation-induced late complication after radiotherapy. Identifying predictive factors for xerostomia will lead to better treatments and improve the quality of life. This study was conducted to establish an effective predictive nomogram for xerostomia by assessing stage I-IVb (AJCC 7th edition) NPC patients between September 2015 and March 2016. Xerostomia was evaluated via the RTOG/EORTC system. The primary endpoint was grade 2-3 xerostomia 1 year after treatment. The predictive factors for xerostomia were analysed using logistic regression analysis. A nomogram was constructed based on combining the predictors and clinical variables. In total, 102 patients with grade 0-1 xerostomia and 93 patients with grade 2-3 xerostomia were included. The independent predictive factors for xerostomia were V25, V30, V35, and V45 of the ipsilateral parotid gland and mean dose of the contralateral parotid gland. The calibration plot for the probability of xerostomia showed good agreement between prediction by the nomogram and actual observation. The concordance index of the nomogram for predicting xerostomia was 0.796 (95% CI: 0.735-0.857, P <0.001), which was higher than any single dosimetric parameter. Our results indicated that the nomogram provided a more accurate prediction of grade 2-3 xerostomia 1 year after treatment.

Predictors for improvement of xerostomia in nasopharyngeal carcinoma patients receiving intensity-modulated radiotherapy

To identify predictors for improvement of xerostomia in patients with nasopharyngeal carcinoma (NPC) treated with intensity-modulated radiotherapy (IMRT).Patients diagnosed with stage I-IVb NPC (according to the 7th edition of the American Joint Committee on Cancer) between September 2015 and March 2016 were retrospectively analyzed. All the patients received IMRT. Predictors for improvement of xerostomia were analyzed using logistic regression analysis. Receiver operating characteristic curve analysis was used to identify the most appropriate cut-off values for predicting factors.This study included 195 patients: xerostomia improved in 109 patients and xerostomia remained unchanged in 86 patients. Volume of the parotid gland ≤52.2 cm was a risk factor for xerostomia improvement (odds ratio [OR] = 3.506, 95% confidence interval [CI]: 1.932-6.362, P = .001). The mean dose of <39 Gy to the ipsilateral parotid gland was a protective factor (OR = 0.417, 95% CI: 0.271-0.641, P = .001). V30 of the contralateral parotid gland ≤52% was a protective factor (OR = 0.593, 95% CI: 0.462-0.760, P = .001).Volume of the parotid gland, the mean dose of the ipsilateral parotid gland, and V30 of the contralateral parotid gland were independent predictors for improvement of xerostomia.

Evaluation of Salivary Gland Function Using Diffusion-Weighted Magnetic Resonance Imaging for Follow-Up of Radiation-Induced Xerostomia

Objective

To investigate the value of diffusion-weighted magnetic resonance imaging (DW-MRI) as a noninvasive tool to assess salivary gland function for follow-up of patients with radiation-induced xerostomia.

Materials and Methods

This study included 23 patients with nasopharyngeal carcinoma who had been treated with parotid-sparing radiotherapy (RT). Salivary function was assessed by DW-MRI pre-treatment and one week and one year post-RT, respectively. The maximum apparent diffusion coefficient (ADC) of parotid glands (pADCmax) and the time to peak ADC of parotid glands (pTmax) during stimulation were obtained. Multivariate analysis was used to analyze factors correlated with the severity of radiation-induced xerostomia.

Results

The ADCs of parotid and submandibular glands (1.26 ± 0.10 × 10⁻³ mm²/s and 1.32 ± 0.07 × 10⁻³ mm²/s pre-RT, respectively) both showed an increase in all patients at one week post-RT (1.75 ± 0.16 × 10⁻³ mm²/s, p < 0.001 and 1.70 ± 0.16 × 10⁻³ mm²/s, p < 0.001, respectively), followed by a decrease in parotid glands at one year post-RT(1.57 ± 0.15 × 10⁻³ mm²/s, p < 0.001) but not in submandibular glands (1.69 ± 0.18 × 10⁻³ mm²/s, p = 0.581). An improvement in xerostomia was found in 13 patients at one year post-RT. Multivariate analysis revealed 4 significant predictors for the improvement of xerostomia, including dose to parotid glands (p = 0.009, odds ratio [OR] = 0.639), the ADC of submandibular glands (p = 0.013, OR = 3.295), pADCmax (p = 0.024, OR = 0.474), and pTmax (p = 0.017, OR = 0.729) at one week post-RT.

Conclusion

The ADC value is a sensitive indicator for salivary gland dysfunction. DW-MRI is potentially useful for noninvasively predicting the severity of radiation-induced xerostomia.

Can sparing of the superficial contralateral parotid lobe reduce xerostomia following radiotherapy for head and neck cancer?

OBJECTIVE

The purpose of this study is to see whether sparing the superficial contralateral parotid lobe can help limiting xerostomia following radiotherapy for head and neck cancer.

METHODS

88 patients that were included in two prospective randomized studies were analysed in the current study. Using the dosimetry of both the parotid glands, we divided our patients in four groups. Group 1 includes patients where we were able to reduce the radiation dose below the threshold in order to spare both the ipsilateral and contralateral parotid glands, Group 2 consists of patients where only the contralateral parotid gland could be spared. Group 3 consists of patients where only the contralateral superficial parotid lobe could be spared, while in Group 4 not even the contralateral superficial lobe could be spared.

RESULTS

When we compared Group 1 and Group 2, we did not observe a significant difference between both groups in terms of xerostomia scores at 6 or 12 months. When we compared these groups with Group 3, we observed significant differences with more xerostomia in Group 3 where only the contralateral superficial lobe was spared. A significant difference was also observed between Group 3 and Group 4 with more xerostomia in Group 4.

CONCLUSION

Sparing of just one superficial parotid lobe results in less xerostomia when compared to not sparing any lobe of both parotid glands. Advances in knowledge: When sparing of the whole contralateral parotid gland is not possible, delineating both the superficial parotid glands and trying to spare at least one of them can mean a way forward in limiting xerostomia in head and neck cancer patients treated with radiotherapy.

IMRT for head and neck cancer: reducing xerostomia and dysphagia

Dysphagia and xerostomia are the main sequellae of chemoradiotherapy for head and neck cancer, and the main factors in reducing long-term patient quality of life. IMRT uses advanced technology to focus the high radiation doses on the targets and avoid irradiation of non-involved tissues. The decisions about sparing organs and tissues whose damage causes xerostomia and dysphagia depends on the evidence for dose-response relationships for the organs causing these sequellae. This paper discusses the evidence for the contribution of radiotherapy to xerostomia via damage of the major salivary glands (parotid and submandibular) and minor salivary glands within the oral cavity, and the contribution of radiotherapy-related effect on important swallowing structures causing dysphagia. Recommendations for dose limits to these organs, based on measurements of xerostomia and dysphagia following radiotherapy, are provided here.

Evidence on effectiveness of intensity-modulated radiotherapy versus 2-dimensional radiotherapy in the treatment of nasopharyngeal carcinoma: Meta-analysis and a systematic review of the literature

BACKGROUND

Current management of nasopharyngeal carcinoma (NPC) uses radiotherapy (RT) as the curative treatment modality. Radiation delivery techniques for NPC can be achieved using 2D conventional RT or intensity-modulated radiotherapy (IMRT).

METHODS

A systematic review and meta-analysis of the literature was undertaken to assess the effectiveness of IMRT versus 2D conventional RT in primary treatment of NPC.

RESULTS

IMRT showed better results than 2D conventional RT in terms of local control, regional control, and overall survival, but when stratified, only in T4, N2, and stage III were the differences that were seen. Objective saliva measurements and physician-graded xerostomia were better in IMRT. However, patient-reported xerostomia showed minimal improvement only in IMRT. The evidence of superiority of IMRT over 2D conventional RT is not clear.

CONCLUSION

In the absence of more clinical data demonstrating the superiority of IMRT in the treatment of nasopharyngeal carcinoma, 2D conventional RT seems to be a reasonable treatment option, especially in limited resource settings. © 2015 Wiley Periodicals, Inc. Head Neck 38: E2130-E2142, 2016.

Superficial parotid lobe-sparing delineation approach: a better method of dose optimization to protect the parotid gland in intensity-modulated radiotherapy for nasopharyngeal carcinoma

PURPOSE

We used a superficial parotid lobe-sparing delineation approach for dose optimization with better protection for the parotid glands in intensity-modulated radiotherapy (imrt) for nasopharyngeal carcinoma (npc) patients.

METHODS

Compared with traditional contouring of the entire parotid glands as organs at risk (oars) in imrt for npc, we used a superficial parotid lobe-sparing delineation approach of contouring the superficial parotid lobes as oars. Changes in dose to the parotid glands, the targets, and other oars were evaluated.

RESULTS

The mean dose to the parotid glands overall decreased by more than 4 Gy in the test plans. Impressively, the mean dose to the superficial parotid lobes in the test plans was not more than 30 Gy, regardless of clinical stage. In T1-3 npc patients, the dose distributions for targets were not significantly different in the control plans and the test plans. However, for some T4 patients, the dose distributions for targets and brainstem in the test plans could not meet clinical requirements.

CONCLUSIONS

The superficial parotid lobe-sparing delineation approach can significantly lower the mean dose to the entire parotid and to the superficial parotid lobe in T1-3 npc patients, which would be expected to result in less xerostomia and better quality of life for those patients.

Organ-sparing radiation therapy for head and neck cancer

To improve locoregional tumor control and survival in patients with locally advanced head and neck cancer (HNC), therapy is intensified using altered fractionation radiation therapy or concomitant chemotherapy. However, intensification of therapy has been associated with increased acute and late toxic effects. The application of advanced radiation techniques, such as 3D conformal radiation therapy and intensity-modulated radiation therapy, is expected to improve the therapeutic index of radiation therapy for HNC by limiting the dose to critical organs and possibly increasing locoregional tumor control. To date, Review articles have covered the prevention and treatment of radiation-induced xerostomia and dysphagia, but few articles have discussed the prevention of hearing loss, brain necrosis, cranial nerve palsy and osteoradionecrosis of the mandible, which are all potential complications of radiation therapy for HNC. This Review describes the efforts to prevent therapy-related complications by presenting the state of the art evidence regarding advanced radiation therapy technology as an organ-sparing approach.

Submandibular salivary gland transfer for the prevention of radiation-induced xerostomia in patients with nasopharyngeal carcinoma: 5-Year outcomes

BACKGROUND

Our aim in this study was to investigate the value of the submandibular salivary gland transfer procedure in prevention of radiation-induced xerostomia in patients with nasopharyngeal carcinoma (NPC).

METHODS

In all, there were 70 patients, consisting of a test group (36 patients) and a control group (34 patients) in a nonrandomized fashion. In the test group, the submandibular salivary gland was transferred to submental space before radiotherapy (XRT) and shielded. Salivary gland functions were evaluated by the amount of saliva and a quality of life questionnaire before and after XRT and 3 and 60 months after XRT.

RESULTS

At 5 years, the trapping and excretion functions of salivary gland were significantly better in the test group (p = .000 and p = .000). The mean weight of saliva after XRT was heavier (1.65 g vs 0.73 g, p = .000), and the incidence of xerostomia was lower in the test group, with no difference in 5-year survival and neck nodal recurrence between the 2 groups.

CONCLUSIONS

Salivary gland transfer procedure prevents XRT-induced xerostomia and improves quality of life of patients with NPC.

Evidence-based organ-sparing radiotherapy in head and neck cancer

Intensification of radiotherapy treatment for locally advanced head and neck cancer by use of altered fractionation schedules or concomitant chemotherapy has resulted in substantially improved locoregional control and survival. However, these improvements have come at the cost of increased acute, and late, toxic effects. The application of technological advances, such as intensity-modulated radiotherapy, is expected to further improve the therapeutic index of radiotherapy for head and neck cancer, by limiting toxicity and possibly by increasing locoregional control. However, the organ-sparing potential of such highly conformal radiotherapy techniques relies heavily on the appropriate selection and accurate delineation of the crucial organs at risk, with the application of rigorous dose constraints during planning. Because xerostomia and dysphagia are the main causes of decreased quality of life after radiotherapy for head and neck cancer, the prevention of these two complications will form the focus of this review.

Contemplation of head and neck intensity-modulated radiotherapy

Intensity-modulated radiootherapy (IMRT) is being rapidly embraced as a radiotherapy technique in many cancer centres across the world. This paper aims to highlight the reported problems associated with the use of IMRT for the treatment of head and neck cancer. Specific areas of concern that are mentioned are the identification of tumour volumes, reproducibility of treatment, issues of tumour resistance and tumour recurrence. Radiotherapy departments are advised to make haste slowly when considering the implementation of this technique.

Psychosocial and economic impact of cancer

This article explores the psychosocial and economic implications of cancer and their relevance to the clinician. After a general overview of the topic, the authors focus on aspects of particular importance to the dental professional, including the psychosocial and economic implications of the oral complications of cancer and its therapy, head and neck cancers, and special issues among children with cancer and cancer survivors.

Intensity-modulated radiotherapy for cervical lymph node metastases from unknown primary cancer

PURPOSE

To compare the effectiveness of intensity-modulated radiotherapy (IMRT) and conventional (two-dimensional) radiotherapy in the treatment of cervical lymph node metastases from unknown primary cancer (UPC).

METHODS AND MATERIALS

Between February 2003 and September 2006, 23 patients with UPC of squamous cell carcinoma were treated with IMRT. Extended putative mucosal and bilateral nodal sites were irradiated to a median dose of 66 Gy. In 19 patients, IMRT was performed after lymph node dissection, and in 4 patients primary radiotherapy was given. The conventional radiotherapy group (historical control group) comprised 18 patients treated to a median dose of 66 Gy between August 1994 and October 2003.

RESULTS

Twenty patients completed treatment. As compared with conventional radiotherapy, the incidence of Grade 3 acute dysphagia was significantly lower in the IMRT group (4.5% vs. 50%, p = 0.003). By 6 months, Grade 3 xerostomia was detected in 11.8% patients in the IMRT group vs. 53.4% in the historical control group (p = 0.03). No Grade 3 dysphagia or skin fibrosis was observed after IMRT but these were noted after conventional radiotherapy (26.7%, p = 0.01) and 26.7%, p = 0.03) respectively). With median follow-up of living patients of 17 months, there was no emergence of primary cancer. One patient had persistent nodal disease and another had nodal relapse at 5 months. Distant metastases were detected in 4 patients. The 2-year overall survival and distant disease-free probability after IMRT did not differ significantly from those for conventional radiotherapy (74.8% vs. 61.1% and 76.3% vs. 68.4%, respectively).

CONCLUSIONS

Use of IMRT for UPC resulted in lower toxicity than conventional radiotherapy, and was similar in efficacy.

Xerostomia and quality of life after intensity-modulated radiotherapy vs. conventional radiotherapy for early-stage nasopharyngeal carcinoma: initial report on a randomized controlled clinical trial

PURPOSE

To compare directly the effect of intensity-modulated radiotherapy (IMRT) vs. conventional radiotherapy (CRT) on salivary flow and quality of life (QoL) in patients with early-stage nasopharyngeal carcinoma (NPC).

METHODS AND MATERIALS

Fifty-one patients with T2, N0/N1, M0 NPC took part in a randomized controlled clinical study and received IMRT or CRT. Stimulated whole (SWS) and parotid (SPS) saliva flow were measured and Medical Outcomes Short Form 36 (SF-36), European Organization for Research and Treatment of Cancer (EORTC) core quetionnaire, and EORTC head-and-neck module (QLQ-H&N35) were completed at baseline and 2, 6, and 12 months after radiotherapy.

RESULTS

Forty-six patients (88%) were in disease remission 12 months after radiotherapy. At 12 months postradiotherapy, 12 (50.0%) and 20 patients (83.3%) in the IMRT group had recovered at least 25% of preradiotherapy SWS and SPS flow respectively, compared with 1 (4.8%) and 2 patients (9.5%), respectively, in the CRT group. Global health scores showed continuous improvement in QoL after both treatments (p < 0.001). However, after 12 months subscale scores for role-physical, bodily pain, and physical function were significantly higher in the IMRT group, indicating a better condition (p < 0.05). Dry mouth and sticky saliva were problems in both groups 2 months after treatment. In the IMRT group, there was consistent improvement over time with xerostomia-related symptoms significantly less common than in the CRT group at 12 months postradiotherapy.

CONCLUSIONS

IMRT was significantly better than CRT in terms of parotid sparing and improved QoL for early-stage disease. The findings support the case for assessment of health-related QoL in relation to head-and-neck cancer using a site-specific approach.

Cevimeline for the Treatment of Postirradiation Xerostomia in Patients With Head and Neck Cancer

PURPOSE

To study the efficacy and safety of cevimeline in two double-blind trials (Studies 003 and 004) enrolling patients with head and neck cancer in whom xerostomia developed after radiotherapy.

METHODS AND MATERIALS

Subjects were randomly assigned to receive cevimeline, 30 mg three times daily, or placebo for 12 weeks, with the possibility of dose escalation to 45 mg three times daily at 6 weeks. The primary efficacy endpoint was the patient's final global evaluation of oral dryness; change in unstimulated salivary flow was a secondary endpoint.

RESULTS

Five hundred seventy subjects (284 in Study 003 and 286 in Study 004) were randomized. Significantly more cevimeline-treated subjects than placebo recipients (47.4% vs. 33.3%, p = 0.0162) in Study 003 reported improvement in dry mouth in the final global evaluation of oral dryness. No significant difference between groups in the final global evaluation was seen in Study 004, in which a high placebo response rate of 47.6% was observed. In both studies, cevimeline-treated subjects had significantly greater increases in the objective measure of unstimulated salivary flow than placebo recipients (p = 0.0093 [Study 003] and p = 0.0215 [Study 004]), whereas no significant differences in stimulated salivary flow were observed. The most frequent adverse event was increased sweating.

CONCLUSION

Cevimeline was well tolerated by patients with xerostomia after radiotherapy for head and neck cancer, and oral administration of 30-45 mg of cevimeline three times daily increased unstimulated salivary flow.

Risk, outcomes, and costs of radiation-induced oral mucositis among patients with head-and-neck malignancies

PURPOSE

To study the risk, outcomes, and costs of radiation-induced oral mucositis (OM) among patients receiving radiotherapy (RT) to head and neck primary cancers.

METHODS AND MATERIALS

A retrospective cohort consisting of 204 consecutive head-and-neck cancer patients who received RT with or without chemotherapy during 2002 was formed; their records were reviewed for clinical and resource use information. Patients who had received prior therapy, had second primary cancers, or received palliative radiation therapy were excluded. The risk of OM was analyzed by multiple variable logistic regression. The cost of care was computed from the provider's perspective in 2006 U.S. dollars and compared among patients with and without OM.

RESULTS

Oral mucositis occurred in 91% of patients; in 66% it was severe (Grade 3-4). Oral mucositis was more common among patients with oral cavity or oropharynx primaries (odds ratio [OR], 44.5; 95% confidence interval [CI], 5.2 to >100; p < 0.001), those who received chemotherapy (OR = 7.8; 95% CI, 1.5-41.6; p = 0.02), and those who were treated with altered fractionation schedules (OR = 6.3; 95% CI, 1.1-35.1; p = 0.03). Patients with OM were significantly more likely to have severe pain (54% vs. 6%; p < 0.001) and a weight loss of > or =5% (60% vs. 17%; p < 0.001). Oral mucositis was associated with an incremental cost of $1700-$6000, depending on the grade.

CONCLUSIONS

Head-and-neck RT causes OM in virtually all patients. Oral mucositis is associated with severe pain, significant weight loss, increased resource use, and excess cost. Preventive strategies are needed.

Radiation-induced xerostomia in patients with head and neck cancer: a literature review

A dry mouth or xerostomia is one of the most common complications during and after radiotherapy for head and neck cancer, because irreparable damage is caused to the salivary glands, which are included in the radiation fields. Xerostomia not only significantly impairs the quality of life of potentially cured cancer patients, it may also lead to severe and long-term oral disorders. Because management of xerostomia is rarely effective, prevention is paramount. Several strategies have been developed to avoid radiation-induced salivary dysfunction without compromising definitive oncologic treatment. These include salivary gland-sparing radiation techniques, such as 3-dimensional conformal or intensity-modulated radiotherapy, concomitant cytoprotectants, and surgical salivary gland transfer. However, these preventive approaches are not applicable to all patients, and comprehensive scientific research that incorporates new biological insights is warranted to optimize the therapeutic index of radiotherapy for head and neck cancer.

French multicenter phase III randomized study testing concurrent twice-a-day radiotherapy and cisplatin/5-fluorouracil chemotherapy (BiRCF) in unresectable pharyngeal carcinoma: Results at 2 years (FNCLCC-GORTEC)

BACKGROUND

Unresectable carcinomas of the oropharynx and hypopharynx still have a poor long-term prognosis. Following a previous phase II study, this phase III multicenter trial was conducted between November 1997 and March 2002.

METHODS

Nontreated, strictly unresectable cases were eligible. Twice-daily radiation: two fractions of 1.2 Gy/day, 5 days per week, with no split (D1-->D46). Total tumor doses: 80.4 Gy/46 day (oropharynx), 75.6 Gy/44 day (hypopharynx). Chemotherapy (arm B): Cisplatin 100 mg/m2 (D1, D22, D43); 5FU, continuous infusion (D1-->D5), 750 mg/m2/day cycle 1; 430 mg/m2/day cycles 2 and 3.

RESULTS

A total of 163 evaluable patients. Grade 3-4 acute mucositis 82.6% arm B/69.5% arm A (NS); Grade 3-4 neutropenia 33.3% arm B/2.4% arm A (p < 0.05). Enteral nutrition through gastrostomy tube was more frequent in arm B before treatment and at 6 months (p < 0.01). At 24 months, overall survival (OS), disease-free survival (DFS), and specific survival (SS) were significantly better in arm B. OS: 37.8% arm B vs. 20.1% arm A (p = 0.038); DFS: 48.2% vs. 25.2% (p = 0.002); SS: 44.5% vs. 30.2% (p = 0.021). No significant difference between the two arms in the amount of side effects at 1 and 2 years.

CONCLUSION

For these unresectable cases, chemoradiation provides better outcome than radiation alone, even with an "aggressive" dose-intensity radiotherapy schedule.