A multi-center survey on adaptive radiation therapy for head and neck cancer in Malaysia

The survey is to assess the current state of adaptive radiation therapy (ART) for head and neck (H&N) cases among radiotherapy centers in Malaysia and to identify any implementation limitations. An online questionnaire was sent to all radiotherapy centers in Malaysia. The 24-question questionnaire consists of general information about the center, ART practices, and limitations faced in implementing ART. 28 out of 36 radiotherapy centers responded, resulting in an overall response rate of 78%. About 52% of the responding centers rescanned and replanned less than 5% of their H&N patients. The majority (88.9%) of the respondents reported the use Cone Beam Computed Tomography alone or in combination with other modalities to trigger the ART process. The main reasons cited for adopting ART were weight loss, changes in the immobilization fitting, and anatomical variation. The adaptation process typically occurred during week 3 or week 4 of treatment. More than half of the respondents require three days or more from re-simulation to starting a new treatment plan. Both target and organ at risk delineation on new planning CT relied heavily on manual delineation by physicians and physicists, respectively. All centers perform patient-specific quality assurance for their new adaptive plans. Two main limitations in implementing ART are "limited financial resources or equipment" and "limitation on technical knowledge". There is a need for a common consensus to standardize the practice of ART and address these limitations to improve the implementation of ART in Malaysia.

Study of the medial group retropharyngeal node metastasis from nasopharyngeal carcinoma based on 3100 newly diagnosed cases

PURPOSE

Patterns of metastases to the medial retropharyngeal lymph nodes (RPLN) from nasopharyngeal carcinoma (NPC) have gain little attention. Since the incidence of dysphagia was closely related to whether the medial RPLN was irradiated, we carried out a prospective study to explore the patterns of the medial RPLN involvement.

METHODS AND MATERIALS

Previously untreated NPC patients were required to receive MRI scan. MRI scanning sequences included pre-contrast T1WI, T2WI, and post-contrast T1WI with fat suppression. All images were evaluated by the multi-disciplinary treatment group of NPC.

RESULTS

3100 cases of NPC entered this study. 2679 (86.4%) cases had involved lymph nodes. The detailed distribution were: 2341 (87.4%) in level IIb, 1798 (67.1%) in level IIa, 1184 (44.2%) in level III, 350 (14.1%) in level IV, 995 (37.1%) in level V, 115(4.3%) in level Ib, 2012 (75.1%) in the retropharyngeal area. But only 6 (0.2%) were located at the medial group, accompanied with the lateral RPLN and other node metastasis. Only one medial RPLN can be identified in a patient, whereas the number of the lateral RPLNs per affected side varied between one and four. The average size of the medial and lateral RPLNs was 8±4 mm (range, 4-17 mm) and 16±9 mm (range, 5-53 mm), respectively.

CONCLUSIONS

① Involvement of the retropharyngeal nodes were mainly located at the lateral group, the medial RPLN was rarely seen. ② Metastasis to the medial RPLN was always accompanied with other node metastasis. ③ Only one medial RPLN can be identified in a patient, whereas the enlarged lateral RPLNs per affected side could be multiple. ④ The average size of the medial RPLN was smaller than the lateral RPLNs.

Treatment outcome for nasopharyngeal carcinoma in University Malaya Medical Centre from 2004-2008

BACKGROUND

Nasopharyngeal carcinoma (NPC) is the commonest radiocurable cancer in Malaysia. This study aimed to determine the treatment outcomes and late effects of radiotherapy for NPC patients treated in University Malaya Medical Centre (UMMC).

MATERIALS AND METHODS

All newly diagnosed patients with NPC referred for treatment to the Oncology unit at UMMC from 2004-2008 were retrospectively analyzed. Treatment outcomes were 5 years overall survival (OS), disease free survival (DFS), cause-specific survival (CSS), loco- regional control (LRC) and radiotherapy-related late effects. The Kaplan-Meier method was used for survival analysis and differences in survival according to AJCC stage was compared using the log-rank test.

RESULTS

A total of 176 patients with newly diagnosed NPC were treated in UMMC during this period. Late presentation was common, with 33.5% presenting with T3-4 disease, 84.7% with N1-3 disease and 75.6% with AJCC stage 3-4 disease. Radical RT was given to 162 patients with 22.7% having RT alone and 69.3% having CCRT. The stipulated OTT was 7 weeks and 72.2% managed to complete their RT within this time period. Neoadjuvant chemotherapy was given to 14.8% while adjuvant chemotherapy was administered to 16.5%. The 5 years OS was 51.6% with a median follow up of 58 months. The 5 years OS according to stage were 81.8% for stage I, 77.9% for stage II, 47.4% for stage III and 25.9% for stage IV. The 5 years overall CSS, DFS and LRC were 54.4%, 48.4% and 70.6%, respectively. RT related late effects were documented in 80.2%. The commonest was xerostomia (66.7%). Other documented late effects were hearing deficit (17.3%), visual deficit (3.1%), neck stiffness (3.1%) , dysphagia (3.4%), cranial nerve palsy (2.5%), pneumonitis (0.6%) and hypothyroidism (1.2%).

CONCLUSIONS

The 5 years OS and LRC in this study are low compared to the latest studies especially those utilizing IMRT. Implementation of IMRT for NPC treatment should be strongly encouraged.