METHODS AND MATERIALS: This retrospective study used data from 5 consecutive patients with NPC who were treated with bolus for large neck nodes using IMRT from November 2011-January 2012 in our institute. All these patients were treated radically with IMRT according to our institution's protocol. Re-planning with IMRT without bolus for these patients with exactly the same target volumes were done for comparison. Comparison of the plans was done by comparing the V70 of PTV70-N, V66.5 of PTV70-N, V65.1 of PTV70-N and the surface dose of the PTV70-N.
RESULTS: The mean size of the largest diameter of the enlarged lymph nodes for the 5 patients was 3.9 cm. The mean distance of the GTV-N to the skin surface was 0.6 cm. The mean V70 of PTV70-N for the 5 patients showed an absolute advantage of 10.8% (92.4% vs. 81.6%) for the plan with bolus while the V66.5 of PTV70-N had an advantage of 8.1% (97.0% vs. 88.9%). The mean V65.1 also had an advantage of 7.1% (97.6% vs. 90.5%). The mean surface dose for the PTV70-N was also much higher at 61.1 Gy for the plans with bolus compared to only 23.5 Gy for the plans without bolus.
CONCLUSION: Neck node bolus technique should be strongly considered in the treatment of NPC with enlarged lymph nodes treated with IMRT. It yields a superior dosimetry compared to non-bolus plans with acceptable skin toxicity.
MATERIALS/METHODS: A total of 10 patients with synchronous bilateral breast cancer who were treated with VMAT at our institution were retrospectively analyzed. Clinical target volume (CTV) included chest wall and regional nodes (supraclavicular fossa and internal mammary chain) and prescription dose was 40.05 Gy in 15 daily fractions. HT and IMPT plans were generated for each patient. Dose-volume statistics, including planning target volume (PTV) coverage and dose to OAR: lungs, heart, thyroid, spinal cord, brachial plexus and esophagus, were compared between modalities using a paired T-test.
RESULTS: Mean age of patients was 61 years (43-84). Majority of the patients (80%) were ER+ PR+ and HER2-. 40% of patients underwent breast reconstruction following surgery. All 3 techniques provided adequate target volume distribution and OAR sparing. Compared to VMAT and HT plans, IMPT had better heart and lung sparing effects, resulting in lower mean and V25 Gy heart dose; mean, V20 Gy and V5 Gy lung dose (p<0.0001). There was no significant difference in VMAT and HT plans for mean heart and lung dose. VMAT plans showed significantly lower V25 Gy heart dose on average (p = 0.04). V5 Gy lung dose was slightly lower in HT compared to VMAT plans, approaching statistical significance (p = 0.08). PTV coverage was adequate for all 3 techniques. All techniques fulfilled cord, esophagus, thyroid and brachial plexus constraints.
CONCLUSION: IMPT plans showed significantly better OAR sparing compared to photon techniques. All 3 techniques met OAR constraints, and resulted in adequate target volume coverage. As IMPT is significantly more costly than VMAT or HT techniques, appropriate patient selection is important to deliver treatment in the most resource-effective manner for patients who would derive the most benefit, for example those with young age or existing heart or lung comorbidities.
METHODS: This retrospective study covered all NPC patients who underwent radical IMRT treatment at the Penang General Hospital from June 2011 to February 2012. Patients of any age and stage of disease with histologically proven diagnosis were included. Information was collected on patient demographics, clinical stage, treatment received, including any neoadjuvant and/or concurrent chemotherapy, acute toxity and completion of IMRT within the OTT.
RESULTS: A total of 26 NPC patients were treated with IMRT during the study period; 88.5% had stage III/IV disease. 45.2% received neo-adjuvant chemotherapy while 50.0% were given concurrent chemo-irradiation. All patients completed the treatment and 92.3% within the 7 weeks OTT. Xerostomia was present in all patients with 92.3% having grade 2. Severe grade III/IV acute toxicity occurred in 73.1% of patients, the commonest of which was oral mucositis (57.6%). This was followed by dysphagia which occurred in 53.8%, skin reactions in 42.3% and weight loss in 19.2%. However, haematological toxicity was mild with only one patient having leucopaenia.
CONCLUSION: IMRT treatment for NPC is feasible in our center. More importantly, it can be delivered within the 7 weeks OTT in the majority of patients. Severe grade 3/4 toxicity is very common (73.1%) and thus maximal nutritional and analgesic support is required throughout the treatment.