A.K. Gandhi

Re-irradiation in head and neck cancers: an Indian tertiary cancer centre experience.

OBJECTIVE To explore the treatment outcomes of patients treated with re-irradiation for recurrent or second primary head and neck cancer. METHOD An analysis was performed of 79 head and neck cancer patients who underwent re-irradiation for second primaries or recurrent disease from January 1999 to December 2011. RESULTS Median time from previous radiation to re-irradiation for second primary or recurrence was 53.6 months (range, 2.7-454.7 months). Median age at diagnosis of first primary was 54 years. Median re-irradiation dose was 45 Gy (range, 45-60 Gy). Acute grade 3 or worse toxicity was seen in 30 per cent of patients. Median progression-free survival for recurrent disease was 15.0 months (95 per cent confidence interval, 8.33-21.66). The following factors had a statistically significant, positive impact on progression-free survival: patient age of less than 50 years (median progression-free survival was 29.43, vs 13.9 months for those aged 50 years or older; p = 0.004) and disease-free interval of 2 years or more (median progression-free survival was 51.66, vs 13.9 months for those with less than 2 years disease-free interval). CONCLUSION Re-irradiation of second primaries or recurrences of head and neck cancers with moderate radiation doses yields acceptable progression-free survival and morbidity rates.

Modern chemoradiation practices for malignant tumors of the trachea: An institutional experience.

Background: Malignant tumors of the trachea are rare. A multimodality treatment approach is often necessary. Outcomes of radical non-surgical approaches are sparse. Radiation combined with sequential or concurrent chemotherapy is an important treatment option. Materials and Methods: We present an analysis of outcomes using modern radiotherapy and chemotherapy for tracheal tumors. Results: Radiation dose escalation using modern techniques is of benefit for these tumors. The results with chemotherapy are encouraging. Conclusions: Radiation plays a distinct role and should be a part of treatment for these tumors. The role of chemotherapy needs to be studied further.

SU-F-P-46: Comparative Study Between Two Normalization Prescriptions for Accelerated Partial Breast Irradiation: A Dosimetric Study

PURPOSE To compare the Accelerated Partial Breast Irradiation (APBI) plan with the normalized basal dose points and 5mm box prescription. METHODS Five patients of APBI were planned twice in Oncentra Master planning TPS (Version 4.3) using TG-43 algorithm. The number of catheters for all the patients was 10 to 16 and implant plane 2 to 3. For planning all catheters were reconstructed. Source loading was done as per HR-CTV contoured. The HR-CTV volume range was from 75cc to 182cc. Plans were normalized in two methods. First all plans were normalized on Basal dose points (PlanA) and second all the plan were normalized on 5mm box (PlanB). The prescription dose (PD) was 35Gy in 10 fractions. All the plans were completely based on normalization and without optimization. Plan evaluation was based on certain parameters coverage Index (CI), dose homogeneity index (DHI), conformity index (COIN), over dose volume index (OI). RESULTS The average and median of CI for planA was 0.835 and 0.8154, for planB 0.82 and 0.799 respectively. The median and average of DHI for planA was 0.66 and 0.6062, for planB 0.67 and 0.62 respectively. The range of COIN for planA and planB was from 0.58 to 0.65 respectively. The range of OI was from 0.083 to 0.169 for planA and planB. The treatment time in planA was in average 1.13 times more than planB as V150% of HR_CTV in planA was 4-6% more. The ipsilateral lung was getting 30% of PD which was 0.6% to 3.5%. CONCLUSION Treatment Planning should be individualized based on implants characteristics. Planning with prescription to basal dose points should be preferred to 5mm box prescription, in order to achieve better DHI and less treatment time.

Role of adjuvant radiation in the management of central neurocytoma: Experience from a tertiary cancer care center of India.

BACKGROUND AND OBJECTIVE Neurocytoma (NC) is a rare benign neuronal tumor. A complete excision remains curative for most of these tumors, but atypical histology and extra-ventricular location often necessitates adjuvant therapy. We intended to explore the clinico-pathological features and treatment outcome in patients of NC in our institute. MATERIALS AND METHODS Medical records were reviewed and data collected on NC over a 6-year period (2006-2012) from the departmental archives. Disease free survival (DFS) was analyzed by Kaplan-Meier method. RESULTS A total of 18 patients met the study criteria. Fourteen patients had intra-ventricular neurocytoma (IVNC), right lateral ventricle being the most common site of origin. Gross total resection and near total resection were achieved in eight cases each whereas tumor decompression and biopsy could be done in two cases. On post-operative histopathological examination, eight patients were found to have atypical NC while 10 patients had typical NC. All patients underwent adjuvant radiation. The median dose of post-operative radiation was 56 Gy. All patients were alive at their final follow-up. One patient had both clinical and radiological evidence of local relapse. In the evaluable patients (n = 18), after a median follow-up of 35 months the DFS rate at 2 years and 3 years are 100% and 83% respectively. CONCLUSION Use of adjuvant radiation to a total dose of 56 Gy enhances the local control and achieves superior survival in patients of NC. Use of 3D conformal planning techniques may help us to achieve better therapeutic ratio in patients with NC.

SU‐E‐T‐587: Whole IMRT, Hybrid IMRT and 3D Conformal Plan a Dosimetric Comparison for Large Target

PURPOSE To dosimetrically compare the whole-IMRT, hybrid-IMRT (combination of IMRT and 3D-CRT) and 3D-conformal radiotherapy (3D- CRT) plans for larger targets. METHODS Five previously treated patients of carcinoma cervix with para-aortic lymph-nodes (target length 33-34cm) were selected. PTV-P (PTV-Primary), PTV-PA (PTV-para-aortic) and organ at risks (OARs) were defined. Three plans were generated using Eclipse TPS for Varian CL2300C/D linear accelerator using 6MV photon beam. Three plans were: (i) Whole-IMRT: IMRT for both PTV-P and PTV-PA (ii) Hybrid-IMRT: IMRT for PTV-P and 3D-CRT for PTV-PA (iii) 3D-CRT: 3D-CRT for both PTV-P and PTV-PA. Prescription dose for PTV-P is 50.4Gy and PTV-PA is 45Gy in 28 fractions. Coverage index (CI=Target volume covered by prescription dose/Target volume), mean doses to bladder, rectum and bowel were used for plan comparison by using DVH. Integral dose (liter-Gray) to normal tissue (i.e., patient volume minus PTV-P and PTV-PA) and total monitor units (MUs) required to deliver a plan was also noted. RESULTS The CI for PTV-P is 0.98±0.20, 0.96±0.09, and 0.95±0.01 for Whole-IMRT, Hybrid-IMRT and 3D-CRT plan and for PTV- PA is 0.98±0.01, 0.98±0.01, and 0.97±0.20. Maximum doses to PTV-P are 5660.85±90.85cGy, 5640.35±70.35cGy and 5813.80±97.40cGy. Maximum doses to PTV-PA are 5000.60±109.10cGy, 5079.85±20.25cGy and 5092.25±19.75cGy. Mean doses to the bladder are 3810±225.80cGy, 3842.10±182.70cGy and 5204±98.25cGy for Whole-IMRT, Hybrid-IMRT and 3D-CRT plan, respectively. Mean doses to rectum are 3955.35±324.95cGy, 3971.15±354.15cGy and 4741.20±371.60cGy. Mean doses to bowel are 2623.35±320.85cGy, 2855.30±371.05cGy and 3011.7±433.80cGy. Average MUs required to deliver one fraction is 1285±87, 1585±186, 485±46 for Whole-IMRT, Hybrid-IMRT and 3D-CRT plans, respectively. Higher integral doses to normal tissue were observed for whole-IMRT (267.60±76 liter-Gy) followed by hybrid-IMRT (259.20±53 liter-Gy) and 3D-CRT (186.30±33 liter-Gy). CONCLUSIONS Whole-IMRT is useful for larger targets compared to hybrid-IMRT in terms of dose conformity, lesser MUs and reduced critical organ doses with little compromise on integral dose, where 3D-CRT sacrificed the OAR sparing.