Kunhi Parambath Haresh

Adenoid Cystic Carcinoma of the Trachea Treated with PET-CT Based Intensity Modulated Radiotherapy

Primary tumors of the trachea are rare and are usually malignant in adults and benign in children. Adenoid cystic carcinoma, which is of salivary gland origin, account for about one thirds of adult primary tracheal tumors. A 49-year-old gentleman presented to us after undergoing a pneumonectomy elsewhere. Computed tomography scan of the thorax at our hospital showed a residual disease in the primary site, size of which was same as that in the preoperative scan. Because there was a compromised respiratory reserve due to pneumonectomy we decided to keep the radiation dose to the remaining lung as low as possible. We treated him by positron emission tomography-computed tomography (PET-CT) directed intensity modulated radiation therapy to a dose of 60 Gy in 30 Fractions over 6 weeks on a linear accelerator. PET helped in exact localization of the target on the planning CT. He tolerated the treatment very well. PET-CT done 1 year posttreatment showed no residual disease. Presently he is disease free with good pulmonary reserve.

Granulocytic sarcoma masquerading as Ewing's sarcoma: A diagnostic dilemma

An eleven-year-old boy presented with a swelling in his left elbow. Radiologically the features were that of an Ewings sarcoma involving the ulna. Histopathology showed small round cell tumor strongly positive for Monoclonal Imperial Cancer research fund 2 (MIC2) antigen. Similar cells in the bone marrow were involved with MIC2 positivity. The patient developed skin lesions, which on biopsy were found to be chloromas. The initial biopsies were reevaluated with special stains revealing granulocytic sarcomas in acute myeloid leukemia masquerading as Ewings due to its MIC2 positivity. The possibility of myeloid neoplasms should be considered routinely with known MIC2 positive round cell tumors.

High-dose-rate interstitial brachytherapy for T1-T2-stage penile carcinoma: short-term results.

PURPOSE Interstitial brachytherapy (IBT) is a preferred treatment option over partial penectomy in selected patients with T1-T2-stage penile carcinoma because of its organ preservation ability. Literature is mostly based on the use of low-dose-rate IBT, and experience with high-dose-rate (HDR) IBT is extremely limited. We studied the role of HDR-IBT alone in patients with T1-T2-stage penile carcinoma. METHODS AND MATERIALS Between April 2010 and July 2013, 14 patients with T1-T2-stage penile carcinoma were treated with HDR-IBT at our center. Size of the primary lesion ranged from 1.5 to 4.0cm. A two-to-four-plane free-hand implant was performed using plastic catheters. The prescribed dose of HDR-IBT was 42-51Gy in 14-17 fractions using twice-a-day fractionation schedule. Patients were followed up regularly for assessment of local control, survival, toxicity, and sexual function. RESULTS At a median followup of 22 months, 2 patients developed recurrent disease at locoregional site. The 3-year overall survival was 83% with penis preservation rate of 93%. All patients developed acute Grade III skin toxicity that healed during 6-8-weeks time. Urethral stenosis and soft tissue necrosis was not seen in any of the patients. A total of 4 patients experienced mild asymptomatic fibrosis in the implanted area. Around 10 patients had satisfactory sexual function status at the last followup visit. CONCLUSIONS Although it was a small sample size, our results have demonstrated excellent local control rate and acceptable toxicity with HDR-IBT in patients with T1-T2-stage penile carcinoma.

High-dose-rate interstitial brachytherapy for liver metastases: first study from India

Purpose To study the safety and efficacy of high-dose-rate interstitial brachytherapy (HDRIBT) in patients with liver metastases (LM). Material and methods Between 2009 and 2011, 10 patients with 12 metastatic lesions in the liver were enrolled in this prospective trial. All patients had either refused surgery or found ineligible for surgery due to various factors. Under CT guidance, 16 gauze blind end stainless steel or rigid plastic brachytherapy needle was inserted in the center of lesion through the percutaneous route. Generally, a single interstitial brachytherapy (IBT) needle for lesions up to 3 cm and multiple needles for lesions more than 3 cm in diameter were inserted. Treatment was delivered with a single high-dose-rate (HDR) dose of 20 Gy prescribed to the target. The needles were removed immediately after the treatment. The endpoints of study were acute complications and local control of the disease. Results The median size of the lesion was 3.8 cm (2.7-7.0 cm). The average time for the entire IBT procedure was 65 minutes (50-105 minutes). Median follow up was 9 months (3-17 months). None of the patients had fatal complications. Minor complications like pain, nausea/vomiting, and asymptomatic pleural effusion were observed in 3, 2 and 1 patients, respectively. Local control rate at 12 months was 75%. The 1-year local progression free survival (LPFS) was 33%. Conclusion Although limited by small sample size, the results of our first study from India suggest that HDRIBT is a safe and effective non surgical option for LM.

A study on the tumor volume computation between different 3D treatment planning systems in radiotherapy.

BACKGROUND Tumor volume plays a crucial role in the survival and local control of the patients treated with radiotherapy. The dose volume histogram also depends on the accuracy of the tumor delineation. AIMS The main aim is to study the variation observed in the computation of the target volume with different treatment planning systems and treatment sites. MATERIALS AND METHODS Sixty patients of different treatment sites which include brain, retinoblastoma, head and neck, lung, gall bladder, liver, anal canal etc, were selected for this study. The tumor volume was delineated on the Eclipse treatment planning systems and CT datasets and DICOM-RT structure sets were transferred to Pinnacle, Oncentra, Plato, Precise, Ergo++, and Tomocon contouring workstations. The recomputed volume from these planning systems was compared with the reference volume obtained from Eclipse. Similarly, the accuracy in generating PTV from CTV was also assessed with different planning systems for 5 and 10 mm. STATISTICAL ANALYSIS USED SPSS 10.0 was used for analysis. RESULTS The overall comparison of the volume with different planning systems showed that Pinnacle calculated relatively larger volume followed by Plato as compared to Eclipse, whereas TOMOCON, Ergo ++, and Oncentra showed reduced volume. As far as the variation in CTV to PTV volume is concerned, pinnacle showed a relatively higher volume as compared to the Eclipse planning systems. CONCLUSION The study shows that all the treatment planning systems showed variation in computing the tumor volume and the CTV to PTV generation also varied with the planning systems.

Pulsed-dose-rate intracavitary brachytherapy for cervical carcinoma: the AIIMS experience.

Objective:The aim of present study was to analyze the results of pulsed-dose-rate (PDR) brachytherapy in patients with cervical carcinoma treated at our center. Methods:From September 2003 to September 2005, 48 patients with histopathologically proved cervical carcinoma, stages IB to IVA, were treated with PDR intracavitary radiotherapy (ICRT) and pelvic irradiation at our center. Radiotherapy consisted of whole pelvis external beam radiation therapy (EBRT) with a dose of 40 Gy in 22 fractions over 4.5 weeks followed by 10 Gy in 5 fractions over 1 week with midline shielding. Weekly chemotherapy (Cisplatin, 40 mg/m2) was administered during the course of EBRT to suitable patients. After an interval of 1 to 2 weeks, a single session of standard ICRT application was done to deliver a dose of 27 Gy to point A by PDR (hourly pulse, 70 cGy). Results:Median age was 50 years (range: 30–65). FIGO stage distribution of the patients was as follows: stage IB, 6; stage IIA, 1; stage IIB, 15; stage IIIB, 25; and stage IVA, 1. Follow-up period ranged from 3 to 50 months (median: 15 months). Ten patients had disease recurrence (5 each in stage IIB and stage IIIB). Eight patients had pelvic failure, 1 had bone metastases, and 1 had supraclavicular node metastases. Overall grades III to IV late toxicity rate at 50 months was 6%. For the median follow-up period of 15 months, the actuarial recurrence-free survival in stages I to II was 82% and stages III to IV was 78%. Conclusion:Our results reveal that PDR ICRT in combination with pelvic EBRT provides excellent pelvic disease control, survival, and low radiation related morbidity rate in the patients with cervical carcinoma.

Impact of patient setup error in the treatment of head and neck cancer with intensity modulated radiation therapy

PURPOSE To study the impact of setup errors on the dose to the target volume and critical structures in the treatment of cancer of nasopharynx with intensity modulated radiation therapy (IMRT). METHODS AND MATERIALS Twelve patients of carcinoma of nasopharynx treated by IMRT with simultaneous integrated boost technique were enrolled. The gross tumor volume, clinical target volume and low-risk nodal region were planned for 70, 59.4 and 54 Gy, respectively, in 33 fractions. Based on the constraints, treatment plans were generated. Keeping it as the base plan, the patient setup error was simulated for 3, 5 and 10mm by shifting the isocenter in all three directions viz. anterior, posterior, superior, inferior, right and left lateral. The plans were evaluated for mean dose, maximum dose, volume of PTV receiving >110% and <93% of the prescribed dose. For both the parotids, the mean dose and the dose received by >50% of the parotid were evaluated. The maximum dose and dose received by 2 cc of spinal cord were also analyzed. RESULTS The dose to the target volume decreases gradually with increase in setup error. The superior and inferior shifts play major role in tumor under-dosage. A setup error of 3mm along the posterior and lateral directions significantly affects the dose to the spinal cord. Similarly, setup error along lateral and anterior directions affects the dose to both parotids. CONCLUSIONS The isocenter position should be verified regularly to ensure that the goal of IMRT is achieved.

Execution of mantle field with multileaf collimator: a simple approach.

BACKGROUND Until very recently mantle field radiotherapy remained the gold standard for the treatment of favorable early-stage Hodgkins lymphoma. The classic mantle includes all the major lymph nodes above the diaphragm and extends from the inferior portion of the mandible to the level of the insertion of the diaphragm. AIMS To describe a simple technique that has been devised to treat the mantle field with the help of multileaf collimator and using computed tomography (CT)-based treatment planning. MATERIALS AND METHODS CT scan was performed with the patient in the supine position and the datasets were transferred to the Eclipse treatment planning system. Elekta Precise linear accelerator equipped with 40 pairs of multileaf collimator (MLC) was used for the execution of the mantle field. The MLCs shapes were designed to take the shape of the conventional customized blocks used for treatment of mantle field. The anterior mantle field was divided into three separate MLC segments with the collimator kept at 0 degrees. The first MLC segment was shaped to cover the neck, clavicular regions, and mediastinum. The second and the third MLC segments covered the right and left axilla, respectively. The posterior fields were opposed to the anterior subfields in a similar fashion. The dose was prescribed at the midplane, using reference points. RESULTS AND CONCLUSION The technique described in this study is very simple, easy to implement, and avoids unnecessary delay in the execution of the mantle field. The mantle field can be easily shaped with the multileaf collimators, without any collimator rotation.

Outcomes of pediatric glioblastoma treated with adjuvant chemoradiation with temozolomide and correlation with prognostic factors

Background: Pediatric glioblastoma (pGBM) patients are underrepresented in major trials for this disease. We aimed to explore the outcome of pGBM patients treated with concurrent and adjuvant temozolomide (TMZ). Materials and Methods: 23 patients of pGBM treated from 2004 to 2010 were included in this retrospective analysis. Adjuvant therapy included conformal radiation 60 gray at 2 gray/fraction daily over 6 weeks with concurrent TMZ 75 mg/m 2 followed by six cycles of adjuvant TMZ 150-200 mg/m 2 (day 1-5) every 4 weeks. Kaplan-Meier estimates of overall survival (OS) were determined. Univariate analysis with log-rank test was used to determine the impact of prognostic variables on survival. Results: Median age at presentation was 11.5 years (range: 7-19 years) and M:F ratio was 15:8. All patients underwent maximal safe surgical resection; 13 gross total resection and 10 sub-total resection. At a median follow-up of 18 months (range: 2.1-126 months), the estimated median OS was 41.9 months. The estimated median OS for patients receiving only concurrent TMZ was 8 months while that for patients receiving concurrent and adjuvant TMZ was 41.9 months (P = 0.081). Estimated median OS for patients who did not complete six cycles of adjuvant TMZ was 9.5 months versus not reached for those who completed at least six cycles (P = 0.0005). Other prognostic factors did not correlate with survival. Conclusions: Our study shows the benefit of TMZ for pGBM patients. Both concurrent and adjuvant TMZ seem to be important for superior OS in this group of patients.

Unresectable basaloid squamous cell carcinoma of the trachea treated with concurrent chemoradiotherapy: A case report with review of literature

Basaloid squamous cell carcinoma is an uncommon variant of squamous cell carcinoma of the trachea. We describe the case of an unresectable basaloid squamous cell carcinoma of the trachea treated with concurrent chemoradiotherapy up to a dose of 60 Gy in 33 fractions with weekly paclitaxel and carboplatin. The pathological recognition of basaloid squamous cell carcinoma and its distinction from adenoid cystic carcinoma of the trachea is important for its management. Combining systemic chemotherapy with locoregional radiation is a logical approach to treatment, especially for the basaloid squamous cell carcinoma of the trachea, given its tendency to metastasize early after definitive therapy.