Prospective study of neoadjuvant chemoradiotherapy using intensity-modulated radiotherapy and 5 fluorouracil for locally advanced rectal cancer - toxicities and response assessment.

AIMS AND OBJECTIVES: The past 2 decades witnessed the strengthening of evidence favoring the role of neoadjuvant chemoradiation (CHRT) in the treatment of locally advanced rectal cancer. The study aims to evaluate the response and acute toxicities to neoadjuvant CHRT using intensity-modulated radiotherapy (IMRT) in the treatment of rectal cancer. Predictive factors to achieve pathological complete response (pCR) were analyzed, as a secondary endpoint. MATERIALS AND METHODS: All consecutive patients who underwent IMRT as part of neoadjuvant CHRT in the treatment of rectal cancer between August 2014 and December 2016 at a tertiary cancer care center were accrued for the study. The cohort underwent CHRT with IMRT technique at a dose of 50.4 Gy in 28 fractions concurrent with continuous infusion of 5 fluorouracil during the first and the last 4 days of CHRT. Surgery was performed 6 weeks later and the pathological response to CHRT was noted. RESULTS: Forty-three subjects were accrued for the study. Radiation dermatitis and diarrhea were the only observed grade ≥3 acute toxicities. Sphincter preservation rate (SPR) was 43.3%. pCR was observed in 32.6%. Univariate and multivariate logistic regression showed that carcinoembryonic antigen was the only independent predictive factor to achieve pCR. CONCLUSION: IMRT as part of neoadjuvant CHRT in the treatment of locally advanced rectal cancer is well tolerated and gives comparable results with respect to earlier studies in terms of pathological response and SPR. Further randomized controlled studies are needed to firmly state that IMRT is superior to 3-dimensional conformal radiotherapy.

Resurrection of whole liver radiotherapy-A case report.

INTRODUCTION: This is a case report of a patient of lymphoma with liver metastasis who had persistent pain and jaundice despite multiple lines of chemotherapy. She underwent palliative liver irradiation. This is an uncommon modality due to fear of radiation induced hepatitis. We reviewed literature available on the use of liver irradiation for palliation and concluded that it can be safely used with good results. A 33-year-old female with Non-Hodgkin's Lymphoma (NHL) presented with obstructive jaundice. She underwent stenting followed by chemotherapy. She was lost to follow up to later present with a progressively increasing right hypochondrial mass, pain and icterus. Ultrasound abdomen revealed massive hepatomegaly with hypodense lesions in both liver lobes and centring the porta with dilatation of biliary radicals. Despite multiple lines of chemotherapy and use of opioids, there was no symptomatic relief in pain, size of mass or any decrease in biochemical parameters. Then she was offered palliative radiation in the form of partial liver irradiation to a dose of 21Gy/7 fractions. She had >50% pain relief after 2 fractions and was off opioids by last fraction. Liver span reduced from 6cm to 1cm below costal margin in mid clavicular line. Radiologically 60% reduction in size of liver lesions was observed. Also, a decreasing trend in biochemical parameters was observed. Use of whole or partial liver irradiation is rare in clinical practice due to fear of radiation induced hepatitis by conventional techniques. Newer techniques of delivering radiation can highly improvise accuracy and permit further dose escalation.

Dosimetric influence of photon beam energy and number of arcs on volumetric modulated arc therapy in carcinoma cervix: A planning study.

AIM: Aim of the present study was to compare the dosimetric impact of different photon beam energies and number of arcs in the treatment of carcinoma cervix. BACKGROUND: Carcinoma cervix is a common cancer in women worldwide with a high morbidity rate. Radiotherapy is used to treat such tumours. Volumetric Modulated Arc Therapy (VMAT) is considered superior to other techniques with multiple arcs and energies. MATERIALS AND METHODS: Twenty patients with carcinoma cervix underwent radiotherapy in a prospective observation study conducted at our institute. Volumetric modulated arc plans with 6 MV, 10 MV and 15 MV photon energies using single arc (SA) and dual arc (DA) were generated. Several physical indices for planning target volume (PTV) like V95%, V100%, V110%, D98%, D50%, D2% and total number of MUs were compared. Normal Tissue Integral Dose (NTID) and dose to a shell structure PHY2.5 and PHY5.0 were analyzed. RESULTS: Comparable dose coverage to PTV was observed for all the energies and arcs. CI for DA6MV (1.095) was better than SA6MV (1.127), SA10MV (1.116) and SA15MV (1.116). Evaluated parameters showed significant reduction in OAR doses. Mean bladder dose for DA6MV (41.90 Gy) was better than SA6MV (42.48 Gy), SA10MV (42.08 Gy) and SA15MV (41.93 Gy). Similarly, p-value for the mean rectal dose calculated was 0.001 (SA6 vs 15), 0.013 (DA6 vs 10) and 0.003 (DA6 vs 15) and subsequently favoured DA6MV. Difference in NTID was very small. CONCLUSIONS: The study showed no greater advantage of higher energy, and DA VMAT plan with 6 MV photon energy was a good choice of treatment for carcinoma cervix as it delivered a highly homogeneous and conformal plan with superior target coverage and better OAR sparing.

Dosimetric impact of setup errors in head and neck cancer patients treated by image-guided radiotherapy.

To assess and analyze the impact of setup uncertainties on target volume coverage and doses to organs at risk (OAR) in head and neck cancer (HNC) patients treated by image-guided radiotherapy (IGRT). Translational setup errors in 25 HNC patients were observed by kilovoltage cone beam computed tomography (kV CBCT). Two plans were generated. Plan one - the original plan which was the initially optimized and approved plan of the patient. All patients were treated according to their respective approved plans at a defined isocenter. Plan two - the plan sum which was the sum of all plans recalculated at a different isocenter according to setup errors in x, y, and z-direction. Plan sum was created to evaluate doses that would have been received by planning target volume (PTV) and OARs if setup errors were not corrected. These 2 plans were analyzed and compared in terms of target volume coverage and doses to OARs. A total 503 kV CBCT images were acquired for evaluation of setup errors in 25 HNC patients. The systematic (mean) and random errors (standard deviation) combined for 25 patients in x, y, and z directions were 0.15 cm, 0.21 cm, and 0.19 cm and 0.09 cm, 0.12 cm, and 0.09 cm, respectively. The study showed that there was a significant difference in PTV coverage between 2 plans. The doses to various OARs showed a nonsignificant increase in the plan sum. The correction of translational setup errors is essential for IGRT treatment in terms of delivery of planned optimal doses to target volume.

Primary Gastric Burkitt's Lymphoma.

The primary gastrointestinal non-Hodgkin's lymphoma, although rare, is among the most common extra-nodal lymphomas, considering that gastric lymphomas are more common than intestinal lymphomas. Burkitt's lymphoma (BL) is an aggressive form of B-cell lymphoma that is typically endemic in Africa, while non-endemic cases are found in the rest of the world. Primary gastric BL is extremely rare and only around 50 cases have been reported worldwide. Here we present the case of a young HIV-negative male, who was referred to our department with a stage IV gastric BL. He was planned for palliative chemotherapy, but after the first cycle of chemotherapy he succumbed to the progression of the disease.

Is volumetric modulated arc therapy (RapidArc) better than intensity modulated radiotherapy for gynecological malignancies? A dosimetric comparison.

AIMS: Evaluation of the dosimetric advantage, if any, of RapidArc (double arc and triple arc [DA and TA]) over standard fixed field intensity-modulated radiation therapy (IMRT) in gynecologic malignancies. MATERIALS AND METHODS: A total of 20 cases of gynecologic malignancies were included. Static IMRT sliding window, single arc (SA), DA and TA plans were generated with eclipse planning system. The prescribed dose was 50.4 Gy/28# to the planning target volumes. RESULTS: IMRT provided target coverage equivalent to DA and inferior to TA (D95% [in Gy]--49.94, 49.58, 49.96, 50.17 for IMRT, SA, DA and TA respectively--all observations in the same sequence). Conformity index 90 (CI 90 (0.964, 0.927, 0.918, 0.822) and homogeneity index (0.0683, 0.119, 0.098, 0.097) of IMRT were superior. TA was superior to other arcs in all parameters except CI 90 (P=0.805) and bladder dose (lower in DA). Rectal, bladder and bowel sparing was best achieved with IMRT followed by TA; bilateral femur dose was lower in arcs. The total monitor units and treatment time of arcs were significantly lower than IMRT, reduced by a factor of 2.41-2.59 and 3.2-3.5 respectively (All P values significant). CONCLUSION: IMRT provided better overall plan for gynecologic malignancies with lower organs at risk dose and target coverage equivalent to DA and TA. Treatment delivery efficiency was higher with RapidArc. The TA plan is dosimetrically superior to DA, but the gain is small. The decision whether or not to add a third arc for a small gain should be individualized.