Subhashini John

Human Papillomavirus 16 E6/E7 Transcript and E2 Gene Status in Patients with Cervical Neoplasia

AbstractBackground: The viral transforming genes E6 and E7 of human papillomavirus (HPV) 16 cause the degradation of tumor suppressor proteins. Expression of these oncoproteins increases following the integration of viral DNA into the host cell, resulting in the disruption of the E2 open reading frame (ORF). Aim: To detect and correlate HPV-16 oncogene transcripts and HPV-16 E2 DNA in cervical biopsies obtained from women (n = 68) with cervical neoplasia. Methods: HPV-16 E6/E7 transcript and HPV-16 E2 DNA detection was performed on the cervical biopsies of 42 women positive for HPV-16 (36 with invasive cervical carcinoma and 6 with cervical intraepithelial neoplasia [CIN]). PCR was used to detect HPV DNA in cervical biopsies then restriction fragment length polymorphism (RFLP) was used to type the HPV DNA. Reverse-transcription (RT)-PCR for HPV-16 E6/E7 oncogene mRNA transcripts and a PCR to detect the HPV-16 E2 DNA was performed on HPV-16-positive samples. Results: HPV-16 E6/E7 mRNA transcripts were not detected in any of the CIN I or II biopsies, but were detected in all cases of CIN III and invasive cancer in different combinations (E6 alone, E6*I, E6*I/E6*II, E6/E6*I/ E6*II) except for one patient with stage IIB cancer treated with radiotherapy. The incidence of episomal E2 DNA was high in this study with 52.4% of the samples positive for episomal E2. It was even detected in patients with advanced stage cancer with 50%, 42%, and 66.6% of samples positive in stages IIB, IIIB, and IV, respectively. Discussion: HPV-16 E6/E7 mRNA oncogene transcripts, in various combinations, were uniformly detectable in the majority of the high-grade cervical lesions examined. Intact episomal E2 DNA was seen in a high proportion of samples, even from advanced cervical lesions. Conservation of the E2 gene with concomitant expression of viral oncogenes in advanced cervical lesions may point to alternate mechanisms, other than integration, bringing about the enhanced expression of E6/E7 mRNA. Conclusions: This study suggests that the detection of the HPV-16 oncogene transcripts could serve as an indicator for assessing the prognosis of patients on radiotherapy. The majority of HPV-16-positive cervical neoplastic lesions are transcriptionally active and express the oncogene transcripts. The increased occurrence of intact HPV-16 episomal E2 DNA in advanced lesions further substantiates the fact that the disruption of E2 ORF is not mandatory for increased oncogene expression. Thus, this study underscores the significance of investigating alternative mechanisms of oncogene expression in HPV-16.

ADXS11-001 immunotherapy targeting HPV-E7: final results from a Phase II study in Indian women with recurrent cervical cancer

Meeting abstracts ADXS11-001 immunotherapy is a live attenuated Listeria monocytogenes ( Lm ) bioengineered to secrete a tLLO-HPV-16-E7 fusion protein targeting HPV-transformed cells. The Lm vector serves as its own adjuvant and infects APC where it cross presents HPV-E7-tLLO fusion peptide,

Hypofractionated palliative radiotherapy in locally advanced inoperable head and neck cancer: CMC vellore experience

Background: A novel, short duration, palliative radiotherapy schedule for inoperable head and neck cancer was evaluated in terms of palliation of cancer-related symptoms and acute toxicities. Materials and Methods: Thirty-six patients with inoperable head and neck cancer were included in the study (2010-2012). All patients received 40 Gy in 10 fractions (equivalent dose: 49.8 Gy in conventional fractionation) with 2 fractions per week. Treatment-related toxicity was assessed using Radiation Therapy Oncology Group criteria. Functional Assessment of Cancer Therapy (Head and Neck, FACT H and N) quality of life (QOL) tool was administered before starting and at the completion of radiotherapy. Mean value before and after treatment was compared (paired t-test, P = 0.05, two-tailed for significance). Results: Thirty-three patients (male: 29, female: 4, mean age: 57.8 ± 9.7 years) were included in the analysis (three patients discontinued treatment due to socioeconomic reasons). All patients had advanced inoperable head and neck cancers (27% IVA, 61% IVB, 9% IVC, TNM stage and 3% recurrent disease). Distressing pain at primary site (42%), dysphagia (18%), neck swelling (30%), and hoarseness (10%) were common presentations. Incidence of grade III mucositis and dermatitis and pain was 18%, 3%, and 24%, respectively. Planned radiotherapy without any interruptions was completed by 73% patients. QOL assessment showed improvement in social well-being (17.4 vs. 20.01, P = 0.03), but no significant change was observed in head and neck specific score (25.1 vs. 25.0, P = NS) after treatment. Reduction of pain was observed in 88% patients and 60% patients had improvement of performance status. Median overall survival of the cohort was 7 months. Conclusions: The study shows that this short duration palliative radiotherapy schedule is a clinically viable option for advanced inoperable head and neck cancer to achieve significant palliation of the main presenting symptoms like pain, dysphagia, and throat pain.

Role of conventional and diffusion weighted MRI in predicting treatment response after low dose radiation and chemotherapy in locally advanced carcinoma cervix.

BACKGROUND AND PURPOSE To assess the diagnostic performance of conventional and diffusion weighted (DWI) magnetic resonance imaging (MRI) in predicting response in locally advanced cervical cancer. MATERIALS AND METHODS Total 24 patients with stage IIB-IIIB squamous cell carcinoma cervix were treated with initial two cycles of paclitaxel and carboplatin and concurrent low dose radiotherapy prior to standard chemoradiation. Response was assessed clinically and radiologically after 3 weeks of initial treatment. Volumetric and functional parameters derived from conventional and diffusion weighted MRI, due to treatment were measured. RESULTS Significant reduction of GTV was noted in MRI (54 cm(3) vs. 11 cm(3), p < 0.01) and DWI (44 cm(3) vs. 6 cm(3), p < 0.01, ΔADC = 0.49 × 10(-3)mm(2)/sec, p < 0.01) after treatment. Tumor volume reduction rate (TVRR) in DWI was significantly higher in pathological good responders (p = 0.03). In this group both mean post treatment apparent diffusion coefficient (ADC) value and ΔADC were significantly higher (p = 0.01 and p = 0.03). ADC was a good predictor for pathological response (area under receiver operating characteristic curve (ROC) 0.814). CONCLUSION TVRR (DWI) and ΔADC can be used as a predictor of early pathological response. Complete response based on DWI, could be a useful predictor of long term disease control.

Radiation dose measurements during kilovoltage-cone beam computed tomography imaging in radiotherapy

OBJECTIVE The use of image guidance during radiotherapy for accurate localization and setup has become the standard care of practice in radiotherapy. This mostly involves the use of kilovoltage-cone beam computed tomography (kV-CBCT) for verification of patient setup on the first few days and on a weekly basis. Some protocols require this to be performed daily and also before and after the treatment. Though the radiation due to this kV-CBCT is small, the repeated use could deliver a dose that could increase the probability of the stochastic effect. The main purpose of this work is to measure radiation dose during image guidance with kV-CBCT. MATERIALS AND METHODS In this work, we have attempted to measure the dose during kV-CBCT for different sites both on a humanoid phantom and on patients undergoing image-guided radiotherapy with MOSFETs calibrated against an ion chamber. RESULTS The dose measurement on patients during kV-CBCT resulted in mean doses of 0.19 and 0.3 cGy to the ipsilateral and contralateral eyes, 0.625 and 1.097 cGy to the surface of the ipsilateral and contralateral breasts, and 3.01 cGy to the surface of the pelvis. CONCLUSION Radiation dose to the eye, breast, and the surface of the pelvis have been arrived at during CBCT. The doses measured on patients agreed closely with those measured on humanoid phantom and with published values.

Radiobiological Response of Cervical Cancer Cell Line in Low Dose Region: Evidence of Low Dose Hypersensitivity (HRS) and Induced Radioresistance (IRR).

BACKGROUND Purpose of the present study was to examine the response of cervical cancer cell line (HeLa cell line) to low dose radiation using clonogenic assay and mathematical modeling of the low dose response by Joiners induced repair model. MATERIALS AND METHODS Survival of HeLa cells following exposure to single and fractionated low doses of γ (gamma)-ray, 6 MV, and 15 MV photon was measured by clonogenic assay. RESULTS HeLa cell line demonstrated marked low dose response consisting of an area of HRS and IRR in the dose region of <1 Gy. The two gradients of the low dose region (αs and αr) were distinctly different with a transition dose (Dc) of 0.28-0.40 cGy. CONCLUSION HeLa cell line demonstrates marked HRS and IRR with distinct transition dose. This may form the biological basis of the clinical study to investigate the chemo potentiating effect of low dose radiation in cervical cancer.

Development of collimator insert for linac based stereotactic irradiation

The aim of this study is to develop collimator inserts of various sizes which are either not commercially available or are expensive to import. The dosimetry parameters such as tissue maximum ratio (TMR), off-axis ratio (OAR) and output factor of the developed collimator insert are compared with that of the commercial collimator insert (Radionics). In order to check the suitability of the collimator insert developed locally for clinical use and to standardize the method of development, a collimator insert of 15 mm identical to the one supplied by Radionics is developed with low-melting alloy (Cerrobend). Moreover for the clinical use of the developed collimator insert, certain acceptance tests are performed which include a collimator concentricity test, beam size check and radiation leakage test. The dose verification is carried out with a thermoluminescent dosimeter (7LiF rods) and an FBX chemical dosimeter in a human-head-shaped Perspex phantom filled with water. The variation between the calculated and measured dose is found to be within +2.4% for 7LiF rods and -2.0% for the FBX chemical dosimeter thus ensuring the suitability of the developed collimator insert for clinical use. This has encouraged us to standardize the method adapted to develop the collimator insert and to develop collimator inserts of different field sizes.

Is the Deep Inspiration Breath-Hold Technique Superior to the Free Breathing Technique in Cardiac and Lung Sparing while Treating both Left-Sided Post-Mastectomy Chest Wall and Supraclavicular Regions

Aims: To evaluate the efficacy of the deep inspirational breath-hold (DIBH) technique and its dosimetric advantages over the free breathing (FB) technique in cardiac (heart and left anterior descending artery [LAD]) and ipsilateral lung sparing in left-sided post-mastectomy field-in-field conformal radiotherapy. DIBH is highly reproducible, and this study aims to find out its dosimetric benefits over FB. Materials and Methods: Nineteen left-sided mastectomy patients were immobilized using breast boards with both arms positioned above the head. All patients had 2 sets of planning CT images (one in FB and another in DIBH) with a Biograph TruePoint HD CT scanner in the same setup. DIBH was performed by tracking the respiratory cycles using a Varian Real-Time Position Management system. The target (chest wall and supraclavicular region), organs at risk (OARs; ipsilateral lung, contralateral lung, heart, LAD, and contralateral breast), and other organs of interests were delineated as per the RTOG (Radiation Therapy Oncology Group) contouring guidelines. The single-isocenter conformal fields in the field treatment plans were generated with the Eclipse Treatment Planning System (Varian Medical Systems) for both FB and DIBH images, and the doses to the target and OARs were compared. The standard fractionation regimen of 50 Gy in 25 fractions over a period of 5 weeks was used for all patients in this study. Results and Discussion: The target coverage parameters (V95, V105, V107, and Dmean) were found to be 97.8 ± 0.9, 6.1 ± 3.4, 0.2 ± 0.3, and 101.9 ± 0.5% in the FB plans and 98.1 ± 0.8, 6.1 ± 3.2, 0.2 ± 0.3, and 101.9 ± 0.4% in the DIBH plans, respectively. The plan quality indices (conformity index and homogeneity index) also showed 1.3 ± 0.2 and 0.1 for the FB plans and 1.2 ± 0.3 and 0.1 for the DIBH plans, respectively. There was a significant reduction in dose to the heart in the DIBH plans compared to the FB plans, with p values of nearly 0 for the V5, V10, V25, V30, and Dmean dosimetric parameters. The difference in ipsilateral lung doses between FB and DIBH showed statistically significant p values, and the differences in mean doses were found to be 7, 15.7, 11.8, and 10.7% for V5, V20, V30, and Dmean, respectively. There was a significant reduction in dose to the LAD in the DIBH compared to the FB plans. Conclusions: DIBH resulted in significant reductions in doses to the heart, LAD, and lungs, since with this technique there was an increase in the distance between the target and the OARs. With appropriate patient selection and adequate training, the DIBH technique is acceptable and achievable for radiotherapy to the chest, and therefore should be considered for all suitable patients, as this could result in fewer radiotherapy-related complications. However, this technique is time-consuming, since the setup is complex, results in an increased time for treatment delivery, and needs patient cooperation and technical expertise.

Current Role of Magnetic Resonance Imaging in Evaluation and Radiotherapy in Locally Advanced Carcinoma Cervix

PurposeAim of this review is to highlight the role of MRI in evaluation and radiotherapy management of cervical cancer through clinical illustrations and short review of the literature.MethodsThe importance of MRI in locally advanced cervical cancer is explored through literature review and clinical examples.ResultsCervical cancer is second common cause of mortality from malignancy in India. Most of the cases present in locally advanced stage. MRI is a useful imaging modality for staging evaluation, radiotherapy planning and assessment of treatment response in this condition. It is particularly useful in diagnosis of parametrial and lower uterine segment involvement. Co-registration of T2 high-resolution MRI with axial CT scan is highly recommended for target volume delineation in high-precision external beam radiotherapy and brachytherapy treatment. Recently, role of diffusion-weighted MRI with quantitative assessment of apparent diffusion coefficient has been shown to be useful for differentiation of residual tumor from postradiotherapy changes.ConclusionsConventional and functional MRI is fast emerging as very useful tool in radiotherapy planning for locally advanced cervix cancer.

Comparison of setup errors based on bony landmarks in high precision radiotherapy in head and neck cancer: Results of a prospective study

Background: Comparison of setup errors for various immobilization devices in head and neck cancer and to determine the treatment margin in high precision radiotherapy using bony landmark based matching. Materials and Methods: Total 20 patients were immobilized with BrainLAB immobilization device (BL) or thermoplastic ray cast (RC) for high precision radiotherapy. Total, systematic, and random errors in mediolateral (ML), craniocaudal (CC) and antero-posterior directions were determined and clinical target volume (CTV) to planning target volume (PTV) margin by Strooms formula was compared. Unpaired t-test was used for comparing errors. The standard deviations (systematic and random errors) in different groups were compared by variance ratio test (Levenes test) and P < 0.05 was considered significant. Results: The total error in ML direction (BL vs. RC) was 1.00 mm versus 1.39 mm (P = 0.03), systematic error 0.09 cm versus 0.197 cm and random error 0.116 cm versus 0.258 cm (F-test, P = 0.001). CTV to PTV margin was significantly lower in BL (0.26 cm vs. 0.57 cm, P < 0.05). In CC direction, BL system had lower total error (0.075 cm vs. 0.157 cm) and a significantly less systematic error (0.116 cm vs. 0.258 cm, F = 7.149, P = 0.015). CTV to PTV margin was less in BL than RC in CC direction (0.34 cm vs. 0.92 cm, P = 0.06). Conclusion: In head and neck region, when electronic portal imaging device based verification is used, for BL margins ranged from 2.6 to 3.7 mm. For RC in the PTV margin was 5.7–9.2 mm. Therefore, a margin of 3 mm for BL and 5–10 mm for RC with online correction in head and neck is adequate.