A study on the impact of patient-related parameters in the ability to spare parotid glands by intensity-modulated radiotherapy for head and neck squamous cell carcinomas.

AIMS AND OBJECTIVES: This study aims to study the effect of geometric- and patient-related variables in achieving the desired dose-volume constraints to parotid for patients undergoing definitive/adjuvant intensity-modulated radiotherapy (IMRT) for head and neck squamous cell carcinomas (HNSCC). SUBJECTS AND METHODS: This retrospective study considered HNSCC patients who underwent IMRT at our center between 2009 and 2014. Patients' details and dose-volume parameters were collected, and correlated with dose to parotids using Pearson's correlation test. RESULTS: Sixty-seven patients were found to be eligible. Oral primary predominated (37.3%) and 53 (79%) had locally advanced disease. The parotid volume (PV) had no impact on mean dose. There was a negative linear correlation between the ratio (Parotid-planning target volume [PTV] overlap)/PV and mean dose to the whole parotid (y = 1.14-0.011×; R2 = 0.509; P = 0.001), suggesting that a ratio of 0.7 resulted in mean dose ≥ 40 Gy and potentially irreversible xerostomia. No association was found between site of primary and parotid dose, but node-positive (N+) patients received significantly higher dose compared to N0 patients (34.5 Gy vs. 29.5 Gy; P = 0.001). N + patients persisted to receive higher dose even when T stage was accounted for (32.5 Gy vs. 28.9 Gy for T2; P = 0.003). On the last follow-up, 35 patients (52%) had >/=Grade II xerostomia. Average mean dose to combined PV was higher in patients with > grade I xerostomia compared to patients with

Genetic Variants in CD44 and MAT1A Confer Susceptibility to Acute Skin Reaction in Breast Cancer Patients Undergoing Radiation Therapy.

PURPOSE: Heterogeneity in radiation therapy (RT)-induced normal tissue toxicity is observed in 10% of cancer patients, limiting the therapeutic outcomes. In addition to treatment-related factors, normal tissue adverse reactions also manifest from genetic alterations in distinct pathways majorly involving DNA damage-repair genes, inflammatory cytokine genes, cell cycle regulation, and antioxidant response. Therefore, the common sequence variants in these radioresponsive genes might modify the severity of normal tissue toxicity, and the identification of the same could have clinical relevance as a predictive biomarker. METHODS AND MATERIALS: The present study was conducted in a cohort of patients with breast cancer to evaluate the possible associations between genetic variants in radioresponsive genes described previously and the risk of developing RT-induced acute skin adverse reactions. We tested 22 genetic variants reported in 18 genes (ie, NFE2L2, OGG1, NEIL3, RAD17, PTTG1, REV3L, ALAD, CD44, RAD9A, TGFßR3, MAD2L2, MAP3K7, MAT1A, RPS6KB2, ZNF830, SH3GL1, BAX, and XRCC1) using TaqMan assay-based real-time polymerase chain reaction. At the end of RT, the severity of skin damage was scored, and the subjects were dichotomized as nonoverresponders (Radiation Therapy Oncology Group grade <2) and overresponders (Radiation Therapy Oncology Group grade ≥2) for analysis. RESULTS: Of the 22 single nucleotide polymorphisms studied, the rs8193 polymorphism lying in the micro-RNA binding site of 3'-UTR of CD44 was significantly (P=.0270) associated with RT-induced adverse skin reactions. Generalized multifactor dimensionality reduction analysis showed significant (P=.0107) gene-gene interactions between MAT1A and CD44. Furthermore, an increase in the total number of risk alleles was associated with increasing occurrence of overresponses (P=.0302). CONCLUSIONS: The genetic polymorphisms in radioresponsive genes act as genetic modifiers of acute normal tissue toxicity outcomes after RT by acting individually (rs8193), by gene-gene interactions (MAT1A and CD44), and/or by the additive effects of risk alleles.

Detection of human papilloma virus in patients with squamous cell carcinoma of the esophagus planned for definitive chemo-radiotherapy, and a study of their clinical characteristics.

CONTEXT: To identify the incidence of human papilloma virus (HPV) infection in squamous esophageal cancer. AIMS: To identify high-risk (HR) HPV positivity rates in patients with squamous carcinoma esophagus and to compare their characteristics with HPV negative counterparts. SETTINGS AND DESIGN: A prospective study, in which tumor biopsies of 18 consecutive patients with squamous carcinoma of the esophagus treated with definitive chemo-radiotherapy (CT-RT) were evaluated for the presence of HPV. SUBJECTS AND METHODS: Tumor biopsies of 18 consecutive patients with squamous carcinoma esophagus treated with definitive CT-RT were assessed for presence of HR HPV DNA by hybrid DNA capture technique (Digene-HC2). The clinical characteristics and treatment outcomes of the two groups were then compared. STATISTICAL ANALYSIS USED: Pearson's Chi-squared test, Kaplan-Mier survival curve/log rank test. RESULTS: Nine patients (50%) tested positive for HR HPV. The clinical features including age, gender, grade, location, and tumor extent were similar between the two groups. All the three patients with residual disease at the end of treatment tested positive for HPV (P = 0.058). At a mean follow-up of 52 weeks, the estimated median recurrence free survival was 37 weeks (95% confidence interval (CI): 13.6-60.4) among HPV positive patients compared to 53 weeks (95% CI: 29.6-76.4 weeks) for the HPV negative (P = 0.93). CONCLUSIONS: There appears to be a high incidence of HPV among patients with squamous oesophageal cancer in coastal Karnataka. Further studies are required to evaluate its causative role and prognostic implications.

A Study on Dosimetric Outcomes and Acute Toxicity of Post Mastectomy Adjuvant Hypofractionated Radiotherapy for Breast Cancer.

INTRODUCTION: Hypofractionated External Beam Radiotherapy (HFRT) is a relatively new adjuvant Radiotherapy (RT) schedule for breast cancers following breast conservation surgery and less commonly, following mastectomy. Here we report our experience on normal tissue exposure and acute toxicity of HFRT after mastectomy. AIM: To assess the dosimetric outcomes and acute toxicity profile of adjuvant HFRT following mastectomy for breast cancer. MATERIALS AND MATERIALS: This prospective observational study considered consecutive patients planned for adjuvant HFRT (42.5 Gy in 16 sessions delivered over 3 weeks) to the chest wall with/without regional nodes between October 2014 and June 2015. The dosimetric parameters including dose homogeneity to the target volume and exposure to heart and lung were analyzed. Acute haematological and dermatological toxicity was recorded until upto three months after completion of RT. RESULTS: Among the 56 patients treated with HFRT, the mean age was 49 years (range: 28-69 years). Pathologically positive nodes and ≥pT3 primary was observed in 44 (78.6%) and 12 (21.4%) patients, respectively. Majority (87.5%) received prior adjunct chemotherapy. RT to the supraclavicular fossa was delivered for 39 (69.6%) patients. The mean V90 and V95 to the Planning Target Volume (PTV) were 95% (± 3.3%) and 93% (± 4%), respectively. The maximum dose received was on average 47.7 Gy (112%; range: 46.2-48.5 Gy). The mean lung dose was 10.2 Gy (± 3.5 Gy) and V20 was 20.9% (± 6%). The mean V25 to heart was 6.6% (± 4.8%) for left sided and 0% for right sided tumours (p=0.001). Acute skin toxicity peaked at completion of RT and was tolerable (grade 0, I, II and III reactions were 75%, 16% and 1.8%, respectively). No patient had ≥ grade III haematological toxicity, and treatment was not interrupted for any patient. CONCLUSION: Adjuvant HFRT could be planned while meeting the dose constraints to normal tissues in all patients and was well tolerated, with mild to moderate acute adverse effects that did not warrant any therapeutic intervention or treatment interruption.

Treatment outcomes after intraluminal brachytherapy following definitive chemoradiotherapy in patients with esophageal cancer.

AIMS AND OBJECTIVES: To report the results of treatment with intraluminal brachytherapy (ILRT) after concurrent chemoradiotherapy for esophageal carcinoma with respect to disease free survival (DFS), dysphagia free interval (DFI), and complications of treatment. MATERIALS AND METHODS: The study retrospectively analyzed the records of 26 eligible patients with nonmetastatic carcinoma of the esophagus treated with definitive chemoradiotherapy followed by ILRT between 2008 and 2011. The DFS and DFI were estimated and factors likely to influence them were analyzed. RESULTS: Nineteen (73%) patients were males. The mean age at presentation was 60 years (range: 47-90 years). All the patients had squamous cell carcinomas. Following treatment, the median DFS was 12.7 months (range: 0-27 months). Sixteen patients (61.5%) had local control of their disease, while one had residual disease at completion of treatment. Other than three patients who were not evaluated for recurrent dysphagia, six (23.1%) had proven local recurrence on follow-up. The estimated mean DFI was 13.8 months (range: 0-27 months). One patient died of tracheoesophageal fistula following treatment. On statistical analysis, only the location of tumor was prognostically significant, with lower third tumors performing worse. Other probable predictors of poor outcome included large volume (> 40 cc), tumor length (> 6 cm), and eccentric location. CONCLUSION: ILRT boost following concurrent chemoradiotherapy is well tolerated and potentially improves outcomes. It might be beneficial in selected patients with esophageal carcinoma. Further studies are required to identify its role in definitive treatment.

Polymorphisms in radio-responsive genes and its association with acute toxicity among head and neck cancer patients.

Cellular and molecular approaches are being explored to find a biomarker which can predict the development of radiation induced acute toxicity prior to radiation therapy. SNPs in radiation responsive genes may be considered as an approach to develop tools for finding the inherited basis of clinical radiosensitivity. The current study attempts to screen single nucleotide polymorphisms/deletions in DNA damage response, DNA repair, profibrotic cytokine as well as antioxidant response genes and its predictive potential with the normal tissue adverse reactions from 183 head and neck cancer patients undergoing platinum based chemoradiotherapy or radiotherapy alone. We analysed 22 polymorphisms in 17 genes having functional relevance to radiation response. Radiation therapy induced oral mucositis and skin erythema was considered as end point for clinical radiosensitivity. Direct correlation of heterozygous and mutant alleles with acute reactions as well as haplotype correlation revealed NBN variants to be of predictive significance in analysing oral mucositis prior to radiotherapy. In addition, genetic linkage disequilibrium existed in XRCC1 polymorphisms for >grade 2 oral mucositis and skin reaction indicating the complex inheritance pattern. The current study indicates an association for polymorphism in NBN with normal tissue radiosensitivity and further warrants the replication of such studies in a large set of samples.

Influence of double-strand break repair on radiation therapy-induced acute skin reactions in breast cancer patients.

PURPOSE: Curative radiation therapy (RT)-induced toxicity poses strong limitations for efficient RT and worsens the quality of life. The parameter that explains when and to what extent normal tissue toxicity in RT evolves would be of clinical relevance because of its predictive value and may provide an opportunity for personalized treatment approach. METHODS AND MATERIALS: DNA double-strand breaks and repair were analyzed by microscopic γ-H2AX foci analysis in peripheral lymphocytes from 38 healthy donors and 80 breast cancer patients before RT, a 2 Gy challenge dose of x-ray exposed in vitro. RESULTS: The actual damage (AD) at 0.25, 3, and 6 hours and percentage residual damage (PRD) at 3 and 6 hours were used as parameters to measure cellular radiosensitivity and correlated with RT-induced acute skin reactions in patients stratified as non-overresponders (NOR) (Radiation Therapy Oncology Group [RTOG] grade <2) and overresponders (OR) (RTOG grade ≥2). The results indicated that the basal and induced (at 0.25 and 3 hours) γ-H2AX foci numbers were nonsignificant (P>.05) between healthy control donors and the NOR and OR groups, whereas it was significant between ORs and healthy donors at 6 hours (P<.001). There was a significantly higher PRD in OR versus NOR (P<.05), OR versus healthy donors (P<.001) and NOR versus healthy donors (P<.01), supported further by the trend analysis (r=.2392; P=.0326 at 6 hours). CONCLUSIONS: Our findings strongly suggest that the measurement of PRD by performing γ-H2AX foci analysis has the potential to be developed into a clinically useful predictive assay.

DNA double-strand break analysis by γ-H2AX foci: a useful method for determining the overreactors to radiation-induced acute reactions among head-and-neck cancer patients.

PURPOSE: Interindividual variability in normal tissue toxicity during radiation therapy is a limiting factor for successful treatment. Predicting the risk of developing acute reactions before initiation of radiation therapy may have the benefit of opting for altered radiation therapy regimens to achieve minimal adverse effects with improved tumor cure. METHODS AND MATERIALS: DNA double-strand break (DSB) induction and its repair kinetics in lymphocytes of head-and-neck cancer patients undergoing chemoradiation therapy was analyzed by counting γ-H2AX foci, neutral comet assay, and a modified version of neutral filter elution assay. Acute normal tissue reactions were assessed by Radiation Therapy Oncology Group criteria. RESULTS: The correlation between residual DSBs and the severity of acute reactions demonstrated that residual γ-H2AX foci in head-and-neck cancer patients increased with the severity of oral mucositis and skin reaction. CONCLUSIONS: Our results suggest that γ-H2AX analysis may have predictive implications for identifying the overreactors to mucositis and skin reactions among head-and-neck cancer patients prior to initiation of radiation therapy.

Predictive and prognostic significance of glutathione levels and DNA damage in cervix cancer patients undergoing radiotherapy.

PURPOSE: To assess the predictive significance of serum glutathione (GSH) and tumor tissue DNA damage in the treatment of cervical cancer patients undergoing chemoradiotherapy. METHODS AND MATERIALS: This study included subjects undergoing hysterectomy (for normal cervix tissue) and cervical cancer patients who underwent conventional concurrent chemoradiotherapy (cisplatin once per week for 5 weeks with concurrent external radiotherapy of 2 Gy per fraction for 5 weeks, followed by two applications of intracavitary brachytherapy once per week after 2 weeks' rest). Blood was collected after two fractions, whereas both blood and tissues were collected after five fractions of radiotherapy in separate groups of subjects. Serum for total GSH content and tissues were processed for single-cell gel electrophoresis (SCGE) assay for DNA damage analysis. Clinical tumor radioresponse was assessed 2 months after the completion of treatment as complete responders (CR) (100% shrinkage), partial responders (PR) (>50%), and nonresponders (NR) (<50%). RESULTS: Serum GSH content depleted significantly after a total dose of 4 Gy and 10 Gy of radiotherapy with a single dose of cisplatin, which was significantly lesser in NR than of CR patients. Similarly, Olive Tail Moment, the index of DNA damage, indicated significantly higher values in the fifth fraction of radiotherapy (5-RT) than in pretreatment. The DNA damage after 5-RT in the NR subgroup was significantly lower than that of CR. CONCLUSIONS: Serum GSH analysis and tumor tissue SCGE assay found to be useful parameters for predicting chemoradioresponse prior to and also at an early stage of treatment of cervical cancers.