Is Clinical Radiosensitivity a Complex Genetically Controlled Event?

The role of radiotherapy in epithelial ovarian cancer: a literature overview

Ovarian cancer (OC) accounts for 3% of all cancer in women and for 5% of all cancer-related deaths. Epithelial Ovarian Cancer (EOC) is a radiosensitive malignancy with a poor prognosis. In the pre-chemotherapy era, radiation therapy (RT) delivered to the abdominopelvic region (whole abdominal irradiation, WAI) has historically played a role in the adjuvant and consolidation setting. Specific cluster of patients with early-stage disease and definite histologies may take advantage of RT. Platinum-based chemotherapy (CT) has replaced RT and plays a major role in most of the clinical settings. Radiation Therapy for palliation is recommended in patients with localized symptoms. Nevertheless, modern RT represents a reliable treatment option, with a mild toxicity profile, particularly effective for oligo-recurrent or progressive disease. The present literature review aims to highlight the historical role of RT in EOC, the actual lines of evidence, and the future perspectives.

De-escalation of breast radiotherapy after conserving surgery in low-risk early breast cancer patients

The reduction in the burden related to treatment is becoming more and more important in modern oncology. Radiation therapy is a mainstay option in the postoperative setting for early breast cancer patients after breast-conserving surgery. Nowadays, different options are available to de-escalate radiotherapy in this scenario such as the use of hypofractionated whole-breast radiation, the selective delivery of the boost dose to the lumpectomy cavity, the introduction of accelerated partial breast irradiation and the omission of treatment in appropriately selected patients with low-risk features. We herein provide a review article on this topic.

Minimizing a Tricky Situation in Breast Irradiation with Helical Tomotherapy

We report on a patient with breast cancer undergoing adjuvant intensity-modulated whole breast and lymph node irradiation with static angle tomotherapy (TomoDirect), who experienced a traumatic ipsilateral humeral fracture and was able to continue radiotherapy with helical tomotherapy and daily dosimetric monitoring by means of the Planned Adaptive module.

Hematologic toxicity in anal cancer patients during combined chemo-radiation: a radiation oncologist perspective

INTRODUCTION

Hematologic toxicity is an important side effect occurring in patients affected with anal cancer, undergoing combined radio-chemotherapy, with consistent clinical meaningfulness. Areas covered: Since more than a half of bone marrow is comprised within the pelvic region, the radiation dose received by this functional compartment is crucial. Modern imaging modalities may provide a useful tool to identify bone marrow and new delivery technology may enhance the radiation oncologist's possibility to selectively spare these structures, potentially decreasing acute hematologic toxicity profile in this setting. Expert commentary: Correlation between dose to pelvic structures and acute hematologic toxicity has been studied in several oncological settings, mainly on a retrospective frame. Different dose metrics were found to be correlated including mean doses and different points within the dose-volume histogram ranging from low to medium-high doses. Several imaging modalities were used to identify bone marrow both morphological and functional. Several clinical endpoints were used. In general, accounting for bone marrow during the treatment planning process may be important to decrease the acute hematologic toxicity profile during concurrent chemo-radiation in anal cancer patients. The most appropriate strategy to address this issue need further investigation and deserve validation in a prospective clinical framework.

Pharmacotherapy for the management of cancer regimen-related oral mucositis

INTRODUCTION

Oral mucositis is a frequent and devastating toxicity secondary to cancer treatment, which may affect 20-40% of patients receiving conventional chemotherapy and 60-85% of patients undergoing hematopoietic stem cell transplantation. The pathobiology of mucositis includes a complex cascade of biologic events in which pro-inflammatory cytokines, ROS, second messengers, and the oral microbiome contribute to tissue damage of the oral mucosa. Management strategies to oral mucositis secondary to chemotherapy include preventative measures and therapeutic approaches.

AREA COVERED

A literature search of published animal and clinical studies was perform to review the epidemiology, pathophysiology and treatment options for cancer regimen-induced mucositis. We also discuss new data coming from recent pertinent clinical trials.

EXPERT OPINION

Mucositis is one of the most common debilitating toxicities secondary to cancer treatment and can adversely affect patients' quality of life. Epidemiological data for mucositis are often under-reported. Research efforts have shown that genetics plays a major role in the development of this toxicity. Although few therapeutic agents are available, several promising drugs are under investigations.

Bilateral Breast Radiation Delivered with Static Angle Tomotherapy (TomoDirect): Clinical Feasibility and Dosimetric Results of a Single Patient

We herein report on a case of synchronous bilateral breast cancer patient undergoing adjuvant intensity-modulated whole breast with static angle tomotherapy (TomoDirect). The patient was treated with a hypofractionated schedule employing a simultaneous integrated boost approach. Radiotherapy schedule was 45 Gy/20 fractions (2.25 Gy daily) to the bilateral whole breast and 50 Gy/20 fractions (2.5 Gy daily) to the 2 lumpectomy cavities. Treatment was delivered over 4 weeks. Dosimetric results were robust with consistent target coverage and adequate normal tissue avoidance. Treatment was generally well-tolerated and acute toxicity profile was mild. The present report highlights the promising clinical feasibility of TomoDirect for bilateral breast irradiation.

Hypericum perforatum and neem oil for the management of acute skin toxicity in head and neck cancer patients undergoing radiation or chemo-radiation: a single-arm prospective observational study

BACKGROUND

Radiation dermatitis is common in patients treated with combined radiotherapy and chemotherapy for head and neck malignancies. Its timely and adequate management is of uttermost importance for both oncological outcomes and global quality of life. We prospectively evaluated the role of hypericum perforatum and neem oil (Holoil®; RIMOS srl, Mirandola, Italy) in the treatment of acute skin toxicity for patients undergoing radiotherapy or chemo-radiotherapy for head and neck cancer.

METHODS

A consecutive series of 28 head and neck cancer patients submitted to radiotherapy (RT) was enrolled onto this mono-institutional single-arm prospective observational study. Patients undergoing both definitive or post-operative radiotherapy were allowed, either as exclusive modality or combined with (concomitant or induction) chemotherapy. We started Holoil treatment whenever bright erythema, moderate oedema or patchy moist desquamation were observed. Holoil® was used during all RT course and during follow up time, until acute skin toxicity recovery.

RESULTS

The maximum detected acute skin toxicity was Grade 1 in 7% of patients, Grade 2 in 68%, Grade 3 in 25%, while at the end of RT was Grade 0 in 3.5%, Grade 1 in 32%, Grade 2 in 61%, Grade 3 in 3.5%. For patients having G2 acute skin toxicity, it mainly started at weeks 4-5; for those having G3, it began during weeks 5-6. Median times spent with G2 or G3 toxicity were 17.5 and 11 days. Patients having G2 acute skin toxicity had a dermatitis worsening in 27% of case (median occurrence time: 7 days). G3 events were reconverted to a G2 profile in all patients (median time: 7 days). Those experiencing a G2 skin event were converted to a G1 score in 23% of cases (median time: 14 days). Time between maximum acute skin toxicity and complete skin recovery after RT was 27 days.

CONCLUSIONS

Holoil® proved to be a safe and active option in the management of acute skin toxicity in head and neck cancer patients submitted to RT or chemo-radiotherapy. A prophylactic effect in the prevention of moist desquamation may be hypothesized for hypericum and neem oil and need to be tested within a prospective controlled study.

Hypofractionation and concomitant boost to deliver adjuvant whole-breast radiation in ductal carcinoma in situ (DCIS): a subgroup analysis of a prospective case series

To report the four-year outcomes of accelerated hypofractionated whole-breast radiotherapy (WBRT) with a concomitant boost (CB) to the tumor bed in ductal carcinoma in situ (DCIS), we performed a subgroup analysis of 103 patients affected with DCIS within a cohort of 960 early breast cancer patients treated with breast conservation and hypofractionated WBRT. Prescription dose to the whole breast was 45 Gy (2.25 Gy/20 fractions) with an additional daily CB of 0.25 Gy to the surgical cavity (2.5 Gy/20 fractions up to 50 Gy). With a median follow-up of 48 months (range 12-91), no local recurrence was observed. Maximum detected acute skin toxicity was as follows: G0 in 35 % of patients, G1 in 54 %, G2 in 9 % and G3 in 2 %. Late skin and subcutaneous toxicity were generally mild with only 1 % of patients experiencing ≥G3 events (telangiectasia). No major lung and heart toxicity were detected. Cosmetic results were excellent in 50 % of patients, good in 37 %, fair in 9 % and poor in 4 %. Quality of life had a generally favorable profile both within the functioning and symptoms domains. The present result supports the hypothesis that DCIS patients could be safely treated with a hypofractionated schedule employing a CB to the lumpectomy cavity.

Detection of volatile biomarkers of therapeutic radiation in breath

Breath testing could provide a rational tool for radiation biodosimetry because radiation causes distinct stress-producing molecular damage, notably an increased production of reactive oxygen species. The resulting oxidative stress accelerates lipid peroxidation of polyunsaturated fatty acids, liberating alkanes and alkane metabolites that are excreted in the breath as volatile organic compounds (VOCs). Breath tests were performed before and after radiation therapy over five days in 31 subjects receiving daily fractionated doses: 180-400 cGy d(-1) standard radiotherapy (n = 26), or 700-1200 cGy d(-1) high-dose stereotactic body radiotherapy (n = 5). Breath VOCs were assayed using comprehensive two-dimensional gas chromatography time-of-flight mass spectrometry. Multiple Monte Carlo simulations identified approximately 50 VOCs as greater-than-chance biomarkers of radiation on all five days of the study. A consistent subset of 15 VOCs was observed at all time points. A radiation response function was built by combining these biomarkers and the resulting dose-effect curve was significantly elevated at all exposures ⩾1.8 Gy. Cross-validated binary algorithms identified radiation exposures ⩾1.8 Gy with 99% accuracy, and ⩾5 Gy with 78% accuracy. In this proof of principal study of breath VOCs, we built a preliminary radiation response function based on 15 VOCs that appears to identify exposure to localized doses of 1.8 Gy and higher. VOC breath testing could provide a new tool for rapid and non-invasive radiation biodosimetry.

Oral mucositis in head and neck cancer: risk, biology, and management

Of the toxicities associated with conventional forms of treatment for head and neck cancers, probably none has such a consistent legacy as oral mucositis.1 Despite the fact that mucosal injury was noted as far back as Marie Curie's first forays into therapeutic radiation, an effective intervention has yet to be developed. In addition to its historic link to radiation, new therapeutic strategies including induction chemotherapy often produce mucositis, and targeted therapies appear to alter mucositis risk and its severity and course.2 The symptomatic effect of oral mucositis is profound. Disabling oral and oropharyngeal pain prevents patients from eating normally, requires opiate analgesics, and in some cases results in alteration or discontinuation of anticancer therapy.3 Furthermore, the health and economic consequences of oral mucositis are far from trivial. The incremental cost of oral mucositis in patients with head and neck cancer exceeds $17,000 (USD).4.

Use of the comet-FISH assay to compare DNA damage and repair in p53 and hTERT genes following ionizing radiation

The alkaline single cell gel electrophoresis (comet) assay can be combined with fluorescent in situ hybridisation (FISH) methodology in order to investigate the localisation of specific gene domains within an individual cell. The number and position of the fluorescent signal(s) provides information about the relative damage and subsequent repair that is occurring in the targeted gene domain(s). In this study, we have optimised the comet-FISH assay to detect and compare DNA damage and repair in the p53 and hTERT gene regions of bladder cancer cell-lines RT4 and RT112, normal fibroblasts and Cockayne Syndrome (CS) fibroblasts following γ-radiation. Cells were exposed to 5Gy γ-radiation and repair followed for up to 60 minutes. At each repair time-point, the number and location of p53 and hTERT hybridisation spots was recorded in addition to standard comet measurements. In bladder cancer cell-lines and normal fibroblasts, the p53 gene region was found to be rapidly repaired relative to the hTERT gene region and the overall genome, a phenomenon that appeared to be independent of hTERT transcriptional activity. However, in the CS fibroblasts, which are defective in transcription coupled repair (TCR), this rapid repair of the p53 gene region was not observed when compared to both the hTERT gene region and the overall genome, proving the assay can detect variations in DNA repair in the same gene. In conclusion, we propose that the comet-FISH assay is a sensitive and rapid method for detecting differences in DNA damage and repair between different gene regions in individual cells in response to radiation. We suggest this increases its potential for measuring radiosensitivity in cells and may therefore have value in a clinical setting.

SNPs in DNA repair or oxidative stress genes and late subcutaneous fibrosis in patients following single shot partial breast irradiation

Background

The aim of this study was to evaluate the potential association between single nucleotide polymorphisms related response to radiotherapy injury, such as genes related to DNA repair or enzymes involved in anti-oxidative activities. The paper aims to identify marker genes able to predict an increased risk of late toxicity studying our group of patients who underwent a Single Shot 3D-CRT PBI (SSPBI) after BCS (breast conserving surgery).

Methods

A total of 57 breast cancer patients who underwent SSPBI were genotyped for SNPs (single nucleotide polymorphisms) in XRCC1, XRCC3, GST and RAD51 by Pyrosequencing technology. Univariate analysis (ORs and 95% CI) was performed to correlate SNPs with the risk of developing ≥ G2 fibrosis or fat necrosis.

Results

A higher significant risk of developing ≥ G2 fibrosis or fat necrosis in patients with: polymorphic variant GSTP1 (Ile105Val) (OR = 2.9; 95%CI, 0.88-10.14, p = 0.047).

Conclusions

The presence of some SNPs involved in DNA repair or response to oxidative stress seem to be able to predict late toxicity.

Trial Registration

ClinicalTrials.gov: NCT01316328

Should we protect the most sensitive people?

The recommendations of the International Commission on Radiological Protection (ICRP) are based on a population average, rather than on the available data for subpopulations. From an ethical point of view, this approach is far from unproblematic. Strong reasons can be given in support of a right for each radiation-exposed person to have the best possible information about the risk to himself or herself, which is often group-specific information. Risk exposures have to be defensible from the perspective of each identifiable group for which a specific risk assessment can be made. Exposing a person to a high risk cannot be justified by pointing out that the risk to an average person would have been much lower. There are two major ways to protect a sensitive group: special standards for the group (differentiated protection) and general standards that are strict enough to protect its members (unified protection). Some major factors that are relevant for the choice between these two protective strategies are identified.

Acute normal tissue reactions in head-and-neck cancer patients treated with IMRT: influence of dose and association with genetic polymorphisms in DNA DSB repair genes

PURPOSE

To investigate the association between dose-related parameters and polymorphisms in DNA DSB repair genes XRCC3 (c.-1843A>G, c.562-14A>G, c.722C>T), Rad51 (c.-3429G>C, c.-3392G>T), Lig4 (c.26C>T, c.1704T>C), Ku70 (c.-1310C>G), and Ku80 (c.2110-2408G>A) and the occurrence of acute reactions after radiotherapy.

MATERIALS AND METHODS

The study population consisted of 88 intensity-modulated radiation therapy (IMRT)-treated head-and-neck cancer patients. Mucositis, dermatitis, and dysphagia were scored using the Common Terminology Criteria (CTC) for Adverse Events v.3.0 scale. The population was divided into a CTC0-2 and CTC3+ group for the analysis of each acute effect. The influence of the dose on critical structures was analyzed using dose-volume histograms. Genotypes were determined by polymerase chain reaction (PCR) combined with restriction fragment length polymorphism or PCR-single base extension assays.

RESULTS

The mean dose (D(mean)) to the oral cavity and constrictor pharyngeus (PC) muscles was significantly associated with the development of mucositis and dysphagia, respectively. These parameters were considered confounding factors in the radiogenomics analyses. The XRCC3c.722CT/TT and Ku70c.-1310CG/GG genotypes were significantly associated with the development of severe dysphagia (CTC3+). No association was found between the investigated polymorphisms and the development of mucositis or dermatitis. A risk analysis model for severe dysphagia, which was developed based on the XRCC3c.722CT/TT and Ku70c.-1310CG/GG genotypes and the PC dose, showed a sensitivity of 78.6% and a specificity of 77.6%.

CONCLUSIONS

The XRCC3c.722C>T and Ku70c.-1310C>G polymorphisms as well as the D(mean) to the PC muscles were highly associated with the development of severe dysphagia after IMRT. The prediction model developed using these parameters showed a high sensitivity and specificity.

Correlation between single nucleotide polymorphisms and jejunal crypt cell apoptosis after whole body irradiation

PURPOSE

To identify loci concerned with radiosensitivity in a mouse model using single nucleotide polymorphism (SNP) markers.

MATERIALS AND METHODS

We subjected 276 second filial generation (F2) mice descended from two inbred mouse strains, radiation-induced apoptosis sensitive C57BL/6JNrs (B6) and radiation-induced apoptosis resistant C3H/HeNrs (C3H), to 2.5 Gy whole-body irradiation. We quantified jejunal crypt apoptosis, performed a genome-wide survey, and identified quantitative trait loci (QTL) associated with radiation sensitivity. We expressed apoptosis levels as an apoptotic score (AS), which was equal to the number of apoptotic bodies divided by the number of crypts. We genotyped the mice for 109 SNP markers.

RESULTS

AS values were 97.7+/-32.9 in B6 mice and 49.0+/-24.9 in C3H mice (p < 0.01). Genome-wide analysis revealed 8 markers (2 on chromosome 9, 4 on 15, 1 on 17, and 1 on 18) affecting radiation-induced jejunal apoptosis with log odds (LOD) scores ranging from 2.11+/-3.91. We found a significant locus on chromosome 15, which was previously reported by Weil and colleagues.

CONCLUSION

These findings support the view that the radiosensitivity of clinically normal tissue depends on variations in several genes.