Pathological complete response and sphincter-sparing surgery after neoadjuvant radiochemotherapy with regional hyperthermia for locally advanced rectal cancer compared with radiochemotherapy alone

Epigenetic targeting to enhance acute myeloid leukemia-directed immunotherapy

AML is a malignant disease of hematopoietic progenitor cells with unsatisfactory treatment outcome, especially in patients that are ineligible for intensive chemotherapy. Immunotherapy, comprising checkpoint inhibition, T-cell engaging antibody constructs, and cellular therapies, has dramatically improved the outcome of patients with solid tumors and lymphatic neoplasms. In AML, these approaches have been far less successful. Discussed reasons are the relatively low mutational burden of AML blasts and the difficulty in defining AML-specific antigens not expressed on hematopoietic progenitor cells. On the other hand, epigenetic dysregulation is an essential driver of leukemogenesis, and non-selective hypomethylating agents (HMAs) are the current backbone of non-intensive treatment. The first clinical trials that evaluated whether HMAs may improve immune checkpoint inhibitors' efficacy showed modest efficacy except for the anti-CD47 antibody that was substantially more efficient against AML when combined with azacitidine. Combining bispecific antibodies or cellular treatments with HMAs is subject to ongoing clinical investigation, and efficacy data are awaited shortly. More selective second-generation inhibitors targeting specific chromatin regulators have demonstrated promising preclinical activity against AML and are currently evaluated in clinical trials. These drugs that commonly cause leukemia cell differentiation potentially sensitize AML to immune-based treatments by co-regulating immune checkpoints, providing a pro-inflammatory environment, and inducing (neo)-antigen expression. Combining selective targeted epigenetic drugs with (cellular) immunotherapy is, therefore, a promising approach to avoid unintended effects and augment efficacy. Future studies will provide detailed information on how these compounds influence specific immune functions that may enable translation into clinical assessment.

Feasibility of ultrasound tomography-guided localized mild hyperthermia using a ring transducer: Ex vivo and in silico studies

BACKGROUND

As of 2022, breast cancer continues to be the most diagnosed cancer worldwide. This problem persists within the United States as well, as the American Cancer Society has reported that ∼12.5% of women will be diagnosed with invasive breast cancer over the course of their lifetime. Therefore, a clinical need continues to exist to address this disease from a treatment and therapeutic perspective. Current treatments for breast cancer and cancers more broadly include surgery, radiation, and chemotherapy. Adjuncts to these methods have been developed to improve the clinical outcomes for patients. One such adjunctive treatment is mild hyperthermia therapy (MHTh), which has been shown to be successful in the treatment of cancers by increasing effectiveness and reduced dosage requirements for radiation and chemotherapies. MHTh-assisted treatments can be performed with invasive thermal devices, noninvasive microwave induction, heating and recirculation of extracted patient blood, or whole-body hyperthermia with hot blankets.

PURPOSE

One common method for inducing MHTh is by using microwave for heat induction and magnetic resonance imaging for temperature monitoring. However, this leads to a complex, expensive, and inaccessible therapy platform. Therefore, in this work we aim to show the feasibility of a novel all-acoustic MHTh system that uses focused ultrasound (US) to induce heating while also using US tomography (UST) to provide temperature estimates. Changes in sound speed (SS) have been shown to be strongly correlated with temperature changes and can therefore be used to indirectly monitor heating throughout the therapy. Additionally, these SS estimates allow for heterogeneous SS-corrected phase delays when heating complex and heterogeneous tissue structures.

METHODS

Feasibility to induce localized heat in tissue was investigated in silico with a simulated breast model, including an embedded tumor using continuous wave US. Here, both heterogenous acoustic and thermal properties were modeled in addition to blood perfusion. We further demonstrate, with ex vivo tissue phantoms, the feasibility of using ring-based UST to monitor temperature by tracking changes in SS. Two phantoms (lamb tissue and human abdominal fat) with latex tubes containing varied temperature flowing water were imaged. The measured SS of the water at each temperature were compared against values that are reported in literature.

RESULTS

Results from ex vivo tissue studies indicate successful tracking of temperature under various phantom configurations and ranges of water temperature. The results of in silico studies show that the proposed system can heat an acoustically and thermally heterogenous breast model to the clinically relevant temperature of 42°C while accounting for a reasonable time needed to image the current cross section (200 ms). Further, we have performed an initial in silico study demonstrating the feasibility of adjusting the transmit waveform frequency to modify the effective heating height at the focused region. Lastly, we have shown in a simpler 2D breast model that MHTh level temperatures can be maintained by adjusting the transmit pressure intensity of the US ring.

CONCLUSIONS

This work has demonstrated the feasibility of using a 256-element ring array transducer for temperature monitoring; however, future work will investigate minimizing the difference between measured SS and the values shown in literature. A hypothesis attributes this bias to potential volumetric average artifacts from the ray-based SS inversion algorithm that was used, and that moving to a waveform-based SS inversion algorithm will greatly improve the SS estimates. Additionally, we have shown that an all-acoustic MHTh system is feasible via in silico studies. These studies have indicated that the proposed system can heat a tumor within a heterogenous breast model to 42°C within a narrow time frame. This holds great promise for increasing the accessibility and reducing the complexity of a future all-acoustic MHTh system.

Simulation CT-based radiomics for prediction of response after neoadjuvant chemo-radiotherapy in patients with locally advanced rectal cancer

Background

To report on the discriminative ability of a simulation Computed Tomography (CT)-based radiomics signature for predicting response to treatment in patients undergoing neoadjuvant chemo-radiation for locally advanced adenocarcinoma of the rectum.

Methods

Consecutive patients treated at the Universities of Tübingen (from 1/1/07 to 31/12/10, explorative cohort) and Florence (from 1/1/11 to 31/12/17, external validation cohort) were considered in our dual-institution, retrospective analysis. Long-course neoadjuvant chemo-radiation was performed according to local policy. On simulation CT, the rectal Gross Tumor Volume was manually segmented. A feature selection process was performed yielding mineable data through an in-house developed software (written in Python 3.6). Model selection and hyper-parametrization of the model was performed using a fivefold cross validation approach. The main outcome measure of the study was the rate of pathologic good response, defined as the sum of Tumor regression grade (TRG) 3 and 4 according to Dworak’s classification.

Results

Two-hundred and one patients were included in our analysis, of whom 126 (62.7%) and 75 (37.3%) cases represented the explorative and external validation cohorts, respectively. Patient characteristics were well balanced between the two groups. A similar rate of good response to neoadjuvant treatment was obtained in in both cohorts (46% and 54.7%, respectively; p = 0.247). A total of 1150 features were extracted from the planning scans. A 5-metafeature complex consisting of Principal component analysis (PCA)-clusters (whose main components are LHL Grey-Level-Size-Zone: Large Zone Emphasis, Elongation, HHH Intensity Histogram Mean, HLL Run-Length: Run Level Variance and HHH Co-occurence: Cluster Tendency) in combination with 5-nearest neighbour model was the most robust signature. When applied to the explorative cohort, the prediction of good response corresponded to an average Area under the curve (AUC) value of 0.65 ± 0.02. When the model was tested on the external validation cohort, it ensured a similar accuracy, with a slightly lower predictive ability (AUC of 0.63).

Conclusions

Radiomics-based, data-mining from simulation CT scans was shown to be feasible and reproducible in two independent cohorts, yielding fair accuracy in the prediction of response to neoadjuvant chemo-radiation.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13014-022-02053-y.

Deep regional hyperthermia combined with modern concurrent chemoradiotherapy increases T-downstaging rate in locally advanced rectal cancer

BACKGROUND

Deep regional hyperthermia might have an additional effect on radiotherapy in treating locally advanced rectal cancer (LARC). This study aimed to investigate the role of hyperthermia combined with modern preoperative concurrent chemoradiotherapy (CRT) for LARC.

METHODS AND MATERIALS

From 2012 to 2018, 152 consecutive patients with LARC treated with neoadjuvant chemoradiation were enrolled and analyzed retrospectively. Pelvic radiotherapy (45-50 Gy) was delivered as volumetric modulated arc therapy (VMAT), concurrently with capecitabine chemotherapy. Fifty patients received hyperthermia combined with CRT (HCRT group) twice a week. Treatment response and outcomes were compared between the two groups. Furthermore, the relationships between peripheral blood neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR) and lymphocyte-to-monocyte ratio (LMR) in response to hyperthermia were analyzed.

RESULTS

Patients treated with hyperthermia had a significantly higher T-downstaging rate than those without hyperthermia (82.0 vs. 62.7%; p = .016). Hyperthermia was an independent favorable predictor of T-downstaging (odds ratio [OR] = 2.473; 95% confidence interval [CI] 1.050-5.826; p = .038). In the HCRT group, a pre-therapeutic elevated NLR (≥3) was associated with a higher T-downstaging rate (100.0 vs. 73.5%, p = .043). However, NLR was not associated with the T-downstaging rate in the CRT group. Five-year rates of locoregional recurrence-free survival (96.8 vs. 94.7%, p = .959), disease-free survival (DFS; 61.4 vs. 79.3%, p = .242), and overall survival (OS; 92.7 vs. 89.8%, p = .831) were not statistically different between the CRT and HCRT groups.

CONCLUSIONS

Hyperthermia can improve preoperative treatment response in LARC. Pretreatment NLR may be a predictive factor for hyperthermia.

Long-Term Feasibility of 13.56 MHz Modulated Electro-Hyperthermia-Based Preoperative Thermoradiochemotherapy in Locally Advanced Rectal Cancer

Simple Summary

We demonstrated that a 13.56 MHz modulated electro-hyperthermia (mEHT) boost is feasible in neoadjuvant treatment for rectal cancer. Herein, we attempted to present the long-term results for this phase 2 trial. Although there are many reports on the usefulness of thermoradiochemotherapy for loco-regional control, so far, only a few cases of survival benefit exist. Thus, this study assessed whether this limitation of hyperthermia could be overcome through the mEHT method featuring an applied energy variable. Following a median follow-up of 58 months for 60 patients, mEHT boost showed comparable results with conventional hyperthermia; potential therapeutic effects were also observed. Moreover, mEHT could be considered a useful tool in combination treatment with radiotherapy owing to its low thermotoxicity and improved treatment compliance.

Abstract

We evaluated the effect of 13.56 MHz modulated electro-hyperthermia (mEHT) boost in neoadjuvant treatment for cT3-4- or cN-positive rectal cancer. Sixty patients who completed the mEHT feasibility trial (ClinicalTrials.gov Identifier: NCT02546596) were analyzed. Whole pelvis radiotherapy of 40 Gy, mEHT boost twice a week during radiotherapy, and surgical resection 6–8 weeks following radiotherapy were performed. The median age was 59. The median follow-up period was 58 (6–85) months. Total/near total tumor regression was observed in 20 patients (33.3%), including nine cases of complete response. T- and N-downstaging was identified in 40 (66.6%) and 53 (88.3%) patients, respectively. The 5-year overall and disease-free survival were 94.0% and 77.1%, respectively. mEHT energy of ≥3800 kJ potentially increased the overall survival (p = 0.039). The ypN-stage and perineural invasion were possible significant factors in disease-free (p = 0.003 and p = 0.005, respectively) and distant metastasis-free (p = 0.011 and p = 0.034, respectively) survival. Tumor regression, resection margin status, and other molecular genetic factors showed no correlation with survival. Although a limited analysis of a small number of patients, mEHT was feasible considering long-term survival. A relatively low dose irradiation (40 Gy) plus mEHT setting could ensure comparable clinical outcomes with possible mEHT-related prognostic features.

Establishment of Tumor Treating Fields Combined With Mild Hyperthermia as Novel Supporting Therapy for Pancreatic Cancer

Pancreatic ductal adenocarcinoma (PDAC) is a highly malignant tumor with poor prognosis and limited therapeutic options. Alternating electrical fields with low intensity called "Tumor Treating Fields" (TTFields) are a new, non-invasive approach with almost no side effects and phase 3 trials are ongoing in advanced PDAC. We evaluated TTFields in combination with mild hyperthermia. Three established human PDAC cell lines and an immortalized pancreatic duct cell line were treated with TTFields and hyperthermia at 38.5°C, followed by microscopy, assays for MTT, migration, colony and sphere formation, RT-qPCR, FACS, Western blot, microarray and bioinformatics, and in silico analysis using the online databases GSEA, KEGG, Cytoscape-String, and Kaplan-Meier Plotter. Whereas TTFields and hyperthermia alone had weak effects, their combination strongly inhibited the viability of malignant, but not those of nonmalignant cells. Progression features and the cell cycle were impaired, and autophagy was induced. The identified target genes were key players in autophagy, the cell cycle and DNA repair. The expression profiles of part of these target genes were significantly involved in the survival of PDAC patients. In conclusion, the combination of TTFields with mild hyperthermia results in greater efficacy without increased toxicity and could be easily clinically approved as supporting therapy.

A Narrative Review of Regional Hyperthermia: Updates From 2010 to 2019

The role of hyperthermia (HT) in cancer therapy and palliative care has been discussed for years in the literature. There are plenty of articles that show good feasibility of HT and its efficacy in terms of tumor response and survival improvements. Nevertheless, HT has never gained enough interest among oncologists to become a standard therapy in clinical practice. The main advantage of HT is the enhancement of chemotherapy (CHT), radiotherapy (RT), chemoradiotherapy (CRT), and immunotherapy benefits. This effect has been confirmed in several types of tumors: esophageal, gastrointestinal, pancreas, breast, cervix, head and neck, and bladder cancers, and soft tissue sarcoma. HT effects include oxygenation and perfusion changes, DNA repair inhibition and immune system activation as a consequence of new antigen exposure. The literature shows a wide variety of randomized, nonrandomized, and observational studies and both prospective and retrospective data to confirm the advantage of HT association to CHT and RT. There are still many ongoing trials on this subject. This article summarizes the available literature on HT in order to update the current knowledge on HT use in association with RT and/or CHT from 2010 up to 2019.

Beneficial effects of modulated electro-hyperthermia during neoadjuvant treatment for locally advanced rectal cancer

PURPOSE

Modulated electro-hyperthermia (mEHT) may enhance the tumor response, although the effectiveness of combined neoadjuvant therapy remains unclear. Therefore, we investigated the role of mEHT with neoadjuvant therapy for locally advanced rectal cancer.

MATERIALS AND METHODS

Clinical data were analyzed for 120 patients who received neoadjuvant treatment for locally advanced rectal cancer (T3/4 or N+, M0) from May 2012 to December 2017. Capecitabine or 5-fluorouracil was administered along with radiotherapy. Patients were categorized into mEHT group (62 patients) and non-mEHT group (58 patients) depending on whether mEHT was added. Surgery was performed 6-8 weeks after the end of radiotherapy.

RESULTS

The median age was 59 years (range, 33-83). The median radiation dose was significantly less for mEHT group (40 Gy) than for non-mEHT group (50.4 Gy). In mEHT group, 80.7% showed down-staging compared with 67.2% in non-mEHT group. For large tumors of more than 65 cm³ (mean), improved tumor regression was observed in 31.6% of mEHT group compared with 0% of non-mEHT group (p = .024). The gastrointestinal toxicity rate of mEHT group was 64.5%, which was found to be statistically significantly less than 87.9% of non-mEHT group (p = .010). The 2-year disease-free survival was 96% for mEHT group and 79% for non-mEHT group (p = .054).

CONCLUSION

The overall mEHT group had a comparable response and survival using less radiation dosing compared with standard care; the subgroup with large tumors showed improved efficacy for tumor regression after mEHT.

Deep regional hyperthermia with preoperative radiochemotherapy in locally advanced rectal cancer, a prospective phase II trial

PURPOSE

The goal of the present study was to investigate the effect of deep regional hyperthermia on early and long-term oncological outcomes in the context of preoperative radiochemotherapy in rectal cancer.

METHODS

In this prospective phase II trial, patients with locally advanced rectal cancer were treated with 5-fluorouracil based preoperative radiochemotherapy with 50.4 Gy in 28 fractions. Deep regional hyperthermia was scheduled twice weekly. Pathological tumor regression was scored according to the Dworak regression system. The primary endpoint was pathological complete response (pCR). Further endpoints were local control (LC), distant control (DC), disease-free survival (DFS) and overall survival (OS). Hyperthermia was defined as feasible if 70% of patients received at least eight treatments. Quality of life was assessed at follow-up by the EORTC-QLQ-C30 and QLQ-CR29 questionnaires. Time to event data was analyzed according to Kaplan-Meier based on first-events. The study was registered on clinicaltrials.gov (NCT02353858).

RESULTS

From 2012 until 2017, 78 patients were recruited. Median follow-up was 54 months. Based on magnetic resonance imaging, the mesorectal fascia was involved or threatened in 60% of the patients. Compliance with radiotherapy was 99%, 91% received both cycles of chemotherapy and 77% had eight or more hyperthermia treatments. Median time from the end of radiotherapy to surgery was 6.7 weeks. A pathological complete response was reported in 14% of the patients, 50% had either Dworak 4 (complete regression) or Dworak 3 regression (scattered tumor cells only). Three year estimates for OS, DFS, LC and DC were 94%, 81%, 96% and 87%. Patients with higher hyperthermia related cumulative temperatures showed stronger tumor regression. Global health status based on EORTC-QLQ-C30 was comparable with data from the general population.

CONCLUSION

Deep regional hyperthermia was feasible, did not compromise standard treatments and resulted in promising long-term oncological outcomes and QoL.

Neoadjuvant Chemoradiation Combined with Regional Hyperthermia in Locally Advanced or Recurrent Rectal Cancer

Simple Summary

The HyRec trial was initially designed to optimize and standardize the treatment of locally recurrent rectal cancer (LRRC). An escalated neoadjuvant treatment schedule, consisting of curative radiotherapy, concurrent chemotherapy with 5-Fluorouracil and Oxaliplatin, and additional regional hyperthermia, was evaluated with the intention to increase the rate of curative resections. Primary endpoints were the feasibility rate defined by the number of therapy-limiting toxicity or treatment withdrawal, and the pathologically confirmed complete remission (pCR) rate. Between 2012 and 2018, 111 patients with Union for International Cancer Control (UICC) stage IIB-IV or any locally recurrent rectal cancer were included. The intensified neoadjuvant and multimodality treatment schedule was feasible and led to comparable early toxicity rates as described by other trials that used the similar chemoradiation protocol. The presented treatment regimen resulted in a very high pCR rate and appears as a promising option for patients with LRRC.

Abstract

Background: To prospectively analyze feasibility and pathological complete response (pCR) rates of neoadjuvant chemoradiotherapy combined with regional hyperthermia (RHT) in patients with locally advanced (LARC) or recurrent (LRRC) rectal cancer. Methods: between 2012 and 2018, 111 patients with UICC stage IIB-IV or any locally recurrent rectal cancer were included (HyRec-Trial, ClinicalTrials.gov Identifier: NCT01716949). Patients received radiotherapy with concurrent 5-Fluororuracil (5-FU)/Capecitabine and Oxaliplatin, and RHT. Stage 1 feasibility analysis evaluated dose-limiting toxicities (DLT) after 19 patients, stage 2 after 59 evaluable patients. Analysis of the pCR rate was based on histopathological reports. Results: the feasibility rates for stages 1 and 2 were 90% (17/19) and 73% (43/59), respectively. In the intention-to-treat population the pCR rate was 19% (20/105; 90% confidence interval (CI) 13.0–26.5). In the per-protocol-analysis, complete tumor regression was seen in 28% (18/64) and 38% (3/8) of the patients with LARC and LRRC, respectively. Complete resection rates (R0) among patients with LARC and LRRC who received surgery were 99% (78/84) and 67% (8/12). Conclusions: the intensified neoadjuvant and multimodality treatment schedule was feasible and led to comparable early toxicity rates as described by other trials that used the similar chemoradiation protocol. The presented treatment regimen resulted in a very high pCR rate and appears as a promising option for patients with LRRC.

MR Thermometry Data Correlate with Pathological Response for Soft Tissue Sarcoma of the Lower Extremity in a Single Center Analysis of Prospectively Registered Patients

Background: There is a strong biologic rationale for using locoregional hyperthermia in soft tissue sarcoma and a randomized trial reported significant improvements with hyperthermia. The aim of this study was to describe the opportunities of magnetic resonance (MR)-based thermometry in a cohort of soft tissue sarcoma patients undergoing combined radiotherapy and locoregional hyperthermia. Patients and Methods: For eleven evaluable patients, tumor volume (V_Tu) and a separate volume for temperature analysis with reliable temperature distribution (V_therm) were contoured for every hyperthermia treatment (103 therapies). Temperature data were recorded for all tumors and were correlated with clinical features and pathologic response data. Results: Of 48 patients with high-risk soft tissue sarcomas treated with radio(chemo)therapy and locoregional hyperthermia, MR thermometry was possible in 11 (23%) patients. For all patients, the temperature superseded by 90% of V_Tu (T90(V_Tu)) and T90 (V_therm) were in the range of 37–43 °C and 40–45 °C, respectively. Larger tumors tended to reach higher temperatures. For tumors showing a pathologic response in the resection specimen after preoperative treatment, temperature (T90 (V_therm)) was significantly higher than in tumors without pathologic response. Conclusion: Lower extremity sarcomas undergoing preoperative treatment with locoregional hyperthermia are especially suitable for MR thermometry. MR thermometry is a promising non-invasive way for temperature measurement during locoregional hyperthermia, showing a positive dose-response relationship.

Recent technological advancements in radiofrequency- andmicrowave-mediated hyperthermia for enhancing drug delivery

Hyperthermia therapy is a potent enhancer of chemotherapy and radiotherapy. In particular, microwave (MW) and radiofrequency (RF) hyperthermia devices provide a variety of heating approaches that can treat most cancers regardless the size. This review introduces the physics of MW/RF hyperthermia, the current state-of-the-art systems for both localized and regional heating, and recent advancements in hyperthermia treatment guidance using real-time computational simulations and magnetic resonance thermometry. Clinical trials involving RF/MW hyperthermia as adjuvant for chemotherapy are also presented per anatomical site. These studies favor the use of adjuvant hyperthermia since it significantly improves curative and palliative clinical outcomes. The main challenge of hyperthermia is the distribution of state-of-the-art heating systems. Nevertheless, we anticipate that recent technology advances will expand the use of hyperthermia to chemotherapy centers for enhanced drug delivery. These new technologies hold great promise not only for (image-guided) perfusion modulation and sensitization for cytotoxic drugs, but also for local delivery of various compounds using thermosensitive liposomes.

The Role of Hyperthermia in the Multidisciplinary Treatment of Malignant Tumors

Hyperthermia is often used in combination with chemotherapy and radiotherapy for cancer treatment. Recently, immunotherapy has become a popular research area, breaking exciting new ground with concurrent immunotherapy and hyperthermia. Much evidence has demonstrated the effectiveness of multidisciplinary synergistic therapy, and the underlying mechanism has been gradually explored. In this review, we focus on the mechanism of various cancer treatments in the current literature and recent advances in hyperthermia. Additionally, we review clinical studies of hyperthermia combined with other therapies in the previous 10 years and propose future prospects for hyperthermia in multidisciplinary synergistic therapy.

Organ Preservation in Rectal Cancer: The Patients' Perspective

Organ preservation after a clinical complete response to radiochemotherapy is currently one of the most discussed topics in the management of rectal cancer. However, the patients' perspective has only been poorly studied so far. In this multicenter study, we examined 49 patients with locally advanced rectal cancer. The willingness to participate in an organ preservation study and the acceptance of the associated aspects such as intensified radiochemotherapy protocols, the need for close follow-up examinations and local regrowth rates were assessed. Attitudes were correlated with baseline quality of life parameters and psychological scales for "fear of progression", "locus of control", "depression", and the "willingness to take risks". A total of 83% of patients would consider the deferral of surgery in case of a clinical complete response (cCR). Three monthly follow-up studies and a 25% local regrowth rate are considered acceptable by 95% and 94% respectively. While 41% would be willing to exchange cure rates for a non-operative treatment strategy, a potentially more toxic radiochemotherapy in order to increase the probability of a cCR was the aspect with the lowest acceptance (55%). Psychological factors, in particular "locus of control" and "willingness to take risks", influenced patient preferences regarding most of the assessed parameters. While in general a broad acceptance of an organ-preserving treatment can be expected, patient preferences and concerns regarding different aspects of this strategy vary widely and require specific consideration during shared decision making.

Watchful Waiting after Radiochemotherapy in Rectal Cancer: When Is It Feasible?

A "watch and wait" strategy in rectal cancer is increasingly considered in patients who achieve an excellent response to radiotherapy. While a growing number of studies have shown the feasibility of this strategy in selected patients, the optimal therapeutic regimen to maximize response rates still needs to be established. Furthermore, accurate response prediction and the management of minor residual findings after radiotherapy remain a matter of debate. Finally, concerns regarding the long-term oncological safety of the "watch and wait" approach have been expressed. Therefore, the present review aims to address the open questions in the context of a "watch and wait" strategy and focuses on the diagnosis of a clinical complete response and the ideal management thereafter.

Cost analysis of a wait-and-see strategy after radiochemotherapy in distal rectal cancer

BACKGROUND

Nonoperative management (NOM) of rectal cancer after radiochemotherapy (RtChx) in patients with a clinical complete response is an emerging strategy with the goal to improve quality of life without compromising cure rates. However close monitoring with both magnetic resonance imaging (MRI) and rectoscopy is required for the early detection of possible local regrowths. We therefore performed a cost analysis comparing the costs of immediate surgery with the costs for MRI and rectoscopy during surveillance as in the upcoming CAO/ARO/AIO-16 trial.

METHODS

MRIs and rectoscopies of patients with a clinical complete response after RtChx over the course of 5 years were simulated and compared with immediate surgery after RtChx. Transition probabilities between health stages (no evidence of disease, local regrowth and salvage surgery, distant failure) were derived from the literature. Costs for ambulatory imaging and endoscopic studies were calculated according to the "Gebührenordnung für Ärzte" (GOÄ), costs for surgery based on the diagnosis-related groups system. Three different scenarios with higher costs for salvage surgery or higher regrowth rates were simulated.

RESULTS

A patient without disease recurrence will generate costs for MRI and rectoscopy of 6344 € over 5 years compared with costs of 14,511 € for immediate radical surgery. When 25% local regrowths with subsequent salvage surgery were included in the model, the average costs per patient are 8299 €. In our simulations a NOM strategy was cost-saving compared with immediate surgery in all three scenarios.

CONCLUSION

A NOM strategy with an intensive surveillance using MRI and rectoscopy will produce costs that are expected to remain below those of immediate surgery.

The first thermic treatment predicts following chemoradiation response with concurrent thermal therapy for the treatment of rectal cancer

The present study aimed to evaluate whether the neoadjuvant chemoradiation response with concurrent thermal therapy for the treatment of rectal cancer can be predicted following the first thermic treatment. Eighty patients with primary rectal adenocarcinoma (≤12 cm from the anal verge) were included in this study. Fifty-four received surgery and pathological response was evaluated. Intensity-modulated radiotherapy was administered conventionally once daily 5 times/week. Neoadjuvant radiotherapy consisted of 50 Gy delivered to the planning target volume in 25 fractions. Concurrent neoadjuvant chemotherapy was delivered in 5-day courses. Capecitabine was administered orally at 1,700 mg/m²/day for 5 days/week. Thermic treatment was performed using the Thermotron-RF 8 and administered once/week for 5 weeks with 50 min irradiation. Patients with a gross tumor volume (GTV) ≤32 cm³ and a radiofrequency (RF) output difference (RO difference) ≥77 Watt/min exhibited pathological complete response (pCR) and CR rates of 50 and 75%, respectively. Those with a GTV ≥80 cm³ and a RO difference ≥77 Watt/min exhibited pCR and CR rates of 42.9 and 42.9%, respectively. The changes in the skin temperature during RF treatment in patients with pCR with a RO difference ≥77 Watt/min increased significantly compared with those of other outcomes, and progressive disease. These data suggest a strategy for predicting which patients will respond best following the first thermic treatment. The results identified that the group of patients with a GTV ≤32 cm³ and a RO difference ≥77 Watt/min (outputable/heatable patients) may respond best.

Selecting patients for hyperthermia combined with preoperative chemoradiotherapy for locally advanced rectal cancer

BACKGROUND

This study investigated the role of hyperthermia combined with preoperative concurrent chemoradiotherapy (CCRT) for locally advanced rectal cancer (LARC) according to hypoxic marker expression.

METHODS

One hundred and nine LARC patients with tissue blocks available for immunohistochemical assessment of carbonic anhydrase 9 (CA9) expression were reviewed. CA9 expression was considered positive when the staining percentage of tumor cells was >25% (n = 31). Pelvic radiotherapy with a total dose of 39.6-45 Gy was delivered concurrently with fluorouracil-based chemotherapy. Hyperthermia was administered to 52 patients twice a week during CCRT. Treatment response and outcomes were compared between hyperthermochemoradiotherapy (HCRT) and CCRT groups.

RESULTS

In patients with positive CA9 expression, the rates of downstaging (p = 0.060) and pathologic complete response (p = 0.064) tended to be higher in the HCRT group than in the CCRT group. Distant metastasis-free survival (p = 0.029) and cancer-specific survival (p = 0.020) were significantly worse in tumors with both positive CA9 expression and poor tumor response. Negative CA9 expression, presence of major tumor response, and the use of hyperthermia were significant favorable prognostic factors for cancer-specific survival after the first recurrence in multivariate analysis.

CONCLUSIONS

Hyperthermia might selectively enhance the preoperative treatment response in LARC with positive CA9 expression and offset the negative effect of hypoxia on prognosis. Pretreatment evaluation of hypoxia could aid in the selection of patients who might benefit from hyperthermia.

Integrating Hyperthermia into Modern Radiation Oncology: What Evidence Is Necessary?

Hyperthermia (HT) is one of the hot topics that have been discussed over decades. However, it never made its way into primetime. The basic biological rationale of heat to enhance the effect of radiation, chemotherapeutic agents, and immunotherapy is evident. Preclinical work has confirmed this effect. HT may trigger changes in perfusion and oxygenation as well as inhibition of DNA repair mechanisms. Moreover, there is evidence for immune stimulation and the induction of systemic immune responses. Despite the increasing number of solid clinical studies, only few centers have included this adjuvant treatment into their repertoire. Over the years, abundant prospective and randomized clinical data have emerged demonstrating a clear benefit of combined HT and radiotherapy for multiple entities such as superficial breast cancer recurrences, cervix carcinoma, or cancers of the head and neck. Regarding less investigated indications, the existing data are promising and more clinical trials are currently recruiting patients. How do we proceed from here? Preclinical evidence is present. Multiple indications benefit from additional HT in the clinical setting. This article summarizes the present evidence and develops ideas for future research.

Equivalence of cell survival data for radiation dose and thermal dose in ablative treatments: analysis applied to essential tremor thalamotomy by focused ultrasound and gamma knife

Thermal dose and absorbed radiation dose have historically been difficult to compare because different biological mechanisms are at work. Thermal dose denatures proteins and the radiation dose causes DNA damage in order to achieve ablation. The purpose of this paper is to use the proportion of cell survival as a potential common unit by which to measure the biological effect of each procedure. Survival curves for both thermal and radiation doses have been extracted from previously published data for three different cell types. Fits of these curves were used to convert both thermal and radiation dose into the same quantified biological effect: fraction of surviving cells. They have also been used to generate and compare survival profiles from the only indication for which clinical data are available for both focused ultrasound (FUS) thermal ablation and radiation ablation: essential tremor thalamotomy. All cell types could be fitted with coefficients of determination greater than 0.992. As an illustration, survival profiles of clinical thalamotomies performed by radiosurgery and FUS are plotted on a same graph for the same metric: fraction of surviving cells. FUS and Gamma Knife have the potential to be used in combination to deliver a more effective treatment (for example, FUS may be used to debulk the main tumour mass, and radiation to treat the surrounding tumour bed). In this case, a model which compares thermal and radiation treatments is valuable in order to adjust the dose between the two.

Organ preservation in rectal cancer - Challenges and future strategies

Neoadjuvant radiochemotherapy with subsequent total mesorectal excision is the standard of care for locally advanced rectal cancer. While this multimodal strategy has decreased local recurrences rates below 5%, long-term morbidities are considerable in terms of urinary, sexual or bowel functioning. At the same time approximately 10–20% of patients have no evidence of residual tumour in their surgical specimen. Pioneering studies from Brazil have suggested that surgery can safely be omitted in carefully selected patients with a clinical complete response after radiochemotherapy. Although confirmatory studies showed similar results, challenges in terms of optimizing radiochemotherapy for organ-preservation, appropriate selection of patients for non-operative management and the safety of this approach remain. The present review will summarize the current data on organ-preservation in rectal cancer and discuss the challenges that need to be addressed in future trials.

Chemoradiotherapy and concurrent radiofrequency thermal therapy to treat primary rectal cancer and prediction of treatment responses

The present study aimed to evaluate a previously reported predictive formula of output-limiting symptoms induced by radiofrequency (RF) to determine the efficacy of this neoadjuvant chemoradiation (NACR) and concurrent RF thermal therapy. The present study included 81 consecutive patients with confirmed diagnoses of rectal adenocarcinoma that was localized in the mid-low rectum (up to 12 cm from the anal verge) who received NACR [intensity-modulated radiotherapy (IMRT), 50 Gy/25 fractions, capecitabine 1,700 mg/m2/day for 5 days/week)] with concurrent thermal therapy (Thermotron-RF8, once a week for 5 weeks with 50 min irradiation). Patients with progressive disease (PD) did not receive RF outputs higher than the predicted value. Some patients who were predicted to receive more output in fact received more than the predicted output. In patients who were predicted to receive moderately higher outputs, 37.5% of the patients experienced pathological complete responses, which was the highest rate, while in those who did not receive more than the predicted output, 66.7% of the patients experienced PD, which was the highest rate in the present study. We speculate that RF thermal therapy may offset the chemoradiation effects in some patients. Adding thermal therapy as a multimodality therapy to NACR potentially affects patients with lower predicted outputs and actual observed outputs slightly higher than the predictive value. Our predictive equation for initial energy output, in which output‑limiting symptoms can be used to predict treatment efficacy, consequently, can be used to decide whether to continue this treatment modality.

Effects of hyperthermia as a mitigation strategy in DNA damage-based cancer therapies

Utilization of thermal therapy (hyperthermia) is defined as the application of exogenous heat induction and represents a concept that is far from new as it goes back to ancient times when heat was used for treating various diseases, including malignancies. Such therapeutic strategy has gained even more popularity (over the last few decades) since various studies have shed light into understanding hyperthermia's underlying molecular mechanism(s) of action. In general, hyperthermia is applied as complementary (adjuvant) means in therapeutic protocols combining chemotherapy and/or irradiation both of which can induce irreversible cellular DNA damage. Furthermore, according to a number of in vitro, in vivo and clinical studies, hyperthermia has been shown to enhance the beneficial effects of DNA targeting therapeutic strategies by interfering with DNA repair response cascades. Therefore, the continuously growing evidence supporting hyperthermia's beneficial role in cancer treatment can also encourage its application as a DNA repair mitigation strategy. In this review article, we aim to provide detailed information on how hyperthermia acts on DNA damage and repair pathways and thus potentially contributing to various adjuvant therapeutic protocols relevant to more efficient cancer treatment strategies.

Long-term local control and survival after preoperative radiochemotherapy in combination with deep regional hyperthermia in locally advanced rectal cancer

PURPOSE

The aim of this study was to evaluate the impact of deep regional hyperthermia on long-term local control and survival in locally advanced non-metastatic rectal cancer.

METHODS

In total 103 patients with locally advanced non-metastatic rectal cancer were treated preoperatively with either neoadjuvant radiochemotherapy alone (n = 43) or the same treatment with additional deep regional hyperthermia (n = 60). The two groups were compared with respect to local control, overall survival (OS), disease-free survival (DFS), and distant metastases-free survival (DMFS).

RESULTS

Patients receiving additional hyperthermia had excellent long-term local control with a 5-year Kaplan-Meier estimate of 98% compared with 87% in the radiochemotherapy only group (p = 0.09). Five-year rates for OS (88% versus 76%, p = 0.08), DFS (77% versus 73%, p = n.s.) and DMFS (75% versus 77%, p = n.s.) were not statistically different between the two groups.

CONCLUSION

Radiochemotherapy combined with hyperthermia results in excellent long-term local control.

Therapeutic hyperthermia: The old, the new, and the upcoming

Hyperthermia has long been used for cancer treatment, either alone or in combination with chemotherapy, radiation therapy, or both. Its efficacy and versatility continue to be well demonstrated in randomized trials across a number of primary cancers, but barriers to its widespread adoption persist including effective delivery and verification systems. This article describes hyperthermia, details its biological mechanisms of action and immunological effects, and summarizes select preclinical data and key clinical trials combining hyperthermia with standard cancer treatments. Current challenges and emerging technologies that have the potential to make this translational therapy more accessible to a greater number of patients are also described.

Regional hyperthermia and moderately dose-escalated salvage radiotherapy for recurrent prostate cancer. Protocol of a phase II trial

BACKGROUND

Current studies on salvage radiotherapy (sRT) investigate timing, dose-escalation and anti-hormonal treatment (ADT) for recurrent prostate cancer. These approaches could either be limited by radiation-related susceptibility of the anastomosis or by suspected side-effects of long-term ADT. A phase II protocol was developed to investigate the benefit and tolerability of regional hyperthermia with moderately dose-escalated radiotherapy.

METHODS

The study hypothesis is that radio-thermotherapy is a safe and feasible salvage treatment modality. The primary endpoint is safety measured by frequency of grade 3+ genitourinary (GU) and gastrointestinal (GI) adverse events (AE) according to Common Toxicity Criteria (CTC) version 4. Feasibility is defined by number of hyperthermia treatments (n ≥ 7) and feasibility of radiotherapy according to protocol. Target volume delineation is performed according to the EORTC guidelines. Radiation treatment is administered with single doses of 2 Gy 5×/week to a total dose of 70 Gy. Regional hyperthermia is given 2×/week to a total of 10 treatments.

RESULTS

European centres participate in the phase II trial using intensity modulated RT (IMRT) or volumetric modulated arc technique (VMAT). The initiating centres were participants of the SAKK 09/10 study, where the same patient criteria and target volume definition (mandatory successful performed dummy run) were applied insuring a high standardisation of the study procedures.

CONCLUSIONS

The introduced phase II study implements highly precise image-guided radiotherapy and regional hyperthermia. If the phase II study is found to be safe and feasible, a multicenter phase III study is planned to test whether the addition of regional hyperthermia to dose-intensified sRT improves biochemical control.

Future directions in combined modality therapy for rectal cancer: reevaluating the role of total mesorectal excision after chemoradiotherapy

Most patients who develop rectal cancer present with locoregionally advanced (T3 or node-positive) disease. The standard management of locoregionally advanced rectal cancer is neoadjuvant concurrent chemoradiotherapy (nCRT), followed by radical resection (low-anterior resection or abdominoperineal resection with total mesorectal excision). Approximately 15% of patients can have a pathologic complete response (pCR) at the time of surgery, indicating that some patients can have no detectable residual disease after nCRT. The actual benefit of surgery in this group of patients is unclear. It is possible that omission of surgery in these patients, termed selective nonoperative management, can limit the toxicities associated with standard, multimodal combined modality therapy without compromising disease control. In this review, we discuss the clinical experiences to date using selective nonoperative management and various attempts at escalation of nCRT to improve the number of patients who have a pCR. We also explore several clinical, laboratory, imaging, histopathologic, and genetic biomarkers that have been tested as tools to predict which patients are most likely to have a pCR after nCRT.

Inactivation of DNA-dependent protein kinase promotes heat-induced apoptosis independently of heat-shock protein induction in human cancer cell lines

The inhibition of DNA damage response pathway seems to be an attractive strategy for cancer therapy. It was previously reported that in rodent cells exposed to heat stress, cell growth was promoted by the activity of DNA-dependent protein kinase (DNA-PK), an enzyme involved in DNA non-homologous end joining (NHEJ) required for double-strand break repair. The absence of a functioning DNA-PK was associated with down regulation of heat shock protein 70 (HSP70). The objective of this study is thus to investigate the role of DNA-PK inhibition in heat-induced apoptosis in human cell lines. The inhibitors of phosphorylation of the DNA-PK catalytic subunit (DNA-PKcs) at Ser2056, such as NU7026 and NU7441, were utilized. Furthermore, knock down of DNA-PKcs was carried out using small interfering RNA (siDNA-PKcs). For heat exposure, cells were placed in water bath at 44°C for 60 min. Apoptosis was evaluated after 24 h incubation flow cytometrically. Proteins were extracted after 24 h and analyzed for HSP70 and HSP40 expression by Western blotting. Total RNA was extracted 6 h after treatment and analyzed using a GeneChip® microarray system to identify and select the up-regulated genes (≥1.5 fold). The results showed an enhancement in heat-induced apoptosis in absence of functioning DNA-PKcs. Interestingly, the expression levels of HSP70 and HSP40 were elevated in the absence of DNA-PKcs under heat stress. The results of genetic network analysis showed that HSPs and JUN genes were up-regulated independently of DNA-PKcs in exposed parent and knock out cells. In the presence of functioning DNA-PKcs, there was an observed up-regulation of anti-apoptotic genes, such as NR1D1, whereas in the absence of DNA-PKcs the pro-apoptotic genes, such as EGR2, were preferentially up-regulated. From these findings, we concluded that in human cells, the inactivation of DNA-PKcs can promote heat-induced apoptosis independently of heat-shock proteins.