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

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.

Long-Term Outcome in a Phase II Study of Regional Hyperthermia Added to Preoperative Radiochemotherapy in Locally Advanced and Recurrent Rectal Adenocarcinomas

Hyperthermia was added to standard preoperative chemoradiation for rectal adenocarcinomas in a phase II study. Patients with T3-4 N0-2 M0 rectal cancer or local recurrences were included. Radiation dose was 54 Gy combined with capecitabine 825 mg/m2 × 2 daily and once weekly oxaliplatin 55 mg/m2. Regional hyperthermia aimed at 41.5–42.5 °C for 60 min combined with oxaliplatin infusion. Radical surgery with total or extended TME technique, was scheduled at 6–8 weeks after radiation. From April 2003 to April 2008, a total of 49 eligible patients were recruited. Median number of hyperthermia sessions were 5.4. A total of 47 out of 49 patients (96%) had the scheduled surgery, which was clinically radical in 44 patients. Complete tumour regression occurred in 29.8% of the patients who also exhibited statistically significantly better RFS and CSS. Rate of local recurrence alone at 10 years was 9.1%, distant metastases alone occurred in 25.6%, including local recurrences 40.4%. RFS for all patients was 54.8% after 5 years and CSS was 73.5%. Patients with T50 temperatures in tumours above median 39.9 °C had better RFS, 66.7% vs. 31.3%, p = 0.047, indicating a role of hyperthermia. Toxicity was acceptable.

Clinical Evidence for Thermometric Parameters to Guide Hyperthermia Treatment

Hyperthermia (HT) is a cancer treatment modality which targets malignant tissues by heating to 40-43 °C. In addition to its direct antitumor effects, HT potently sensitizes the tumor to radiotherapy (RT) and chemotherapy (CT), thereby enabling complete eradication of some tumor entities as shown in randomized clinical trials. Despite the proven efficacy of HT in combination with classic cancer treatments, there are limited international standards for the delivery of HT in the clinical setting. Consequently, there is a large variability in reported data on thermometric parameters, including the temperature obtained from multiple reference points, heating duration, thermal dose, time interval, and sequence between HT and other treatment modalities. Evidence from some clinical trials indicates that thermal dose, which correlates with heating time and temperature achieved, could be used as a predictive marker for treatment efficacy in future studies. Similarly, other thermometric parameters when chosen optimally are associated with increased antitumor efficacy. This review summarizes the existing clinical evidence for the prognostic and predictive role of the most important thermometric parameters to guide the combined treatment of RT and CT with HT. In conclusion, we call for the standardization of thermometric parameters and stress the importance for their validation in future prospective clinical studies.

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.

1.5 T MR-linac planning study to compare two different strategies of rectal boost irradiation

PURPOSE

To compare treatment plans of two different rectal boost strategies: up-front versus adaptive boost at the 1.5 T MR-Linac.

METHODS

Patients with locally advanced rectal cancer (LARC) underwent standard neoadjuvant radiochemotherapy with 50.4 Gy in 28 fractions. T2-weighted MRI prior and after the treatment session were acquired to contour gross tumor volumes (GTVs) and organs at risk (OARs). The datasets were used to simulate four different boost strategies (all with 15 Gy/5 fractions in addition to 50.4 Gy): up-front boost (5 daily fractions in the first week of treatment) and an adaptive boost (one boost fraction per week). Both strategies were planned using standard and reduced PTV margins. Intra-fraction motion was assessed by pre- and post-treatment MRI-based contours.

RESULTS

Five patients were included and a total of 44 MRI sets were evaluated. The median PTV volumes of the adaptive boost were significantly smaller than for the up-front boost (81.4 cm3 vs 44.4 cm3 for PTV with standard margins; 31.2 cm3 vs 15 cm3 for PTV with reduced margins; p = 0.031). With reduced margins the rectum was significantly better spared with an adaptive boost rather than with an up-front boost: V60Gy and V65Gy were 41.2% and 24.8% compared with 59% and 29.9%, respectively (p = 0.031). Median GTV intra-fractional motion was 2 mm (range 0-8 mm).

CONCLUSIONS

The data suggest that the adaptive boost strategy exploiting tumor-shrinkage and reduced margin might result in better sparing of rectum and anal canal. Individual margin assessment, motion management and real-time adaptive radiotherapy appear attractive applications of the 1.5 T MR-Linac for further testing of individualized and safe dose escalation in patients with rectal cancer.

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.

Neutrophil-to-Lymphocyte Ratio in Rectal Cancer-Novel Biomarker of Tumor Immunogenicity During Radiotherapy or Confounding Variable?

The aim of this study was to investigate the predictive value of blood-derived makers of local and systemic inflammatory responses on early and long-term oncological outcomes. A retrospective analysis of patients with locally advanced rectal cancer treated with preoperative long-course 5-fluorouracil-based radiochemotherapy was performed. Differential blood counts before neoadjuvant treatment were extracted from the patients' electronic charts. Optimal cut-off values for neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), and lymphocyte-to-monocyte ratio (LMR) were determined. Potential clinical and hematological prognostic factors for disease-free survival (DFS) were studied using uni- and multivariate analysis. A total of 220 patients were included in the analysis. Median follow-up was 67 months. Five-year DFS and overall survival (OS) were 70% and 85%, respectively. NLR with a cut-off value of 4.06 was identified as optimal to predict DFS events. In multivariate analysis, only tumor volume (HR 0.33, 95% CI (0.14-0.83), p = 0.017) and NLR (HR 0.3, 95% CI (0.11-0.81), p = 0.017) remained significant predictors of DFS. Patients with a good histological response (Dworak 3 and 4) to radiotherapy also had a lower NLR than patients with less pronounced tumor regression (3.0 vs. 4.2, p = 0.015). A strong correlation between primary tumor volume and NLR was seen (Pearson's r = 0.64, p < 0.001). Moreover, patients with T4 tumors had a significantly higher NLR than patients with T1-T3 tumors (6.6 vs. 3.3, p < 0.001). An elevated pretherapeutic NLR was associated with higher T stage, inferior DFS, and poor pathological response to neoadjuvant radiochemotherapy. A strong correlation between NLR and primary tumor volume was seen. This association is important for the interpretation of study results and for the design of translational studies which are warranted.

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.

Clinical effects of high frequency hyperthermia-assisted irinotecan chemotherapy on patients with middle and advanced colorectal cancer and its safety assessment

Clinical effects of high frequency hyperthermia-assisted irinotecan chemotherapy on patients with middle and advanced colorectal cancer and its safety assessment were investigated. A retrospective analysis was performed on the medical records of 103 patients with middle and advanced colorectal cancer treated in Cancer Center of Guangzhou Medical University from May 2011 to June 2015, including 48 patients receiving irinotecan plus conventional treatment (irinotecan group) and 55 patients receiving high frequency hyperthermia-assisted irinotecan plus conventional treatment (combination group). The treatment effects, severity and incidence of adverse reactions, quality of life and 3-year survival rates of patients were analyzed and compared between the two groups. After 4 courses of treatment, there were statistically significant differences in the proportions of patients with partial remission and objective remission, with those in combination group higher than those in irinotecan group (both P<0.05). After 4 courses of treatment, no patient died. After 4 courses of treatment, those that increased in different degrees (all P<0.05), compared with those in combination group were significantly higher than those in irinotecan group (all P<0.05). The 1-, 2- and 3-year survival rates of patients in irinotecan group were 31.25% (15 cases), 22.92% (11 cases) and 12.50% (6 cases), respectively. Those in combination group were 58.18% (32 cases), 29.09% (16 cases) and 16.36% (9 cases), respectively. The results of K-M survival curve analysis showed that there was no statistically significant difference in survival rate between the two groups of patients (P=0.050). High frequency hyperthermia-assisted chemotherapy for patients with middle and advanced colorectal cancer can effectively improve its treatment effects and patients' quality of life, with better treatment safety, worthy of clinical promotion.

Treatment outcomes of concurrent hyperthermia and chemoradiotherapy for pancreatic cancer: Insights into the significance of hyperthermia treatment

Patients with locally advanced unresectable pancreatic cancer (LAUPC) have a poor prognosis. In addition their quality of life impaired by cancer pain and biliary tract infections. Therefore, multimodality therapy and selection of optimal treatment methods are essential for achieving prolonged survival. The present study investigated the significance of using hyperthermia concurrently with multimodality therapy to improve treatment outcomes in patients with LAUPC. In total, 13 patients receiving concurrent hyperthermia and chemoradiotherapy (HCR) or chemoradiotherapy (CR) alone for LAUPC between 2002 and 2013 were analyzed retrospectively. Of the 13 patients, 5 received concurrent HCR and 8 received CR. The chemotherapy regimens were 5-fluorouracil (5-FU) in 5 patients and gemcitabine hydrochloride (GEM) in the other 8. Patients who gave consent for hyperthermia treatment received GEM plus CR. The median overall survival period for all patients was 12 months and the 1-year survival rate was 55%; the corresponding values were 12 months and 57% in the GEM CR group, and 15 months and 80% in the HCR group. Univariate analyses was perfomed to identify factors predicting recurrence after treatment. The potential prognostic factors analyzed were: Age, sex, performance status, location, tumor size, the tumor marker CA 19-9, total radiation dose, chemotherapy and hyperthermia. Univariate analysis for factors associated with outcomes revealed a significant difference favoring the HCR group [relative risk=15.97 (95% confidence interval: 12.87-19.83) P=0.021]. In conclusion, hyperthermia merits active recommendation to pancreatic cancer patients who have a positive attitude toward this treatment and whose performance status is satisfactory.

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.

It's Getting Hot in Here: Targeting Cancer Stem-like Cells with Hyperthermia

Cancer stem-like cells (CSCs) are a subset of cancer cells that are resistant to conventional radiotherapy and chemotherapy. As such, CSCs have been recognized as playing a large role in tumor initiation and recurrence. Although hyperthermia is broadly used in cancer treatment either alone or in combination with radio- or chemo-therapy, its potential to target CSCs is not well understood. In this review, we discuss different types of hyperthermia and potential mechanisms of action in cancer treatment, particularly in regards to killing CSCs.