Age and comorbidity considerations related to radiotherapy and chemotherapy administration

Treatment of unresectable stage III non-small cell lung cancer for patients who are under-represented in clinical trials

Concurrent chemoradiotherapy (cCRT) followed by one year of consolidation durvalumab is the current standard-of-care for patients with unresectable stage III non-small cell lung cancer (NSCLC), of good functional status. However, cCRT and consolidation durvalumab may be challenging to administer for selected patient populations underrepresented or even excluded in clinical trials: older and/or frail patients; those with cardiovascular or respiratory comorbidities in which treatment-related adverse events may be higher, and patients with pre-existing autoimmune disorders for whom immunotherapy use is controversial. In this narrative review, we discuss the current evidence, challenges, ongoing clinical trials and potential future treatment scenarios in relevant subgroups of patients with locally advanced NSCLC, who are underrepresented in clinical trials.

Association between adjuvant radiation treatment and breast cancer-specific mortality among older women with comorbidity burden: A comparative effectiveness analysis of SEER-MHOS

BACKGROUND

The National Comprehensive Cancer Network suggested that older women with low-risk breast cancer (LRBC; i.e., early-stage, node-negative, and estrogen receptor-positive) could omit adjuvant radiation treatment (RT) after breast-conserving surgery (BCS) if they were treated with hormone therapy. However, the association between RT omission and breast cancer-specific mortality among older women with comorbidity is not fully known.

METHODS

1105 older women (≥65 years) with LRBC in 1998-2012 were queried from the Surveillance, Epidemiology, and End Results-Medicare Health Outcomes Survey data resource and were followed up through July 2018. Latent class analysis was performed to identify comorbidity burden classes. A propensity score-based inverse probability of treatment weighting (IPTW) was applied to Cox regression models to obtain subdistribution hazard ratios (HRs) and 95% CI for cancer-specific mortality considering other causes of death as competing risks, overall and separately by comorbidity burden class.

RESULTS

Three comorbidity burden (low, moderate, and high) groups were identified. A total of 318 deaths (47 cancer-related) occurred. The IPTW-adjusted Cox regression analysis showed that RT omission was not associated with short-term, 5- and 10-year cancer-specific death (p = 0.202 and p = 0.536, respectively), regardless of comorbidity burden. However, RT omission could increase the risk of long-term cancer-specific death in women with low comorbidity burden (HR = 1.98, 95% CI = 1.17, 3.33), which warrants further study.

CONCLUSIONS

Omission of RT after BCS is not associated with an increased risk of cancer-specific death and is deemed a reasonable treatment option for older women with moderate to high comorbidity burden.

Mitochondrial metabolism: a predictive biomarker of radiotherapy efficacy and toxicity

INTRODUCTION

Radiotherapy is a mainstay of cancer treatment. Clinical studies revealed a heterogenous response to radiotherapy, from a complete response to even disease progression. To that end, finding the relative prognostic factors of disease outcomes and predictive factors of treatment efficacy and toxicity is essential. It has been demonstrated that radiation response depends on DNA damage response, cell cycle phase, oxygen concentration, and growth rate. Emerging evidence suggests that altered mitochondrial metabolism is associated with radioresistance.

METHODS

This article provides a comprehensive evaluation of the role of mitochondria in radiotherapy efficacy and toxicity. In addition, it demonstrates how mitochondria might be involved in the famous 6Rs of radiobiology.

RESULTS

In terms of this idea, decreasing the mitochondrial metabolism of cancer cells may increase radiation response, and enhancing the mitochondrial metabolism of normal cells may reduce radiation toxicity. Enhancing the normal cells (including immune cells) mitochondrial metabolism can potentially improve the tumor response by enhancing immune reactivation. Future studies are invited to examine the impacts of mitochondrial metabolism on radiation efficacy and toxicity. Improving radiotherapy response with diminishing cancer cells' mitochondrial metabolism, and reducing radiotherapy toxicity with enhancing normal cells' mitochondrial metabolism.

Survival in breast cancer patients with a delayed DIEP flap breast reconstruction after adjustment for socioeconomic status and comorbidity

Purpose

Overall survival in breast cancer patients receiving a delayed deep inferior epigastric perforator (DIEP) flap breast reconstruction is better than in those without delayed breast reconstruction. This study aimed at determining the impact of socioeconomic status (SES) and comorbidity on these observations.

Materials and methods

This matched cohort study included all consecutive women undergoing a delayed DIEP flap reconstruction at Karolinska University Hospital, Sweden, between 1999 and 2013. Controls had not received any delayed breast reconstruction and were relapse-free after a corresponding follow-up interval. Matching was by year of and age at mastectomy, tumour stage and lymph node status. Charlson Comorbidity Index (CCI) and socioeconomic data were obtained from national registers. Associations with breast cancer-specific (BCSS) and overall survival (OS) were investigated by Kaplan-Meier survival estimates and Cox proportional hazard regression analysis.

Results

Women in the DIEP group (N = 254) more often continued education after primary school (88.6% versus 82.6%, P = 0.026), belonged to the high-income group (76.0% versus 63.1%, P < 0.001), were in a partnership (57.1% versus 55.7%, P = 0.024) and healthier (median CCI 1.00 (range 0–13) versus 2.00 (range 0–16), P = 0.021) than the control group (N = 729). After adjustment for tumour and treatment factors, SES and comorbidity, OS remained significantly better for the DIEP group than the control group (HR 2.27, 95% CI 1.44–3.55).

Conclusion

Women with a delayed DIEP flap reconstruction are a subgroup of higher socioeconomic status and better health. Higher survival estimates for the DIEP group persisted after adjusting for those differences, suggesting the presence of further unmeasured covariates.

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Women with a delayed DIEP flap reconstruction have a higher socioeconomic status.

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They also have less comorbidity than women with no delayed reconstruction.

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Superior survival in DIEP patients is not eliminated by adjustments for such differences.

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Unmeasured selection to the reconstructive process may explain observed survival differences.

Survival After Breast Conservation vs Mastectomy Adjusted for Comorbidity and Socioeconomic Status: A Swedish National 6-Year Follow-up of 48 986 Women

Question

Does breast conservation offer a survival benefit compared with mastectomy when results are adjusted for main confounders such as comorbidity and socioeconomic status?

Findings

In this large cohort study based on prospectively collected national data from 48 986 patients with breast cancer, overall and breast cancer–specific survival were significantly better after breast-conserving surgery followed by radiotherapy than after mastectomy with or without radiotherapy despite stepwise adjustment for tumor characteristics, treatment, demographics, comorbidity, and socioeconomic background.

Meaning

Breast conservation seems to offer a survival benefit independent of measured confounders and should be given priority if both breast conservation and mastectomy are valid options.

Importance

Cohort studies show better survival after breast-conserving surgery (BCS) with postoperative radiotherapy (RT) than after mastectomy (Mx) without RT. It remains unclear whether this is an independent effect or a consequence of selection bias.

Objective

To determine whether the reported survival benefit of breast conservation is eliminated by adjustment for 2 pivotal confounders, comorbidity and socioeconomic status.

Design, Setting, and Participants

Cohort study using prospectively collected national data. Swedish public health care; nationwide clinical data from the National Breast Cancer Quality Register, comorbidity data from Patient Registers at the National Board of Health and Welfare, and individual-level education and income data from Statistics Sweden. The cohort included all women diagnosed as having primary invasive T1-2 N0-2 breast cancer and undergoing breast surgery in Sweden from 2008 to 2017. Data were analyzed between August 19, 2020, and November 12, 2020.

Exposures

Locoregional treatment comparing 3 groups: breast-conserving surgery with radiotherapy (BCS+RT), mastectomy without radiotherapy (Mx-RT), and mastectomy with radiotherapy (Mx+RT).

Main Outcomes and Measures

Overall survival (OS) and breast cancer–specific survival (BCSS). Main outcomes were determined before initiation of data retrieval.

Results

Among 48 986 women, 29 367 (59.9%) had BCS+RT, 12413 (25.3%) had Mx-RT, and 7206 (14.7%) had Mx+RT. Median follow-up was 6.28 years (range, 0.01-11.70). All-cause death occurred in 6573 cases, with death caused by breast cancer in 2313 cases; 5-year OS was 91.1% (95% CI, 90.8-91.3) and BCSS was 96.3% (95% CI, 96.1-96.4). Apart from expected differences in clinical parameters, women receiving Mx-RT were older, had a lower level of education, and lower income. Both Mx groups had a higher comorbidity burden irrespective of RT. After stepwise adjustment for all covariates, OS and BCSS were significantly worse after Mx-RT (hazard ratio [HR], 1.79; 95% CI, 1.66-1.92 and HR, 1.66; 95% CI, 1.45-1.90, respectively) and Mx+RT (HR, 1.24; 95% CI, 1.13-1.37 and HR, 1.26; 95% CI, 1.08-1.46, respectively) than after BCS+RT.

Conclusions and Relevance

Despite adjustment for previously unmeasured confounders, BCS+RT yielded better survival than Mx irrespective of RT. If both interventions are valid options, mastectomy should not be regarded as equal to breast conservation.

Treatment strategies for locally advanced non-small cell lung cancer in elderly patients: Translating scientific evidence into clinical practice

Treatment of locally advanced NSCLC (LA-NSCLC) is focused on multimodal strategy, including chemotherapy and radiotherapy (in combination or as alternative treatments), followed by surgery in selected cases. Recently, durvalumab consolidation after definitive chemo-radiation has shown a meaningful overall survival benefit. However, it is important to note that elderly patients represent a high proportion of NSCLC population and frailty and comorbidities can significantly limit treatment options. Indeed, elderly patients are under-represented in clinical trials and data to drive treatment selection in this category of patients are scanty. Available data, main issues and controversies on multimodal treatment in elderly LA-NSCLC patients will be reviewed in this paper.

Treatment decision-making and the added value of the general practitioner: A qualitative exploration of cancer patients' perspectives

OBJECTIVE

Cancer patients are increasingly involved in decision-making for cancer treatment. General practitioners' (GPs) support in this process is advocated. Therefore, GPs need to be aware of patients' treatment decision-making process and their potential role. We aim to understand the treatment decision-making process and to explore the added value of GP involvement, from the perspective of cancer patients treated with curative intent.

METHODS

An explorative qualitative study was performed. Semi-structured interviews were conducted with 20 purposively sampled Dutch cancer patients treated with curative intent.

RESULTS

Patients' treatment decision-making process was dominated by a focus on 'safeguarding survival'. Patients generally followed the treatment plan as proposed by their physician and did not always experience having a treatment choice. The majority of patients expressed added value for GP involvement, mainly to provide psychological support, but also for providing shared decision-making (SDM) support.

CONCLUSION

The treatment decision-making process of cancer patients treated with curative intent is dominated by the urge to 'safeguard survival'. GPs should be aware of their added value in providing psychological support and their potential role to support SDM following a cancer diagnosis.

Palliative Radiation Therapy in Older Adults With Cancer: Age-Related Considerations

There are many additional considerations when treating older adults with cancer, especially in the context of palliative care. Currently, radiation therapy is underutilised in some countries and disease sites, but there is also evidence of unnecessary treatment in other contexts. Making rational treatment decisions for older adults necessitates an underlying appraisal of the person's physiological reserve capacity. This is termed 'frailty', and there is considerable heterogeneity in its clinical presentation, from patients who are relatively robust and suitable for standard treatment, to those who are frail and perhaps require a different approach. Frailty assessment also presents an important opportunity for intervention, when followed by Comprehensive Geriatric Assessment (CGA) in those who require it. Generally, a two-step approach, with a short initial screening, followed by CGA, is advocated in geriatric oncology guidelines. This has the potential to optimise care of the older person, and may also reverse or slow the development of frailty. It therefore has an important impact on the patient's quality of life, which is especially valued in the context of palliative care. Frailty assessment also allows a more informed discussion of treatment outcomes and a shared decision-making approach. With regards to the radiotherapy regimen itself, there are many adaptations that can better facilitate the older person, from positioning and immobilisation, to treatment prescriptions. Treatment courses should be as short as possible and take into account the older person's unique circumstances. The additional burden of travel to treatment for the patient, caregiver or family/support network should also be considered. Reducing treatments to single fractions may be appropriate, or alternatively, hypofractionated regimens. In order to enhance care and meet the demands of a rapidly ageing population, future radiation oncology professionals require education on the basic principles of geriatric medicine, as many aspects remain poorly understood.

The vision and role of geriatric oncology in surgical treatment of the elderly patient

The phenomenon of population aging is constantly on the rise, as are the medical needs of elderly subjects. Oncological treatment concerns an ever larger number of elderly patients, raising a number of not only practical and medical questions, but also the ethical interrogations associated with therapeutic decision-making, quality of life and therapeutic obstinacy (futile medical care). Surgeons are increasingly preoccupied by elderly patients on account of the cancer rate among them, and they are compelled to cope with challenges such as morbimortality and prolonged hospitalization. Geriatric oncology is a discipline of increasing importance of which the goal consists in comprehensive care of the elderly cancer patient, care taking into full account his physical and psychological aging, his somatic and cognitive comorbidities, and, last but least, his life expectancy. The opinions and recommendations of geriatric oncologists provide increasingly more orientation for the oncological therapeutic decision-making processes. The objective of this attempt at clarification is to discuss the contributions of this discipline to everyday surgical activity, to provide surgeons with some tools facilitating initial evaluation of their patients, and to remind the reader of situations in which oncological assistance is of paramount importance.

The effect of comorbidities on outcomes in colorectal cancer survivors: a population-based cohort study

PURPOSE

To examine the prevalence of comorbidities and the association of these comorbidities with demographics, tumor characteristics, treatments received, overall survival, and causes of death in a population-based cohort of colorectal cancer (CRC) patients.

METHODS

Adult patients with stage I-III CRC diagnosed between 2004 and 2015 were included. Comorbidities were captured using Charlson comorbidity index. Causes of death were categorized using International Classification of Diseases, tenth revision codes. Patients were categorized into five mutually exclusive comorbid groups (cardiovascular disease alone, diabetes alone, cardiovascular disease plus diabetes, other comorbidities, or no comorbidities). Data were analyzed using descriptive statistics, Kaplan-Meier survival analyses, and Cox proportional hazards models.

RESULTS

There were 12,265 patients. Mean follow-up was 3.8 years. Approximately one third of patients had a least one comorbidity, with cardiovascular disease and diabetes being most common. There were statistically significant differences across comorbid groups on treatments received and overall survival. Those with comorbidity had lower odds of treatment and greater risk of death than those with no comorbidity. Those with cardiovascular disease plus diabetes fared the worst for prognosis (median overall survival 3.3 [2.8-3.7] years; adjusted HR for death, 2.27, 95% CI 2.0-2.6, p < .001). Cardiovascular disease was the most common cause of non-CRC death.

CONCLUSIONS

CRC patients with comorbidity received curative intent treatment less frequently and experienced worse outcomes than patients with no comorbidity. Cardiovascular disease was the most common cause of non-cancer death.

IMPLICATIONS FOR CANCER SURVIVORS

Management of comorbidities, including healthy lifestyle coaching, at diagnosis and into survivorship is an important component of cancer care.

Feasibility of radiotherapy in nonagenarian patients: a retrospective study

PURPOSE

Specific information about radiation therapy in nonagenarians is limited. In order to shed more light on the feasibility of radiotherapy in this challenging subgroup, a retrospective study was performed.

METHODS

The data of 93 consecutive patients receiving irradiation treatment at the Department of Radiation Oncology, Ordensklinikum Linz Barmherzige Schwestern between June 2005 and December 2016 were analyzed. Patient- and treatment-related factors were extracted from the patient records. Overall survival (OS) was defined as time from irradiation to death or last follow-up. The survival rates were analyzed using the Kaplan-Meier method and log-rank test.

RESULTS

The study population of 93 patients was between 90 and 99 years old (median 91 years). It included 59 women (63%) and 34 men (37%). Of these, 38 (41%) received definitive radiotherapy, 14 (15%) received neoadjuvant or adjuvant radiotherapy, whereas a palliative regimen was prescribed in 44% of the cases (n = 41). In all, 79 patients (85%) were able to complete their prescribed course of radiotherapy. While 16 (17%) patients reported grade 2 toxicities or higher, 4 had ≥grade 3 side effects (4%). The median survival was significantly higher in patients treated with adjuvant, neoadjuvant or definitive radiotherapy (13.8 months) compared to patients treated with palliative radiotherapy (3.6 months; p < 0.001).

CONCLUSION

Even in patients managed without preradiotherapy comprehensive geriatric assessment, carefully planned fractionated radiotherapy was feasible and resulted in acceptable rates of acute toxicities.

How Should Palliative Thoracic Radiotherapy Be Fractionated for Octogenarians with Lung Cancer?

BACKGROUND/AIM

Geriatric oncology practice should be based on dedicated studies and real-world experience. Therefore, we evaluated survival outcomes after palliative thoracic radiotherapy in octogenarian patients with lung cancer and analyzed prognostic factors.

PATIENTS AND METHODS

We carried out a retrospective analysis of 51 patients with a median age of 83 years. Three different fractionation regimens were compared: two fractions of 8.5 Gy, 10 fractions of 3 Gy, and higher doses than 30 Gy (maximum biologically equivalent dose in 2-Gy fractions (EQD2) was always lower than 50 Gy). No concomitant chemotherapy was prescribed. Patients with incomplete radiotherapy (16%) were included, in line with the intention-to-treat principle, i.e. based on prescribed rather than accumulated dose.

RESULTS

Median survival was 3.4 months. We observed a relatively high proportion of patients who received radiotherapy in the last 30 days of life (24%). Nevertheless, approximately 10% of patients were alive 3-5 years after treatment. Prognosis was similar for those with stage III and IV disease. Multivariate analysis identified four significant prognostic factors for shorter survival: reduced performance status, serum C-reactive protein (CRP) ≥30 mg/l, leukocytosis, and prescribed radiation dose ≤30 Gy (EQD2=33 Gy). The three different radiotherapy regimens resulted in median survival of 2.4, 2.6 and 11.8 months, respectively.

CONCLUSION

Survival outcomes were highly variable. Given that survival after 10 fractions of 3 Gy was indistinguishable from that after two fractions of 8.5 Gy, we suggest that the latter regimen should be considered for patients with poor prognosis. Patients with favorable prognostic factors should be treated with higher radiation doses, e.g. 15 fractions of 3 Gy.

Patient-reported symptoms and performance status before palliative radiotherapy in geriatric cancer patients (octogenarians)

Purpose

To evaluate differences in baseline parameters including performance status and self-reported symptom burden between geriatric and non-geriatric cancer patients, and to assess the hypothesis that these factors might predispose older patients to incomplete radiotherapy and short survival.

Patients and methods

Retrospective comparison of geriatric and non-geriatric patients treated with palliative radiotherapy (age ⩾80 years and <80 years, respectively). Between 2013 and 2015, 26 geriatric and 76 non-geriatric patients were treated. The Edmonton symptom assessment system (ESAS) was employed to document baseline symptoms.

Results

Most patients received radiotherapy for bone metastases, commonly 5-10 fractions. Geriatric patients had significantly less pain at rest and depression. No strong trends towards higher symptom burden in older patients emerged for any of the items. Overall survival was similar in the two subgroups with different age and also in a separate age-stratified analysis of patients with performance status >2. Relatively few patients were irradiated in the terminal stage of disease, defined as final 30 days of life (8% in geriatric and 12% in other patients, p = 0.73). A higher number of geriatric patients failed to complete their prescribed course of radiotherapy (14 vs. 3%, p = 0.08), despite lower rates of prescription of more than 10 fractions in this group (15 vs. 23%, p > 0.2).

Conclusions

These data support utilization of palliative radiotherapy irrespective of age. However, care should be taken in assigning the right fractionation regimen in order to avoid lengthy treatment courses when survival is limited, such as in patients with performance status >2.

The impact of comorbidity on cancer and its treatment

Answer questions and earn CME/CNE Comorbidity is common among cancer patients and, with an aging population, is becoming more so. Comorbidity potentially affects the development, stage at diagnosis, treatment, and outcomes of people with cancer. Despite the intimate relationship between comorbidity and cancer, there is limited consensus on how to record, interpret, or manage comorbidity in the context of cancer, with the result that patients who have comorbidity are less likely to receive treatment with curative intent. Evidence in this area is lacking because of the frequent exclusion of patients with comorbidity from randomized controlled trials. There is evidence that some patients with comorbidity have potentially curative treatment unnecessarily modified, compromising optimal care. Patients with comorbidity have poorer survival, poorer quality of life, and higher health care costs. Strategies to address these issues include improving the evidence base for patients with comorbidity, further development of clinical tools to assist decision making, improved integration and coordination of care, and skill development for clinicians. CA Cancer J Clin 2016;66:337-350. © 2016 American Cancer Society.

[Radiation therapy for elderly patients]

Cancer is a disease that predominantly occurs in older patients who represent a quarter of the population in western countries. Numerous types of cancer are observed in elderly people. Radiotherapy is one of the most powerful treatments against cancer. Most of published studies have demonstrated feasibility of radiotherapy in curative or palliative intent whatever cancer types are considered. Complete geriatric assessment and a multidisciplinary approach are the key points. The purpose of this review is to highlight sights of radiation oncology specifically related to aging. Particular emphasis is placed on logistic and technical aspects of radiation, as dose, irradiated volume, fractionation and the potential usefulness of new technologies.

A review of the management of elderly patients with non-small-cell lung cancer

Most patients with non-small-cell lung cancer (NSCLC) are elderly but evidence to guide appropriate treatment decisions for this age group is generally scant. Careful evaluation of the elderly should be undertaken to ensure that treatment appropriate for the stage of the tumour is guided by patient characteristics and not by age. The Comprehensive Geriatric Assessment (CGA) remains the preferred option, but briefer tools may be appropriate to select patients for further evaluation. The predicted outcome should be used to guide management decisions together with a reappraisal of polypharmacy. Patient expectations should also be taken into account. Management recommendations are generally similar to those of general guidelines for the NSCLC population, although the risks of surgery and toxicity of chemotherapy and radiotherapy are often increased in the elderly compared with younger patients; therefore, patients should be closely scrutinised and subjected to a CGA to ensure suitability of the planned treatment. If surgery is indicated, then lobectomy is generally the preferred option, although limited resection may be more feasible for some. Radiotherapy with curative intent is an alternative, with stereotactic body radiotherapy the most likely preferred modality. Adjuvant chemotherapy is also an appropriate approach, whereas adjuvant radiotherapy is generally not recommended. Concurrent chemoradiotherapy should be considered for elderly patients with inoperable locally advanced disease and chemotherapy for advanced/metastatic disease. Efforts should also be made to increase participation of elderly patients with NSCLC in clinical trials, thereby enhancing evidence-based treatment decisions for this majority group. This will require overcoming barriers relating to trial design and to physician and patient awareness and attitudes.

Impact of comorbidity on survival after palliative radiotherapy

PURPOSE

To evaluate prognostic factors for survival after palliative radiotherapy (PRT) with consideration of different comorbidities and the Charlson comorbidity index (CCI).

PATIENTS AND METHODS

Between 2007 and 2012, 525 consecutive patients were treated with PRT and included in this retrospective study. Most patients received PRT for bone metastases, for brain metastases, or in order to improve thoracic symptoms from lung cancer. Median age was 69 years. Uni- and multivariate analyses were performed.

RESULTS

Only 7% of patients had no comorbidity. A CCI of 1–2 was present in 49%, a CCI of 3–4, in 36%, and a higher CCI in 9% of patients. Younger patients, female patients, and patients who had not been smokers had significantly less comorbidity. Patients without comorbidity had significantly better median performance status (PS) and were more likely to receive palliative systemic therapy. Both lower CCI and absence of more than one cancer diagnosis independently predicted longer survival. Further significant parameters in multivariate analysis were PS and number of organs with metastatic involvement. Exploratory analyses suggested that the impact of CCI was largest in patients older than 60 years and was absent in those with brain metastases.

CONCLUSION

We recommend assessment of comorbidity when prescribing PRT and selecting the optimal fractionation regimen, because most patients with severe comorbidities had limited survival. One of the possible explanations could be that only a minority of these patients are fit for systemic therapy, which plays an important role in the overall treatment concept.

The Molecular Crosstalk between the MET Receptor Tyrosine Kinase and the DNA Damage Response-Biological and Clinical Aspects

Radiation therapy remains an imperative treatment modality for numerous malignancies. Enduring significant technical achievements both on the levels of treatment planning and radiation delivery have led to improvements in local control of tumor growth and reduction in healthy tissue toxicity. Nevertheless, resistance mechanisms, which presumably also involve activation of DNA damage response signaling pathways that eventually may account for loco-regional relapse and consequent tumor progression, still remain a critical problem. Accumulating data suggest that signaling via growth factor receptor tyrosine kinases, which are aberrantly expressed in many tumors, may interfere with the cytotoxic impact of ionizing radiation via the direct activation of the DNA damage response, leading eventually to so-called tumor radioresistance. The aim of this review is to overview the current known data that support a molecular crosstalk between the hepatocyte growth factor receptor tyrosine kinase MET and the DNA damage response. Apart of extending well established concepts over MET biology beyond its function as a growth factor receptor, these observations directly relate to the role of its aberrant activity in resistance to DNA damaging agents, such as ionizing radiation, which are routinely used in cancer therapy and advocate tumor sensitization towards DNA damaging agents in combination with MET targeting.

The pharmacological bases of the antiangiogenic activity of paclitaxel

In the mid 1990s, researchers began to investigate the antiangiogenic activity of paclitaxel as a possible additional mechanism contributing to its antineoplastic activity in vivo. In the last decade, a number of studies showed that paclitaxel has antiangiogenic activity that could be ascribed to the inhibition of either tubule formation or cell migration, and to an antiproliferative effect towards activated endothelial cells. Furthermore, paclitaxel was shown to downregulate VEGF and Ang-1 expression in tumor cells, and to increase the secretion of TSP-1 in the tumor microenvironment. Moreover, the new pharmaceutical formulations of paclitaxel (such as liposome-encapsulated paclitaxel, ABI-007, and paclitaxel entrapped in emulsifying wax nanoparticles) enhanced the in vivo antiangiogenic activity of the drug. Thus, the preclinical data of paclitaxel may be exploited to implement a novel and rational therapeutic strategy to control tumor progression in patients.