Radiotherapy waiting times for women with breast cancer: a population-based cohort study

Timing and Delays in Breast Cancer Evaluation and Treatment

BACKGROUND

Even small delays in the treatment of breast cancer are a frequently expressed concern of patients. Knowledge about this subject is important for clinicians to counsel patients appropriately and realistically, while also optimizing care. Although data and quality measures regarding time to chemotherapy and radiotherapy have been present for some time, data regarding surgical care are more recent and no standard exists. This review was written to discuss our current knowledge about the relationship of treatment times to outcomes.

METHODS

The published medical literature addressing delays and optimal times to treatment was reviewed in the context of our current time-dependent standards for chemotherapy and radiotherapy. The surgical literature and the lack of a time-dependent surgical standard also were discussed, suggesting a possible standard.

RESULTS

Risk factors for delay are numerous, and tumor doubling times are both difficult to determine and unhelpful to assess the impact of longer treatment times on outcomes. Evaluation components also have a time cost and are inextricable from the patient's workup. Although the published literature has lack of uniformity, optimal times to each modality are strongly suggested by emerging data, supporting the current quality measures. Times to surgery, chemotherapy, and radiotherapy all have a measurable impact on outcomes, including disease-free survival, disease-specific survival, and overall survival.

CONCLUSIONS

Delays have less of an impact than often thought but have a measurable impact on outcomes. Optimal times from diagnosis are < 90 days for surgery, < 120 days for chemotherapy, and, where chemotherapy is administered, < 365 days for radiotherapy.

A biological network-based regularized artificial neural network model for robust phenotype prediction from gene expression data

BACKGROUND

Stratification of patient subpopulations that respond favorably to treatment or experience and adverse reaction is an essential step toward development of new personalized therapies and diagnostics. It is currently feasible to generate omic-scale biological measurements for all patients in a study, providing an opportunity for machine learning models to identify molecular markers for disease diagnosis and progression. However, the high variability of genetic background in human populations hampers the reproducibility of omic-scale markers. In this paper, we develop a biological network-based regularized artificial neural network model for prediction of phenotype from transcriptomic measurements in clinical trials. To improve model sparsity and the overall reproducibility of the model, we incorporate regularization for simultaneous shrinkage of gene sets based on active upstream regulatory mechanisms into the model.

RESULTS

We benchmark our method against various regression, support vector machines and artificial neural network models and demonstrate the ability of our method in predicting the clinical outcomes using clinical trial data on acute rejection in kidney transplantation and response to Infliximab in ulcerative colitis. We show that integration of prior biological knowledge into the classification as developed in this paper, significantly improves the robustness and generalizability of predictions to independent datasets. We provide a Java code of our algorithm along with a parsed version of the STRING DB database.

CONCLUSION

In summary, we present a method for prediction of clinical phenotypes using baseline genome-wide expression data that makes use of prior biological knowledge on gene-regulatory interactions in order to increase robustness and reproducibility of omic-scale markers. The integrated group-wise regularization methods increases the interpretability of biological signatures and gives stable performance estimates across independent test sets.

ÖGRO survey on radiotherapy capacity in Austria : Status quo and estimation of future demands

BACKGROUND

A comprehensive evaluation of the current national and regional radiotherapy capacity in Austria with an estimation of demands for 2020 and 2030 was performed by the Austrian Society for Radiation Oncology, Radiobiology and Medical Radiophysics (ÖGRO).

MATERIALS AND METHODS

All Austrian centers provided data on the number of megavoltage (MV) units, treatment series, fractions, percentage of retreatments and complex treatment techniques as well as the daily operating hours for the year 2014. In addition, waiting times until the beginning of radiotherapy were prospectively recorded over the first quarter of 2015. National and international epidemiological prediction data were used to estimate future demands.

RESULTS

For a population of 8.51 million, 43 MV units were at disposal. In 14 radiooncological centers, a total of 19,940 series with a mean number of 464 patients per MV unit/year and a mean fraction number of 20 (range 16-24) per case were recorded. The average re-irradiation ratio was 14%. The survey on waiting times until start of treatment showed provision shortages in 40% of centers with a mean waiting time of 13.6 days (range 0.5-29.3 days) and a mean maximum waiting time of 98.2 days. Of all centers, 21% had no or only a limited ability to deliver complex treatment techniques. Predictions for 2020 and 2030 indicate an increased need in the overall number of MV units to a total of 63 and 71, respectively.

CONCLUSION

This ÖGRO survey revealed major regional differences in radiooncological capacity. Considering epidemiological developments, an aggravation of the situation can be expected shortly. This analysis serves as a basis for improved public regional health care planning.

QuickStart radiotherapy: an inter-professional approach to expedite radiotherapy treatment in early breast cancer

Background and purpose

This study aims to develop an expedited radiotherapy (RT) process and evaluate its time savings in women requiring whole breast RT.

Material and methods

An inter-professional RT team streamlined the computed tomography (CT) simulation and treatment pathway for a ‘QuickStart’ process. Target delineation was performed by an advanced practice radiation therapist and approved by the radiation oncologist (RO) for planning. Automated breast planning software was used for treatment planning and standard quality checks were performed. To assess time savings, the initial 25 QuickStart patients were matched with women who underwent whole breast simulation on the same day (±3 days), treated using the conventional process.

Results

A total of 73 post-lumpectomy women were treated through the QuickStart process; the median consent-to-RT was 2 days (range: 0–13) and the mean CT simulation-to-RT treatment was 2 hours and 42 minutes (SD 0:30). In the subgroup analysis, QuickStart patients saved an average of 11 days from CT simulation-to-RT and had shorter median wait-times for both surgery/chemotherapy-to-RT (60 versus 38 days;p=0·002) and consultation-to-RT (7 versus 20 days;p&lt;0·001).

Conclusions

Through inter-professional team efforts and the application of automated planning software, we have achieved a process that significantly decreases patient wait-times while maintaining the quality of whole breast RT.

Factors influencing time between surgery and radiotherapy: A population based study of breast cancer patients

This study describes variation in the time interval between surgery and radiotherapy in breast cancer (BC) patients and assesses factors at patient, hospital and radiotherapy centre (RTC) level influencing this variation. To do so, the factors were investigated in BC patients using multilevel logistic regression. The study sample consisted of 15,961 patients from the Netherlands Cancer Registry at 79 hospitals and 19 (RTCs) with breast-conserving surgery or mastectomy directly followed by radiotherapy. The percentage of patients starting radiotherapy ≤42 days varied from 14% to 94%. Early year of incidence, higher age, higher stage, mastectomy, higher ASA category and no availability of radiotherapy facilities were significantly associated with a longer time interval between radiotherapy and surgery. More patients received radiotherapy ≤42 days in hospitals with on-site radiotherapy facilities (OR 1.36, p = 0.024). Among the remainder, significant variation was found at the RTC level (11.1%, σ(2) = 0.254, SE 0.054), and at the hospital level (6.4% σ2 = 0.443, SE 0.163) (ICC 0.064). The significant delay and unexplained variance remaining at the RCT and hospital level suggests delays caused by the patient referral pathway from hospital to RCT, and indicates potential for improvement at both levels.

Availability and outcomes of radiotherapy in Central Poland during the 2005-2012 period - an observational study

BACKGROUND

Using a cross-database integrative approach, we performed an epidemiological analysis in a representative region of central Poland to evaluate the availability of radiotherapy (RTx) and overall survival of adult patients undergoing RTx for cancer.

METHODS

Epidemiological data on cancer incidence in the 2005-2012 period were obtained from the Nationwide Cancer Registry. Using data from the Ministry of Internal Affairs, we collected survival information of all patients treated in the only centre providing RTx for a region inhabited by approximately 2.6 million people.

RESULTS

After filtering out individuals on the basis of exclusion criteria, the final dataset covered 17,736 patients. Availability of RTx increased marginally, from 23.5% (2005) to 24.4% (2011, R = 0.39, p = 0.38), with the highest values noted in patients with cervical (78.5%), prostate (70.6%) and breast cancer (62.7%). However, due to the decreasing population of the region, we noted increasing disparity in the likelihood of receiving RTx depending on the patient's area of residence, with rural areas becoming progressively more neglected. The best prognosis was noted among patients with breast or prostate cancer with 5-year OS rates reaching 81.2% and 83.3%, respectively. Multivariate analysis controlling for type of diagnosis and patient age showed a time-dependent improvement in outcomes (HR(95% CI): 0.96(0.94-0.98); p < 0.0001).

CONCLUSIONS

Availability of RTx in Poland is still below that reported by developed European centres. Survival of patients undergoing radical RTx has gradually improved, although it is still below that of leading RTx departments, potentially due to delayed diagnosis or organisational barriers, necessitating further investigations.

Partial breast irradiation techniques in early breast cancer

Whole breast irradiation represents an integral part of combined breast-conserving treatment of early breast cancer. A new concept includes replacing traditionally fractionated whole breast postoperative radiotherapy by accelerated partial breast irradiation. The latter involves a variety of techniques and may be applied intraoperatively or shortly after the surgery. The intraoperative techniques include photon or electron external beam irradiation and interstitial high dose rate (HDR) brachytherapy, whereas the postoperative techniques comprise interstitial brachytherapy, be it HDR, pulse dose rate (PDR) or low dose rate (LDR), intracavitary brachytherapy and external beam radiotherapy using electrons, photons or protons. This article presents accelerated partial breast irradiation techniques, ongoing phase III trials evaluating their value and recommendations for clinical practice.

Waiting times for radiotherapy after breast-conserving surgery and the association with survival: a path analysis

AIMS

To investigate the association between radiotherapy waiting times and survival in women who have undergone breast-conserving surgery using data from two English cancer registry regions. The data were analysed using path analysis to account for the complex variable interrelationships within the data.

MATERIALS AND METHODS

Cases of female invasive breast cancer diagnosed during the period 1 January 1998 to 31 December 2005 were identified and linked to an extract of Hospital Episode Statistics data. A subset of these linked records where women underwent breast-conserving surgery was extracted (n=18,158). Patient, tumour and treatment information were extracted. A path model was developed with three outcome variables: survival, time to receive radiotherapy and receipt of chemotherapy before radiotherapy.

RESULTS

During the study period, the median radiotherapy waiting time in region 1 increased from 70 days to 128.5 days. In region 2, the median wait increased from 44 days in 1998 to 68 days in 2001, then decreased to 42 days by 2005. In the path model, radiotherapy waiting time was not associated with survival (hazard ratio=1.00, 95% confidence interval 0.99-1.01 per week increase in both regions). Patients receiving chemotherapy before radiotherapy waited 12.3 weeks (region 1) and 6.3 weeks (region 2) longer for their radiotherapy than those not receiving chemotherapy. Patients with stage II/III disease waited longer than patients with stage I disease. Younger age, diagnosis of stage II/III disease and presence of co-morbidities were associated with increased odds of receiving chemotherapy before radiotherapy.

CONCLUSIONS

This study found no association between waiting times for radiotherapy and survival in two regions of England, despite increases in waiting times over the study period. Such an association, if real, may only become apparent after a longer period of follow-up.

Partial breast irradiation: a review of techniques and indications

The addition of whole-breast external beam radiotherapy (EBRT) to breast-conserving surgery results in a significant reduction in the risk of death due to breast cancer, but this may be offset by an increase in deaths from other causes and toxicity to surrounding organs. Because of this, and with a view to patterns of local recurrence, irradiation of the tumour bed has been explored in selected patients with early breast cancer using a variety of radiotherapeutic modalities. This review article explores the treatment options for partial breast irradiation and examines their role within the field of breast cancer treatment.

Impact of interval from breast conserving surgery to radiotherapy on local recurrence in older women with breast cancer: retrospective cohort analysis

OBJECTIVES

To determine if the length of interval between breast conserving surgery and start of radiotherapy affects local recurrence and to identify factors that might be associated with delay in older women with breast cancer.

DESIGN

Retrospective cohort analysis with Cox proportional hazards models to study the association between time to radiotherapy and local recurrence, and propensity score and instrumental variable analyses to confirm findings. Logistic regression investigated factors associated with later start of radiotherapy.

SETTING

Linked database (Surveillance, Epidemiology, and End Results Program-Medicare) in the United States

PARTICIPANTS

18 050 women aged over 65 with stage 0-II breast cancer diagnosed in 1991-2002 who received breast conserving surgery and radiotherapy but not chemotherapy.

MAIN OUTCOME MEASURE

Local recurrence.

RESULTS

Median time from surgery to start of radiotherapy was 34 days, with 29.9% (n=5389) of women starting radiotherapy after six weeks. Just over 4% (n=734) of the cohort experienced a local recurrence. After adjustment for clinical and sociodemographic factors, intervals over six weeks were associated with increased likelihood of local recurrence (hazard ratio 1.19, 95% confidence interval 1.01 to 1.39, P=0.033). When the interval was modelled continuously (assessing accumulation of risk by day), the effect was statistically stronger (hazard ratio 1.005 per day, 1.002 to 1.008, P=0.004). Propensity score and instrumental variable analysis confirmed these findings. Instrumental variable analysis showed that intervals over six weeks were associated with a 0.96% increase in recurrence at five years (P=0.026). In multivariable analysis, starting radiotherapy after six weeks was significantly associated with positive nodes, comorbidity, history of low income, Hispanic ethnicity, non-white race, later year of diagnosis, and residence outside the southern states of the US.

CONCLUSIONS

There is a continuous relation between the interval from breast conserving surgery to radiotherapy and local recurrence in older women with breast cancer, suggesting that starting radiotherapy as soon as possible could minimise the risk of local recurrence. There are considerable disparities in time to starting radiotherapy after breast conserving surgery. Regions of the US known to have increased rates of breast conserving surgery had longer intervals before radiotherapy, suggesting limitations in capacity. Given the known negative impact of local recurrence on survival, mechanisms to ameliorate disparities and policies regarding waiting times for treatment might be warranted.

Correlates and effect of suboptimal radiotherapy in women with ductal carcinoma in situ or early invasive breast cancer

BACKGROUND

The study aimed to identify factors associated with less-than-optimal radiotherapy (RT) and its impact on disease-free survival in women aged 66+ years diagnosed with stage I breast cancer or ductal carcinoma in situ (DCIS).

METHODS

The subjects were women diagnosed from 1991 to 1999 in the linked Surveillance, Epidemiology, and End Results (SEER)-Medicare database who underwent breast-conserving surgery and RT within 12 months postdiagnosis. The authors conducted descriptive and multivariate survival analyses, and considered age, race, poverty, marital status, comorbidity indices, rural/urban, radiation oncologist density, comedo necrosis histology (DCIS only), chemotherapy receipt (stage I only), and RT completion (3+ weeks of treatment) and delay (8+ weeks postsurgery without chemotherapy; 4+ weeks postchemotherapy).

RESULTS

Of 7791 subjects, 16% experienced RT delay, and 3% had incomplete RT. Subjects with stage I disease who were more likely to delay RT were of black race (odds ratio [OR], 1.56; 95% confidence interval [CI], 1.17-2.08), whereas women in areas of high radiation oncologist density were less likely to delay (OR, 0.73; 95% CI, 0.66-0.81). Those living in high poverty areas were less likely to complete RT (P < .03), as were those undergoing chemotherapy (OR, 1.82; 95% CI, 1.15-2.88). Stage I breast cancer patients with delayed RT were more likely to experience a subsequent breast event (OR, 1.14; 95% CI, 1.00-1.30), and those with incomplete RT had a higher rate of overall mortality (OR, 1.32; 95% CI, 1.06-1.63). Factors associated with lower subsequent breast events included older age, lower poverty, and being married. RT delays of 12+ weeks (or 8+ weeks postchemotherapy) had a strongly negative impact on subsequent events (OR, 3.94; 95% CI, 2.51-6.17 for DCIS; OR, 2.77; 95% CI, 1.84-2.59 for stage I).

CONCLUSIONS

RT should be facilitated to ensure completion and timeliness, especially for early invasive breast cancer patients.

The occurrence of invasive cancers following a diagnosis of breast carcinoma in situ

Approximately 1 in every 600 women attending breast-screening programmes in the United Kingdom is diagnosed with breast carcinoma in situ (BCIS). However, there is little information on the occurrence of subsequent cancers (other than second breast cancers) in these women. We investigated the occurrence of invasive cancers in 12 836 women diagnosed with BCIS in southeast England between 1971 and 2003, using data from the Thames Cancer Registry. A greater than expected number of subsequent cancers was found for two sites: breast (standardised incidence ratio (SIR) 1.96; 95% confidence interval (CI) 1.79–2.14) and corpus uteri (SIR 1.42; 95% CI 1.11–1.78). For subsequent ipsilateral breast cancer in those treated with breast conservation, the excess was independent of the time since diagnosis of BCIS, whereas for subsequent contralateral breast cancer, there was a steady decline in excess over time. For subsequent uterine cancer, the excess became statistically significant only at >5 years after BCIS diagnosis, consistent with a treatment effect. This was further supported by Cox regression anaysis: the risk of subsequent uterine cancer was significantly increased in women receiving hormonal therapy compared with those not receiving it, with a hazard ratio of 2.97 (95% CI 1.84–4.80).