De-escalation of axillary treatment in the event of a positive sentinel lymph node biopsy in cT1-2 N0 breast cancer treated with mastectomy: nationwide registry study (BOOG 2013-07).

BACKGROUND: Trials have demonstrated the safety of omitting completion axillary lymph node dissection in patients with cT1-2 N0 breast cancer operated with breast-conserving surgery who have limited metastatic burden in the sentinel lymph node. The aim of this registry study was to provide insight into the oncological safety of omitting completion axillary treatment in patients operated with mastectomy who have limited-volume sentinel lymph node metastasis. METHODS: Women diagnosed in 2013-2014 with unilateral cT1-2 N0 breast cancer treated with mastectomy, with one to three sentinel lymph node metastases (pN1mi-pN1a), were identified from the Netherlands Cancer Registry, and classified by axillary treatment: no completion axillary treatment, completion axillary lymph node dissection, regional radiotherapy, or completion axillary lymph node dissection followed by regional radiotherapy. The primary endpoint was 5-year regional recurrence rate. Secondary endpoints included recurrence-free interval and overall survival, among others. RESULTS: In total, 1090 patients were included (no completion axillary treatment, 219 (20.1%); completion axillary lymph node dissection, 437 (40.1%); regional radiotherapy, 327 (30.0%); completion axillary lymph node dissection and regional radiotherapy, 107 (9.8%)). Patients in the group without completion axillary treatment had more favourable tumour characteristics and were older. The overall 5-year regional recurrence rate was 1.3%, and did not differ significantly between the groups. The recurrence-free interval was also comparable among groups. The group of patients who did not undergo completion axillary treatment had statistically significantly worse 5-year overall survival, owing to a higher percentage of non-cancer deaths. CONCLUSION: In this registry study of patients with cT1-2 N0 breast cancer treated with mastectomy, with low-volume sentinel lymph node metastasis, the 5-year regional recurrence rate was low and comparable between patients with and without completion axillary treatment.

De-escalation of radiotherapy after primary chemotherapy in cT1-2N1 breast cancer (RAPCHEM; BOOG 2010-03): 5-year follow-up results of a Dutch, prospective, registry study.

BACKGROUND: Primary chemotherapy in breast cancer poses a dilemma with regard to adjuvant locoregional radiotherapy, as guidelines for locoregional radiotherapy were originally based on pathology results of primary surgery. We aimed to evaluate the oncological safety of de-escalated locoregional radiotherapy in patients with cT1-2N1 breast cancer treated with primary chemotherapy, according to a predefined, consensus-based study guideline. METHODS: In this prospective registry study (RAPCHEM, BOOG 2010-03), patients referred to one of 17 participating radiation oncology centres in the Netherlands between Jan 1, 2011, and Jan 1, 2015, with cT1-2N1 breast cancer (one to three suspicious nodes on imaging before primary chemotherapy, of which at least one had been pathologically confirmed), and who were treated with primary chemotherapy and surgery of the breast and axilla were included in the study. The study guideline comprised three risk groups for locoregional recurrence, with corresponding locoregional radiotherapy recommendations: no chest wall radiotherapy and no regional radiotherapy in the low-risk group, only local radiotherapy in the intermediate-risk group, and locoregional radiotherapy in the high-risk group. Radiotherapy consisted of a biologically equivalent dose of 25 fractions of 2 Gy, with or without a boost. During the study period, the generally applied radiotherapy technique in the Netherlands was forward-planned or inverse-planned intensity modulated radiotherapy. 5-year follow-up was assessed, taking into account adherence to the study guideline, with locoregional recurrence rate as primary endpoint. We hypothesised that 5-year locoregional recurrence rate would be less than 4% (upper-limit 95% CI 7·8%). This study was registered at ClinicalTrials.gov, NCT01279304, and is completed. FINDINGS: 838 patients were eligible for 5-year follow-up analyses: 291 in the low-risk group, 370 in the intermediate-risk group, and 177 in the high-risk group. The 5-year locoregional recurrence rate in all patients was 2·2% (95% CI 1·4-3·4). The 5-year locoregional recurrence rate was 2·1% (0·9-4·3) in the low-risk group, 2·2% (1·0-4·1) in the intermediate-risk group, and 2·3% (0·8-5·5) in the high-risk group. If the study guideline was followed, the locoregional recurrence rate was 2·3% (0·8-5·3) for the low-risk group, 1·0% (0·2-3·4) for the intermediate-risk group, and 1·4% (0·3-4·5) for the high-risk group. INTERPRETATION: In this study, the 5-year locoregional recurrence rate was less than 4%, which supports our hypothesis that it is oncologically safe to de-escalate locoregional radiotherapy based on locoregional recurrence risk, in selected patients with cT1-2N1 breast cancer treated with primary chemotherapy, according to this predefined, consensus-based study guideline. FUNDING: Dutch Cancer Society. TRANSLATION: For the Dutch translation of the abstract see Supplementary Materials section.

Ten-year recurrence rates for breast cancer subtypes in the Netherlands: A large population-based study.

Here we report for the first time the relation between breast cancer subtypes and 10-year recurrence rates and mortality in the Netherlands. All operated women diagnosed with invasive non-metastatic breast cancer in 2005 in the Netherlands were included. Patients were classified into breast cancer subtypes according to ER, PR, HER2 status and grade: luminal A, luminal B, HER2 positive and triple negative. Percentages and hazards of recurrence were compared among subtypes. Adjusted 10-year overall (OS) and recurrence-free survival (RFS) were calculated using multivariable Cox regression. Of 8,062 patients, 4,482 (56%) were luminal A, 2,090 (26%) luminal B, 504 (6%) HER2 positive and 986 (12%) triple negative. Local recurrences (7.5%) and distant metastases (25.6%) occurred most often in HER2 positive disease and the least often in luminal A (3.7% and 9.5%, respectively). Regional recurrences were most often diagnosed in triple negative disease (5.2%), and the least often in luminal A (1.7%). HER2 positive and triple negative subtypes had the highest recurrence rates in the second year, while luminal A and B showed a more continuous pattern over time, with lobular tumours recurring more often. After adjustment for differences in baseline characteristics, triple negative disease showed worse 10-year OS and triple negative and HER2 positive disease had the lowest 10-year RFS. In the Netherlands, breast cancer subtypes are important predictors for 10-year recurrence rates. Knowledge on recurrence and survival rates according to these different subtypes, in combination with other prognostic factors, can support patient-tailored treatment and individualised follow-up.

Effectiveness of low-dose radiation therapy on symptoms in patients with knee osteoarthritis: a randomised, double-blinded, sham-controlled trial.

OBJECTIVES: Low-dose radiation therapy (LDRT) for benign disorders such as knee osteoarthritis (OA) is widely used in some parts of the world, despite absence of controlled studies. We evaluated the effect of LDRT on symptoms and inflammation in patients with knee OA. METHODS: In this randomised, double-blinded, sham-controlled clinical trial (RCT), we recruited patients with knee OA (clinical ACR criteria) in the Netherlands, aged ≥50 years, pain score ≥5/10 and non-responding to analgesics and exercise therapy. Patients were randomised 1:1 to receive LDRT (1 Gray per fraction) or sham intervention six times in 2 weeks, stratified by pain (<8 versus ≥8/10). Primary outcome was the proportion of OMERACT-OARSI responders, 3 months postintervention. Secondary outcomes included pain, function and inflammatory signs assessed by ultrasound, MRI and serum inflammatory markers. RESULTS: We randomly assigned 55 patients: 27 (49%) to LDRT and 28 (51%) to sham. At 3 months postintervention, 12/27 patients (44%; 95% CI 26% to 63%) in the LDRT vs 12/28 patients (43%; 95% CI 25% to 61%) in the sham group responded; difference 2% (95% CI 25% to 28%), OR adjusted for the stratifying variable was 1.1 (95% CI 0.4 to 3.2). Also, for clinical and any of the inflammatory signs, no differences were observed. CONCLUSIONS: We found no substantial beneficial effect on symptoms and inflammatory signs of LDRT in patients knee OA, compared with sham treatment. Therefore, based on this RCT and the absence of other high-quality evidence, we advise against the use of LDRT as treatment for knee OA. TRIAL REGISTRATION NUMBER: NTR4574.

An actualised population-based study on the use of radiotherapy in breast cancer patients in the Netherlands.

The utilization rate of RT increased from 64.4% in 2011 to 70.3% in 2015. After BCS and mastectomy, 97.3% and 26.1% of the patients received RT, respectively. For patients undergoing BCS and mastectomy, lower age and ER + tumours were associated with higher RT utilisation rates. After mastectomy, also larger tumour sizes, lymph node involvement, grade-2 and 3 tumours and diagnosis in more recent years were associated with higher RT use.

Breast conserving therapy and mastectomy revisited: Breast cancer-specific survival and the influence of prognostic factors in 129,692 patients.

This large population-based study compared breast-conserving surgery with radiation therapy (BCT) with mastectomy on (long-term) breast cancer-specific (BCSS) and overall survival (OS), and investigated the influence of several prognostic factors. Patients with primary T1-2N0-2M0 breast cancer, diagnosed between 1999 and 2012, were selected from the Netherlands Cancer Registry. We investigated the 1999-2005 (long-term outcome) and the 2006-2012 cohort (contemporary adjuvant systemic therapy). Cause of death was derived from the Statistics Netherlands (CBS). Multivariable analyses, per time cohort, were performed in T1-2N0-2, and separately in T1-2N0-1 and T1-2N2 stages. The T1-2N0-1 stages were further stratified for age, hormonal receptor and HER2 status, adjuvant systemic therapy and comorbidity. In total, 129,692 patients were included. In the 1999-2005 cohort, better BCSS and OS for BCT than mastectomy was seen in all subgroups, except in patients < 40 years with T1-2N0-1 stage. In the 2006-2012 cohort, superior BCSS and OS were found for T1-2N0-1, but not for T1-2N2. Subgroup analyses for T1-2N0-1 showed superior BCSS and OS for BCT in patients >50 years, not treated with chemotherapy and with comorbidity. Both treatments led to similar BCSS in patients <50 years, without comorbidity and those treated with chemotherapy. Although confounding by severity and residual confounding cannot be excluded, this study showed better long-term BCSS for BCT than mastectomy. Even with more contemporary diagnostics and therapies we identified several subgroups that may benefit from BCT. Our results support the hypothesis that BCT might be preferred in most breast cancer patients when both treatments are suitable.

Second Cancer Risk Up to 40 Years after Treatment for Hodgkin's Lymphoma.

BACKGROUND: Survivors of Hodgkin's lymphoma are at increased risk for treatment-related subsequent malignant neoplasms. The effect of less toxic treatments, introduced in the late 1980s, on the long-term risk of a second cancer remains unknown. METHODS: We enrolled 3905 persons in the Netherlands who had survived for at least 5 years after the initiation of treatment for Hodgkin's lymphoma. Patients had received treatment between 1965 and 2000, when they were 15 to 50 years of age. We compared the risk of a second cancer among these patients with the risk that was expected on the basis of cancer incidence in the general population. Treatment-specific risks were compared within the cohort. RESULTS: With a median follow-up of 19.1 years, 1055 second cancers were diagnosed in 908 patients, resulting in a standardized incidence ratio (SIR) of 4.6 (95% confidence interval [CI], 4.3 to 4.9) in the study cohort as compared with the general population. The risk was still elevated 35 years or more after treatment (SIR, 3.9; 95% CI, 2.8 to 5.4), and the cumulative incidence of a second cancer in the study cohort at 40 years was 48.5% (95% CI, 45.4 to 51.5). The cumulative incidence of second solid cancers did not differ according to study period (1965-1976, 1977-1988, or 1989-2000) (P=0.71 for heterogeneity). Although the risk of breast cancer was lower among patients who were treated with supradiaphragmatic-field radiotherapy not including the axilla than among those who were exposed to mantle-field irradiation (hazard ratio, 0.37; 95% CI, 0.19 to 0.72), the risk of breast cancer was not lower among patients treated in the 1989-2000 study period than among those treated in the two earlier periods. A cumulative procarbazine dose of 4.3 g or more per square meter of body-surface area (which has been associated with premature menopause) was associated with a significantly lower risk of breast cancer (hazard ratio for the comparison with no chemotherapy, 0.57; 95% CI, 0.39 to 0.84) but a higher risk of gastrointestinal cancer (hazard ratio, 2.70; 95% CI, 1.69 to 4.30). CONCLUSIONS: The risk of second solid cancers did not appear to be lower among patients treated in the most recent calendar period studied (1989-2000) than among those treated in earlier periods. The awareness of an increased risk of second cancer remains crucial for survivors of Hodgkin's lymphoma. (Funded by the Dutch Cancer Society.).

The 2016 Assisi Think Tank Meeting on breast cancer: white paper.

PURPOSE: To identify weak points in daily routine use of radiation therapy (RT) for non-metastatic breast cancer patients, particularly when data are lacking or equivocal, a "think tank" of experts met in Assisi. METHODS: Before the meeting, controversial issues on non-metastatic breast cancer were identified and reviewed, and clinical practice investigated by means of an online questionnaire. During the 3-day meeting, topics were discussed in-depth with attendees and potential sponsors that are involved in breast cancer treatment. RESULTS: Three issues were identified as needing further investigation: (1) Regional lymph node treatment in early-stage breast cancer; (2) Combined post-mastectomy RT and breast reconstruction; (3) RT in patients treated with primary systemic therapy. Future research proposals included the following: (1) Participating in appropriately selected on-going clinical trials; (2) Designing new randomized controlled clinical trials and prospective population cohort studies; (3) Setting-up large database(s) to generate predictive response models and detect biomarkers for tailored loco-regional treatments. CONCLUSIONS: It is hoped that the ATTM findings, as described in the present white paper, will stimulate a new generation of radiation oncologists to focus on research in these areas, and that the white paper will become a tool for multidisciplinary groups to help them design research proposals and strategies.

Duration of androgen suppression in the treatment of prostate cancer.

BACKGROUND: The combination of radiotherapy plus long-term medical suppression of androgens (> or = 2 years) improves overall survival in patients with locally advanced prostate cancer. We compared the use of radiotherapy plus short-term androgen suppression with the use of radiotherapy plus long-term androgen suppression in the treatment of locally advanced prostate cancer. METHODS: We randomly assigned patients with locally advanced prostate cancer who had received external-beam radiotherapy plus 6 months of androgen suppression to two groups, one to receive no further treatment (short-term suppression) and the other to receive 2.5 years of further treatment with a luteinizing hormone-releasing hormone agonist (long-term suppression). An outcome of noninferiority of short-term androgen suppression as compared with long-term suppression required a hazard ratio of more than 1.35 for overall survival, with a one-sided alpha level of 0.05. An interim analysis showed futility, and the results are presented with an adjusted one-sided alpha level of 0.0429. RESULTS: A total of 1113 men were registered, of whom 970 were randomly assigned, 483 to short-term suppression and 487 to long-term suppression. After a median follow-up of 6.4 years, 132 patients in the short-term group and 98 in the long-term group had died; the number of deaths due to prostate cancer was 47 in the short-term group and 29 in the long-term group. The 5-year overall mortality for short-term and long-term suppression was 19.0% and 15.2%, respectively; the observed hazard ratio was 1.42 (upper 95.71% confidence limit, 1.79; P=0.65 for noninferiority). Adverse events in both groups included fatigue, diminished sexual function, and hot flushes. CONCLUSIONS: The combination of radiotherapy plus 6 months of androgen suppression provides inferior survival as compared with radiotherapy plus 3 years of androgen suppression in the treatment of locally advanced prostate cancer. (ClinicalTrials.gov number, NCT00003026.)

Are breast conservation and mastectomy equally effective in the treatment of young women with early breast cancer? Long-term results of a population-based cohort of 1,451 patients aged ≤ 40 years.

To compare the effectiveness of breast-conserving therapy (BCT) and mastectomy, all women aged ≤ 40 years, treated for early-stage breast cancer in the southern part of the Netherlands between 1988 and 2005, were identified. A total of 562 patients underwent mastectomy and 889 patients received BCT. During follow-up, 23 patients treated with mastectomy and 135 patients treated with BCT developed a local relapse without previous or simultaneous evidence of distant disease. The local relapse risk for patients treated with mastectomy was 4.4% (95% confidence interval (CI) 2.4-6.4) at 5 years and reached a plateau after 6 years at 6.0% (95% CI 3.5-8.5). After BCT, the 5-, 10- and 15-year risks were 8.3% (95% CI 6.3-10.5), 18.4% (95% CI 15.0-21.8) and 28.2% (95% CI 23.0-33.4), respectively (P < 0.0001). Adjuvant systemic therapy following BCT reduced the 15-year local relapse risk from 32.9% (95% CI 26.7-39.1) to 16.1% (95% CI 9.1-23.1), (P = 0.0007). In conclusion, local tumor control in young patients with early-stage breast cancer is worse after BCT than after mastectomy. Adjuvant systemic therapy significantly improves local control following BCT and also for that reason it should be considered for most patients ≤ 40 years. Long-term follow-up is highly recommended for young patients after BCT, because even with systemic treatment an annual risk of local relapse of 1% remains up to 15 years after treatment.

Exclusive endocrine therapy or partial breast irradiation for women aged ≥70  years with luminal A-like early stage breast cancer (NCT04134598 - EUROPA): Proof of concept of a randomized controlled trial comparing health related quality of life by patient reported outcome measures.

BACKGROUND: Postoperative radiation therapy after breast conserving surgery in the older adult population is a matter of debate; although radiation therapy was shown to benefit these patients concerning local disease control, the absolute benefit was small and potentially negligible. Partial breast irradiation has been introduced as an alternative treatment approach for low-risk patients. Older adult patients with early breast cancer constitute a unique population with regards to prognosis and potential comorbidities, thus minimizing treatment to maintain health-related quality of life (HRQoL) without compromising survival is extremely important. Estimates of the patient's risk of benefit and/or harm with treatment should be performed together with an assessment of baseline comorbidities, life expectancy, and care preferences. Published data suggest that radiation therapy or endocrine therapy alone resulted in excellent disease control in older women with early breast cancer, and that the combination of both treatments has less incremental benefit than expected. Conversely, the toxicity profile of endocrine therapy is well known, often significantly impacting long term HRQoL of these potentially frail patients. METHODS: Patients older than 70  years receiving breast conserving surgery with T1N0, Luminal A-like tumors will be randomized to receive partial breast irradiation-alone or endocrine therapy-alone. The main objectives are to determine patient reported outcome measures in terms of HRQoL, as assessed by the EORTC QLQ-C30 using the global health status of patients, and to demonstrate a non-inferior local control rate between arms. Secondary endpoints are represented by individual scales from QLQ-C30 and module QLQ-BR45 scores; ELD14 questionnaire; geriatric COre DatasEt assessment; distant control rate, adverse events rates, breast cancer specific, and overall survival. DISCUSSION: The EUROPA trial is a new randomized trial focused on older adults (≥70  years) affected by good prognosis primary breast cancer. Our assumption is that postoperative radiation therapy-alone avoids the long-term toxicity of endocrine therapy and favorably impacts on HRQoL in this population. In the current report we present the trial's background and methods, focusing on perspectives in the field of precision medicine. TRIAL REGISTRATION: The trial is registered with ClinicalTrial.gov Identifier NCT04134598 / EUROPA trial.

The Assisi Think Tank Meeting Breast Large Database for Standardized Data Collection in Breast Cancer-ATTM.BLADE.

Background: During the 2016 Assisi Think Tank Meeting (ATTM) on breast cancer, the panel of experts proposed developing a validated system, based on rapid learning health care (RLHC) principles, to standardize inter-center data collection and promote personalized treatments for breast cancer. Material and Methods: The seven-step Breast LArge DatabasE (BLADE) project included data collection, analysis, application, and evaluation on a data-sharing platform. The multidisciplinary team developed a consensus-based ontology of validated variables with over 80% agreement. This English-language ontology constituted a breast cancer library with seven knowledge domains: baseline, primary systemic therapy, surgery, adjuvant systemic therapies, radiation therapy, follow-up, and toxicity. The library was uploaded to the BLADE domain. The safety of data encryption and preservation was tested according to General Data Protection Regulation (GDPR) guidelines on data from 15 clinical charts. The system was validated on 64 patients who had undergone post-mastectomy radiation therapy. In October 2018, the BLADE system was approved by the Ethical Committee of Fondazione Policlinico Gemelli IRCCS, Rome, Italy (Protocol No. 0043996/18). Results: From June 2016 to July 2019, the multidisciplinary team completed the work plan. An ontology of 218 validated variables was uploaded to the BLADE domain. The GDPR safety test confirmed encryption and data preservation (on 5000 random cases). All validation benchmarks were met. Conclusion:BLADE is a support system for follow-up and assessment of breast cancer care. To successfully develop and validate it as the first standardized data collection system, multidisciplinary collaboration was crucial in selecting its ontology and knowledge domains. BLADE is suitable for multi-center uploading of retrospective and prospective clinical data, as it ensures anonymity and data privacy.

Prostatic duct adenocarcinoma: clinical characteristics, treatment options, and outcomes - a Rare Cancer Network study.

BACKGROUND: To evaluate the clinical characteristics, contemporary treatment options, and outcome of prostatic duct adenocarcinoma (PDA), we initiated a Rare Cancer Network (RCN) study. MATERIALS AND METHODS: Six member institutions of the RCN collected clinical data on 31 patients. Treatment consisted of definitive radiotherapy in 14 patients and radical prostatectomy in 16 patients. One patient was treated with androgen deprivation alone. The mean follow-up period was 56 months. RESULTS: Of the 14 patients managed with radiotherapy, 1 patient developed bone metastases and died of prostate cancer, and 1 patient had a biochemical relapse 8 years after definitive radiotherapy. Of the 16 patients who underwent radical prostatectomy, 2 patients developed bone metastases, one of who died of disease. Three patients that relapsed after prostatectomy were successfully salvaged with radiotherapy. The patient that was treated with androgen deprivation alone developed bone metastases at 10 months, was treated with chemotherapy, and was alive after 22 months. CONCLUSIONS: Our results suggest that PDA is a cancer with a behavior similar to that of high Gleason grade acinar carcinoma. Good local control can be achieved by either radiation or surgery. Postoperative radiotherapy seems to work as an adjuvant or salvage treatment, and most tumors appear to respond to androgen deprivation.

Winter is over: The use of Artificial Intelligence to individualise radiation therapy for breast cancer.

Artificial intelligence demonstrated its value for automated contouring of organs at risk and target volumes as well as for auto-planning of radiation dose distributions in terms of saving time, increasing consistency, and improving dose-volumes parameters. Future developments include incorporating dose/outcome data to optimise dose distributions with optimal coverage of the high-risk areas, while at the same time limiting doses to low-risk areas. An infinite gradient of volumes and doses to deliver spatially-adjusted radiation can be generated, allowing to avoid unnecessary radiation to organs at risk. Therefore, data about patient-, tumour-, and treatment-related factors have to be combined with dose distributions and outcome-containing databases.

Increased risk for second primary rectal cancer after pelvic radiation therapy.

BACKGROUND: The aim of this study was to analyse the association between pelvic radiation therapy (RT) and the development of rectal cancer as a second primary cancer. METHODS: Data on patients treated for a primary pelvic cancer between 1989 and 2007 were retrieved from the population-based Netherlands Cancer Registry. Patients treated for more than one pelvic cancer were excluded. To estimate the cumulative incidence of rectal cancer, Fine and Gray's competing risk model was used with death as a competing event. Survival was calculated using multivariable Cox regression. RESULTS: A total of 192,658 patients were included, of which 62,630 patients were treated with RT for their pelvic cancer. Primary tumours were located in the prostate (50.1%), bladder (19.2%), endometrium (13.9%), ovaries (10.0%), cervix (6.4%) and vagina (0.4%). At a median interval of 6 years (range 0-24), 1369 patients developed a rectal cancer. Overall, the risk for rectal cancer was increased in patients who underwent RT for the previous pelvic cancer (subhazard ratio [SHR]: 1.72, 95% confidence interval [CI]: 1.55-1.91). Analysis for each tumour location specifically showed an increased risk in patients who received RT for prostate (SHR: 1.89, 95% CI: 1.66-2.16) or endometrial cancer (SHR: 1.50, 95% CI: 1.13-2.00). A protective effect of RT was observed for patients with bladder cancer (SHR 0.67, 95% CI: 0.47-0.94). There was no survival difference between patients with rectal cancer with or without previous RT (hazard ratio: 0.94, 95% CI: 0.79-1.11). CONCLUSIONS: Patients who received RT for a previous pelvic cancer were at increased risk for rectal cancer. The risk was modest and pronounced in patients receiving RT for prostate and endometrial cancer.

Long-term efficacy of low-dose radiation therapy on symptoms in patients with knee and hand osteoarthritis: follow-up results of two parallel randomised, sham-controlled trials.

BACKGROUND: Low-dose radiation therapy is commonly used as treatment for benign diseases, including osteoarthritis, in some countries (eg, Germany). We have previously presented our 3-month follow-up results of two randomised sham-controlled trials, in which no substantial effects of low-dose radiation therapy on clinical outcomes were seen in patients with knee and hand osteoarthritis. Here we report the 6-month and 12-month results of these studies. METHODS: In one randomised sham-controlled trial, patients with knee osteoarthrosis were recruited, and in the other trial patients with hand osteoarthritis were recruited. All patients were recruited from the department of rheumatology of Sint Maartenskliniek (Nijmegen, The Netherlands) and the trials were undertaken in parallel. Patients were eligible if they had knee or hand osteoarthritis according to American College of Rheumatology (ACR) criteria, had a pain score of 5 or more on a 0-10 scale for at least 15 of the past 30 days, and did not meet 2011 modified ACR criteria for fibromyalgia. In each study, patients were randomly assigned (1:1), stratified by pain score (<8 vs ≥8) using a computer-generated randomisation list and stratified block randomisation, to low-dose radiation therapy (six fractions of 1 Gy low-dose radiation therapy in 2 weeks) or sham (six sessions with 0 Gy of radiation therapy in 2 weeks) intervention. Patients and researchers involved in patient contact or assessments were masked to group allocation, whereas the radiotherapy technologist who did the treatment was unmasked. Patients completed questionnaires (numeric rating scale of patients' global assessment and validated measures for pain and functioning) at baseline and at 1, 2, 3, 6, and 12 months after starting treatment. The primary outcome was the proportion of participants who responded according to the Outcome Measures in Rheumatology Osteoarthritis Research Society International responder criteria at 3 months, which has been reported previously. Here we report the proportion of participants who responded at 6 months and 12 months, and other clinical outcomes of pain, functioning, and patients' global assessment of their symptoms. We used logistic and linear mixed-models analyses to assess differences in number of responders and continuous outcomes. Safety was assessed in all participants who received at least one fraction of low-dose radiation or sham treatment. This study is registered with the Netherlands Trial Registry, NTR4574, and is closed to accrual. FINDINGS: Between Oct 14, 2015, and May 3, 2017, 213 patients were screened for inclusion for the knee osteoarthritis study, of whom 55 were eligible and randomly assigned to low-dose radiation therapy (n=27) or sham intervention (n=28). In parallel, for the hand osteoarthritis study, 368 patients were screened and 56 were randomly assigned low-dose radiation (n=28) or sham intervention (n=28). Some minor imbalances in baseline demographic characteristics in terms of sex and age were seen in both the knee and hand cohorts. In the knee osteoarthritis cohort, 48 patients were assessible at 6 months and 50 were assessible at 12 months, and in the hand osteoarthritis cohort 52 patients were assessible at 6 and 12 months. We found no significant differences at 6 or 12 months in the proportion of participants who had a response for both groups. In the knee osteoarthritis group, at 6 months, the number of responders was nine (41%) of 22 patients who received low-dose radiation therapy versus nine (35%) of 26 patients who received the sham intervention (difference in proportion 7% [95% CI -20 to 33]; odds ratio [OR] 1·34 [95% CI 0·41 to 4·42]); and at 12 months, 13 (52%) of 25 patients versus 11 (44%) of 25 patients responded (difference in proportion 8% [-19 to 35]; OR 1·41 [0·45 to 4·48]). In the hand osteoarthritis group, at 6 months, the number of responders was seven (28%) of 25 patients who received low-dose radiation therapy versus 11 (31%) of 27 patients who received the sham intervention (difference in proportion 12% [-38 to 13]; OR 0·57 [0·18 to 1·81]); and at 12 months, eight (31%) of 26 patients versus seven (27%) of 26 patients responded (difference in proportion 4% [-20 to 29]; OR 1·23 [0·37 to 4·12]). We did not find any difference between groups in other clinical outcomes at 6 or 12 months. Three participants with knee osteoarthritis in the sham intervention group and two participants with hand osteoarthritis in the low-dose radiation therapy group had serious adverse effects, none of which were considered to be related to the intervention. INTERPRETATION: We did not find evidence of a delayed effect of low-dose radiation therapy for patients with knee and hand osteoarthritis. Our placebo-controlled results suggest that the large effects of low-dose radiation therapy reported in clinical practice and observational studies can probably be explained by a regression to the mean effect and response to placebo. FUNDING: Dutch Arthritis Foundation and Stichting Landelijk Katholiek Reumacentrum, Netherlands.

Different statistical techniques dealing with confounding in observational research: measuring the effect of breast-conserving therapy and mastectomy on survival.

PURPOSE: Propensity trimming, hierarchical modelling and instrumental variable (IV) analysis are statistical techniques dealing with confounding, cluster-related variation or confounding by severity. This study aimed to explain (dis)advantages of these techniques in estimating the effect of breast-conserving therapy (BCT) and mastectomy on 10-year distant metastasis-free survival (DMFS). METHODS: All women diagnosed in 2005 with primary T1-2N0-1 breast cancer treated with BCT or mastectomy were selected from the Netherlands Cancer Registry. We used multivariable Cox regression to correct for confounding. Propensity trimming was used to create a more homogeneous population for which the treatment choice was not self-evident. Hospital of surgery was used as hierarchical level to handle hospital-related variation, and as IV to deal with unmeasured confounding. RESULTS: Multivariable Cox regression showed higher 10-year DMFS for BCT than mastectomy [HR 0.70 (95% CI 0.60-82)]. Propensity trimming on the 10-90th and the 20-80th percentile of the propensity score distribution and hierarchical modelling showed similar HRs. IV analysis showed no significant difference between BCT and mastectomy. CONCLUSION: Unmeasured confounding is very difficult to eliminate in observational research. We cannot conclude that BCT or mastectomy has a causal relationship with 10-year DMFS. It is crucial to critically evaluate all model's assumptions, and to be careful in drawing firm conclusions.

Overall and disease-specific survival of Hodgkin lymphoma survivors who subsequently developed gastrointestinal cancer.

BACKGROUND: Hodgkin lymphoma (HL) survivors have an increased risk of gastrointestinal (GI) cancer. This study aims to evaluate whether survival of patients who survived HL and developed GI cancer differs from survival of first primary GI cancer patients. METHODS: Overall and cause-specific survival of GI cancer patients in a HL survivor cohort (GI-HL, N = 104, including esophageal, gastric, small intestinal, and colorectal cancer) was compared with survival of a first primary GI cancer patient cohort (GI-1, N = 1025, generated by case matching based on tumor site, gender, age, and year of diagnosis). Cox proportional hazards regression was used for survival analyses. Multivariable analyses were adjusted for GI cancer stage, grade of differentiation, surgery, radiotherapy, and chemotherapy. RESULTS: GI-HL cancers were diagnosed at a median age of 54 years (interquartile range 45-60). No differences in tumor stage or frequency of surgery were found. GI-HL patients less often received radiotherapy (8% vs 23% in GI-1 patients, P < 0.001) and chemotherapy (28% vs 41%, P = 0.01) for their GI tumor. Compared with GI-1 patients, overall and disease-specific survival of GI-HL patients was worse (univariable hazard ratio (HR) 1.30, 95% confidence interval (CI) 1.03-1.65, P = 0.03; and HR 1.29, 95% CI 1.00-1.67, P = 0.049, respectively; multivariable HR 1.33, 95% CI 1.05-1.68, P = 0.02; and HR 1.33, 95% CI 1.03-1.72, P = 0.03, respectively). CONCLUSIONS: Long-term overall and disease-specific survival of GI cancer in HL survivors is worse compared with first primary GI cancer patients. Differences in tumor stage, grade of differentiation, or treatment could not explain this worse survival.