Summary Background Incorporation of a taxane as adjuvant treatment for early breast cancer offers potential for further improvement of anthracycline-based treatment. The UK TACT study (CRUK01/001) ...investigated whether sequential docetaxel after anthracycline chemotherapy would improve patient outcome compared with standard chemotherapy of similar duration. Methods In this multicentre, open-label, phase III, randomised controlled trial, 4162 women (aged >18 years) with node-positive or high-risk node-negative operable early breast cancer were randomly assigned by computer-generated permuted block randomisation to receive FEC (fluorouracil 600 mg/m2 , epirubicin 60 mg/m2 , cyclophosphamide 600 mg/m2 at 3-weekly intervals) for four cycles followed by docetaxel (100 mg/m2 at 3-weekly intervals) for four cycles (n=2073) or control (n=2089). For the control regimen, centres chose either FEC for eight cycles (n=1265) or epirubicin (100 mg/m2 at 3-weekly intervals) for four cycles followed by CMF (cyclophosphamide 600 mg/m2 , methotrexate 40 mg/m2 , and fluorouracil 600 mg/m2 at 4-weekly intervals) for four cycles (n=824). The primary endpoint was disease-free survival. Analysis was by intention to treat (ITT). This study is registered as an International Standard Randomised Controlled Trial, number ISRCTN79718493. Findings All randomised patients were included in the ITT population. With a median follow-up of 62 months, disease-free survival events were seen in 517 of 2073 patients in the experimental group compared with 539 of 2089 controls (hazard ratio HR 0·95, 95% CI 0·85–1·08; p=0·44). 75·6% (95% CI 73·7–77·5) of patients in the experimental group and 74·3% (72·3–76·2) of controls were alive and disease-free at 5 years. The proportion of patients who reported any acute grade 3 or 4 adverse event was significantly greater in the experimental group than in the control group (p<0·0001); the most frequent events were neutropenia (937 events vs 797 events), leucopenia (507 vs 362), and lethargy (456 vs 272). Interpretation This study did not show any overall gain from the addition of docetaxel to standard anthracycline chemotherapy. Exploration of predictive biomarker-defined subgroups might have the potential to better target the use of taxane-based therapy. Funding Cancer Research UK (CRUK 01/001), Sanofi-Aventis, Pfizer, and Roche.
Summary Background 5-year results of the UK Standardisation of Breast Radiotherapy (START) trials suggested that lower total doses of radiotherapy delivered in fewer, larger doses (fractions) are at ...least as safe and effective as the historical standard regimen (50 Gy in 25 fractions) for women after primary surgery for early breast cancer. In this prespecified analysis, we report the 10-year follow-up of the START trials testing 13 fraction and 15 fraction regimens. Methods From 1999 to 2002, women with completely excised invasive breast cancer (pT1–3a, pN0–1, M0) were enrolled from 35 UK radiotherapy centres. Patients were randomly assigned to a treatment regimen after primary surgery followed by chemotherapy and endocrine treatment (where prescribed). Randomisation was computer-generated and stratified by centre, type of primary surgery (breast-conservation surgery or mastectomy), and tumour bed boost radiotherapy. In START-A, a regimen of 50 Gy in 25 fractions over 5 weeks was compared with 41·6 Gy or 39 Gy in 13 fractions over 5 weeks. In START-B, a regimen of 50 Gy in 25 fractions over 5 weeks was compared with 40 Gy in 15 fractions over 3 weeks. Eligibility criteria included age older than 18 years and no immediate surgical reconstruction. Primary endpoints were local-regional tumour relapse and late normal tissue effects. Analysis was by intention to treat. Follow-up data are still being collected. This study is registered as an International Standard Randomised Controlled Trial, number ISRCTN59368779. Findings START-A enrolled 2236 women. Median follow-up was 9·3 years (IQR 8·0–10·0), after which 139 local-regional relapses had occurred. 10-year rates of local-regional relapse did not differ significantly between the 41·6 Gy and 50 Gy regimen groups (6·3%, 95% CI 4·7–8·5 vs 7·4%, 5·5–10·0; hazard ratio HR 0·91, 95% CI 0·59–1·38; p=0·65) or the 39 Gy (8·8%, 95% CI 6·7–11·4) and 50 Gy regimen groups (HR 1·18, 95% CI 0·79–1·76; p=0·41). In START-A, moderate or marked breast induration, telangiectasia, and breast oedema were significantly less common normal tissue effects in the 39 Gy group than in the 50 Gy group. Normal tissue effects did not differ significantly between 41·6 Gy and 50 Gy groups. START-B enrolled 2215 women. Median follow-up was 9·9 years (IQR 7·5–10·1), after which 95 local-regional relapses had occurred. The proportion of patients with local-regional relapse at 10 years did not differ significantly between the 40 Gy group (4·3%, 95% CI 3·2–5·9) and the 50 Gy group (5·5%, 95% CI 4·2–7·2; HR 0·77, 95% CI 0·51–1·16; p=0·21). In START-B, breast shrinkage, telangiectasia, and breast oedema were significantly less common normal tissue effects in the 40 Gy group than in the 50 Gy group. Interpretation Long-term follow-up confirms that appropriately dosed hypofractionated radiotherapy is safe and effective for patients with early breast cancer. The results support the continued use of 40 Gy in 15 fractions, which has already been adopted by most UK centres as the standard of care for women requiring adjuvant radiotherapy for invasive early breast cancer. Funding Cancer Research UK, UK Medical Research Council, UK Department of Health.
Summary Background The effects of extra-pleural pneumonectomy (EPP) on survival and quality of life in patients with malignant pleural mesothelioma have, to our knowledge, not been assessed in a ...randomised trial. We aimed to assess the clinical outcomes of patients who were randomly assigned to EPP or no EPP in the context of trimodal therapy in the Mesothelioma and Radical Surgery (MARS) feasibility study. Methods MARS was a multicentre randomised controlled trial in 12 UK hospitals. Patients aged 18 years or older who had pathologically confirmed mesothelioma and were deemed fit enough to undergo trimodal therapy were included. In a prerandomisation registration phase, all patients underwent induction platinum-based chemotherapy followed by clinical review. After further consent, patients were randomly assigned (1:1) to EPP followed by postoperative hemithorax irradiation or to no EPP. Randomisation was done centrally with computer-generated permuted blocks stratified by surgical centre. The main endpoints were feasibility of randomly assigning 50 patients in 1 year (results detailed in another report), proportion randomised who received treatment, proportion eligible (registered) who proceeded to randomisation, perioperative mortality, and quality of life. Patients and investigators were not masked to treatment allocation. This is the principal report of the MARS study; all patients have been recruited. Analyses were by intention to treat. This trial is registered, number ISRCTN95583524. Findings Between Oct 1, 2005, and Nov 3, 2008, 112 patients were registered and 50 were subsequently randomly assigned: 24 to EPP and 26 to no EPP. The main reasons for not proceeding to randomisation were disease progression (33 patients), inoperability (five patients), and patient choice (19 patients). EPP was completed satisfactorily in 16 of 24 patients assigned to EPP; in five patients EPP was not started and in three patients it was abandoned. Two patients in the EPP group died within 30 days and a further patient died without leaving hospital. One patient in the no EPP group died perioperatively after receiving EPP off trial in a non-MARS centre. The hazard ratio HR for overall survival between the EPP and no EPP groups was 1·90 (95% CI 0·92–3·93; exact p=0·082), and after adjustment for sex, histological subtype, stage, and age at randomisation the HR was 2·75 (1·21–6·26; p=0·016). Median survival was 14·4 months (5·3–18·7) for the EPP group and 19·5 months (13·4 to time not yet reached) for the no EPP group. Of the 49 randomly assigned patients who consented to quality of life assessment (EPP n=23; no EPP n=26), 12 patients in the EPP group and 19 in the no EPP group completed the quality of life questionnaires. Although median quality of life scores were lower in the EPP group than the no EPP group, no significant differences between groups were reported in the quality of life analyses. There were ten serious adverse events reported in the EPP group and two in the no EPP group. Interpretation In view of the high morbidity associated with EPP in this trial and in other non-randomised studies a larger study is not feasible. These data, although limited, suggest that radical surgery in the form of EPP within trimodal therapy offers no benefit and possibly harms patients. Funding Cancer Research UK ( CRUK/04/003 ), the June Hancock Mesothelioma Research Fund, and Guy's and St Thomas' NHS Foundation Trust.
Summary Background The optimum endocrine treatment for postmenopausal women with advanced hormone-receptor-positive breast cancer that has progressed on non-steroidal aromatase inhibitors (NSAIs) is ...unclear. The aim of the SoFEA trial was to assess a maximum double endocrine targeting approach with the steroidal anti-oestrogen fulvestrant in combination with continued oestrogen deprivation. Methods In a composite, multicentre, phase 3 randomised controlled trial done in the UK and South Korea, postmenopausal women with hormone-receptor-positive breast cancer (oestrogen receptor ER positive, progesterone receptor PR positive, or both) were eligible if they had relapsed or progressed with locally advanced or metastatic disease on an NSAI (given as adjuvant for at least 12 months or as first-line treatment for at least 6 months). Additionally, patients had to have adequate organ function and a WHO performance status of 0–2. Participants were randomly assigned (1:1:1) to receive fulvestrant (500 mg intramuscular injection on day 1, followed by 250 mg doses on days 15 and 29, and then every 28 days) plus daily oral anastrozole (1 mg); fulvestrant plus anastrozole-matched placebo; or daily oral exemestane (25 mg). Randomisation was done with computer-generated permuted blocks, and stratification was by centre and previous use of an NSAI as adjuvant treatment or for locally advanced or metastatic disease. Participants and investigators were aware of assignment to fulvestrant or exemestane, but not of assignment to anastrozole or placebo. The primary endpoint was progression-free survival (PFS). Analyses were by intention to treat. This trial is registered with ClinicalTrials.gov , numbers NCT00253422 (UK) and NCT00944918 (South Korea). Findings Between March 26, 2004, and Aug 6, 2010, 723 patients underwent randomisation: 243 were assigned to receive fulvestrant plus anastrozole, 231 to fulvestrant plus placebo, and 249 to exemestane. Median PFS was 4·4 months (95% CI 3·4–5·4) in patients assigned to fulvestrant plus anastrozole, 4·8 months (3·6–5·5) in those assigned to fulvestrant plus placebo, and 3·4 months (3·0–4·6) in those assigned to exemestane. No difference was recorded between the patients assigned to fulvestrant plus anastrozole and fulvestrant plus placebo (hazard ratio 1·00, 95% CI 0·83–1·21; log-rank p=0·98), or between those assigned to fulvestrant plus placebo and exemestane (0·95, 0·79–1·14; log-rank p=0·56). 87 serious adverse events were reported: 36 in patients assigned to fulvestrant plus anastrozole, 22 in those assigned to fulvestrant plus placebo, and 29 in those assigned to exemestane. Grade 3–4 adverse events were rare; the most frequent were arthralgia (three in the group assigned to fulvestrant plus anastrozole; seven in that assigned to fulvestrant plus placebo; eight in that assigned to exemestane), lethargy (three; 11; 11), and nausea or vomiting (five; two; eight). Interpretation After loss of response to NSAIs in postmenopausal women with hormone-receptor-positive advanced breast cancer, maximum double endocrine treatment with 250 mg fulvestrant combined with oestrogen deprivation is no better than either fulvestrant alone or exemestane. Funding Cancer Research UK and AstraZeneca.
Summary Background Adjuvant chemotherapy for early breast cancer has improved outcomes but causes toxicity. The UK TACT2 trial used a 2×2 factorial design to test two hypotheses: whether use of ...accelerated epirubicin would improve time to tumour recurrence (TTR); and whether use of oral capecitabine instead of cyclophosphamide would be non-inferior in terms of patients' outcomes and would improve toxicity, quality of life, or both. Methods In this multicentre, phase 3, randomised, controlled trial, we enrolled patients aged 18 years or older from 129 UK centres who had histologically confirmed node-positive or high-risk node-negative operable breast cancer, had undergone complete excision, and were due to receive adjuvant chemotherapy. Patients were randomly assigned to receive four cycles of 100 mg/m2 epirubicin either every 3 weeks (standard epirubicin) or every 2 weeks with 6 mg pegfilgrastim on day 2 of each cycle (accelerated epirubicin), followed by four 4-week cycles of either classic cyclophosphamide, methotrexate, and fluorouracil (CMF; 600 mg/m2 cyclophosphamide intravenously on days 1 and 8 or 100 mg/m2 orally on days 1–14; 40 mg/m2 methotrexate intravenously on days 1 and 8; and 600 mg/m2 fluorouracil intravenously on days 1 and 8 of each cycle) or four 3-week cycles of 2500 mg/m2 capecitabine (1250 mg/m2 given twice daily on days 1–14 of each cycle). The randomisation schedule was computer generated in random permuted blocks, stratified by centre, number of nodes involved (none vs one to three vs four or more), age (≤50 years vs >50 years), and planned endocrine treatment (yes vs no). The primary endpoint was TTR, defined as time from randomisation to first invasive relapse or breast cancer death, with intention-to-treat analysis of standard versus accelerated epirubicin and per-protocol analysis of CMF versus capecitabine. This trial is registered with ISRCTN, number 68068041, and with ClinicalTrials.gov , number NCT00301925. Findings From Dec 16, 2005, to Dec 5, 2008, 4391 patients (4371 women and 20 men) were recruited. At a median follow-up of 85·6 months (IQR 80·6–95·9) no significant difference was seen in the proportions of patients free from TTR events between the accelerated and standard epirubicin groups (overall hazard ratio HR 0·94, 95% CI 0·81–1·09; stratified p=0·42). At 5 years, 85·9% (95% CI 84·3–87·3) of patients receiving standard epirubicin and 87·1% (85·6–88·4) of those receiving accelerated epirubicin were free from TTR events. 4358 patients were included in the per-protocol analysis, and no difference was seen in the proportions of patients free from TTR events between the CMF and capecitabine groups (HR 0·98, 95% CI 0·85–1.14; stratified p=0·00092 for non-inferiority). Compared with baseline, significantly more patients taking CMF than those taking capecitabine had clinically relevant worsening of quality of life at end of treatment (255 58% of 441 vs 235 50% of 475; p=0·011) and at 12 months (114 34% of 334 vs 89 22% of 401; p<0·001 at 12 months) and had worse quality of life over time (p<0·0001). Detailed toxicity and quality-of-life data were collected from 2115 (48%) of treated patients. The most common grade 3 or higher adverse events in cycles 1–4 were neutropenia (175 16%) and fatigue (56 5%) of the 1070 patients treated with standard epirubicin, and fatigue (63 6%) and infection (34 3%) of the 1045 patients treated with accelerated epirubicin. In cycles 5–8, the most common grade 3 or higher adverse events were neutropenia (321 31%) and fatigue (109 11%) in the patients treated with CMF, and hand-foot syndrome (129 12%) and diarrhoea (67 6%) in the 1044 patients treated with capcitabine. Interpretation We found no benefit from increasing the dose density of the anthracycline component of chemotherapy. However, capecitabine could be used in place of CMF without significant loss of efficacy and with improved quality of life. Funding Cancer Research UK, Amgen, Pfizer, and Roche.
Summary Background The necessary margin of excision for cutaneous melanomas greater than 2 mm in thickness is controversial. At a median follow-up of 5 years, findings from our previously published ...randomised trial of narrow (1 cm) versus wide (3 cm) excision margins in patients with thick cutaneous melanomas showed that narrow margins were associated with an increased frequency of locoregional relapse, but no significant difference in overall survival was apparent. We now report a long-term survival analysis of that trial. Methods We did a randomised, open-label multicentre trial in 59 hospitals—57 in the UK, one in Poland, and one in South Africa. Patients with one primary localised cutaneous melanoma greater than 2 mm in Breslow thickness on the trunk or limbs (excluding palms or soles) were randomly assigned (1:1) centrally to receive surgery with either a 1 cm or 3 cm excision margin following an initial surgery. The randomisation lists were generated with random permuted blocks and stratified by centre and extent of initial surgery. The endpoints of this analysis were overall survival and melanoma-specific survival. Analyses were done in the intention-to-treat population. This trial was not registered because it predated mandatory trial registration. Findings Between Dec 16, 1992, and May 22, 2001, we randomly assigned 900 patients to surgery with either a 1 cm excision margin (n=453) or a 3 cm excision margin (n=447). At a median follow-up of 8·8 years (106 months IQR 76–135, 494 patients had died, with 359 of these deaths attributed to melanoma. 194 deaths were attributed to melanoma in the 1 cm group compared with 165 in the 3 cm group (unadjusted hazard ratio HR 1·24 95% CI 1·01–1·53; p=0·041). Although a higher number of deaths overall occurred in the 1 cm group compared with the 3 cm group (253 vs 241), the difference was not significant (unadjusted HR 1·14 95% CI 0·96–1·36; p=0·14). Surgical complications were reported in 35 (8%) patients in the 1 cm excision margin group and 65 (15%) patients in the 3 cm group. Interpretation Our findings suggest that a 1 cm excision margin is inadequate for cutaneous melanoma with Breslow thickness greater than 2 mm on the trunk and limbs. Current guidelines advise a 2 cm margin for melanomas greater than 2 mm in thickness but only a 1 cm margin for thinner melanomas. The adequacy of a 1 cm margin for thinner melanomas with poor prognostic features should be addressed in future randomised studies. Funding Cancer Research UK, North Thames National Health Service Executive, Northern and Yorkshire National Health Service Executive, British United Provident Association Foundation, British Association of Plastic Surgeons, the Meirion Thomas Cancer Research Fund, and the National Institute for Health and Research Biomedical Research Centre at The Royal Marsden NHS Foundation Trust.
Summary Background Few trials of adjuvant breast radiotherapy have incorporated patient-reported breast symptoms and related areas of quality of life. We assessed these measures in a quality-of-life ...study that was part of the randomised START (Standardisation of Breast Radiotherapy) trials. Methods In START trial A, 2236 patients were randomly assigned to receive either 39 Gy or 41·6 Gy delivered in 13 fractions over 5 weeks or a global standard of 50 Gy in 25 fractions. In START trial B, 2215 women were randomly assigned to receive either 40 Gy in 15 fractions over 3 weeks or the same control regimen (50 Gy in 25 fractions) as in trial A. 2739 patients were eligible for the quality-of-life study of whom 2208 (81%) were accrued (1129 patients from trial A and 1079 from trial B). Participants completed the EORTC QLQ-C30 and BR23 questionnaires and protocol-specific radiotherapy items up to 5 years after radiotherapy. We compared results across regimens with generalised estimating equations and survival analyses. The START trials are registered, ISRCTN59368779. Findings At 5 years, up to 40% women reported moderate or marked changes to the breast after radiotherapy, and arm and shoulder pain affected up to a third of patients. Breast symptoms and body image concerns reduced over time. Rates of radiotherapy adverse effects were lower for the 39 Gy regimen in trial A and the 40 Gy regimen in trial B, compared with the 50 Gy control regimen; rates of radiotherapy adverse effects were similar between the 41·6 Gy and 50 Gy regimens in trial A. Adverse change in skin appearance was significantly lower for patients who received 39 Gy compared with those who received 50 Gy (HR 0·63, 95% CI 0·47–0·84) and for those who received 40 Gy compared with those who received 50 Gy (0·76, 0·60–0·97); no significant difference was observed between patients who received 41·6 Gy and those who received 50 Gy in trial A (0·83, 0·63–1·08). Patient self-ratings of breast symptoms discriminated a 10% difference in randomised dose intensity. Up to a third of women reported moderate or marked pain in the arm and shoulder over 5 years whilst more than 10% experienced moderate or marked arm and hand swelling, with no significant difference in arm/shoulder subscale scores between the regimens in trial A or trial B; many baseline arm and shoulder symptoms were associated with prior surgery. Interpretation A substantial proportion of women report moderate or marked breast, arm, and shoulder symptoms over 5 years of follow-up after radiotherapy, but with no detriment to body image. Nonetheless, most patients stand to gain from hypofractionated radiotherapy regimens with a potential for fewer adverse effects; this strengthens the evidence from the START trials for hypofractionated regimens for women requiring radiotherapy for early breast cancer. Funding Cancer Research UK, UK Medical Research Council, UK Department of Health.
Summary Background Tamoxifen preserves bone in postmenopausal women, but non-steroidal aromatase inhibitors accelerate bone loss and increase fracture risk. We aimed to study the effect on bone ...health in a subgroup of women included in the Intergroup Exemestane Study (IES), a large randomised trial that compared the switch to the steroidal aromatase inhibitor exemestane with continuation of tamoxifen in the adjuvant treatment of postmenopausal breast cancer. Methods Results were analysed from 206 evaluable patients from the IES, in which postmenopausal women with histologically confirmed and completely resected unilateral breast cancer (that was oestrogen-receptor positive or of unknown status), who were disease-free after 2–3 years of treatment with tamoxifen were randomised to continue oral tamoxifen 20 mg/day or switch to oral exemestane 25 mg/day to complete a total of 5 years of adjuvant endocrine therapy. The primary endpoint was change in bone-mineral density (BMD) assessed by dual energy X-ray absorptiometry. Changes in biochemical markers of bone turnover were also analysed in this substudy, and the incidence of fractures in the entire study reported. The IES is registered on the Current Controlled Trials website http://www.controlled-trials.com/ISRCTN11883920. Findings Within 6 months of switching to exemestane, BMD was lowered by 0·051 g/cm3 (2·7%; 95% CI 2·0–3·4; p<0·0001) at the lumbar spine and 0·025 g/cm3 (1·4%; 0·8–1·9; p<0·0001) at the hip compared with baseline. BMD decreases were only 1·0% (0·4–1·7; p=0·002) and 0·8% (0·3–1·4; p=0·003) in year 2 at the lumbar spine and hip, respectively. No patient with BMD in the normal range at trial entry developed osteoporosis. Bone resorption and formation markers increased at all time points in women receiving exemestane (p<0·001). With a median follow-up in all IES participants (n=4274) of 58 months, 162 (7%) and 115 (5%) patients in the exemestane and tamoxifen groups, respectively, had fractures (odds ratio 1·45 1·13–1·87; p=0·003). Interpretation These results indicate that the increase in survival shown previously with the IES switch strategy is achieved at the expense of some detriment to skeletal health, so the risk-benefit ratio to women needs to be individually assessed.
Summary Background Aromatase inhibitors are more effective than is tamoxifen in prevention of breast-cancer recurrence, but at the expense of increased musculoskeletal side-effects, such as carpal ...tunnel syndrome. The aim of this study was to assess risk factors and the prognostic value of musculoskeletal symptoms during treatment with the steroidal aromatase inhibitor exemestane or with tamoxifen after 2–3 years of tamoxifen. Methods In the Intergroup Exemestane Study, postmenopausal women treated for early invasive breast cancer who remained disease free and on treatment after 2–3 years of tamoxifen were randomised to switch to exemestane or to continue tamoxifen for the remainder of the 5-year period of endocrine treatment. The primary endpoint for this retrospective analysis was occurrence of carpal tunnel syndrome and any musculoskeletal events, analysed in the safety population, which consisted of all patients who had received any trial treatment. As well as case-report forms, questionnaires were distributed retrospectively to gain more details of cases of carpal tunnel syndrome. The relation between musculoskeletal symptoms reported by 6 months from randomisation and survival from 9 months onwards was assessed by Cox proportional hazards models. The trial is registered, number ISRCTN11883920. It has completed accrual and follow-up is continuing for enrolled participants. Findings After a median follow-up of 91·0 months (IQR 83·0–99·2), carpal tunnel syndrome had been reported for 66 (2·8%) of 2319 patients in the exemestane group compared with 13 (0·6%) of 2338 in the tamoxifen group (odds ratio OR 5·23, 99% CI 2·39–11·49; p<0·0001). More events occurred during treatment in the exemestane group than in the tamoxifen group (66 2·8% vs seven 0·3%, adjusted OR 9·90, 99% CI 3·52–27·82; p<0·0001). There was no significant difference between groups in events in the post-treatment period (ten with exemestane 0·4% vs seven with tamoxifen 0·3%; p=0·46). More patients in the exemestane group (1082 of 2319 patients, 46·7%) had musculoskeletal symptoms than in the tamoxifen group (901 of 2338, 38·5%; OR 1·48, 99% CI 1·32–1·67, p<0·0001). More events occurred during treatment in the exemestane group than in the tamoxifen group (984 42·4% vs 776 33·2%, adjusted OR 1·59, 99% CI 1·32–1·91; p<0·0001), with this difference persisting to some extent in the post-treatment period (449 19·4% vs 390 16·7%; p=0·017). Of 73 on-treatment cases of carpal tunnel syndrome, 58 (79·5%) completed questionnaires were available. 27 patients (46·6%) had bilateral carpal tunnel syndrome and 31 (53·4%) had unilateral disease; 40 (69·0%) underwent surgical release. The disorder greatly affected daily-life activities in 21 (36·2%) cases. Occurrence of musculoskeletal symptoms, including carpal tunnel syndrome, was associated with improved disease-free survival in unadjusted analysis (p=0·023), but not with overall survival (p=0·36). However, after adjustment for possible confounding factors, musculoskeletal symptoms were not associated with disease-free survival (hazard ratio HR 0·96, 95% CI 0·82–1·14, p=0·67) or overall survival (HR 1·02, 95% CI 0·84–1·25, p=0·82). Interpretation Occurrence of carpal tunnel syndrome is higher in patients with breast cancer given exemestane than in those treated with tamoxifen, and surgical release might be necessary in most cases. Development of musculoskeletal symptoms in the first 6 months of treatment is not an independent biomarker of improved disease outcome. Further investigation is warranted into the relation between treatment-emergent musculoskeletal symptoms and clinical outcome in patients with breast cancer receiving hormonal therapy. Funding Pfizer.