San Antonio 2016 Highlights Part 2

Highlights from the San Antonio Breast Cancer Symposium 2016: Part 2

On Thursday, results from the PERTAIN trial, a trial that randomised 258 hormone positive, HER2 positive metastatic breast cancer patients to herceptin, aromastase inhibitor (AI) - plus taxane chemotherapy at clinician discretion - and pertuzamab compared to no pertuzamab, were presented. Progression free survival (PFS) was 18.9 months in pertuzamab arm and 15.8 in no pertuzamab arm, p=0.007. In the no chemotherapy subgroup (approx 50%), PFS was 21.7 and 12.4 months respectively, p=0.01. The conclusion was that the addition of pertuzamab to herceptin and AI in this group is beneficial.

In session S3-04, Dr Mothaffar Rimawi discussed the National Surgical Adjuvant Breast and Bowel Project (NSABP) B52, which investigated the addition of AI to chemotherapy and dual anti-HER2 therapy in the neoadjuvant setting. The hypothesis is that ER is a pathway of resistance to anti-HER2 therapy and so blocking this will reduce resistance and increase response.Pathological complete response(pCR) was no different between the two groups, implying that although AI is not antagonistic to chemo and anti-HER2, it also provided no benefit.

Dr Reshma Jagsi, Professor and Deputy Chair in the Department of Radiation Oncology at the University of Michigan Health System, presented session S3-07 on Thursday, discussing a prospective multicentre (11 centres) study of patient reported outcome measures (PROMs) and complications following breast reconstruction in 553 patients (83% immediate) receiving post mastectomy radiotherapy (RT) and 1,401 without. The results showed that complications occurred in 39% of implant based reconstructions (96% immediate) and 26% of autologous reconstructions that were followed by RT. Complications also occurred in 22% of implant based reconstructions and 28% of autologous reconstructions that were not followed by RT.

In the radiotherapy subgroup, autologous reconstruction had a 0.47 odds ratio for complications vs implant, however absolute numbers of autologous vs implant were not provided. Radiotherapy was associated with a 2.6 higher odds of complications in the implant group, with no significant increase in risk of complications for the autologous group. Obesity and bilateral surgery were also identified as independent risk factors for complications.

The data also showed that implant failure occurred in 19% of implant based with RT, 1% autologous with RT, 4% implant no RT and 2% autologous no  RT. PROMS breastQscores were consistent with the above, being (for example)  48, 60, 63, and 68 respectively for satisfaction with breast.

On Friday Dr Norah Lynn Henry presented results from a randomised trial of serotonin and norepinephrine reuptake inhibitors (SNRIs) to manage joint pain secondary to aromastase inhibitors (AI). Data showed that approximately one in ten patients benefitted from the drug, over and above benefit from placebo, and approximately three in ten participants experienced side effects. Interestingly, six out of ten saw an improvement in joint symptoms (of two points or more on a 10 point scale) from placebo alone.

In session 5-04, Dr Rowan T Chlebowski presented the results of the 16-year follow up to the randomised low fat dietary intervention trial. As part of this trial 48,835 women were randomised to 18 dietary advice sessions for a year after breast cancer diagnosis, compared to a control group that had dietary advice sheets alone. Women were also encouraged to reduce their fat intake. The results showed that women in the intervention group maintained weight loss over the follow up period and saw a small reduction in breast cancer risk. They also saw a significant benefit in reducing the risk of death from other causes. Reducing fat intake in women with breast cancer does not definitely reduce the future risk of breast cancer death but does improve overall health with a reduced risk of death from all causes.