The challenges and promise of sweat sensing.

The potential of monitoring biomarkers in sweat for health-related applications has spurred rapid growth in the field of wearable sweat sensors over the past decade. Some of the key challenges have been addressed, including measuring sweat-secretion rate and collecting sufficient sample volumes for real-time, continuous molecular analysis without intense exercise. However, except for assessment of cystic fibrosis and regional nerve function, the ability to accurately measure analytes of interest and their physiological relevance to health metrics remain to be determined. Although sweat is not a crystal ball into every aspect of human health, we expect sweat measurements to continue making inroads into niche applications involving active sweating, such as hydration monitoring for athletes and physical laborers and later for medical and casual health monitoring of relevant drugs and hormones.

Factors Influencing Recurrence in Medial Breast Cancer Tumors After Skin Sparing Mastectomy and Immediate Breast Reconstruction.

BACKGROUND: Skin sparing mastectomy (SSM) with immediate breast reconstruction (IBR) has been established as a safe option for curative-intent surgical resection. Prior studies have shown that medial location of the primary tumor is associated with increased risk of local recurrence. The purpose of this study is to determine the factors associated with recurrence and survival in individuals with breast cancers located in the inner quadrants (medial) who underwent SSM with IBR. METHODS: A retrospective chart review was done on individuals with medial breast cancer who received SSM with IBR in British Columbia between 1980 and 2012. RESULTS: Of 136 individuals with medial breast cancer undergoing SSM with IBR, 27.9% experienced local recurrence and 42.6% overall recurrence. Factors associated with recurrence were T-stage (44.8 vs. 22.4% with T2 disease, P = .02), transverse rectus abdominis muscle (TRAM) flap reconstruction (48.3 vs. 29.5%, P = .00395), prior breast surgery (87.9 vs. 63%, P = .002), and prior radiation therapy (74.1 vs. 38.5%, P < .0001). LR was associated with higher mortality (OR 2.78, 95% CI: 1.26-6.09). CONCLUSION: For patients with medial tumors undergoing SSM with IBR, potential risk factors for recurrence are T-stage, TRAM flap reconstruction, prior breast surgery, and prior radiation therapy. Local recurrence is associated with poor survival.

Population-based assessment of sentinel lymph node biopsy in the management of cutaneous melanoma.

BACKGROUND: Sentinel lymph node biopsy (SLNB) for melanoma plays a central role in determining prognosis and guiding treatment and surveillance strategies. Despite widely published guidelines for SLNB, variation exists in its use. We aimed to determine the frequency of and predictive factors for SLNB in patients with clinically node-negative melanoma in British Columbia. METHODS: A retrospective review was performed of patients with clinically node-negative melanoma diagnosed between January 2015 and December 2017. Patients included had a Breslow depth greater than 0.75 mm or a Breslow depth less than or equal to 0.75 mm with ulceration, or a mitotic rate greater than or equal to 1/mm2. SLNB was considered to be indicated for clinical stages IB to IIC (American Joint Committee on Cancer's AJCC Cancer Staging Manual, seventh edition). RESULTS: A total of 759 patients were included. SLNB was performed in 54.8% (363/662) of patients when indicated. SLNB was more likely to be performed for tumours with a Breslow depth greater than 1.0 mm or a mitotic rate greater than or equal to 1/mm2. SLNB was less likely to be performed in patients older than 75 years and with a nonextremity tumour location. Compliance with SLNB guidelines decreased distant recurrence but did not significantly affect regional recurrence, nor did it have a significant impact on overall survival among patients aged 75 years and younger. CONCLUSION: SLNB is being underutilized in British Columbia. These results are concerning and highly relevant given the rapidly evolving field of adjuvant systemic therapy for high-risk patients and the increased proportion of patients who should be considered for SLNB on the basis of the eighth edition of the AJCC Cancer Staging Manual and current guidelines. Efforts should be made to increase the use of SLNB in appropriate patients.

Resettable Microfluidics for Broad-Range and Prolonged Sweat Rate Sensing.

Wearable sweat sensors are emerging as promising platforms for personalized and real-time tracking of evolving health and fitness parameters. While most wearable sweat sensors focus on tracking biomarker concentration profiles, sweat secretion rate is a key metric with broad implications for assessing hydration, cardiac, and neural conditions. Here we present a wearable microfluidic sensor for continuous sweat rate measurement. A discrete impedimetric sensing scheme relying on interdigitated electrodes within a microfluidic sweat collector allows for precise and selective sweat rate measurement across a broad physiological range. Integration of a manually activated pressure pump to expel sweat from the device prevents sensor saturation and enables continuous sweat rate tracking over hours. By enabling broad range and prolonged sweat rate measurement, this platform tackles a key obstacle to realizing meaningful and actionable sweat sensing for applications in exercise physiology and medicine.

A unique case of free-floating gastric band tubing causing intraabdominal sepsis in a patient with locked-in syndrome secondary to Guillain-Barré syndrome.

Laparoscopic adjustable gastric banding is a known bariatric procedure that has largely fallen out of favor in our modern surgical era. Several case reports describe various complications secondary to gastric band slippage. Here we present a unique complication not related to gastric band slippage, but intraabdominal sepsis secondary to free-floating gastric band tubing after removal of the subcutaneous port in a patient with locked-in syndrome secondary to Guillain-Barré syndrome.

Canadian Melanoma Conference Recommendations on High-Risk Melanoma Surveillance: A Report from the 14th Annual Canadian Melanoma Conference; Banff, Alberta; 20-22 February 2020.

Introduction: There are a lack of established guidelines for the surveillance of high-risk cutaneous melanoma patients following initial therapy. We describe a novel approach to the development of a national expert recommendation statement on high-risk melanoma surveillance (HRS). Methods: A consensus-based, live, online voting process was undertaken at the 13th and 14th annual Canadian Melanoma Conferences (CMC) to collect expert opinions relating to "who, what, where, and when" HRS should be conducted. Initial opinions were gathered via audience participation software and used as the basis for a second iterative questionnaire distributed online to attendees from the 13th CMC and to identified melanoma specialists from across Canada. A third questionnaire was disseminated in a similar fashion to conduct a final vote on HRS that could be implemented. Results: The majority of respondents from the first two iterative surveys agreed on stages IIB to IV as high risk. Surveillance should be conducted by an appropriate specialist, irrespective of association to a cancer centre. Frequency and modality of surveillance favoured biannual visits and Positron Emission Tomography Computed Tomography (PET/CT) with brain magnetic resonance imaging (MRI) among the systemic imaging modalities available. No consensus was initially reached regarding the frequency of systemic imaging and ultrasound of nodal basins (US). The third iterative survey resolved major areas of disagreement. A 5-year surveillance schedule was voted on with 92% of conference members in agreement. Conclusion: This final recommendation was established following 92% overall agreement among the 2020 CMC attendees.

A wearable patch for continuous analysis of thermoregulatory sweat at rest.

The body naturally and continuously secretes sweat for thermoregulation during sedentary and routine activities at rates that can reflect underlying health conditions, including nerve damage, autonomic and metabolic disorders, and chronic stress. However, low secretion rates and evaporation pose challenges for collecting resting thermoregulatory sweat for non-invasive analysis of body physiology. Here we present wearable patches for continuous sweat monitoring at rest, using microfluidics to combat evaporation and enable selective monitoring of secretion rate. We integrate hydrophilic fillers for rapid sweat uptake into the sensing channel, reducing required sweat accumulation time towards real-time measurement. Along with sweat rate sensors, we integrate electrochemical sensors for pH, Cl-, and levodopa monitoring. We demonstrate patch functionality for dynamic sweat analysis related to routine activities, stress events, hypoglycemia-induced sweating, and Parkinson's disease. By enabling sweat analysis compatible with sedentary, routine, and daily activities, these patches enable continuous, autonomous monitoring of body physiology at rest.

Factors that determine whether a patient receives completion axillary lymph node dissection after a positive sentinel lymph node biopsy for breast cancer in British Columbia.

BACKGROUND: Completion axillary lymph node dissection (CALND) is recommended in the setting of positive sentinel lymph node biopsy (SLNB) but is associated with a higher rate of postoperative complications. In this study, the characteristics and outcomes of patients who did and did not have CALND are compared. METHODS: We identified all patients with breast cancer with positive sentinel lymph nodes (SLNs) who did not have concurrent CALND from 2003 to 2006 using a prospectively collected database (British Columbia Cancer Breast Outcomes database) and retrospective chart review. Patient and tumour characteristics were compared between those who received CALND and those who did not. RESULTS: Among 185 patients with positive SLNs identified by SLNB, 90 had a CALND and 95 had no further surgical therapy. Patients who did not receive CALND had more sentinel nodes removed (p < 0.001), a lower percentage of positive SLNs (p < 0.001) and lower pathologic N stage (p = 0.044) than those who did receive CALND. The size of the breast lesion, size of the largest SLN deposit, estrogen receptor status, grade, lymphovascular invasion, histology and multifocality were not significantly different between groups. Sixty-two percent of women who did not have CALND received radiation to the axilla. Postoperative complication rates (including lymphedema) were higher in the CALND group (21%) compared with the SLNB group (7%). The rates of locoregional recurrence (1% in both groups) and systemic metastases (6% in the CALND group v. 8% in the SLNB group) were similar at 36 months' follow-up. CONCLUSION: Compared with women who had CALND, women who did not receive CALND had on average a lower N stage with 3 or more SLNs removed and less than 50% node positivity. Most of these women received radiation therapy to the axilla and had comparable recurrence rates to those who had CALND.

Management and outcomes of isolated axillary node recurrence in breast cancer.

HYPOTHESIS: Management strategies affect the outcome of axillary recurrence in breast cancer. DESIGN: Population-based analysis. SETTING: Cancer agency breast cancer database. PATIENTS: Two hundred twenty women diagnosed with stage 0 through III breast cancer between 1989 and 2003 who subsequently developed an isolated axillary relapse. MAIN OUTCOME MEASURES: Overall survival rate and disease-free survival rate according to treatment strategy of the axillary recurrence. RESULTS: Among 19 789 women diagnosed with stage 0 through III breast cancer during the study era, 220 had an isolated axillary recurrence (Kaplan-Meier 5-year isolated axillary relapse rate, 1.0%). The median interval between primary breast cancer diagnosis and axillary recurrence was 2.2 years (range,1.8 months to 11.9 years). Median follow-up time after axillary recurrence was 5.4 years. Treatment for the axillary recurrence included lymph node biopsy (47.3%), complete axillary dissection (25.9%), axillary radiation (65.0%), chemotherapy (24.1%), and hormonal therapy (68.2%). The 5-year Kaplan-Meier overall survival rate estimate after axillary recurrence was 49.3% (95% confidence interval, 42.0-56.3). Median survival time from the isolated axillary recurrence was 4.9 years (range, 2.0 months to 15.1 years). Overall (P < .001) and disease-free (P = .006) survival times were highest in those treated with a combination of surgery and radiation. Other factors associated with improved overall survival rate were an interval from diagnosis to relapse greater than 2.5 years (P = .003), no initial axillary radiation (P < .001), asymptomatic presentation of the recurrence (P = .05), and subsequent systemic treatment (P = .02). CONCLUSIONS: The 5-year isolated axillary recurrence rate of women treated for breast cancer was 1.0%. Multimodality management at the time of recurrence, including axillary surgery, radiation, and systemic therapy, significantly improved overall and disease-free survival.

Practice patterns of lymph-node mapping and sentinel-node biopsy for breast cancer in British Columbia.

INTRODUCTION: Because there is no standardized technique for mapping of lymph nodes and no optimal technique for evaluating the sentinel node, we decided to evaluate practice patterns for sentinel-node biopsy (SNB) for breast cancer in British Columbia 5 years after its introduction in 1996. METHODS: We carried out mail and telephone surveys of general surgeons performing at least 1 SNB (n = 28) or not performing SNB (n = 50), and carried out telephone surveys or on-site visits with pathologists (n = 7) and nuclear medicine physicians (n = 5) from institutions supporting SNB in the province. We collected data on training, perceived indications and techniques for the surgical, imaging and pathologic assessments of SNB to obtain data on practice patterns in 2001 and the degree of consistency among surgeons and institutions involved in performing SNB and reasons for not adopting the SNB technique. RESULTS: By 2001, SNB was incorporated into the practice of 19% of surgeons (28 of 150) performing breast cancer surgery in British Columbia. The survey response rate among SNB surgeons was 89% (25 of 28). Twelve (48%) of the 25 surgeons implemented SNB in the context of a validation study. Ten (40%) of the 25 had no data management support to monitor their results. Surgical training included intraoperative mentoring alone (48%), formal training courses alone (20%), both (24%) and self-teaching (8%). One-third of the surgeons had performed fewer than 10 procedures. Five surgeons had abandoned routine axillary dissection. There was considerable variation regarding the indications for SNB, definition of a sentinel node and surgical techniques. All nuclear medicine departments had a written lymphatic mapping protocol, but each used a different volume and activity of radiotracer. Immunohistochemical evaluation of the sentinel nodes was performed at just 3 pathology laboratories. The survey response rate from surgeons not practising SNB was 54% (27 of 50). Among 24 responders in active practice, 7 (29%) planned to perform SNB; 79% had not decided on the SNB indications. Lack of operating room time was a major limiting factor. CONCLUSIONS: There was considerable variation in the surgical, nuclear medicine and pathology techniques for SNB in the absence of a planned approach for its implementation in British Columbia. Developing consensus around written guidelines for the indications and techniques of SNB may reduce this variation.

T1a breast carcinoma and the role of axillary dissection.

HYPOTHESIS: Axillary dissection (AD) does not affect recurrence or survival in T1a breast cancer. DESIGN: Cohort study comparing patients who underwent AD and those who did not. SETTING: Provincial cancer agency. PATIENTS: Six hundred ninety-one women with pathologically diagnosed T1a tumors. MAIN OUTCOME MEASURES: Rates of axillary metastases stratified according to grade and lymphovascular and/or neural invasion, rates of relapse, and disease-specific survival. RESULTS: Grade 1, 2, and 3 tumors without lymphovascular and/or neural invasion had axillary nodal involvement rates of 0.7%, 7%, and 7.8% of patients, respectively; with lymphovascular and/or neural invasion, axillary nodes were involved in 9.1%, 39.3%, and 44.4%, respectively. No statistically significant differences were found between the cohorts in relapse rates (P =.70) or survival (P =.84). CONCLUSION: Higher tumor grade and lymphovascular and/or neural invasion increased the rate of nodal metastases in T1a tumors, but AD did not improve relapse rates or breast cancer-specific survival.

Effect of emergent presentation on outcome from rectal cancer management.

BACKGROUND: We have previously reported outcomes for all rectal cancers in BC in 1996. We found that our local recurrence rates and survival were suboptimal relative to current standards in recent literature. METHODS: In this retrospective, population-based study, we report the influence of emergent presentation (obstruction, perforation, massive hemorrhage) on outcomes, types of surgical procedures and use of staging investigations, and use of adjuvant radiation and chemotherapy. RESULTS: There were 452 invasive adenocarcinomas of the rectum of which 45 were emergent and 407 nonemergent. Disease-specific survival at 4 years for emergent and nonemergent stage II cancers were 66% versus 80%, respectively, and for stage III cancers, 60% versus 73%, respectively (P <0.04). Local recurrence rates at 4 years for emergent and nonemergent stage II cancers were 20% versus 15%, respectively, and for stage III cancers, 70% and 20%, respectively (P <0.05). Surgical resection more frequently involved a stoma for emergent (60%) than for nonemergent (35%) cases (P <0.01). Percent of patients having complete staging investigations were similar between emergent (42%) and nonemergent patients (39%). Adjuvant radiation was given in similar proportion to emergent (61%) and nonemergent (55%) patients. Adjuvant chemotherapy was given to a slightly higher proportion of emergent patients (63%) than nonemergent patients (43%). CONCLUSIONS: We conclude that outcome from rectal cancer management is worse for emergent than nonemergent presentation. Since there is no difference in use of staging investigations or adjuvant therapy, the difference in outcome is likely due to difference in surgical technique between emergent and nonemergent cases.

Outcomes of sentinel node biopsy for breast cancer in British Columbia, 1996 to 2001.

BACKGROUND: This study evaluated the outcomes of the first 5 years of sentinel node biopsy (SNB) in British Columbia (BC), Canada, 1996 to 2001. METHODS: There were 547 SNB procedures for breast cancer performed by 29 surgeons at 12 hospitals in BC between October 1996 and July 2001. Identification, accuracy, and false-negative rates were determined and correlated to patient, tumor, and surgical factors with the chi-square test. RESULTS: SNB mapping was performed using blue dye alone (15%), radiopharmaceutical alone (6%), or both (79%). A completion axillary dissection was performed in 93%. A median of 2 (range 1 to 16) sentinel nodes was biopsied. The overall identification rate was 88%, accuracy was 92%, and false-negative rate was 22%. All rates were improved in younger (age <50 years) compared with older women. A positive lymphoscintiscan and the mapping agent used were associated with higher identification rates but not accuracy or false negative rates. Increasing surgeon experience was not significantly associated with improvements in identification or false-negative rates. CONCLUSIONS: The potential of SNB was not fully translated into surgical practice in BC by 2001.

Effects of positive resection margin and tumor distance from anus on rectal cancer treatment outcomes.

PURPOSE: Rectal cancer outcome depends on stage, technical aspects of surgical excision, and use of adjuvant chemoradiation. Here, we examine effects of positive resection margin and tumor distance from the anus in stage 2 and 3 cancers on 4-year disease-specific survival and recurrence. METHODS: We reviewed all 495 rectal cancer patients registered in British Columbia in 1996. RESULTS: There were 481 cases analyzed: 29 in situ, 134 stage 1, 107 stage 2, 100 stage 3, 83 stage 4, and 28 unknown stage. Survival was significantly affected by presence of positive resection margin in stage 2 and 3 cancers, P = 0.0001. Lower tumor distance from the anus for stage 2 and 3 cancers worsened survival, P = 0.0007, and overall recurrence, P =0.016, but not local recurrence, P = 0.11. Adjuvant postoperative combined radiation and chemotherapy in stage 2 and 3 cancers significantly improved survival, P = 0.070 and local recurrence, P = 0.018, but not overall recurrence, P = 0.19. CONCLUSIONS: Presence of positive resection margin and tumor distance from the anus affect survival, local recurrence, and overall recurrence. Adjuvant postoperative combined radiation and chemotherapy improved our outcomes. Our local recurrence rates for rectal cancers are worse than currently reported standards of less than 10%. Improved surgical excision and use of adjuvant preoperative radiation and chemotherapy may improve outcome.