Impact of anastomotic leak on recurrence and survival after colorectal cancer surgery: a BioGrid Australia analysis

BACKGROUND

There is conflicting evidence regarding the oncological impact of anastomotic leak following colorectal cancer surgery. This study aims to test the hypothesis that anastomotic leak is independently associated with local recurrence and overall and cancer-specific survival.

METHODS

Analysis of prospectively collected data from multiple centres in Victoria between 1988 and 2015 including all patients who underwent colon or rectal resection for cancer with anastomosis was presented. Overall and cancer-specific survival rates and rates of local recurrence were compared using Cox regression analysis.

RESULTS

A total of 4892 patients were included, of which 2856 had completed 5-year follow-up. The overall anastomotic leak rate was 4.0%. Cox regression analysis accounting for differences in age, sex, body mass index, American Society of Anesthesiologists score and tumour stage demonstrated that anastomotic leak was associated with significantly worse 5-year overall survival (χ ² = 6.459, P = 0.011) for colon cancer, but only if early deaths were included. There was no difference in 5-year colon cancer-specific survival (χ ² = 0.582, P = 0.446) or local recurrence (χ ² = 0.735, P = 0.391). For rectal cancer, there was no difference in 5-year overall survival (χ ² = 0.266, P = 0.606), cancer-specific survival (χ ² = 0.008, P = 0.928) or local recurrence (χ ² = 2.192, P = 0.139).

CONCLUSION

Anastomotic leak may reduce 5-year overall survival in colon cancer patients but does not appear to influence the 5-year overall survival in rectal cancer patients. There was no effect on local recurrence or cancer-specific survival.

Comparing oncological outcomes of laparoscopic versus open surgery for colon cancer: Analysis of a large prospective clinical database

BACKGROUND

Oncological outcomes of laparoscopic colon cancer surgery have been shown to be equivalent to those of open surgery, but only in the setting of randomized controlled trials on highly selected patients. The aim of this study is to investigate whether this finding is generalizable to real world practice.

METHODS

Analysis of prospectively collected data from the BioGrid Australia database was undertaken. Overall and cancer specific survival rates were compared with cox regression analysis controlling for the confounders of age, sex, BMI, ASA score, hospital site, year surgery performed, procedure, tumor stage, and adjuvant chemotherapy.

RESULTS

Between 2003 and 2009, 1,106 patients underwent elective colon cancer resection. There were differences between the laparoscopic and open cohorts in BMI, procedure, post-operative complication rate, and tumor stage. When baseline confounders were accounted for using cox regression analysis, there was no difference in 5 year overall survival (χ(2) test 1.302, P = 0.254), or cancer specific survival (χ(2) test 0.028, P = 0.866).

CONCLUSION

This large prospective clinical study validates previous trial results, and confirms that there is no difference in oncological outcome between laparoscopic and open surgery for colon cancer.

Differential regulation of muscarinic receptor mRNA levels in neuroblastoma cells by chronic agonist exposure: a comparative polymerase chain reaction study

The human neuroblastoma line SH-SY5Y expresses three muscarinic receptor genes (m1, m2, and m3). In this study, we have investigated the effect of agonist exposure on the steady state levels of each muscarinic receptor transcript, using a comparative polymerase chain reaction (PCR) assay that allows changes in levels of very rare transcripts to be monitored. Northern blot analysis of cellular RNA revealed the presence of m3 mRNA, whereas PCR amplification of SH-SY5Y cDNA additionally revealed the presence of m1 and m2 transcripts. Cell surface muscarinic receptor number, as assessed by N-[3H]methylscopolamine binding to whole cells, rapidly decreased to 42% of control levels within 1 hr of exposure to 100 microM carbachol; this was followed by a slower decline to 6% of control levels after 48 hr. Total receptor number, measured by binding of [3H]quinuclidinyl benzilate, showed a much slower decline to 21% of control levels after 48 hr of treatment. Comparative PCR analysis showed that each muscarinic transcript was differentially regulated. The level of transcript encoding the major receptor population, the m3 mRNA, was rapidly elevated within 1 hr of agonist challenge and subsequently decreased to about 30% of prestimulation levels within 9 hr; this decrease was sustained for the time course of the experiment. m2 mRNA levels showed a transient increase followed by a decrease to 30% of prestimulation levels after 6 hr but, in contrast to the m3 transcripts, this depression was followed by a transient rise to 270% of prestimulation levels after 24 hr before declining to normal levels by 72 hr after stimulation. Exposure of cells to agonist clearly instigates a complex pattern of changes in levels of receptor and receptor mRNA; comparison of the relative time courses of these changes indicates that the decline in m3 transcripts precedes the loss of muscarinic receptor binding sites.

The dielectric properties of rabbit tissue, pure water and various liquids suitable for tissue phantoms at 35 GHz

Newly developed microwave apparatus was used to measure the complex permittivity of some rabbit tissues and water over the temperature range 20-37 degrees C. Various liquid mixtures which might be suitable as phantom tissue equivalents at 35 GHz were also considered. Some of the measured tissue data were compared with previous lower frequency data and it was concluded that the observed behaviour was not anomalous.

Dielectric properties of lens tissue at microwave frequencies

The relative permittivity and conductivity of rabbit eye lens were measured in the frequency domain between 2 and 18 GHz at temperatures of 37 and 20 degrees C. An analysis of the data suggested that a significant proportion of the bulk water in nuclear and cortical lens tissue may behave differently to pure water. In addition, the Maxwell-Fricke mixture theory was used to estimate the amount of hydrated water that relaxes far below 1 GHz.

Dielectric properties of mammalian brain tissue between 1 and 18 GHz

A newly developed frequency domain technique was used to measure the dielectric properties of white matter, grey matter and macerated rabbit brain at 20 and 37 degrees C. An analysis of the data showed that between 1 and 4 GHz there were substantial contributions from processes other than the gamma dispersion. However, above 7.5 GHz it appeared that mainly free water was relaxing although evidence of a small spread of relaxation times was found for the bulk water in the white matter. Mouse and rat brain were also measured but no significant differences were found between the species. The quantity of bound water was estimated but there was no evidence of a difference in the amount between either the tissues or the temperatures.

Dielectric properties of developing rabbit brain at 37 degrees C

The dielectric properties of developing rabbit brain were measured at 37 degrees C between 10 MHz and 18 GHz using time domain and frequency domain systems. The results show a variation with age of the dielectric properties of brain. An analysis of the data suggests that the water dispersion in the brain of newly born animals can be represented by a Debye equation. This dispersion increases in complexity with age, and there is evidence of a smaller additional relaxation process centered around 1 GHz. It is concluded that the principal contribution to this subsidiary dispersion region arises from water of hydration.