Prognostic value of specific KRAS mutations in patients with colorectal peritoneal metastases

BACKGROUND

There is little evidence on KRAS mutational profiles in colorectal cancer (CRC) peritoneal metastases (PM). This study aims to determine the prevalence of specific KRAS mutations and their prognostic value in a homogeneous cohort of patients with isolated CRC PM treated with cytoreductive surgery and hyperthermic intraperitoneal chemotherapy.

MATERIALS AND METHODS

Data were collected from 13 Italian centers, gathered in a collaborative group of the Italian Society of Surgical Oncology. KRAS mutation subtypes have been correlated with clinical and pathological characteristics and survival [overall survival (OS), local (peritoneal) disease-free survival (LDFS) and disease-free survival (DFS)].

RESULTS

KRAS mutations occurred in 172 patients (47.5%) out of the 362 analyzed. Two different prognostic groups of KRAS mutation subtypes were identified: KRASMUT1 (G12R, G13A, G13C, G13V, Q61H, K117N, A146V), median OS > 120 months and KRASMUT2 (G12A, G12C, G12D, G12S, G12V, G13D, A59E, A59V, A146T), OS: 31.2 months. KRASMUT2 mutations mainly occurred in the P-loop region (P < 0.001) with decreased guanosine triphosphate (GTP) hydrolysis activity (P < 0.001) and were more frequently related to size (P < 0.001) and polarity change (P < 0.001) of the substituted amino acid (AA). When KRASMUT1 and KRASMUT2 were combined with other known prognostic factors (peritoneal cancer index, completeness of cytoreduction score, grading, signet ring cell, N status) in multivariate analysis, KRASMUT1 showed a similar survival rate to KRASWT patients, whereas KRASMUT2 was independently associated with poorer prognosis (hazard ratios: OS 2.1, P < 0.001; DFS 1.9, P < 0.001; LDFS 2.5, P < 0.0001).

CONCLUSIONS

In patients with CRC PM, different KRAS mutation subgroups can be determined according to specific codon substitution, with some mutations (KRASMUT1) that could have a similar prognosis to wild-type patients. These findings should be further investigated in larger series.

Radiological assessment of peritoneal carcinomatosis: a primer for resident

The imaging has critical responsibility in the assessment of peritoneal lesions along with estimating the overall extent. Valuing disease burden is crucial for selection of combining cytoreductive surgery (CRS) and intraperitoneal hyperthermic chemotherapy (HIPEC) treatment. An approach that combines the strength of several imaging tools and increases diagnostic accuracy, should be chosen, even if the preferred imaging tool in patients with suspected Peritoneal Carcinomatosis (PC) is CT. The outcomes of PC are mainly correlated to tumor spread, localization, and lesion size. Accurate assessment of these features is critical for prognosis and treatment planning. These data can be evaluated by Peritoneal Cancer Index (PCI), a quantitative index suggested by Harman and Sugarbaker. Additionally, precise predictive biomarkers should be established to predict PC in patients at risk. The radiomics analysis could predict PC throughout the evaluation of cancers heterogeneity.

Angiogenesis and vessel co-option in a mathematical model of diffusive tumor growth: The role of chemotaxis

This work considers the propagation of a tumor from the stage of a small avascular sphere in a host tissue and the progressive onset of a tumor neovasculature stimulated by a pro-angiogenic factor secreted by hypoxic cells. The way new vessels are formed involves cell sprouting from pre-existing vessels and following a trail via a chemotactic mechanism (CM). Namely, it is first proposed a detailed general family of models of the CM, based on a statistical mechanics approach. The key hypothesis is that the CM is composed by two components: i) the well-known bias induced by the angiogenic factor gradient; ii) the presence of stochastic changes of the velocity direction, thus giving rise to a diffusive component. Then, some further assumptions and simplifications are applied in order to derive a specific model to be used in the simulations. The tumor progression is favored by its acidic aggression towards the healthy cells. The model includes the evolution of many biological and chemical species. Numerical simulations show the onset of a traveling wave eventually replacing the host tissue with a fully vascularized tumor. The results of simulations agree with experimental measures of the vasculature density in tumors, even in the case of particularly hypoxic tumors.

Multicentre randomized clinical trial of colonic J pouch or straight stapled colorectal reconstruction after low anterior resection for rectal cancer

BACKGROUND

Colonic J pouch reconstruction has been found to be associated with a lower incidence of anastomotic leakage than straight anastomosis. However, studies on this topic are underpowered and retrospective. This randomized trial evaluated whether the incidence of anastomotic leakage was reduced after colonic J pouch reconstruction compared with straight colorectal anastomosis following anterior resection for rectal cancer.

METHODS

This multicentre RCT included patients with rectal carcinoma who underwent low anterior resection followed by colorectal anastomosis. Patients were assigned randomly to receive a colonic J pouch or straight colorectal anastomosis. The main outcome measure was the occurrence of major anastomotic leakage. The incidence of global (major plus minor) anastomotic leakage and general complications were secondary outcomes. Risk factors for anastomotic leakage were identified by regression analysis.

RESULTS

Of 457 patients enrolled, 379 were evaluable (colonic J pouch arm 190, straight colorectal arm 189). The incidence of major and global anastomotic leakage, and general complications was 14·2, 19·5 and 34·2 per cent respectively in the colonic J pouch group, and 12·2, 19·0 and 27·0 per cent in the straight colorectal anastomosis group. No statistically significant differences were observed between the two arms. In multivariable logistic regression analysis, male sex (odds ratio 1·79, 95 per cent c.i. 1·02 to 3·15; P = 0·042) and high ASA fitness grade (odds ratio 2·06, 1·15 to 3·71; P = 0·015) were independently associated with the occurrence of anastomotic leakage.

CONCLUSION

Colonic J pouch reconstruction does not reduce the incidence of anastomotic leakage and postoperative complications compared with conventional straight colorectal anastomosis. Registration number NCT01110798 (http://www.clinicaltrials.gov).

Practice parameters for early rectal cancer management: Italian Society of Colorectal Surgery (Società Italiana di Chirurgia Colo-Rettale; SICCR) guidelines

The introduction of new technologies for diagnosis and screening programs led to an increasing rate of early detection of colorectal cancer. This, associated with the evolution of endoscopic techniques of local excision, led to the assessment of new strategies to reduce morbidity related to treatment, especially for early rectal cancer (ERC). Nevertheless, the definition of ERC and its staging and treatment algorithm are still under debate. The Italian Society of Colorectal Surgery developed practice guidelines to provide recommendations on the diagnosis, staging and treatment of ERC. A systematic review on the topic was performed by a multidisciplinary group of experts selected based on their clinical and scientific expertise in endoscopy, endoscopic ultrasound, magnetic resonance and surgery, with the aid of an external international audit.

Practice parameters for early colon cancer management: Italian Society of Colorectal Surgery (Società Italiana di Chirurgia Colo-Rettale; SICCR) guidelines

Early colon cancer (ECC) has been defined as a carcinoma with invasion limited to the submucosa regardless of lymph node status and according to the Royal College of Pathologists as TNM stage T1 NX M0. As the potential risk of lymph node metastasis ranges from 6 to 17% and the preoperative assessment of lymph node metastasis is not reliable, the management of ECC is still controversial, varying from endoscopic to radical resection. A meeting on recent advances on the management of colorectal polyps endorsed by the Italian Society of Colorectal Surgery (SICCR) took place in April 2014, in Genoa (Italy). Based on this material the SICCR decided to issue guidelines updating the evidence and to write a position statement paper in order to define the diagnostic and therapeutic strategy for ECC treatment in context of the Italian healthcare system.

A haemodynamic model of the venous network of the lower limbs

The pathologies of the venous system are characterized by a relevant socioeconomic impact in western countries. To this regard, the blood flow correction allows to solve the most important venous pathologies. In these cases, in order to guarantee the restoration of normal blood flow by means of proper modifications of the venous network, the correct planning of haemodynamics surgical operations is needed; such planning in turn depends on the right analysis of the possible consequences of flow modification. To this end, a mathematical model, that allows to precisely study the physiological and pathological behaviour of the venous network of the lower limbs, has been developed. The final goal is to use this model as an instrument helpful to plan surgical operations and give guidelines for the design and the test of new artificial devices. As for the modelling processing, a lumped parameters model has been derived with a resolution which allows to take into account the anatomic characteristics of the venous system.

[Our experience with treatment of varicocele in a day-surgery protocol]

In the last few years the increasing interest for non-invasive operating techniques has allowed to reevaluate the sublinguinal varicocelectomy surgical technique for idiopathic varicocele surgical treatment. During the years 1998-2001, 29 patients have been operated on sub-inguinal varicocelectomy (14 patients were suffering from idiopathic varicocele of third grade, 11 of second grade, 3 of first grade, and 1 subclinical). Out of the 29 patients, only 10 were unable to procreate. All patients were operated under local anesthesia and discharged the same day (day-surgery). Owing to Authors' experience, the sublinguinal varicocelectomy by optical magnifying devices represents the "gold standard" in the idiopathic varicocele treatment because it allows to minimize relapsing rates, to limit post-operation complications, to improve the reproductive faculty of seminal fluid both qualitatively and quantitatively, to cut patient's operating costs significantly, to keep the operation time within acceptable limits, and to be easily learned and carried out.