Re: Leucocyte depletion of perioperative blood transfusion does not affect long-term survival and recurrence in patients with gastrointestinal cancer

The Editors welcome topical correspondence from readers relating to articles published in the Journal. Responses should be sent electronically via the BJS website (www.bjs.co.uk). All letters will be reviewed and, if approved, appear on the website. A selection of these will be edited and published in the Journal. Letters must be no more than 250 words in length.

Re: Meta-analysis of defunctioning stomas in low anterior resection for rectal cancer Br J Surg (Br J Surg 2009; 96: 462-472)

The Editors welcome topical correspondence from readers relating to articles published in the Journal. Responses should be sent electronically via the BJS website (www.bjs.co.uk). All letters will be reviewed and, if approved, appear on the website. A selection of these will be edited and published in the Journal. Letters must be no more than 250 words in length.

Should indeterminate lung lesions reported on staging CT scans influence the management of patients with colorectal cancer?

OBJECTIVE

The aim of this study was to determine the significance of indeterminate lung lesions reported from staging CT scans on patients with colorectal cancer.

METHOD

CT-scan reports of 439 patients were reviewed to identify patients in which indeterminate lung lesion had been reported. The tumour, node, metastasis (TNM) stage of these patients was recorded together with any follow-up scan reports or multidisciplinary team (MDT) discussions regarding these lesions.

RESULTS

Twenty-three patients had definite lung metastases. Forty-five patients had indeterminate lung lesions. Of these, 22 patients had N1 or N2 disease, 20 had N0 disease and three patients were not operated on due to comorbidity. Of these 45 patients, 30 had further follow-up scans. In 19, the indeterminate lesions were unchanged and were therefore downgraded to benign lesions. The lesions had progressed or new lesions had developed in five. These patients were therefore shown to have metastatic lung disease. All five of these patients had N1 or N2 disease. One patient had a primary rather than metastatic lung lesion. Follow-up scans showed the lesion to be no longer present in five. Of the remainder, One patient declined further follow up. Three patients did not have a follow up scan for reasons not mentioned in their records. Two patients were not scanned because further MDT review of the original scans showed that the lesions were not metastases. Four patients died before follow up scans were done. (one postoperative myocardial infarction (MI), one postoperative sepsis, one postoperative cerebrovascular accident (CVA) and one inferior vena cava (IVC) obstruction). Five patients have not yet had follow-up scan at the time of writing.

CONCLUSION

Since the introduction of spiral CT scanners, smaller lesions are being seen at the time of preoperative staging. Our study concludes that only a small proportion of indeterminate lung lesions did develop into definite metastases and those that did had node positive disease. Indeterminate lung lesions are not a reason to delay surgery for colorectal cancer.

Lymph node metastasis in T1 adenocarcinoma of the colon and rectum

The biology of colorectal cancer differs according to location within the large intestine. To evaluate the clinical significance of tumor location as a risk factor for lymph node metastasis (LNM), we performed a detailed pathological review of T1 adenocarcinomas of the colon and rectum. T1 adenocarcinomas of the colon and rectum treated by radical resection (n=428) were identified from prospective clinical databases at two institutions. Tumor location was assigned as right colon (cecum to transverse), left colon (splenic flexure to sigmoid), or rectum (0-18 cm from AV). Pathology slides were reviewed, extent of submucosal invasion (sm width, sm depth) was quantified using an optical micrometer, and morphologic features of the cancer and its infiltrating margin were recorded. The overall rate of LNM was 10%. On univariate analysis, LNM was significantly more common in the rectum (27/176, 15%) compared to the left colon (13/160, 8%, p=.04) or right colon (3/92, 3%, p=.003). However, on multivariate analysis, deep submucosal invasion and lymphovascular invasion were independent and significant risk factors, whereas tumor location was not. T1 colorectal cancers have a progressively higher risk of LNM as their location becomes more distal. However, the increasing rate of LNM observed in cancers of the left colon and rectum is explained by a higher prevalence of high-risk pathologic features. In early colorectal cancers, tumor morphology is the strongest clinical predictor of metastatic behavior.

Comparison of the effects of radiographic contrast media on dehydration and filterability of red blood cells from donors homozygous for hemoglobin A or hemoglobin S

Iodinated radiographic contrast media have traditionally been contraindicated in patients with sickle cell disease because their high osmolality may induce osmotic shrinkage of red blood cells, impair blood flow through the microcirculation, and precipitate or exacerbate a sickle cell crisis. This study investigated that concept by comparing the hematological and rheological effects in vitro of four X-ray contrast media of differing osmolalities: Visipaque (290 mOsm/kg), Hexabrix (600 mOsm/kg), Omnipaque (844 mOsm/kg), and RenoCal-76 (1940 mOsm/kg). Blood was tested from 10 normal and 10 sickle cell donors at drug concentrations of 0, 1, 10, and 30% w/v in an attempt to approximate the relative concentrations of contrast medium to blood that might occur during the bolus-injection and circulation-diluted phases of drug administration. Parameters evaluated included hematology, red cell morphology, and red cell flow resistance through a micropore filter to approximate the microcirculatory effects. Significant hematological effects for both normal and sickle cell donors included a concentration dependent decrease in hematocrit and MCV, and increase in MCHC, all of which varied directly with the osmolality of the contrast media in the order of RenoCal-76 > Omnipaque > Hexabrix > Visipaque. The contrast media had minor effects on red blood cell morphology except for RenoCal-76, 10-30% in which marked echinocytosis was observed. There was no significant increase in the number of irreversibly sickled cells in donors with hemoglobin S. Filterability of red cell suspensions through capillary size pores was impaired in both normal and sickle cell samples in direct proportion to the osmolality of the contrast media, as listed above. Filterability effects were greater for sickle cells than for normal red cells. Visipaque, which was closest to isotonicity, had little effect on red cell volume and had no significant effect on filterability of normal or sickle cells. These results suggest that microcirculatory impairment following infusion of contrast media may occur in sickle patients because of the unusual rheological sensitivity of HbSS red cells, and may be avoided by choice of an isotonic medium.