The Pharmacological Basis of Therapeutics A Textbook of Pharmacology, Toxicology and Therapeutics for Physicians and Medical Students. By Prof. Louis Goodman and Prof. Alfred Gilman. Pp. xiii + 1383. (New York: The Macmillan Company, 1941.) 50s. net.

The Pharmacological Basis of Therapeutics

Five cases are described where minute foci of adenocarcinoma have been demonstrated in the mesorectum several centimetres distal to the apparent lower edge of a rectal cancer. In 2 of these there was no other evidence of lymphatic spread of the tumour. In orthodox anterior resection much of this tissue remains in the pelvis, and its is suggested that these foci might lead to suture-line or pelvic recurrence. Total excision of the mesorectum has, therefore, been carried out as a part of over 100 consecutive anterior resections. Fifty of these, which were classified as 'curative' or 'conceivably curative' operations, have now been followed for over 2 years with no pelvic or staple-line recurrence.

The mesorectum in rectal cancer surgery--the clue to pelvic recurrence?

Background Under the auspices of the College of American Pathologists, the current state of knowledge regarding pathologic prognostic factors (factors linked to outcome) and predictive factors (factors predicting response to therapy) in colorectal carcinoma was evaluated. A multidisciplinary group of clinical (including the disciplines of medical oncology, surgical oncology, and radiation oncology), pathologic, and statistical experts in colorectal cancer reviewed all relevant medical literature and stratified the reported prognostic factors into categories that reflected the strength of the published evidence demonstrating their prognostic value. Accordingly, the following categories of prognostic factors were defined. Category I includes factors definitively proven to be of prognostic import based on evidence from multiple statistically robust published trials and generally used in patient management. Category IIA includes factors extensively studied biologically and/or clinically and repeatedly shown to have prognostic value for outcome and/or predictive value for therapy that is of sufficient import to be included in the pathology report but that remains to be validated in statistically robust studies. Category IIB includes factors shown to be promising in multiple studies but lacking sufficient data for inclusion in category I or IIA. Category III includes factors not yet sufficiently studied to determine their prognostic value. Category IV includes factors well studied and shown to have no prognostic significance. Materials and methods The medical literature was critically reviewed, and the analysis revealed specific points of variability in approach that prevented direct comparisons among published studies and compromised the quality of the collective data. Categories of variability recognized included the following: (1) methods of analysis, (2) interpretation of findings, (3) reporting of data, and (4) statistical evaluation. Additional points of variability within these categories were defined from the collective experience of the group. Reasons for the assignment of an individual prognostic factor to category I, II, III, or IV (categories defined by the level of scientific validation) were outlined with reference to the specific types of variability associated with the supportive data. For each factor and category of variability related to that factor, detailed recommendations for improvement were made. The recommendations were based on the following aims: (1) to increase the uniformity and completeness of pathologic evaluation of tumor specimens, (2) to enhance the quality of the data needed for definitive evaluation of the prognostic value of individual prognostic factors, and (3) ultimately, to improve patient care. Results and conclusions Factors that were determined to merit inclusion in category I were as follows: the local extent of tumor assessed pathologically (the pT category of the TNM staging system of the American Joint Committee on Cancer and the Union Internationale Contre le Cancer [AJCC/UICC]); regional lymph node metastasis (the pN category of the TNM staging system); blood or lymphatic vessel invasion; residual tumor following surgery with curative intent (the R classification of the AJCC/UICC staging system), especially as it relates to positive surgical margins; and preoperative elevation of carcinoembryonic antigen elevation (a factor established by laboratory medicine methods rather than anatomic pathology). Factors in category IIA included the following: tumor grade, radial margin status (for resection specimens with nonperitonealized surfaces), and residual tumor in the resection specimen following neoadjuvant therapy (the ypTNM category of the TNM staging system of the AJCC/UICC). (ABSTRACT TRUNCATED)

Prognostic factors in colorectal cancer. College of American Pathologists Consensus Statement 1999.

The sequence of events in haematogenous metastasis from colonic carcinoma was analysed, using 1541 necropsy reports from 16 centres. The findings are consistent with the cascade hypothesis that metastases develop in discrete steps, first in the liver, next in the lungs and finally, in other sites. Deviations of necropsy findings from the cascade model are largely explained on the basis of false negative reports. In only 216 of 1194 cases was there suggestive evidence that metastatic patterns (excluding lymph nodes) were causally related to lymphatic or non-haematogenous pathways. The incidence of metastatic involvement in 'other' (quaternary) sites correlated with target organ blood-flow (ml min-) per g, only when bone marrow and thyroid were excluded. In the thyroid the incidence was lower than expected on the basis of blood flow per g tissue; this may indicate that the thyroid is an unfavourable site for metastatic growth of colonic carcinoma. In the bone marrow it is higher; the latter may be due to delivery of cancer cells via both arterial blood and the vertebral venous plexus. Recognition of this pattern of metastases in the bone marrow could be important with respect of diagnosis and therapy, in patients with colonic carcinoma.

Haematogenous metastastic patterns in colonic carcinoma: An analysis of 1541 necropsies

Preoperative assessment of prognostic factors in rectal cancer using high-resolution magnetic resonance imaging. Background: The aim was to determine the accuracy of preoperative magnetic resonance imaging (MRI) in the evaluation of pathological prognostic factors that influence local recurrence and survival in rectal cancer. Methods: Ninety-eight patients undergoing total mesorectal excision for biopsy-proven rectal cancer were assessed prospectively using high-resolution MM for tumour (T) and nodal (N) staging using the tumour node metastasis classification, depth of extramural tumour spread, the presence or absence of extramural venous invasion, a threatened circumferential resection margin and serosal involvement at or above the peritoneal reflection. Preoperative magnetic resonance assessment of these prognostic factors was compared with histopathological findings in carefully matched whole-mount sections of the resection specimen. Results: There was 94 per cent weighted agreement (weighted kappa = 0.67) between MM and pathology assessment of T stage. Agreement between MM and histological assessment of nodal status was 85 per cent (kappa = 0.68). Although involvement of small veins by tumour was not discernible using MRI, large (calibre greater than 3 mm) extramural venous invasion was identified correctly in 15 of 18 patients (kappa = 0.64). MRI predicted circumferential resection margin involvement with 92 per cent agreement (kappa = 0.81). Seven of nine patients with peritoneal perforation by tumour (stage T4) were identified correctly using MRI. Conclusion: High-resolution MRI of the rectum allows preoperative identification of important surgical and pathological prognostic risk factors. This may allow both better selection and assessment of patients undergoing preoperative therapy.

Preoperative assessment of prognostic factors in rectal cancer using high-resolution magnetic resonance imaging

A histopathological study of 703 surgical specimens from patients with adenocarcinoma of the rectum revealed invasion of veins by primary growth in almost 52 per cent. Follow-up studies on the patients showed that the corrected 5-year survival rate was significantly worse and liver metastases developed more frequently when venous invasion was present. Invasion of extramural veins was particularly significant whereas spread confined to intramural veins was less important. Invasion of large (thick-walled) veins was of greater consequence than invasion of small (thin-walled) veins and spread into thick-walled extramural veins had the greatest adverse influence of all. Venous spread of tumour takes place in parallel with local spread as measured by the Dukes' stage but exerts an influence on prognosis independent of the Dukes' stage. Similarly, vein invasion parallels the number of lymph node metastases but appears to exert an independent influence on prognosis. Observation of venous spread provides a precise assessment of the likely behaviour of rectal carcinoma and supplements, but does not replace indices such as the Dukes' stage or the number of lymph node metastases in routine use. The implications for surgical technique and management are discussed.

The clinical significance of invasion of veins by rectal cancer.

Histologic evidence of venous invasion was demonstrated in 52 percent of 703 cases of rectal carcinoma. Quantitation of venous invasion and follow-up study showed that invasion of extramural veins was associated with a low 5 year survival rate (33 percent), whereas invasion limited to intramural veins was not. Spread into thick-walled extramural veins carries a very poor prognosis (15 of 91 patients survived 5 years). The corrected 5 year survival rate for stage C patients with invasion of thick-walled extramural veins was only 8 percent. Host reactions in and around the walls of invaded veins increase the survival rate; inflammatory damage to the vein walls and endarteritis obliterans are particularly important in this respect.

Spread of rectal cancer within veins. Histologic features and clinical significance.

Cardiac and pulmonary effects of acebutolol

Is measurement of placental function and maternal weight worth while

Using a balance, randomized, crossover design, single intravenous (1 mg/kg) or oral (3 X 100 mg) doses of acebutolol were administered at weekly intervals to 6 healthy volunteers. For each subject venous blood samples and timed urine collections were obtained after each treatment. Plasma and urinary acebutolol levels were measured by a spectrophotometric method that measures acebutolol and its N-acetyl metabolite (which has equivalent cardiac activity). Using a computer program, various pharmacokinetic parameters were estimated from the date of each subject. From the intravenous data (obtained up to 6 hr after dosing), the following mean (+/-SD) values were found: distribution half-life (T 1/2D), 0.60 (+/-0.43) hr, plasma elimination half-life (T 1/2El), 3.2 (+/-1.1) hr, apparent volume of distribution (VD), 224 (+/-69) L, and apparent VD/kg, 3.0 (+/-0.8) L/kg. Using the oral data (obtained up to 10 hr after dosing), the value for T 1/2El was 3.2 (+/-0.9) hr. The mean cumulative urinary recovery (expressed as % dose) after the intravenous route was about 60%, while that after the oral route was of the order of 35%, suggesting that about half of the oral dose reached the systemic circulation. The mean creatinine clearance of the 6 subjects was 103 (+/-7) ml/min, while the value (obtained between 2 and 4 hr after intravenous dosing) for renal clearance of acebutolol as measured was 298 (+/-68) ml/min and the corresponding plasma clearance was 818 (+/-64) ml/min. These results support the occurrence of substantial nonrenal elimination and renal tubular secretion.

Monica Leighton

Papers

The clinical significance of invasion of veins by rectal cancer.

Spread of rectal cancer within veins. Histologic features and clinical significance.

Cardiac and pulmonary effects of acebutolol

Is measurement of placental function and maternal weight worth while

Observations on the pharmacokinetics of acebutolol.