Scottish Bowel Screening Programme colonoscopy quality - scope for improvement?

AIM

The delivery of the Scottish Bowel Screening Programme (SBoSP) is rooted in the provision of a high quality, effective and participant-centred service. Safe and effective colonoscopy forms an integral part of the process. Additional accreditation as part of a multi-faceted programme for participating colonoscopists, as in England, does not exist in Scotland. This study aimed to describe the quality of colonoscopy in the SBoSP and compare this to the English national screening standards.

METHODS

Data were collected from the SBoSP between 2007 and 2014. End-points for analysis were caecal intubation, cancer, polyp and adenoma detection, and complications. Overall results were compared with 2012 published English national standards for screening and outcomes from 2006 to 2009.

RESULTS

During the study period 53 332 participants attended for colonoscopy. The colonoscopy completion rate was 95.6% overall. The mean cancer detection rate was 7.1%, the polyp detection rate was 45.7% and the adenoma detection rate was 35.5%. The overall complication rate was 0.47%.

CONCLUSION

Colonoscopy quality in the SBoSP has exceeded the standard set for screening colonoscopy in England, despite not adopting a multi-faceted programme for screening colonoscopy. However, the overall adenoma detection rate in Scotland was 9.1% lower than that in England which has implications for colonoscopy quality and may have an impact on cancer prevention rates, a key aim of the SBoSP.

An evidence-based treatment algorithm for colorectal polyp cancers: results from the Scottish Screen-detected Polyp Cancer Study (SSPoCS)

OBJECTIVES

Colorectal polyp cancers present clinicians with a treatment dilemma. Decisions regarding whether to offer segmental resection or endoscopic surveillance are often taken without reference to good quality evidence. The aim of this study was to develop a treatment algorithm for patients with screen-detected polyp cancers.

DESIGN

This national cohort study included all patients with a polyp cancer identified through the Scottish Bowel Screening Programme between 2000 and 2012. Multivariate regression analysis was used to assess the impact of clinical, endoscopic and pathological variables on the rate of adverse events (residual tumour in patients undergoing segmental resection or cancer-related death or disease recurrence in any patient). These data were used to develop a clinically relevant treatment algorithm.

RESULTS

485 patients with polyp cancers were included. 186/485 (38%) underwent segmental resection and residual tumour was identified in 41/186 (22%). The only factor associated with an increased risk of residual tumour in the bowel wall was incomplete excision of the original polyp (OR 5.61, p=0.001), while only lymphovascular invasion was associated with an increased risk of lymph node metastases (OR 5.95, p=0.002). When patients undergoing segmental resection or endoscopic surveillance were considered together, the risk of adverse events was significantly higher in patients with incomplete excision (OR 10.23, p<0.001) or lymphovascular invasion (OR 2.65, p=0.023).

CONCLUSION

A policy of surveillance is adequate for the majority of patients with screen-detected colorectal polyp cancers. Consideration of segmental resection should be reserved for those with incomplete excision or evidence of lymphovascular invasion.

A survey of reporting of colorectal cancer in Scotland: compliance with guidelines and effect of proforma reporting

AIMS

The main purpose of the study was to present a baseline audit of reporting of colorectal cancers resection specimens in Scotland, audited against the Royal College of Pathologists (RCPath) standards (2007) and NHS Quality Improvement Scotland (NHS QIS) standards.

METHODS

50 consecutive rectal and 50 consecutive colonic cancer cases from 2011 were audited from 10 Scottish health boards involved in colorectal cancer reporting (n=953). The rates of reporting of serosal involvement, extramural venous invasion (EMVI) and the mean numbers of lymph nodes found were audited against RCPath standards and compared between units that routinely used a reporting proforma versus those that did not.

RESULTS

The performance in reporting of rectal cancer was generally worse than for colonic cancer, with only three units meeting the RCPath standards for reporting of rectal cancer. There were significant differences between units that routinely used a proforma, with the non-proforma group failing to meet the minimum standards for both serosal involvement (6%) and EMVI (24%). In the non-proforma group, 56% of rectal cases had a mean lymph node count of 12 or more compared with 81% in the proforma group.

CONCLUSIONS

Significant differences exist in the frequencies with which important adverse prognostic features are reported by pathologists across 10 Scottish health boards. This has potential implications for patient care. Health boards that make routine use of reporting proformas are more likely to meet RCPath guidelines for reporting of these important pathological parameters.

Patterns of uptake in a biennial faecal occult blood test screening programme for colorectal cancer

AIM

The patterns of response in faecal occult blood test (FOBT) screening were studied.

METHOD

A total of 251,578 people invited three times for faecal occult blood testing were categorized according to how they responded to the invitations, as follows: YNN, NYN, NNY, NYY, YNY, YYN, YYY or NNN (Y = response; N = no response).

RESULTS

Overall, 163,038 (64.8%) responded at least once, and of those the biggest category was YYY (98,494, 60.4%). Of 1927 cancers diagnosed in the age group eligible for screening, there were 405 screen-detected cancers, 529 interval cancers and 993 cancers arising in people who had not been screened for over 2 years (i.e. falling outside the interval cancer category). In the YYY group, 79 screen-detected cancers would have been missed had the members of this group responded YNN and 65 had they responded YYN. In the YYN group, 104 screening cancers would have been missed if they had followed the YNN pattern. In most cases, the screen-detected cancers were diagnosed at the last invitation accepted, indicating that, after a diagnosis of cancer, further screening invitations were rarely accepted. Accordingly, the numbers of screen-detected and interval cancers were adjusted for likely pattern of response according to the proportion of the whole population falling into each pattern. With this adjustment, 40.9% of the cancers in the YYY group were screen detected compared with 29.3% in the YYN group and 20.7% in the YNN group (P < 0.001). Among those who responded once, twice and three times, the stage distribution of screen-detected cancers was similar, indicating that the prognosis of screen-detected cancer is unlikely to be poorer if not detected at the first screen.

CONCLUSION

This study is the first to examine patterns of response to screening invitations and confirms the importance to individuals of continuing to accept repeated screening invitations.

Low faecal haemoglobin concentration potentially rules out significant colorectal disease

AIM

The study aimed to determine whether faecal haemoglobin (Hb) concentration can assist in deciding who with lower abdominal symptoms will benefit from endoscopy.

METHOD

Faecal Hb concentrations were measured on single samples from 280 patients referred for lower gastrointestinal tract endoscopy from primary care in NHS Tayside who completed a faecal immunochemical test (FIT) for Hb and underwent subsequent endoscopy.

RESULTS

Among 739 invited patients, FIT and endoscopy were completed by 280 (median age 63 (18-84) years; 59.6% women), with a median time between FIT and endoscopy of 9 days. Six (2.1%) participants had cancer, 23 (8.2%) had high-risk adenoma (HRA) (more than three adenomas or any > 1 cm), 31 (11.1%) low-risk adenoma (LRA) and 26 (9.3%) inflammatory bowel disease (IBD) as the most serious diagnosis. Those with cancer had a median faecal Hb of > 1000 ng Hb/ml buffer. Those with cancer + HRA + IBD had a median faecal Hb concentration of 75 ng Hb/ml buffer (95% CI 18-204), which was significantly higher than that of all remaining participants without significant colorectal disease (P < 0.0001). Using a cut-off faecal Hb concentration of 50 ng Hb/ml buffer, negative predictive values of 100.0%, 94.4%, 93.4% and 93.9% were found for cancer, HRA, LRA and IBD. Patients with reasons for referral other than rectal bleeding and family history did not have high faecal Hb concentrations.

CONCLUSION

Faecal Hb concentration measurements have considerable potential to contribute to reducing unnecessary endoscopy for the majority of symptomatic patients.

Negative screening colonoscopy after a positive guaiac faecal occult blood test: not a contraindication to continued screening

AIM

In guaiac faecal occult blood test (gFOBT) screening at least 50% of positive individuals will have a colonoscopy negative for colorectal neoplasia. The question of continuing screening in this group has not been addressed.

METHOD

Data on participants aged 50-69 years with a positive gFOBT result and a negative colonoscopy were followed through the biennial screening pilot conducted between 2000 and 2007 in Scotland.

RESULTS

In the first screening round, 1527 colonoscopies were negative for neoplasia. 1300 were re-invited in the second round, 905 accepted, and 157 had a positive gFOBT result, giving a positivity rate of 17.4%. Colonoscopy revealed 20 subjects with adenoma and six with invasive cancer. In the third screening round 1031 were invited for a third time and 730 accepted: 55 had a positive gFOBT test, giving a positivity rate of 7.5%. In this group, six colonoscopies revealed adenomas but there were no cancers diagnosed. In the third screening round, 108 individuals had had two positive gFOBT results and two subsequent negative colonoscopies. Eighty-four were invited for a third gFOBT, 66 accepted and 19 (25.6%) had a positive result none of whom had an adenoma or carcinoma.

CONCLUSION

These data indicate that a negative colonoscopy following a positive gFOBT is not a contraindication for further screening, although this is likely to have a low yield of neoplastic pathology after two negative colonoscopies.

The impact of population-based faecal occult blood test screening on colorectal cancer mortality: a matched cohort study

Background:

Randomised trials show reduced colorectal cancer (CRC) mortality with faecal occult blood testing (FOBT). This outcome is now examined in a routine, population-based, screening programme.

Methods:

Three biennial rounds of the UK CRC screening pilot were completed in Scotland (2000–2007) before the roll out of a national programme. All residents (50–69 years) in the three pilot Health Boards were invited for screening. They received a FOBT test by post to complete at home and return for analysis. Positive tests were followed up with colonoscopy. Controls, selected from non-pilot Health Boards, were matched by age, gender, and deprivation and assigned the invitation date of matched invitee. Follow-up was from invitation date to 31 December 2009 or date of death if earlier.

Results:

There were 379 655 people in each group (median age 55.6 years, 51.6% male). Participation was 60.6%. There were 961 (0.25%) CRC deaths in invitees, 1056 (0.28%) in controls, rate ratio (RR) 0.90 (95% confidence interval (CI) 0.83–0.99) overall and 0.73 (95% CI 0.65–0.82) for participants. Non-participants had increased CRC mortality compared with controls, RR 1.21 (95% CI 1.06–1.38).

Conclusion:

There was a 10% relative reduction in CRC mortality in a routine screening programme, rising to 27% in participants.

Interval cancers in a FOBT-based colorectal cancer population screening programme: implications for stage, gender and tumour site

BACKGROUND

Between 2000 and 2007, a demonstration pilot of biennial guaiac faecal occult blood test (GFOBT) screening was carried out in Scotland.

METHODS

Interval cancers were defined as cancers diagnosed within 2 years (ie, a complete screening round) of a negative GFOBT. The stage and outcome of the interval cancers were compared with those arising contemporaneously in the non-screened Scottish population. In addition, the gender and site distributions of the interval cancers were compared with those in the screen-detected group and the non-screened population.

RESULTS

Of the cancers diagnosed in the screened population, interval cancers comprised 31.2% in the first round, 47.7% in the second, and 58.9% in the third, although this was due to a decline in the numbers of screen-detected cancers rather than an increase in interval cancers. There were no consistent differences in the stage distribution of interval cancers and cancers from the non-screened population, and, in all three rounds, both overall and cancer-specific survival were significantly better for patients diagnosed with interval cancers (p<0.01). The percentage of cancers arising in women was significantly higher in the interval cancer group (50.2%) than in either the screen-detected group (35.3%, p<0.001) or the non-screened group (40.6%, p<0.001). In addition, the proportion of both right-sided and rectal cancers was significantly higher in the interval cancer group than in either the screen-detected (p<0.001) or non-screened (p<0.004) groups.

CONCLUSIONS

Although GFOBT screening is associated with substantial interval cancer rates that increase with screening round, the absolute numbers do not. Interval cancers are associated with a better prognosis than cancers arising in a non-screened population, and GFOBT appears to preferentially detect cancers in men and the left side of the colon at the expense of cancers in women and in the right colon and rectum.

Pyrosequencing-based methods reveal marked inter-individual differences in oncogene mutation burden in human colorectal tumours

Background:

The epidermal growth factor receptor-targeted monoclonal antibody cetuximab (Erbitux) was recently introduced for the treatment of metastatic colorectal cancer. Treatment response is dependent on Kirsten-Ras (K-Ras) mutation status, in which the majority of patients with tumour-specific K-Ras mutations fail to respond to treatment. Mutations in the oncogenes B-Raf and PIK3CA (phosphoinositide-3-kinase) may also influence cetuximab response, highlighting the need for a sensitive, accurate and quantitative assessment of tumour mutation burden.

Methods:

Mutations in K-Ras, B-Raf and PIK3CA were identified by both dideoxy and quantitative pyrosequencing-based methods in a cohort of unselected colorectal tumours (n=102), and pyrosequencing-based mutation calls correlated with various clinico-pathological parameters.

Results:

The use of quantitative pyrosequencing-based methods allowed us to report a 13.7% increase in mutation burden, and to identify low-frequency (<30% mutation burden) mutations not routinely detected by dideoxy sequencing. K-Ras and B-Raf mutations were mutually exclusive and independently associated with a more advanced tumour phenotype.

Conclusion:

Pyrosequencing-based methods facilitate the identification of low-frequency tumour mutations and allow more accurate assessment of tumour mutation burden. Quantitative assessment of mutation burden may permit a more detailed evaluation of the role of specific tumour mutations in the pathogenesis and progression of colorectal cancer and may improve future patient selection for targeted drug therapies.

Effect of gender, age and deprivation on key performance indicators in a FOBT-based colorectal screening programme

OBJECTIVES

To assess the effect of gender, age and deprivation on key performance indicators in a colorectal cancer screening programme.

SETTING

Between March 2000 and May 2006 a demonstration pilot of biennial guaiac faecal occult blood test (gFOBT) colorectal screening was carried out in North-East Scotland for all individuals aged 50-69 years.

METHODS

The relevant populations were subdivided, by gender, into four age groups and into five deprivation categories according to the Scottish Index of Multiple Deprivation (SIMD), and key performance indicators analysed within these groups.

RESULTS

In all rounds, uptake of the gFOBT increased with age (P < 0.001), decreased with increasing deprivation in both genders (P < 0.001), and was consistently higher in women than in men in all age and all SIMD groups. In addition, increasing deprivation was negatively associated with uptake of colonoscopy in men with a positive gFOBT (P < 0.001) although this effect was not observed in women. Positivity rates increased with age (P < 0.001) and increasing deprivation (P < 0.001) in both genders in all rounds, although they were higher in men than in women for all age and SIMD categories. Cancer detection rates increased with age (P < 0.001), were higher in men than in women in all age and SIMD categories, but were not consistently related to deprivation. In both genders, the positive predictive value (PPV) for cancer increased with age (P < 0.001) and decreased with increasing deprivation (P < 0.001) in all rounds and was consistently higher in men than in women in all age and SIMD categories.

CONCLUSIONS

In this population-based colorectal screening programme gender, age, and deprivation had marked effects on key performance indicators, and this has implications both for the evaluation of screening programmes and for strategies designed to reduce inequalities.

Effect of repeated invitations on uptake of colorectal cancer screening using faecal occult blood testing: analysis of prevalence and incidence screening

OBJECTIVE

To analyse the effects of prevalence and incidence screening on uptake and detection of cancer in an ongoing, dynamic programme for colorectal screening using faecal occult blood testing.

DESIGN

Analysis of prevalence and incidence screening.

SETTING

Three rounds of biennial colorectal screening using the guaiac faecal occult blood test in east and north east Scotland, March 2000 to May 2007.

PARTICIPANTS

Adults aged 50-69.

MAIN OUTCOME MEASURES

Uptake of screening, test positivity (percentage of those invited who returned a test that was positive and triggered an invitation for colonoscopy), positive predictive value, and stage of cancer.

RESULTS

Of 510 990 screening episodes in all three rounds, 248 998 (48.7%) were for prevalence, 163 483 (32.0%) were for first incidence, and 98 509 (19.3%) were for second incidence. Uptake of a first invitation for prevalence screening was 53% and for a second and third invitation was 15% and 12%. In the cohort invited for the first round, uptake of prevalence screening rose from 55% in the first round to 63% in the third. The uptake of first incidence screening on a first invitation was 54% and on a second invitation was 86% and on a first invitation for second incidence screening was 46%. The positivity rate in prevalence screening was 1.9% and the uptake of colonoscopy was 87%. The corresponding values for a first incidence screen were 1.7% and 90% and for a second incidence screen were 1.1% and 94.5%. The positive predictive value of a positive faecal occult blood test result for cancer was 11.0% for prevalence screening, 6.5% for the first incidence screen, and 7.5% for the second incidence screen. The corresponding values for the positive predictive value for adenoma were 35.5%, 29.4%, and 26.7%. The proportion of cancers at stage I dropped from 46.5% for prevalence screening to 41% for first incidence screening and 35% for second incidence screening.

CONCLUSIONS

Repeat invitations to those who do not take up the offer of screening increases the number of those who accept, for both prevalence screening and incidence screening. Although the positive predictive value for both cancer and adenomas fell between the prevalence screen and the first incidence screen, they did not fall between the first and second incidence screens. The deterioration in cancer stage from prevalence to incidence screening suggests that some cancers picked up at incidence screening may have been missed on prevalence screening, but the stage distribution is still favourable. These data vindicate the policies of continuing to offer screening to those who fail to participate and continuing to offer biennial screening to those who have accepted previous offers.

Activating K-Ras mutations outwith 'hotspot' codons in sporadic colorectal tumours - implications for personalised cancer medicine

Background:

Response to EGFR-targeted therapies in colorectal cancer patients has been convincingly associated with Kirsten-Ras (K-Ras) mutation status. Current mandatory mutation testing for patient selection is limited to the K-Ras ‘hotspot’ codons 12 and 13.

Methods:

Colorectal tumours (n=106) were screened for additional K-Ras mutations, phenotypes compared in transformation and Ras GTPase activating assays and gene and pathway changes induced by individual K-Ras mutants identified by microarray analysis. Taqman-based gene copy number and FISH analyses were used to investigate K-Ras gene amplification.

Results:

Four additional K-Ras mutations (Leu₁₉Phe (1 out of 106 tumours), Lys₁₁₇Asn (1 out of 106), Ala₁₄₆Thr (7 out of 106) and Arg₁₆₄Gln (1 out of 106)) were identified. Lys₁₁₇Asn and Ala₁₄₆Thr had phenotypes similar to the hotspot mutations, whereas Leu₁₉Phe had an attenuated phenotype and the Arg₁₆₄Gln mutation was phenotypically equivalent to wt K-Ras. We additionally identified a new K-Ras gene amplification event, present in approximately 2% of tumours.

Conclusions:

The identification of mutations outwith previously described hotspot codons increases the K-Ras mutation burden in colorectal tumours by one-third. Future mutation screening to facilitate optimal patient selection for treatment with EGFR-targeted therapies should therefore be extended to codon 146, and in addition should consider the unique molecular signatures associated with individual K-Ras mutations.

Results from the first three rounds of the Scottish demonstration pilot of FOBT screening for colorectal cancer

OBJECTIVES

To assess the effects of the first three rounds of a pilot colorectal screening programme based on guaiac faecal occult blood testing (gFOBT) and their implications for a national population-based programme.

METHODS

A demonstration pilot programme was conducted in three Scottish NHS Boards. Residents aged between 50 and 69 years registered on the Community Health Index were included in the study.

RESULTS

In the first round, the uptake was 55.0%, the positivity rate was 2.07% and the cancer detection rate was 2.1/1000 screened. In the second round, these were 53.0%, 1.90% and 1.2/1000, respectively, and in the third round, 55.3%, 1.16% and 0.7/1000, respectively. In the first round, the positive predictive value of the gFOBT was 12.0% for cancer and 36.5% for adenoma; these fell to 7.0% and 30.3% in the second round and were maintained at 7.5% and 29.1% in the third round. The percentage of screen-detected cancers diagnosed at Dukes' stage A was 49.2% in the first round, 40.1% in the second round and 36.3% in the third round.

CONCLUSIONS

These results are compatible with those of previous randomised trials done in research settings, demonstrating that population-based colorectal cancer screening is feasible in Scotland and should lead to a comparable reduction in disease-specific mortality.

Automated immunochemical quantitation of haemoglobin in faeces collected on cards for screening for colorectal cancer

BACKGROUND

Simple card collection systems are becoming available for faecal immunochemical tests (FITs) as well as guaiac faecal occult blood tests (gFOBTs). FITs are now obtainable that allow quantitation of haemoglobin, so that the analytical detection limit can be set to give a positivity rate that is manageable in terms of the available colonoscopy. A combination of a card collection device and an automated FIT analytical system could be advantageous.

METHODS

The quantitation of haemoglobin in samples collected on cards with a new analytical system and the relationship between faecal haemoglobin concentration and pathology were investigated in a cohort of gFOBT-positive individuals.

RESULTS

All groups had large ranges of haemoglobin concentration and there was overlap between the groups. Median haemoglobin concentrations in participants with normal findings on colonoscopy (167), diverticular disease (43), hyperplastic polyps (41), low risk adenoma (63), higher risk adenoma (35) and cancer (27) were 13.5, 15.6, 16.8, 15.2, 65.6 and 168.9 ng/ml haemoglobin, respectively. Those with diverticular disease, hyperplastic polyps and low risk adenoma were not significantly different from the normal group (p>0.2), but those with higher risk adenoma had significantly higher concentrations (p<0.001), as did those with cancer (p<0.001). Receiver operating characteristic analysis demonstrates that the cut-off concentration can be set to give appropriate clinical characteristics; optimum sensitivity and specificity are achieved at 26.7 ng/ml.

CONCLUSIONS

The haemoglobin in faeces on simple FIT card collection devices can be immunoturbidimetrically analysed quantitatively, and the concentration relates to the presence or absence of significant neoplastic disease.

Expression of proliferating cell nuclear antigen in lung cancer: a systematic study and correlation with DNA ploidy

Heterogeneity of expression of the proliferating cell nuclear antigen (PCNA) was assessed immunohistochemically in 156 tissue samples from 33 surgically resected pulmonary carcinomas using the monoclonal antibody 19A2. The DNA content of each of these samples was measured by flow cytometry. Mean PCNA expression was higher in squamous carcinomas than in adenocarcinomas but there was marked intra-tumour variation in PCNA index in almost all cases. Intra-tumour heterogeneity of DNA content was noted in 11 cases. The PCNA index of these cases (34.1) was higher than that of DNA homogeneous cases (19.4). The wide variation in PCNA expression between different samples within a tumour would indicate that systematic sampling and counting will be necessary in future immunohistochemical studies of cell proliferation in tumour material.

Relationship between point gene mutation, chromosomal abnormality, and tumour suppressor gene methylation status in colorectal adenomas

Epigenetic mechanisms in carcinogenesis may have a significant role in the development of colorectal cancer. To investigate this phenomenon in early-stage disease, promoter methylation status in the tumour suppressor genes APC, MGMT, hMLH1, P14/P14ARF, and CDKN2A/P16 was investigated in 78 colorectal adenomas. These had previously been characterized for mutations of APC, KRAS, and TP53 genes and for chromosomal abnormality by comparative genomic hybridization (CGH). APC hypermethylation was seen in 52 tumours (66.7%). APC showed either methylation or mutation in 66 lesions (84.6%), but these events were not statistically associated. MGMT methylation was detected in 39 cases (50%). Adenomas with this abnormality showed a significantly lower number of chromosomal changes by CGH (p < 0.02), confirming that DNA repair defect of this type is associated with a lower level of chromosomal instability. An hMLH1 methylation defect was seen in only one adenoma (1.3%), from a patient who had a synchronous cancer showing the same defect. Methylation of P14 (P14ARF) was seen in 31 adenomas (39.7%) and CDKN2A (P16) abnormality in 25 (32.1%). DNA methylation at two or more loci was seen in 46 tumours (59%), while 11 lesions (14.1%) showed no evidence of hypermethylation at any of the loci studied. Methylation at any or all of MGMT, P14 or P16 was significantly associated with APC methylation (p = 0.01). Those neoplasms with more than two methylated genes showed significantly fewer chromosomal abnormalities than adenomas with one or no methylated loci (p < 0.001). There was no association between specific individual chromosomal abnormalities, APC, KRAS or TP53 mutations and any pattern of methylation abnormality. We conclude that methylation abnormality is very common in pre-invasive colorectal neoplasia, and that high level methylation is associated with low level chromosomal instability.

Medications with anticoagulant properties increase the likelihood of a negative colonoscopy in faecal occult blood test population screening

OBJECTIVE

The aim of this study was to evaluate the effect of medication with anticoagulant properties on the false positive rate in a population-based faecal occult blood test (FOBt) colorectal screening programme.

METHODS

Eight hundred and forty-six consecutive individuals found to be FOBt-positive in the Scottish arm of the national colorectal cancer screening pilot were studied. All were aged between 50 and 69 years and underwent colonoscopy. Before the procedure the participants' current medication was recorded, and correlated with the colonoscopic findings.

RESULTS

Of 846 participants, 301 (35.6%) were taking regular anticoagulant medication at the time of FOB testing. Of these, 143 (47.5%) had colorectal neoplasia found on colonoscopy, whereas of those not taking anticoagulant medication, 308 (56.5%) were found to have neoplasia. This 9% difference was statistically significant (P = 0.012).

CONCLUSION

These results indicate that in a population screened for colorectal neoplasia by FOB testing, anticoagulant medication being taken at the time of testing is associated with an increased likelihood of a negative colonoscopy.

The prognostic significance of K-ras, p53, and APC mutations in colorectal carcinoma

BACKGROUND

Accumulation of molecular alterations, including mutations in Kirsten-ras (K-ras), p53, and adenomatous polyposis coli (APC), contribute to colorectal carcinogenesis. Our group has previously characterised a panel of sporadic colorectal adenocarcinomas for mutations in these three genes and has shown that p53 and K-ras mutations rarely occur in the same colorectal tumour. This suggests that mutations in these genes are on separate pathways to colorectal cancer development and may influence patient prognosis independently.

AIMS

To correlate the presence or absence of mutations in K-ras, p53, and APC with survival in a cohort of colorectal cancer patients.

PATIENTS

A series of 107 inpatients treated surgically for colorectal cancer in Tayside, Scotland between November 1997 and December 1999.

METHODS

Colorectal tumours were characterised for mutations in K-ras, p53, and APC. Kaplan-Meier survival curves were constructed using overall survival and disease specific survival as the primary end points. Patient survival was analysed using the log rank test and Cox proportional hazards model.

RESULTS

Patients with K-ras mutations had significantly poorer overall survival than patients without K-ras mutations (p = 0.0098). Multivariate analysis correcting for Dukes' stage, age, and sex confirmed this (hazard ratio 2.9 (95% confidence interval 1.4-6.2); p = 0.0040). K-ras mutations were also significantly associated with poorer disease specific survival. The presence of APC and p53 mutations did not affect survival in this cohort of patients (p = 0.9034 and p = 0.8290, respectively).

CONCLUSIONS

Our data indicate that the presence of K-ras mutations predicts poor patient prognosis in colorectal cancer, independently of tumour stage.

Lower gastrointestinal symptoms are not predictive of colorectal neoplasia in a faecal occult blood screen-positive population

BACKGROUND

The aim of this study was to evaluate the incidence of lower gastrointestinal symptoms in faecal occult blood (FOB) test-positive participants in a colorectal screening programme, and to compare the colonoscopic findings in symptomatic and asymptomatic individuals.

METHODS

Five hundred and sixty-three consecutive individuals with a positive FOB test in the Scottish arm of the national colorectal cancer screening pilot were studied. All were aged between 50 and 69 years and underwent colonoscopy. Before the procedure the participants were given a standard questionnaire to elicit gastrointestinal symptoms; these were correlated with the colonoscopic findings.

RESULTS

Of the 563 participants, 439 (78.0 per cent) had one or more lower gastrointestinal symptoms and 124 (22.0 per cent) were symptom free. Taking adenoma and carcinoma together, 322 (57.2 per cent) of the subjects were found to have colorectal neoplasia, and 128 (22.7 per cent) had a completely normal colon. Rectal bleeding was the most common symptom, followed by change in bowel habit, abdominal pain, tenesmus, unexplained weight loss, rectal pain and unexplained anaemia. No significant associations were found between any of these symptoms and the findings at colonoscopy.

CONCLUSION

In a FOB test-positive screened population, lower gastrointestinal symptoms are common, but are not predictive of colorectal neoplasia.

Prognostic indicators for gastrointestinal stromal tumours: a clinicopathological and immunohistochemical study of 108 resected cases of the stomach

AIMS

Whether immunohistochemical markers increase accuracy in predicting prognosis for gastrointestinal stromal tumours (GISTs) remains uncertain. However, past studies have used only small, heterogeneous patient groups. Our aim was to test previously studied and more novel morphological features as well as four immunohistochemical markers as prognostic indicators amongst a large cohort of surgically resected, gastric GISTs.

METHODS AND RESULTS

Tissues from 127 gastric mesenchymal tumours were collected retrospectively and subjected to repeat histological assessment and immunophenotyping. Further immunohistochemistry was performed for Ki67, p53, Bcl-2 and cyclin D1. Complete follow-up data were collected for 108 patients with immunophenotyped diagnoses of GIST (i.e. c-kit+ tumours). At the census point, 52 patients were alive, 24 had died from their GISTs and the remainder of other causes. Univariate analysis showed the following predicted for shorter disease-specific survival: size > or =50 mm; necrosis, no intratumoral lymphocytes; mitotic count > or =5/50 high power fields; Ki67 labelling index > or =5%; p53 immunopositivity. Of these variables, multivariate analyses showed only mitotic count and, to a lesser extent, Ki67 labelling to be independent prognostic indicators.

CONCLUSIONS

Mitotic count remains the best predictor of outcome following surgical resection of gastric GISTs. Ki67 immunohistochemistry does not provide better prognostication and p53, Bcl-2 and cyclin D1 immunohistochemistry provide no additional prognostication.

Prognostic indicators for gastrointestinal stromal tumours: a clinicopathological and immunohistochemical study of 108 resected cases of the stomach

AIMS

Whether immunohistochemical markers increase accuracy in predicting prognosis for gastrointestinal stromal tumours (GISTs) remains uncertain. However, past studies have used only small, heterogeneous patient groups. Our aim was to test previously studied and more novel morphological features as well as four immunohistochemical markers as prognostic indicators amongst a large cohort of surgically resected, gastric GISTs.

METHODS AND RESULTS

Tissues from 127 gastric mesenchymal tumours were collected retrospectively and subjected to repeat histological assessment and immunophenotyping. Further immunohistochemistry was performed for Ki67, p53, Bcl-2 and cyclin D1. Complete follow-up data were collected for 108 patients with immunophenotyped diagnoses of GIST (i.e. c-kit+ tumours). At the census point, 52 patients were alive, 24 had died from their GISTs and the remainder of other causes. Univariate analysis showed the following predicted for shorter disease-specific survival: size > or =50 mm; necrosis, no intratumoral lymphocytes; mitotic count > or =5/50 high power fields; Ki67 labelling index > or =5%; p53 immunopositivity. Of these variables, multivariate analyses showed only mitotic count and, to a lesser extent, Ki67 labelling to be independent prognostic indicators.

CONCLUSIONS

Mitotic count remains the best predictor of outcome following surgical resection of gastric GISTs. Ki67 immunohistochemistry does not provide better prognostication and p53, Bcl-2 and cyclin D1 immunohistochemistry provide no additional prognostication.

Effects of low dose fluticasone/salmeterol combination on surrogate inflammatory markers in moderate persistent asthma

BACKGROUND

Noninvasive surrogate markers provide valuable information on the asthmatic inflammatory process. We wished to examine the effects of low dose fluticasone/salmeterol combination on different commonly used inflammatory markers in moderate persistent asthma.

METHODS

Twenty-five moderate persistent atopic asthmatics were enrolled of whom 20 completed an open label study. Following an initial 4 week steroid washout period in which patients took salmeterol 50 microg dry powder inhaler 1 puff BD, they received the addition of fluticasone as fluticasone 100 microg/salmeterol 50 microg combination dry powder inhaler 1 puff BD for the next 2 weeks. Exhaled nitric oxide, spirometry, methacholine PD20, sputum/blood eosinophils and sputum/serum eosinophil cationic protein (ECP) were measured following the salmeterol only and fluticasone/salmeterol combination treatment periods.

RESULTS

Compared to salmeterol alone (i.e. after the steroid washout), the use of fluticasone/salmeterol combination conferred significant improvements (P < 0.05) in all surrogate markers of inflammation apart from serum ECP. Geometric mean fold changes were 4.3-fold/1.3-fold for sputum/blood eosinophils, 2.2-fold/1.2-fold for sputum/serum ECP, 2.3-fold for methacholine PD20 and 1.8-fold for exhaled nitric oxide.

CONCLUSIONS

Surrogate markers apart from serum ECP may be used as a guide to evaluate the anti-inflammatory effects of low dose inhaled corticosteroids. Sputum markers tend to be more sensitive than blood when assessing the anti-inflammatory response.

The colorectal adenoma-carcinoma sequence

BACKGROUND

It is widely accepted that the adenoma-carcinoma sequence represents the process by which most, if not all, colorectal cancers arise. The evidence supporting this hypothesis has increased rapidly in recent years and the purpose of this article is to review this evidence critically and highlight its clinical significance.

METHODS

Medline searches were used to identify recent key articles relating to the adenoma-carcinoma sequence. Further pertinent articles were obtained by manual scanning of the reference lists of identified papers.

RESULTS

The evidence supporting the adenoma-carcinoma sequence can be classified as epidemiological, clinicopathological and genetic. The most recent and largest body of data relates to molecular genetic events and their cellular effects; however, many other approaches, such as cytogenetics, molecular cytogenetics and cytometry, have also yielded valuable information.

CONCLUSION

Recent work continues to support the adenoma-carcinoma sequence, but there is a paucity of data on the interrelationship between different genetic mutations and on the relationship between molecular and other types of genetic abnormalities. The clinical utility of the observations described has yet to be fully realized and global genetic analysis of colorectal tumours may prove to be central in rational adenoma management.

Primary T cell lymphoma of salivary gland: a report of a case and review of the literature

Lymphoma of the salivary gland accounts for 5% of cases of extranodal lymphoma and 10% of malignant salivary gland tumours. Most primary salivary gland lymphomas are B marginal zone lymphomas arising on a background of sialadenitis associated with autoimmune disorders such as Sjorgen's syndrome. Primary T cell lymphoma of the salivary gland is rare. This report describes a case of primary T cell lymphoma arising in the parotid gland of an elderly white man, which was notable for its striking resemblance to a B cell extranodal marginal zone lymphoma. Immunohistochemistry and gene rearrangement studies confirmed the clonal T cell nature of the tumour. There was no molecular evidence of Epstein-Barr virus (EBV) infection of neoplastic or surroundings cells. Only 14 cases of primary T cell lymphoma of the salivary glands have been recorded in the literature, most being from the Orient and having extremely variable prognosis. Those with a T/natural killer cell phenotype are associated with EBV infection. This case highlights the fact that T cell lymphoma in the salivary gland can mimic closely the morphological features of B cell extranodal marginal zone lymphoma.

Overexpression and poly-ubiquitylation of the DEAD-box RNA helicase p68 in colorectal tumours

The DEAD box RNA helicase, p68, is upregulated in exponentially growing cells and shows cell cycle-dependent changes in nuclear localization. Although some other DEAD box proteins have been implicated in cancer, there have been no reports of any link between p68 status and carcinogenesis. In the present study we have analysed specimens from 50 patients with colorectal adenocarcinomas, including cases in which an adenomatous polyp was also present, by immunohistochemistry and Western blotting. Our data indicate that p68 protein is consistently overexpressed in tumours as compared with matched normal tissue. Examination of the levels of p68 mRNA from both normal and tumour tissue showed no obvious specific increase in p68 mRNA levels in tumours nor any evidence of underlying mutations in the p68 coding region. Interestingly, however, the accumulated p68 appears to be poly-ubiquitylated, suggesting a possible defect in proteasome-mediated degradation in these tumours. This overexpression/ubiquitylation is observed in both pre-invasive and invasive lesions suggesting that the dysregulation of p68 expression occurs early during tumour development. Finally, we demonstrate that ubiquitylation of p68 occurs in cultured cells, thereby providing a model for the molecular analysis of this process and its potential role in tumorigenesis.

Lymphangioleiomyomatosis. A series of three case reports illustrating the link with high oestrogen states

Lymphangioleiornyomatosis is a rare lung disorder characterised by cystic air spaces and smooth muscle proliferation. The condition, which most commonly presents with dyspnoea, pneumothoraces or cough, is only described in females and is most commonly diagnosed during childbearing years. Three cases are presented which illustrate typical features of the disease and the association with high oestrogen levels. The first had recurrent pneumothoraces during her first pregnancy. The second lady was post menopausal at diagnosis but her symptoms predated her menopause. The third, presented with dyspnoea, abnormal chest sensations and a pneumothorax. She had a history of hyperprolactinaemia with secondary amenorhoea due to low oestrogen levels which had been corrected prior to her presentation. All three patients had reduced gas transfer and abnormalities in spirometry, two had reticular shadowing on their chest radiograph and all had typical appearances on lung computerised tomography. Although disease progression was variable, all patients showed a gradual decline in lung function.

Chromosomal imbalances in gastric and esophageal adenocarcinoma: specific comparative genomic hybridization-detected abnormalities segregate with junctional adenocarcinomas

The incidence of adenocarcinoma arising at the esophagogastric junction (EGJ) is increasing at a rate greater than that for any other form of solid malignancy. Commensurate with this, the incidence of histologically similar tumors arising in the gastric body and antral mucosa is declining. The increased incidence of the proximal group of tumors may reflect, in part, the higher prevalence of Barrett esophagus. These epidemiological features suggest that histologically similar tumors arising at the EGJ and from the distal stomach are different, which may be reflected in the genetic abnormalities that characterize the two groups of tumors. The purpose of this study was to screen genomic DNA from adenocarcinomas of the esophagus and stomach for regions of chromosomal imbalance, using comparative genomic hybridization to determine whether tumors at the EGJ (junctional tumors) have a different profile compared with tumors of the distal stomach. Tumor samples were derived from a series of 48 gastroesophageal adenocarcinomas (20 junctional and 28 distal) that were acquired prospectively from patients undergoing esophagogastrectomy. These tumors are characterized by several regions of chromosomal imbalance with no obvious correlation between most regions of abnormal copy number and tumor type. However, our study shows for the first time cytogenetic abnormalities (5p+ and 18q-) that identify statistically significant differences (P < 0.02 and < 0.05, respectively) between junctional and distal gastric tumors. These differences are gain of 5p (55% [11/20] of junctional tumors vs. 21% [6/28] of distal gastric tumors) and loss of 18q (25% [5/20] cases of junctional tumors vs. 4% [1/28] of distal tumors) segregating with tumors of the EGJ. These abnormalities may distinguish distinct tumor subtypes that are recognized in epidemiological and clinical studies but that are otherwise histologically identical.

An investigation of the Peutz-Jeghers gene (LKB1) in sporadic breast and colon cancers

AIMS

To explore the role of the Peutz-Jeghers gene (LKB1) in sporadic breast and colon cancers.

METHODS

Thirty consecutive sporadic carcinomas of the breast and 23 of the colon were selected. DNA was extracted from paraffin wax embedded tissue and analysed for loss of heterozygosity (LOH) at microsatellite markers D19S886 and D19S565 close to the LKB1 gene. Tumours showing LOH were screened for LKB1 mutations by single strand conformational polymorphism (SSCP).

RESULTS

Five breast carcinomas showed LOH (21% and 7% of those informative for D19S886 and D19S565, respectively). Five of the colorectal carcinomas showed LOH (15% and 36% of those informative for D19S886 and D19S565, respectively), with one sample showing allele loss with both markers. Screening of these 10 carcinomas by SSCP identified one migrational shift but sequencing revealed an intronic polymorphism only. Therefore, no coding mutations were found in these carcinomas.

CONCLUSIONS

These findings suggest that although allele loss at the LKB1 locus occurs relatively frequently in sporadic breast and colon cancers, mutations do not seem to be a feature.

Expression of the p53 homologue p63alpha and deltaNp63alpha in normal and neoplastic cells

A burgeoning family of p53-related genes have been described recently, including p73 and p63. Both these genes encode proteins with many similarities to p53 but also with the potential for forming a range of related species by alternative promoter usage and alternative splicing. In order to begin the characterization of p63, we generated a polyclonal serum (designated SC1) that recognizes the C-terminus of p63alpha. We have shown that this reagent recognizes p63alpha but not p53 nor p73. By western blot analysis both p63alpha and the N-terminal truncated form of p63alpha (DeltaNp63alpha) were found in a range of cell lines. Similar immunoblot analysis of tissues reveals considerable complexity with at least four SC1-immunoreactive isoforms being identified. In immunohistological studies SC1 immunoreactivity is widely detectable, being predominantly associated with proliferative compartments in epithelia. However, non-proliferative populations can also show SC1 immunostaining. No simple relationship between the isoforms identified by immunoblotting of tissue lysates and the tissue immunostaining characteristics was identified. A previously unrecognized species intermediate in mobility between p63alpha and DeltaNp63alpha was found in several tissues, including nerve and peripheral blood lymphocytes. Interestingly, there is suppression of p63alpha expression in HaCat cells in a time- and concentration-dependent manner after UV and MMS treatment. Our data provide further information about the complexity of p63 and the SC1 serum will prove to be a useful tool in further studies of this p53 homologue.

Patch incorporation in diaphragmatic hernia

BACKGROUND/PURPOSE

Biomaterial insertion often is required for closure of congenital diaphragmatic hernia (CDH). The optimal biomaterial remains uncertain. This study was designed to compare a commonly used patch (polytetrafluoroethylene) with a recently available fabric, fluorinated polyester. The aim of this study was to determine the clinical performance, histological tissue-polymer interaction, bacterial adhesion, and shrinkage rates of biomaterial inserted endoscopically into a CDH lamb model.

METHODS

Polytetrafluoro-ethylene (PTFE) and fluorinated polyester (FP) were randomised for laparoscopic patch insertion into 12 lambs. All lambs (age <4 weeks) underwent 3-port laparoscopy, surgical creation of diaphragmatic hernia, and sutured patch placement. Two PTFE and 2 FP lambs were killed at 1-, 3-, and 6-month intervals postoperatively. Postmortem examination histopathology, electron microscopy, and specific bacterial broth immersion (Escherichia coil, Staphylococcus aurens, and epidermidis) were performed.

RESULTS

All 12 lambs completed the study with intact patches that were fully peritonised. One abdominal adhesion was noted in a FP lamb at 6 months. FP was comparatively easier to insert, manipulate, and suture endoscopically. Histopathology findings showed that PTFE patches created a strong peripheral foreign body reaction with dystrophic calcification, whereas FP was well incorporated with intrapatch fibroblastic activity and neovascularsation. No significant difference in resistance to bacterial adhesion of relevant organisms was noted between the materials. Graft shrinkage for FP was 7% in one direction only, evident by 3 months.

CONCLUSIONS

Fluorinated polyester has advantages in this laparoscopic lamb model. It shows rapid and sustained incorporation with intrapatch neovascularisation when compared with polytetrafluoro-ethylene's significant foreign body reaction. It was preferred for its endoscopic handling and suturing properties. The laparoscopic techniques used may contribute to the general lack of adhesions, and insufficient data are available to comment on the comparative effect of the materials on adhesion formation. No difference was demonstrated in resistance to bacterial adherence in the harvested materials.

Merkel cells in the human oesophagus

Merkel cells (MCs) are well recognized in the basal layers of the skin and oral mucosa, but this paper describes for the first time the presence of MCs in the human oesophagus. These cells are not identified in neonatal oesophagus, but are seen singly and in clusters in adult specimens. Application of stereological techniques shows that MCs are more numerous in the mid-oesophageal region. Cells expressing established markers of MCs have also been demonstrated in two out of six primary small cell carcinomas of the oesophagus. Further investigation of the role of MCs in oesophageal innervation and epithelial biology will be of interest.

Pulmonary adenocarcinoma: classification and molecular biology

Pulmonary adenocarcinoma is increasing in incidence. Current classification systems based purely on morphological features are of little clinical relevance. Recent descriptions of genetic abnormalities, particularly in K-ras, p53, and c-erb-B2, may form the basis of a new taxonomy having direct prognostic relevance. Study of these molecular lesions has also helped to define a new pathway of tumourigenesis in the lung parenchyma, through alveolar atypical hyperplasia (AAH) to clinical adenocarcinoma.

Neuroendocrine differentiation in lung cancer

The human lung has a resident population of neuroendocrine (NE) cells. These are characterised by the presence of neurosecretory granules and by a number of histochemical and immunocytochemical reactions. NE differentiation is a defining feature of classical and atypical carcinoid tumours and is seen in most small cell lung cancers (SCLC). Such differentiation has also been described in up to one third of non-small cell lung cancers (NSCLC). As demonstrated in an accompanying paper in this issue of the Journal, the reporting of NE differentiation varies with the technical approach used and with the nature of the tissue specimen. This phenomenon is a reflection of the histological and biological heterogeneity of lung cancer and has not been shown to be of clinical utility.

A comparison of flow and image DNA cytometry in prediction of patient prognosis in surgically resected small cell lung cancer

We have previously reported that flow cytometric tumor DNA content may be of prognostic significance in surgically resected small cell lung cancer (SCLC). We are particularly interested in determining prospective parameters for better selection of 'good prognosis' patients to proceed to surgery. Since flow cytometric measurements are poorly, if at all, applicable to endoscopic biopsy and cytology specimens we compared an image cytometric system to flow cytometry and clinical parameters in an extended series of surgically resected SCLC. Clinical follow-up was obtained on 75 patients having surgical resection for SCLC in the years 1981-92. Paraffin blocks were prepared for cytometry in standard fashion. Flow DNA histograms were characterised as diploid/tetraploid (n = 45) or DNA aneuploid (n = 27). DNA histograms obtained by image analysis were divided into type I (peridiploid n = 43) or type II (non-diploid with a minority of cells in peridiploid region; n = 31); 5c exceeding rate, 2c deviation index and malignancy grade were also computed. Overall two year survival was 27/75 patients (36%). Stage of disease was confirmed as a predictor of outcome with only 3/17 (18%) N2 patients surviving for 2 years as compared to 24/52 (46%) patients with N0/N1 disease. Image cytometric histogram classification just reached statistical significance with type I histograms indicating a better prognosis (20/43 survivors (47%) versus 7/31 (23%) patients with type II profiles, P < 0.05). Flow cytometry, 5cER, 2cD1 and malignancy grade were not useful in predicting prognosis. The results do not indicate a significant role for cytometry in SCLC.

Loss of heterozygosity at 5q21 in non-small cell lung cancer: a frequent event but without evidence of apc mutation

Four genetic polymorphisms in the APC and MCC genes at chromosome 5q21 were analysed for loss of heterozygosity (LOH) in 97 primary squamous carcinomas and adenocarcinomas of the lung. LOH was identified in at least two polymorphic loci in 41 percent of informative cases. There was no significant difference in the frequency of LOH between squamous carcinomas and adenocarcinomas. Within the adenocarcinoma group, however, LOH appeared to be more common in tumours having a bronchial origin (5/9; 56 per cent) than in parenchymal adenocarcinoma (6/21; 29 per cent). All 32 tumours showing LOH at one or more polymorphic sites were examined for mutations in the mutation cluster region (MCR) of APC by single-strand conformational polymorphism (SSCP) analysis. Mutations were not detected in any of these cases. We therefore propose that it is likely that a tumour suppressor gene on 5q other than APC is involved in the pathogenesis of lung cancer.

Lung tumours immunoreactive for parathyroid hormone related peptide: analysis of serum calcium levels and tumour type

Secretion by tumours of parathyroid hormone-related peptide (PTHrP) in quantities sufficient to raise circulating levels results in the syndrome of humoral hypercalcaemia of malignancy (HHM). Since HHM is commonly associated with squamous carcinoma of lung and rarely with adenocarcinoma or lung neuroendocrine tumours, immunopositivity was related to tumour type, to assess whether this difference was due to a low general incidence of PTHrP expression in the latter two groups. Seventy-six of 82 tumours were immunopositive: 22 of 22 squamous carcinomas, 21 of 25 small cell lung carcinomas, 14 of 15 carcinoids, and 19 of 20 adenocarcinomas. These data confirm and extend previous observations on squamous and neuroendocrine tumours but are in contrast with previous findings in adenocarcinoma, which have suggested that only a small proportion of cases express the peptide. They suggest that the differences in incidence of HHM in the various tumour types are due to patterns of secretion, rather than differences in expression of PTHrP. The second aim of this study was therefore to assess whether tumours immunopositive for PTHrP, but not associated with HHM, might secrete PTHrP at levels which might result in more subtle changes in calcium metabolism. Preoperative calcium levels were analysed in a series of 56 patients with immunopositive lung tumours of all types. One small cell carcinoma was associated with hypercalcaemia, but there was no evidence of any other alteration in serum calcium. These data indicate that the majority of tumours expressing PTHrP do not secrete it in amounts sufficient to alter calcium metabolism.

Pulmonary actinomycosis--a master of disguise

Three cases of pulmonary actinomycosis are described. In all three cases, an initial diagnosis of pulmonary malignant neoplasia was made. The correct diagnosis was made histologically after the three patients underwent either lobectomy or pneumonectomy. All patients recovered after appropriate therapy. Pulmonary actinomycosis should always be considered in the differential diagnosis of pulmonary neoplasia, especially in young adults.

Interobserver variation in cell selection for DNA image cytometry

AIMS

To describe a systematic investigation of interobserver differences in interpretation of nuclear morphology in preparations of small cell lung cancer (SCLC).

METHODS

The screening/reviewing facility on the highly optimised microscope environment was used to individually tag 127 nuclei, chosen to reflect the spectrum of morphological appearances in nuclear preparations from three biopsy specimens of SCLC. Each nucleus was reviewed and labelled as control (lymphocyte), malignant or unsatisfactory by each of four observers. DNA histograms were plotted for each specimen using the nuclei identified as malignant by each participant. The histograms were compared in terms of identification of DNA stemlines and by calculation of a 5c exceeding rate (5cER).

RESULTS

Interobserver variation in assessment of morphology was seen in 55.1% of nuclei. Disagreement occurred most frequently in the malignant/unsatisfactory category. Differences in morphological classification had little influence on histogram assessment by means of visual inspection but did show an effect on 5cER.

CONCLUSIONS

There are significant interobserver differences in subjective assessment of nuclear morphology in cytometric preparations. This effect may seriously influence cytometric measurements.

Primary small-cell cancer of the esophagus

Primary small-cell cancer of the esophagus is a rare tumor that disseminates early with a uniformly poor prognosis if untreated. Sixteen patients with malignant dysphagia referred to the Thoracic Surgical Unit, City Hospital, Edinburgh, within a 10-year period had a diagnosis of primary small-cell cancer of the esophagus. Seven patients underwent subtotal esophagectomy or esophagogastrectomy, either alone or with adjuvant chemotherapy or radiotherapy, with a mean survival of 20 months (standard deviation 35.4 months, range 2 weeks to 96 months). The remaining nine patients had disseminated disease when they were first seen and were treated symptomatically by intubation alone (1 patient), intubation and palliative chemotherapy or radiotherapy (3 patients), palliative chemotherapy (2 patients), palliative radiotherapy (1 patient), or no therapy (2 patients), with a mean survival of 4.8 months (standard deviation 2.6 months, range 2 to 9 months). Patients seen with this aggressive tumor should be assessed urgently for evidence of metastatic spread and then offered resection in combination with chemotherapy if they are otherwise fit for operation. This treatment regimen has given us one long-term survivor (96 months) who, we believe, is the only patient to have been cured of this condition. Patients seen with disseminated disease should have symptomatic treatment of the dysphagia combined with palliative chemotherapy.

Atypical alveolar hyperplasia: relationship with pulmonary adenocarcinoma, p53, and c-erbB-2 expression

Atypical alveolar hyperplasia (AAH) has recently been described in human lungs in association with primary lung cancer, particularly adenocarcinoma. Unlike proximal bronchogenic carcinoma, peripheral (parenchymal) adenocarcinoma of the lung does not have a well-recognized progenitor lesion. Epidemiological morphometric, and cytofluorometric data in the literature suggest that AAH is a candidate premalignant entity. In this study, 97 AAH lesions were found in lungs resected from 29 patients (1-13 lesions per case, mean 3.5) being treated for presumed carcinoma (25/29 had adenocarcinoma). From a study case-load of 285 adenocarcinoma-bearing lungs, the AAH incidence was 8.8 per cent. Sections of 67 AAH lesions from 19 patients were stained using monoclonal antibodies against Ki67 (MIB1), p53 (DO7), and c-erbB-2 (NCL-CB11). Ki67 was expressed in up to 10 per cent of AAH nuclei. Thirty-nine lesions (58 per cent) showed stainable p53 protein, while five (7 per cent) expressed membrane c-erbB-2 oncoprotein. These latter five lesions were all strongly positive for p53, and both p53 and c-erbB staining was associated with increased cellular crowding and pleomorphism in AAH. These data demonstrate that AAH exhibits some genetic changes associated with malignancy and thereby support the hypothesis that AAH is premalignant.

Measurement of nuclear DNA content in histological and cytological specimens: principles and applications

Nuclear DNA content can be measured in histological and cytological material by the techniques of image and flow cytometry. The measurement depends on the availability of stoichiometric markers for DNA. Results are expressed in DNA histograms from which tumour DNA ploidy and cell proliferation status can be estimated. Flow cytometry analyses large numbers of cells and gives the most meaningful cell cycle data. Image cytometry is more specifically targeted to the population of interest and can accurately measure rare events. A large body of literature exists relating DNA cytometry to clinical outcome, but there are considerable inconsistencies between clinical series which may be due, in many instances, to problems of histogram interpretation and tumour sampling. Rapid 'user-friendly' systems currently under development may increase the clinical acceptance of DNA cytometry.

Synchronous primary lung cancers: prevalence in surgical material and clinical implications

BACKGROUND

The prevalence of synchronous primary lung neoplasms in surgical resection specimens was assessed. The associated clinical features and prognostic implications were investigated.

METHODS

All surgical resections for lung cancer performed during seven years were reviewed. Synchronous tumours were defined by the presence of more than one tumour mass in the lung, by differences in histological subtype, by the presence of separate bronchial origins, or by differences in DNA stemlines. Clinical data were abstracted from case notes and information from the tumour registry.

RESULTS

Just under 2% of all surgical specimens in the study period contained more than one primary carcinoma. The patients did not differ clinically from the general population of patients having surgery for lung cancer. The overall prognosis was poor (mean survival 27 months) but was significantly better for patients with synchronous squamous carcinomas (mean survival 49 months).

CONCLUSION

Synchronous primary lung carcinomas are associated with a poor prognosis except in patients having tumours only of squamous histological type.

Expression of the pro-opiomelanocortin gene in lung neuroendocrine tumours: in situ hybridization and immunohistochemical studies

Neuroendocrine tumours of the lung may be associated with the ectopic adrenocorticotrophin (ACTH) syndrome and may synthesize and secrete ACTH-related peptides in the absence of the syndrome. However, immunocytochemical analysis may not confirm these biochemical findings, particularly in small cell carcinoma, which is poorly granulated. To investigate further the morphological evidence for expression of the pro-opiomelanocortin (POMC) gene in neuroendocrine lung tumours, we have examined a series of 46 small cell carcinomas and 13 carcinoid tumours of the lung by in situ hybridization for POMC mRNA using a digoxigenin-labelled oligoprobe. We have compared the findings with the immunocytochemical detection of ACTH and beta-endorphin. In situ hybridization was positive in 15 of 46 small cell carcinomas (33 per cent) and in 8 of 13 carcinoid tumours (62 per cent). Immunocytochemical staining was positive in only one carcinoid tumour. These in situ hybridization studies have corroborated biochemical data indicating POMC gene expression in a high proportion of lung neuroendocrine tumours. This suggests that the low levels of expression detected by immunocytochemistry may be due to low levels of hormone storage. Multivariate analysis showed a weak negative association between POMC expression and survival in small cell carcinomas, although this did not reach statistical significance.

Alveolar atypical hyperplasia in association with primary pulmonary adenocarcinoma: a clinicopathological study of 10 cases

BACKGROUND

A distinctive cytologically atypical lesion has been found in patients with primary adenocarcinoma of the lung. The aim of this study was to characterise the lesion and assess its role in tumour pathogenesis.

METHODS

Lung parenchyma from 175 consecutive resection specimens for primary pulmonary adenocarcinoma were examined. Foci of atypical hyperplasia were identified. Cell proliferation state and expression of S100 and carcinoembryonic antigens were evaluated by immunohistochemistry. Clinical data on cigarette smoking and occupational exposure to carcinogens were abstracted from inpatient case notes.

RESULTS

Ten cases (5.7%) with these distinctive cytologically atypical lesions were identified. The lesions showed immunohistochemical evidence of increased cell proliferation and focal carcinoembryonic antigen expression. The associated adenocarcinomas were of peripheral (parenchymal) type. There was an association with cigarette smoking and two of the 10 patients had synchronous carcinomas elsewhere in the lung.

CONCLUSION

The clinical and pathological associations of these lesions suggest that they may be important in the histogenesis of primary pulmonary adenocarcinoma.