Alimentary tractGastric cancer after positive screening faecal occult blood testing and negative assessment
Introduction
Screening for colorectal cancer (CRC), with faecal occult blood testing (FOBT) has been shown to be effective in reducing mortality from CRC [1], [2], [3], [4]. Although the positive predictive value (PPV) of immunochemical FOBT for colorectal neoplasm (cancer or adenoma) may be as high as 37% [5], no lesion is found in a substantial proportion of FOBT+ subjects. As FOBT+ might be caused by upper digestive tract bleeding (gastric cancer (GC) or other disease, such as esophageal cancer, ulcerative esophagitis, and gastric and duodenal ulcer), it may be argued whether this tract should be investigated in FOBT+ subjects with negative assessment of the colon.
A screening programme for CRC is ongoing since 1980s in Florence District. Detailed features of the programme have been already reported [5]. All residents aged 50–70 years are invited to undergo FOBT every other year. FOBT+ subjects are assessed by total colonoscopy, with double-contrast enema (DCE) being performed when colonoscopy is incomplete or refused [6]. Classic guaiac FOBT was employed until 1995 and was thereafter replaced by immunochemical FOBT (reversed passive haemagglutination until 2000, latex agglutination thereafter) [7], [8]. The effectiveness of the programme in reducing CRC mortality has been assessed by means of a case-control study [9].
The aim of the present study was to assess the frequency of GC in FOBT+ subjects with negative diagnostic assessment (henceforth referred to as DA−), and to evaluate whether it might be worthwhile to screen these subjects by upper digestive tract endoscopy.
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Materials and methods
All subjects at their first screening visit during 1985–2001 were identified in our screening database. Subjects (a) aged <40 or >74 years, or (b) FOBT+ and assessed only by DCE, or (c) with GC detected before FOBT date (five cases) were excluded. The remaining cases were eligible for the study. FOBT+/DA− subjects were then compared with FOBT− and with FOBT+/DA+ subjects.
The number of GC expected in the study cohort was calculated by applying GC incidence rates (provided by the Tuscany Cancer
Results
Between January 1985 and December 2001, 5580 FOBT+ subjects underwent diagnostic assessment. Colonoscopy was complete in 3428 subjects (62.4%) and incomplete in 2075 (37.2%). For 77 subjects (0.1%) information on colonoscopy was missing. Incomplete colonoscopy was supplemented by DCE in 1699 cases (81.9%). It is worth noting that a substantial increase in colonoscopy completeness was observed over time: 37.3% (288/773), 61.1% (2093/3423) and 80.1% (1047/1307) during 1985–1990, 1991–1996 or
Discussion
The present study is based on a relatively large FOBT screening series, followed up by cancer registry, and thus allowing a reliable estimate of FOBT+ PPV for GC. The high rate of incomplete colonoscopy in the first period of the study might be of concern, as it might suggest a higher probability of false negative diagnostic assessment. This figure is probably overestimated as in the first period of the study missing information on the upper limit reached by colonoscopy was assumed as
Conflict of interest statement
None declared.
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Cited by (26)
Systematic upper endoscopy concomitant with colonoscopy performed within the colorectal cancer screening program: Impact on the patients’ management
2021, Clinics and Research in Hepatology and GastroenterologyCitation Excerpt :The same question remains after the introduction of FIT: despite a positive test, an advanced adenoma or CRC is found in less than 50% of cases [20]. Different studies have given conflicted results [14,15,21–23], and no firm recommendations could be proposed [24]. To propose an upper endoscopy in addition to colonoscopy to search for potential upper digestive lesions, is a technically easy approach since both examinations may be performed during the same general anesthesia.
Risk of Oral and Upper Gastrointestinal Cancers in Persons With Positive Results From a Fecal Immunochemical Test in a Colorectal Cancer Screening Program
2018, Clinical Gastroenterology and HepatologyCitation Excerpt :In line with our findings, these studies reported a low positive predictive value (PPV) for upper GI cancers. Zappa et al,16 who identified gastric cancers after linkage to a local cancer registry, reported a PPV for FOBT of 0.4% (22 of 5580 within 3 years after FOBT) for gastric cancer in FIT positives (including positives with a negative or positive colonoscopy). A PPV for FOBT of 0.4% (14 of 3555 within 3 years after FOBT) for gastric cancer in FOBT positives with a negative colonoscopy was reported, resulting in a number needed to scope of 254.
FOBT is not an effective way to screen for gastric cancer
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