Pre-diagnostic colonoscopies reduce cancer mortality - results from linked population-based data in South Australia.

BACKGROUND: To investigate the association between pre-diagnostic colonoscopy and colorectal cancer mortality in South Australia. METHODS: Colonoscopy histories were obtained for colorectal cancer patients diagnosed in 2003-2013 using linked Medical Benefits Schedule (MBS) claims, hospital-inpatient and cancer-registry data. Colonoscopy histories included the year of colonoscopy, numbers of examinations, and the time from first colonoscopy to diagnosis. Histories of multiple exposures to colonoscopies, and exposures of greater than a year from initial colonoscopy to diagnosis, were regarded as indicators of screening or surveillance activity. Colonoscopies occurring within one year of diagnosis were regarded as more likely to be a response to cancer symptoms than those occurring > 1 year before diagnosis. Associations between colonoscopy history and post-diagnostic survival were analysed using sub-hazard ratios (SHRs) from competing risk regression adjusted for socio-demographic and cancer characteristics. RESULTS: Having pre-diagnostic colonoscopy was associated with an unadjusted reduction in risk of colorectal cancer death of 17% (SHR: 0.83, 95% CI 0.78-0.89). After adjusting for time period and sociodemographic characteristics, the risk of colorectal cancer death reduced by 17% for one pre-diagnostic colonoscopy examination; 27% for two pre-diagnostic colonoscopy examinations; and 45% for three or more pre-diagnostic colonoscopy examinations. Those with a time of over one year from first colonoscopy in the study window to diagnosis, when compared with less than one year, had a 17% lower risk of colorectal cancer death in this adjusted analysis. These reductions were substantially reduced or eliminated when also adjusting for less advanced stage. CONCLUSIONS: Pre-diagnostic colonoscopy, and more so, multiple colonoscopies and first colonoscopy occurring over one year from initial colonoscopy to diagnosis, were associated with longer survival post diagnosis. This was largely explained by less advanced cancer stage at the time of diagnosis.

The unfolded protein response is activated in Helicobacter-induced gastric carcinogenesis in a non-cell autonomous manner.

Mucous metaplasia (MM) is an aberrant secretory phenotype that arises during Helicobacter-induced gastric carcinogenesis. HSPA5, a key modulator of the unfolded protein response (UPR) activated by endoplasmic reticulum (ER) stress is overexpressed in gastric cancer (GC). We studied activation of the UPR in MM and GC in humans and mice. We assessed RNA and protein levels of ER stress markers (HSPA5, XBP1, and CHOP) in human GC, and correlated with Helicobacter pylori (H. pylori) status, then surveyed HSPA5 in normal gastric mucosa and gastric pre-neoplasia including gastritis and intestinal metaplasia (IM). The role of H. pylori infection in the UPR was assessed by co-culture with AGS GC cells. ER stress markers in metaplasia and dysplasia from transgenic K19-Wnt1/C2mE mice and C57Bl/6 mice with chronic Helicobacter felis (H. felis) infection were compared. HSPA5 was overexpressed in 24/73 (33%) of human GC. Induction of HSPA5 and XBP1 splicing was associated with H. pylori-associated GC (P=0.007 for XBP1 splicing). HSPA5 was overexpressed in MM but not gastritis in patients with H. pylori infection. Stimulation of AGS cells with CagA-positive H. pylori suppressed HSPA5 expression and XBP1 splicing. In the normal gastric mucosa of human and mouse, HSPA5 was constitutively expressed in MIST1-positive chief cells. Increased Hspa5 and Chop expression were found in dysplasia of C57Bl/6 mice with chronic H. felis infection but was absent in spontaneous gastric dysplasia in K19-Wnt1/C2mE mice with concomitant loss of Mist1 expression, similar to that observed in H. pylori-associated human GC. Induction of the UPR in the milieu of Helicobacter-induced chronic inflammation and MM may promote neoplastic transformation of Helicobacter-infected gastric mucosa.

Time from diagnosis to treatment of colorectal cancer in a South Australian clinical registry cohort: how it varies and relates to survival.

OBJECTIVES: Some early studies indicated lower survival with longer time from diagnosis to cancer treatment, but others showed the reverse. We investigated time to treatment of colorectal cancer and associations with survival. SETTING AND PARTICIPANTS: Clinical registry data for colorectal cancer cases diagnosed in 2000-2010 at four major public hospitals in South Australia and treated by surgery (n=1675), radiotherapy (n=616) and/or systemic therapy (n=1556). DESIGN: A historic cohort design, with rank-order tests for ordinal clinical and sociodemographic predictors and multiple logistic regression for comparing time from diagnosis to treatment. Unadjusted Kaplan-Meier estimates and adjusted Cox proportional hazards regression were used to investigate disease-specific survival by time to treatment. OUTCOME MEASURES: Time to treatment and survival from diagnosis to death from colorectal cancer. RESULTS: Treatment (any type) commenced for 87% of surgical cases <60 days of diagnosis, with 80% having surgery within this period. Of those receiving radiotherapy, 59% began this treatment <60 days, and of those receiving systemic therapy, the corresponding proportion was 56%. Adjusted analyses showed treatment delay >60 days was more likely for rectal cancers, 2006-2010 diagnoses, residents of northern than other metropolitan regions and for surgery, younger ages <50 years and unexpectedly, those residing closer to metropolitan services. Adjusting for clinical and sociodemographic factors, and diagnostic year, better survival occurred in <2 years from diagnosis for time to treatment >30 days. Survival in the 3-10 years postdiagnosis generally did not differ by time to treatment, except for lower survival for any treatment >90 days for surgical cases. CONCLUSIONS: The lower survival <2 years from diagnosis for treatment <30 days of diagnosis is consistent with other studies attributed to preferencing more complicated cases for earlier care. Lower 3-10 years survival for surgical cases first treated >90 days from diagnosis is consistent with previously reported U-shaped relationships.