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Introduction There is emerging evidence that metformin may have a protective effect in patients with cancer. However, its current evidence in locally advanced rectal cancer (LARC) is inconclusive. We aim to assess the effect of metformin on long-term outcomes in patients with LARC who received neoadjuvant therapy and surgical resection.Methods A retrospective review of 324 patients with nonmetastatic LARC who received neoadjuvant therapy and major surgical resection from 2004 to 2018. There were 27 patients who received metformin before surgery and 297 patients who did not receive metformin.Results Metformin users were associated with a significantly higher age, BMI, ASA score, and 30-day readmissions (P< .05). There was no difference in overall survival (OS, P= .18) or disease-free survival (DFS, P= .33) between the two groups. On Cox regression, metformin intake did not predict OS (HR 0.85, 95% CI 0.4-1.77) when controlled for age (HR 1.04, 1.02-1.06), sex (HR 1.13, 0.69-1.85), BMI (HR 0.97, 0.92-1.02), ASA score (HR: 1.7, 1.06-2.73), TNT (HR 0.31, 0.1-0.92), pathological Stage III disease (HR 2.55, 1.51-4.32), extramural vascular invasion (EMVI) (HR 3.06, 1.7-5.5), and adjuvant therapy (HR 0.1, 0.04-0.27 for <25 months OS and HR 0.3, 0.15-0.59 for ≥25 months). Disease-free survival showed a similar trend with no significant effect of metformin (HR 0.77, 0.39-1.52) when controlled for age, sex, BMI, ASA, TNT, Stage III disease, EMVI, and adjuvant therapy.Conclusion Metformin does not affect long-term survival in LARC treated with neoadjuvant therapy followed by surgical resection. Studies with larger sample sizes are needed to validate the findings further.

Introduction The ideal time interval between the completion of chemoradiotherapy and subsequent surgical resection of advanced stage rectal tumors is highly debated. Our aim is to study the effect of the time interval between the completion of chemoradiotherapy and surgical resection on postoperative and oncologic outcomes in rectal cancer.Methods Patients who underwent neoadjuvant chemoradiotherapy for resected locally advanced rectal tumors between 2004 and 2015 were included in this analysis. The time interval was calculated from the date of radiation completion to date of surgery. Patients were split into 2 groups based on the time interval (<8 weeks and >8 weeks). Postoperative outcomes (anastomotic leak, pathologic complete response (pCR), and readmission) and survival were assessed with multivariable logistic regression and Cox regression models while adjusting for relevant confounders.Results 200 patients (62% male) underwent resection with a median time interval of 8 weeks from completion of radiotherapy. On multivariable logistic regression, there was no significant increase in odds between time interval to surgery and anastomotic leak (aOR = .8 [.27-2.7], P= .8), pCR (aOR = 1.2[.58-2.6] P= .6), or readmission (aOR = 1.02, 95% CI:0.49-2.24, P= .9). Time interval to surgery was not an independent prognostic factor for overall (HR = 1.04 CI = .4-2.65, P= .9) and disease-free survival (HR = 1.2 CI = .5-2.9, P= .6).Conclusion The time interval between neoadjuvant radiotherapy completion and surgical resection does not affect anastomotic leak rate, achievement of pCR, or overall and disease-free survival in patients with rectal cancer. Extended periods of time to surgical resection are relatively safe.

Introduction Screening and early detection reduce morbidity and mortality in colorectal cancer. Our aim is to study the effect of income disparities on the clinical characteristics of patients with colorectal cancer in Massachusetts.Methods Patients were extracted from a database containing all surgically treated colorectal cancers between 2004 and 2015 at a tertiary hospital in Massachusetts. We split patients into 2 groups: “above-median income” and “below-median income” according to the median income of Massachusetts ($74,167).Results The analysis included 817 patients. The above-median income group consisted of 528 patients (65%) and the below-median income group consisted of 289 patients (35%). The mean age of presentation was 64 ± 15 years for the above-median income group and 67 ± 15 years for the below-median income group (P= .04). Patients with below-median income were screened less often (P< .001) and presented more frequently with metastatic disease (P= .02). Patients with above-median income survived an estimated 15 months longer than those with below-median income (P< .001). The survival distribution was statistically significantly different between the groups for stage III disease (P= .004), but not stages I, II, or IV (P= 1, 1, and .2, respectively). For stage III disease, a lower proportion of below-median income patients received chemotherapy (61% vs. 79%, P= .002) and a higher proportion underwent nonelective surgery (5% vs. 2%, P= .007).Conclusions In Massachusetts, patients with colorectal cancer residing in lower income areas are screened less, received adjuvant chemotherapy less, and have worse outcomes, especially when analyzing those who present with stage III disease.