Survival outcomes of left-sided versus right-sided colon cancer.

Abstract

502 Background: Right-sided colon cancers (RCC) are defined up to the splenic flexure where as left-sided colon cancers (LCC) involve the descending, sigmoid, and rectosigmoid regions. The landmark CALGB/SWOG 80405 study concluded that sidedness was an independent prognostic factor for survival in stage IV adenocarcinoma of the colon or rectum, with a poorer prognosis in RCC. This raises the question as to whether or not stage of malignancy plays a role. We performed a retrospective analysis on survival for stage I to IV colon cancer treated at our institution in order to assess if tumor location is an independent prognostic factor as described in previous studies. Methods: Primary site of cancer, sex, age at diagnosis, vital status, and year of diagnosis for stage I, II, III, and IV colon cancer was collected from our institution’s tumor registry from 2007 to 2017. The inclusion criteria included those diagnosed with stage I to IV colon cancer at 18 years of age and above. Exclusion criteria included a diagnosis of both RCC and LCC and patients under age 18. The median of overall survival and time to recurrence between LCC and RCC were compared using Wilcoxon Rank Sum Test with two-sided significance level at 0.05. Results: Time to overall survival and time to recurrence was shown to have no significant difference between RCC and LCC (p = 0.3398 and 0.9467, respectively). Cox proportional hazards model adjusted for age and sex also support the claim (p = 0.1725 and 0.0633). There was a statistically significant difference in age between the two groups with the older mean age seen in RCC (68 versus 62). The distribution of recurrence was statistically significant with a higher recurrence in RCC (p = 0.0105). Conclusions: Unlike CALGB/SWOG 80405, our analysis included the transverse colon as part of RCC and examined stage I to IV colon cancer to ultimately conclude that there was no significant difference in overall survival or time to recurrence. Our study suggests that tumor location is not an independent prognostic factor on survival for all stages of colon cancer. However, a higher suspicion for recurrence may be needed for those diagnosed with RCC. Future investigations involving molecular subtypes and mutations are needed to further clarify prognosis and tumor sidedness.

The treatment paradigm of right-sided metastatic colon cancer: harboring BRAF mutation makes the difference

“…By now we know that RCC is a completely different entity with a different embryological origin, molecular pathways (harboring BRAF, PIK3CA, and KRAS mutations, more frequently with MSI-H phenotye) and poorer outcome than LCC [2][3][4][5][6][7][8][9][10][11][12][13][14][15]. Therefore, a better understanding of RCC behavior is crucial to explain the different response to chemotherapy and the available targeted agents.…”

“…Patients affected with RCC reported an increased frequency of vascular invasion, mucinous type, high grade, invasive tumor border and a higher total number of harvested lymph nodes [11] but with lower rates of node positivity [12] than the left-side colon cancer (LCC) [13].…”

ASCO-GI 2019: Metastasiertes Kolorektalkarzinom

“…Diverse Zentren haben nun die eigenen Datenbanken sowie Studiendaten auf den prognostischen Wert der Seitigkeit des Kolonkarzinoms ausgewertet und präsentierten kontroverse Ergebnisse beim ASCO GI in San Francisco. [4]. In dieser Analyse wurde das Colon transversum zu den rechtsseitigen Tumoren gezählt und Tumoren in den Stadien I bis IV berücksichtigt.…”