Chemotherapy reduces long-term quality of life in recurrence-free colon cancer survivors (LaTE study)-a nationwide inverse probability of treatment-weighted registry-based cohort study and survey.

AIM: Stage III colon cancer is routinely treated with adjuvant chemotherapy, which causes significant short-term morbidity. Its effect on long-term quality of life (QoL) is poorly investigated. The aim of this study was to investigate long-term QoL after curative treatment for colon cancer and explore the impact of chemotherapy on general and disease-specific QoL. METHOD: All patients aged under 75 years operated on for colon cancer between 30 September 2007 and 1 October 2019 were identified by the Cancer Registry of Norway. Exclusion criteria were distant metastasis, recurrence, dementia and rectal/rectosigmoid cancer operation. The primary outcome measure was Gastrointestinal Quality of Life Index (GIQLI). Secondary outcome measures included the Short Form Health Survey (SF-36). To achieve balanced groups when assessing differences in outcome measures the analyses were weighted by inverse probability weights based on a multiple logistic regression model with prechosen confounders. RESULTS: A total of 8627 patients were invited and 3109 responded (36% response rate). After exclusions 3025 patients were included, of whom 1148 (38%) had received adjuvant chemotherapy and 1877 (62%) had surgery alone, with mean follow-up of 75.5 versus 74.5 months, respectively. The GIQLI differed significantly between the groups [mean 111.0 (SD 18.4) vs. 115.6 (SD 17.8), respectively; mean difference: -4.6 (95% CI -5.9; -3.2); p < 0.001]. Those with the highest neurotoxicity exhibited the lowest GIQLI. The adjuvant chemotherapy group scored significantly lower in six of eight SF-36 domains compared with the surgery alone group. The main differences were found in social, physical and emotional function. CONCLUSION: Long-term QoL was significantly lower in patients who received adjuvant chemotherapy than in patients who did not. Neurotoxicity was closely related to reduced QoL in these patients. The low response rate limits the generalizability of the results.

Stratification of Stage III colon cancer may identify a patient group not requiring adjuvant chemotherapy.

PURPOSE: Adjuvant chemotherapy for colon cancer with lymph node involvement (Stage III) has been the standard of care since the 1990s. Meanwhile, considerable evolvement of surgery combined with dedicated histopathological examinations may have led to stage migration. Furthermore, prognostic factors other than lymph node involvement have proven to affect overall survival. Thus, adjuvant chemotherapy in Stage III colon cancer should be reconsidered. The objective was to compare recurrence rates and survival in stage III colon cancer patients treated with or without adjuvant chemotherapy. Further, to assess the impact of extensive mesenterectomy, lymph node stage and vascular invasion on outcome. METHODS: Consecutive patients operated for Stage III colon carcinoma between 31 December 2005 and 31 December 2015 were identified in the pathological code register by matching colon (T67) and either adenocarcinoma (M81403) or mucinous adenocarcinoma (M84803), with lymph node (T08) and metastasis of adenocarcinoma (M81406 or M84806). Medical records of all identified patients were reviewed. RESULTS: Of 216 identified patients, 69 received no postoperative adjuvant chemotherapy (group NC), 69 insufficient adjuvant chemotherapy (FLV or < minimum recommended 6 cycles FLOX, group IC), and 78 sufficient adjuvant chemotherapy (≥ 6 cycles FLOX, group SC). When adjusted for age and comorbidity, 5-year overall survival did not differ statistically significant between groups (76% vs. 83% vs. 85%, respectively). Vascular invasion and a high lymph node ratio significantly reduced overall survival. CONCLUSION: The findings imply that subgroups of Stage III colon cancer patients have good prognosis also without adjuvant chemotherapy. For definite conclusions about necessity of adjuvant chemotherapy, prospective trials are needed.