Jin K. Kim

PURPOSE: Prospective data on the efficacy of a watch-and-wait strategy to achieve organ preservation in patients with locally advanced rectal cancer treated with total neoadjuvant therapy are limited. METHODS: In this prospective, randomized phase II trial, we assessed the outcomes of 324 patients with stage II or III rectal adenocarcinoma treated with induction chemotherapy followed by chemoradiotherapy (INCT-CRT) or chemoradiotherapy followed by consolidation chemotherapy (CRT-CNCT) and either total mesorectal excision (TME) or watch-and-wait on the basis of tumor response. Patients in both groups received 4 months of infusional fluorouracil-leucovorin-oxaliplatin or capecitabine-oxaliplatin and 5,000 to 5,600 cGy of radiation combined with either continuous infusion fluorouracil or capecitabine during radiotherapy. The trial was designed as two stand-alone studies with disease-free survival (DFS) as the primary end point for both groups, with a comparison to a null hypothesis on the basis of historical data. The secondary end point was TME-free survival. RESULTS: Median follow-up was 3 years. Three-year DFS was 76% (95% CI, 69 to 84) for the INCT-CRT group and 76% (95% CI, 69 to 83) for the CRT-CNCT group, in line with the 3-year DFS rate (75%) observed historically. Three-year TME-free survival was 41% (95% CI, 33 to 50) in the INCT-CRT group and 53% (95% CI, 45 to 62) in the CRT-CNCT group. No differences were found between groups in local recurrence-free survival, distant metastasis-free survival, or overall survival. Patients who underwent TME after restaging and patients who underwent TME after regrowth had similar DFS rates. CONCLUSION: Organ preservation is achievable in half of the patients with rectal cancer treated with total neoadjuvant therapy, without an apparent detriment in survival, compared with historical controls treated with chemoradiotherapy, TME, and postoperative chemotherapy.

Multiple steroid receptors (SR) have been proposed to localize to the plasma membrane. Some structural elements for membrane translocation of the estrogen receptor alpha (ER alpha) have been described, but the mechanisms relevant to other steroid receptors are entirely unknown. Here, we identify a highly conserved 9 amino acid motif in the ligand binding domains (E domains) of human/mouse ER alpha and ER beta, progesterone receptors A and B, and the androgen receptor. Mutation of the phenylalanine or tyrosine at position-2, cysteine at position 0, and hydrophobic isoleucine/leucine or leucine/leucine combinations at positions +5/6, relative to cysteine, significantly reduced membrane localization, MAP and PI 3-kinase activation, thymidine incorporation into DNA, and cell viability, stimulated by specific SR ligands. The localization sequence mediated palmitoylation of each SR, which facilitated caveolin-1 association, subsequent membrane localization, and steroid signaling. Palmitoylation within the E domain is therefore a crucial modification for membrane translocation and function of classical sex steroid receptors.

Clinical trials frequently include multiple end points that mature at different times. The initial report, typically based on the primary end point, may be published when key planned co-primary or secondary analyses are not yet available. Clinical Trial Updates provide an opportunity to disseminate additional results from studies, published in JCO or elsewhere, for which the primary end point has already been reported. To assess long-term risk of local tumor regrowth, we report updated organ preservation rate and oncologic outcomes of the OPRA trial (ClinicalTrials.gov identifier: NCT02008656 ). Patients with stage II/III rectal cancer were randomly assigned to receive induction chemotherapy followed by chemoradiation (INCT-CRT) or chemoradiation followed by consolidation chemotherapy (CRT-CNCT). Patients who achieved a complete or near-complete response after finishing treatment were offered watch-and-wait (WW). Total mesorectal excision (TME) was recommended for those who achieved an incomplete response. The primary end point was disease-free survival (DFS). The secondary end point was TME-free survival. In total, 324 patients were randomly assigned (INCT-CRT, n = 158; CRT-CNCT, n = 166). Median follow-up was 5.1 years. The 5-year DFS rates were 71% (95% CI, 64 to 79) and 69% (95% CI, 62 to 77) for INCT-CRT and CRT-CNCT, respectively ( P = .68). TME-free survival was 39% (95% CI, 32 to 48) in the INCT-CRT group and 54% (95% CI, 46 to 62) in the CRT-CNCT group ( P = .012). Of 81 patients with regrowth, 94% occurred within 2 years and 99% occurred within 3 years. DFS was similar for patients who underwent TME after restaging (64% [95% CI, 53 to 78]) and patients in WW who underwent TME after regrowth (64% [95% CI, 53 to 78]; P = .94). Updated analysis continues to show long-term organ preservation in half of the patients with rectal cancer treated with total neoadjuvant therapy. In patients who enter WW, most cases of tumor regrowth occur in the first 2 years.

4008 Background: Organ preservation (OP) with a watch and wait strategy (WW) and total neoadjuvant therapy (TNT) are new treatment paradigms for patients with locally advanced rectal cancer. The safety and efficacy of WW and of TNT have not been studied prospectively. Methods: Patients with MRI stage II and III rectal adenocarcinoma were randomized to 4 months of FOLFOX or CAPEOX before (Induction) or after (Consolidation) fluorouracil or capecitabine based chemoradiotherapy (CRT). Patients were re-staged 8-12 weeks after finishing TNT with digital rectal exam, flexible sigmoidoscopy and MRI. Patients with complete or near-complete clinical response were offered WW. Those with incomplete response had total mesorectal excision. The trial was designed so that each arm served as its own single-stage study that discriminates between 3-year disease-free survival (DFS) rates of 75% (historical null) and 85%, with 86% power, and a two-sided type I error of 5%. Secondary objectives included comparing DFS, OP, and distant metastasis-free survival (DMFS) rates between the two arms using the log-rank test. Results: Of 324 patients enrolled, 307 (152 I, 155 C) are currently evaluable for the time-to-event analysis as of 2/1/2020. Median follow-up is 2.1 years; 52 DFS events were observed. Patient demographics and tumor characteristics were generally balanced across the two arms. Full compliance with systemic chemotherapy was 82% and 81% for the I- and C-arms, respectively. The median radiation dose was 5400 cGy for both arms. Table shows 3-y DFS, DMFS, and OP rates. Conclusions: A WW strategy for patients with locally advanced rectal cancer that achieve a clinical complete response to TNT results in organ preservation for a high proportion of patients without compromising survival. Up-front CRT followed by consolidation chemotherapy resulted in a numerically higher WW rate compared to induction chemotherapy followed by CRT. Clinical trial information: NCT02008656 . [Table: see text]