Long-term outcomes to neoadjuvant pembrolizumab based on pathological response for patients with resectable stage III/IV cutaneous melanoma.

BACKGROUND: While neoadjuvant immunotherapy for melanoma has shown promising results, the data have been limited by a relatively short follow-up time, with most studies reporting 2-year outcomes. The goal of this study was to determine long-term outcomes for stage III/IV melanoma patients treated with neoadjuvant and adjuvant programmed cell death receptor 1 (PD-1) inhibition. PATIENTS AND METHODS: This is a follow-up study of a previously published phase Ib clinical trial of 30 patients with resectable stage III/IV cutaneous melanoma who received one dose of 200 mg IV neoadjuvant pembrolizumab 3 weeks before surgical resection, followed by 1 year of adjuvant pembrolizumab. The primary outcomes were 5-year overall survival (OS), 5-year recurrence-free survival (RFS), and recurrence patterns. RESULTS: We report updated results at 5 years of follow-up with a median follow-up of 61.9 months. No deaths occurred in patients with a major pathological response (MPR, <10% viable tumor) or complete pathological response (pCR, no viable tumor) (n = 8), compared to a 5-year OS of 72.8% for the remainder of the cohort (P = 0.12). Two of eight patients with a pCR or MPR had a recurrence. Of the patients with >10% viable tumor remaining, 8 of 22 patients (36%) had a recurrence. Additionally, the median time to recurrence was 3.9 years for patients with ≤10% viable tumor and 0.6 years for patients with >10% viable tumor (P = 0.044). CONCLUSIONS: The 5-year results from this trial represent the longest follow-up of a single-agent neoadjuvant PD-1 trial to date. Response to neoadjuvant therapy continues to be an important prognosticator with regard to OS and RFS. Additionally, recurrences in patients with pCR occur later and are salvageable, with a 5-year OS of 100%. These results demonstrate the long-term efficacy of single-agent neoadjuvant/adjuvant PD-1 blockade in patients with a pCR and the importance of long-term follow-up for these patients. TRIAL REGISTRATION: Clinicaltrials.gov, NCT02434354.

The Landmark Series: Randomized Trials Examining Surgical Margins for Cutaneous Melanoma.

Between 1980 and 2004, six randomized, controlled trials (RCTs) have been performed to evaluate the width of surgical margin excision for primary cutaneous melanoma and its influence on recurrence and survival. These trials have led to the current recommendation of not more than a 2-cm margin excision and have allowed reduced morbidity of surgery for primary melanoma. Long-term follow-up data has been published which has led to impactful knowledge of the natural history of this disease, yet controversy remains for 1- to 2-mm thickness melanomas. Interpretation of these trials must be done in light of them enrolling patients before the use of sentinel node biopsy and contemporary immunotherapy regimens. These RCTs as well as a contemporary, actively enrolling trial are summarized and discussed in this review.

Preoperative radiotherapy in the management of retroperitoneal liposarcoma.

BACKGROUND: Histological subtype influences both prognosis and patterns of treatment failure in retroperitoneal sarcoma. Previous studies on the efficacy of neoadjuvant radiotherapy (NRT) have incorporated multiple histological types with heterogeneous tumour biology. The survival impact of NRT specifically for patients with retroperitoneal liposarcoma is poorly defined. METHODS: Patients who underwent resection with curative intent for retroperitoneal liposarcoma and who received NRT or surgery alone were identified in the US National Cancer Data Base (2004-2013). Cox regression was used to identify co-variables associated with overall survival. NRT and surgery-alone cohorts were matched 1 : 1 by propensity scores based on the survival hazard on Cox modelling. Overall survival was compared by Kaplan-Meier estimates. RESULTS: A total of 2082 patients with retroperitoneal liposarcoma were identified; 1908 underwent surgery alone and 174 received NRT before surgical resection. Median tumour size was 22·0 cm and 34·9 per cent of tumours were high grade. In the unmatched cohort, NRT was not associated with improved overall survival (χ2 = 3·49, P = 0·062). In the propensity score-matched cohort, NRT was associated with an improvement in survival (median overall survival 129·2 versus 84·3 months; P = 0·046; hazard ratio (HR) 1·54, 95 per cent c.i. 1·01 to 2·36). This effect appeared most pronounced for tumours with adjacent organ invasion (median overall survival not reached versus 63·8 months; P = 0·044; HR 1·79, 1·01 to 3·19). CONCLUSION: NRT improved survival in patients undergoing surgery for retroperitoneal liposarcoma, particularly those with high-risk pathological features.

Lymph node evaluation and survival after curative-intent resection of duodenal adenocarcinoma: A matched cohort study.

BACKGROUND: Lymph node (LN) metastasis in patients with duodenal adenocarcinoma is associated with poor prognosis; however, the optimal extent of LN assessment and the interaction between LN assessment and adjuvant systemic therapy is poorly understood. METHODS: Resected non-metastatic duodenal adenocarcinoma patients (n = 1743) were identified in the National Cancer Database (1998-2011). Logistic regression analysis identified covariates associated with LN metastasis. The influence of increasing LN cut-off points on overall survival (OS) was analysed using the log-rank test and Cox proportional hazards modelling. Adjuvant chemotherapy (AC) and surgery alone cohorts were matched (1:1) by propensity scores based on the likelihood of nodal metastasis or survival hazard on Cox modelling. OS in the matched cohort was compared by Kaplan-Meier estimates. RESULTS: LN metastases were present in 865 (49.6%) patients. Increasing LN assessment was associated with an increased likelihood of nodal involvement (P = 0.008). In node-negative patients, increasing LN assessment was associated with a decreased risk of death, with the largest actuarial survival differences observed for ≥15 LN (hazard ratio [HR] 0.63, 95% confidence interval [CI] 0.48-0.82, P = 0.001). In the propensity score-matched cohort of node-negative patients, AC was associated with non-significant improvements in 5-year actuarial (66.1% versus 58.7%, HR 0.79, 95% CI 0.53-1.18, P = 0.249), and did not vary by adequacy of LN counts (<15 LNs: HR 0.79, 95% CI 0.51-1.24, P = 0.305; ≥15 LNs: HR 0.90, 95% CI 0.35-2.30, P = 0.900). CONCLUSIONS: The extent of LN identification has prognostic significance in resected node-negative duodenal adenocarcinoma, but cannot be implicated in the selection of node-negative patients for AC.

The beta protein of phage lambda promotes strand exchange.

Bacteriophage lambda encodes a 28 kDa protein called beta that binds to single-stranded DNA and promotes the renaturation of complementary single strands. beta Protein fails to bind directly to duplex DNA but remains bound to the DNA product of renaturation that beta itself catalyzes. These observations led to an examination of the ability of beta protein to promote strand exchange. beta Protein caused the replacement of a 43-mer oligonucleotide annealed to M13 circular single-stranded DNA by a homologous 63-mer whose 20 extra nucleotide residues were complementary to the adjacent 3' region of M13 DNA. The role of beta protein in this reaction was manifested in several ways: beta protein pushed the exchange through four to eight mismatches, which blocked exchange mediated by spontaneous renaturation and branch migration; beta imposed a polarity on the strand exchange that was lacking in the spontaneous reaction; and beta remained bound to the heteroduplex product of strand exchange. These observations reveal a mechanism by which a protein can drive strand exchange in one direction without using ATP or any other exogenous source of energy.

The beta protein of phage lambda binds preferentially to an intermediate in DNA renaturation.

Phage lambda encodes two recombination proteins that are required for homologous recombination in a recA- host strain. Of these two recombination proteins, one is an exonuclease whose action on double-stranded DNA produces 3' single-stranded ends; the other, called beta protein, is a DNA binding protein that promotes the renaturation of complementary single strands. The enzymes of phage lambda provide a model for understanding a recombination pathway called "single-strand annealing". Further investigation of the binding of beta protein to DNA has revealed a new mechanism of renaturation. As reported before, beta protein binds directly to single-stranded DNA, but not to double-stranded DNA. However, in the experiments reported here, we observed that beta protein bound more strongly to a presumed intermediate in the renaturation reaction that beta itself catalyzed, and beta thereby protected all of a renatured duplex 83-mer oligonucleotide from nuclease digestion.