Pathological response post neoadjuvant therapy for locally advanced rectal cancer is an independent predictor of survival

AIM

Neoadjuvant treatment (NaT) for locally advanced rectal cancer prior to surgery has led to improved outcomes. However, the relationship between pathological response to NaT and survival is not entirely clear. The aim of this study was to assess the degree of pathological response to NaT on survival outcomes.

METHODS

Clinical and pathological data were collected from a prospectively maintained pathology database between 2005 and 2017. The primary outcome was the overall survival based on pathological response categorized as complete, good partial, partial and minimal. Univariate and multivariate analyses were conducted to identify variables predictive of survival. Cox proportional hazard ratios were used for survival.

RESULTS

A total of 596 patients had surgery following NaT for locally advanced rectal cancer. The median follow-up was 4.57 years (interquartile range 2.21-8.15 years). The overall survival for complete pathological response was 75.6% vs. 37.3% for minimal response (P < 0.001). The overall survival at the end of the study in the good partial vs. partial response groups was 58.9% vs. 39% (P < 0.001). On multivariate analysis, the degree of pathological response remains an independent variable for overall and disease-specific survival across all categories.

DISCUSSION

In addition to other pathological variables, the degree of pathological response to NaT is an independent predictor for survival outcomes. Future verification of these findings elsewhere could support NaT response being used for adjuvant therapy decision making.

A Phase I study of weekly intravenous oxaliplatin in combination with oral daily capecitabine and radiation therapy in the neoadjuvant treatment of rectal adenocarcinoma

PURPOSE

We conducted a Phase I study to determine the maximum tolerated dose (MTD) of neoadjuvant capecitabine, oxaliplatin, and radiation therapy (RT) in Stage II to III rectal adenocarcinoma.

METHODS AND MATERIALS

Capecitabine was given orally twice daily Monday through Friday concurrently with RT. Oxaliplatin was given i.v. once weekly x 5 (for 5 weeks) starting the first day of RT. RT was given daily except on weekends and holidays at 1.8 Gy per fraction x 28. Escalation for capecitabine or oxaliplatin was to occur in cohorts of three patients until the maximum tolerated dose (MTD) was defined. Endorectal tumor biopsy samples were obtained before and on Day 3 of treatment to explore the effects of treatment on thymidine phosphorylase, thymidylate synthase, dihydropyrimidine dehydrogenase, DNA repair, and apoptosis.

RESULTS

Twelve patients were enrolled on this study. Two of 6 patients at dose level (DL) 1 (capecitabine 825 mg/m2 orally (p.o.) given twice daily (b.i.d.); oxaliplatin 50 mg/m2/week) had a dose-limiting diarrhea. One of 6 patients at DL (-)1 (capecitabine 725 mg/m2 p.o., b.i.d.; oxaliplatin 50 mg/m2/week) experienced-dose-limiting diarrhea. Three of 11 patients who underwent resection had a complete pathologic response. No remarkable variations in rectal tumor biologic endpoints were noted on Day 3 of treatment in comparison to baseline. However, a higher apotosis index was observed at baseline and on Day 3 in complete pathologic responders (no statistical analysis performed).

CONCLUSIONS

Capecitabine 725 mg/m2 p.o., twice daily in combination with oxaliplatin 50 mg/m2/week and RT 50.4 Gy in 28 fractions is the recommended dose for future studies.

Phase I trial of capecitabine and weekly irinotecan in combination with radiotherapy for neoadjuvant therapy of rectal cancer

PURPOSE

To establish the feasibility and efficacy of capecitabine in combination with weekly irinotecan (CAPIRI) with concurrent pelvic radiotherapy (RT) in patients with locally advanced rectal cancer.

PATIENTS AND METHODS

Nineteen patients with rectal cancer clinical stage T3-4, Nx received weekly irinotecan 50 mg/m(2) (days 1, 8, 15, 22, 29) and two doses of capecitabine (days 1 through 38; dose level [DL] I, 500 mg/m(2) bid; DL II, 625 mg/m(2) bid) according to phase I methodology. Three-dimensional conformal RT was given to a dose of 50.4 Gy (45 Gy + 5.4 Gy).

RESULTS

On DL I, no dose-limiting toxicities occurred, whereas diarrhea grade 3 affected three of seven patients on DL II. Twelve patients were treated on DL I and received a median relative dose-intensity of 100% for both drugs. Grade 3 or 4 adverse events were observed in only one of these patients (asthenia grade 3). All patients underwent surgery and R0 resection was achieved in all patients. Pathologic complete remission was observed in four patients and another five patients had only microfoci of residual tumor.

CONCLUSION

Preoperative chemoradiotherapy with CAPIRI is feasible and well tolerated. The preliminary efficacy is good, and the tolerability is at least comparable with data for fluorouracil plus irinotecan chemoradiotherapy. Larger phase II trials of the CAPIRI-RT schedule clearly are warranted.

Four Decades of Continuing Innovation With Fluorouracil: Current and Future Approaches to Fluorouracil Chemoradiation Therapy

Purpose

Chemoradiotherapy, the combination of external radiation therapy and concurrent chemotherapy, has been the basis for the oncologic management of many patients since its development in the 1960s. Fluorouracil (FU) chemoradiotherapy has demonstrated success in several organ sites with multiple dosing schedules that now guide the selection of oral analogs of FU to provide new chemoradiotherapy options.

Methods

This article reviews the metabolism and pharmacology of FU and the advantages of administration of FU by continuous infusion or bolus. The potential role and impact of the oral fluorouracil prodrugs UFT, S-1, BOF-A2, and capecitabine as replacements for intravenous administration are discussed. The results of recent chemoradiotherapy studies with FU from 2000 to 2003 are summarized in rectal, head and neck, esophageal, gastric, pancreatic, biliary, anal, and cervical cancers.

Results

Chemoradiotherapy with FU has the potential to widen the therapeutic window by minimizing normal tissue toxicity while maintaining effective tumor toxicity. Overall, FU chemoradiotherapy maximizes local control and, for some tumor sites (such as head and neck, pancreatic, biliary, cervical, esophageal, and gastric cancers), improves survival rates. Moreover, FU chemoradiotherapy results in improved organ preservation with excellent functional outcome in several anatomic sites including head and neck cancer, anal, and rectal cancer, with improved sphincter preservation.

Conclusion

FU chemoradiotherapy continues to play an important role in the management of many cancer sites. During the last four decades, optimal dosing schedules have produced a therapeutic gain. The introduction of oral prodrug analogs will likely further improve the results of FU therapy in several organ systems, such as the rectum, head and neck, and esophagus.