Time factor and treatment strategies in subclinical disease

Significance of overall concurrent chemoradiotherapy duration on survival outcomes of stage IIIB/C non-small-cell lung carcinoma patients: Analysis of 956 patients

Background

To investigate the detrimental effects of prolonged overall radiotherapy duration (ORTD) on survival outcomes of stage IIIB/C NSCLC patients treated with concurrent chemoradiotherapy (C-CRT)

Methods

The study cohort consisted of 956 patients who underwent C-CRT for stage IIIB/C NSCLC. Primary endpoint was the association between the ORTD and overall survival (OS) with locoregional progression-free survival (LRPFS) and PFS comprising the secondary endpoints. Receiver operating characteristic (ROC) curve analysis was utilized for accessibility of the cut-off that interacts with survival outcomes. Multivariate Cox model was utilized to identify the independent associates of survival outcomes.

Results

The ROC curve analysis exhibited significance at 49 days of ORTD cut-off that dichotomized patients into ORTD<50 versus ORTD≥50 days groups for OS [area under the curve (AUC): 82.8%; sensitivity: 81.1%; specificity: 74.8%], LRPFS (AUC: 91.9%; sensitivity: 90.6%; specificity: 76.3%), and PFS (AUC: 76.1%; sensitivity: 72.4%; specificity: 68.2%), respectively. Accordingly, ORTD≥50 days group had significantly shorter median OS (P<0.001), LRPFS (P<0.001), and PFS (P<0.001); and 10-year actuarial locoregional control (P<0.001) and distant metastases-free (P<0.011) rates than the ORTD<50 days group. The ORTD retained its significant association with survival outcomes at multivariate analyses independent of the other favorable covariates (p<0.001, for OS, LRPFS, and PFS): Stage IIIB disease (versus IIIC), lymph node bulk <2 cm (versus ≥2 cm), and 2–3 chemotherapy cycles (versus 1). The higher sensitivity for LRPFS (90.6%) than PFS (72.4%) on ROC curve analysis suggested the prolonged ORTD-induced decrements in locoregional control rates as the major cause of the poor survival outcomes.

Conclusions

Longer ORTD beyond ≥50 days was associated with significantly poorer OS, LRPFS and PFS outcomes, where reduced locoregional control rates appeared to be the main causative.

Combining targeted agents and hypo- and hyper-fractionated radiotherapy in NSCLC

Radical radiotherapy remains the cornerstone of treatment for patients with unresectable locally advanced non small cell lung cancer (NSCLC) either as single modality treatment for poor performance status patients or with sequential or concomitant chemotherapy for good performance status patients. Advances in understanding of tumour molecular biology, targeted drug development and experiences of novel agents in the advanced disease setting have brought targeted agents into the NSCLC clinic. In parallel experience using modified accelerated fractionation schedules in locally advanced disease have demonstrated improved outcomes compared to conventional fractionation in the single modality and sequential chemo-radiotherapy settings. Early studies of targeted agents combined with (chemo-) radiotherapy in locally advanced disease in different clinical settings are discussed below and important areas for future studies are high-lighted.

The therapeutic and adverse effects of modified radiation fields for patients with rectal cancer

PURPOSE

To compare the therapeutic effect and complications of modified radiation fields (MRFs) with those of conventional pelvic radiation fields (CPRFs) for rectal cancer.

METHODS AND MATERIALS

From December 1996 to October 2009, a total of 160 patients with rectal carcinoma who received total mesorectal excision and postoperative radiotherapy were examined. Ninety-four patients were in the CPRFs group, and 66 were in the MRFs group. The dose was 50 Gy per 25 fractions in the initial plan.

RESULTS

The treatment volume and the volume of small bowel that received more than 15 Gy of the MRFs was smaller than that of the CPRFs (P < .001). The rates of local recurrence, overall survival, and disease-free survival were not statistically significant between the MRFs and CPRFs groups (P > .05). There was a statistical difference (P < .05) in the incidence of acute toxicity, which included serious complications in the lower digestive tract (grade ≥3). The completion rate for the initial radiotherapy plan was higher in the MRFs group than in the CPRFs group (P = .027).

CONCLUSIONS

Compared with CPRFs, MRFs manifested a lower incidence of complications and the same therapeutic effects. This finding will facilitate the clinical application of MRFs for patients with rectal cancer.

Incidental irradiation of mediastinal and hilar lymph node stations during 3D-conformal radiotherapy for non-small cell lung cancer

PURPOSE

To estimate the doses of incidental irradiation in particular lymph node stations (LNS) in different extents of elective nodal irradiation (ENI) in 3D-conformal radiotherapy (3D-CRT) for non-small cell lung cancer (NSCLC). METHODS; Doses of radiotherapy were estimated for particular LNS delineated according to the recommendations of the University of Michigan in 220 patients treated using 3D-CRT with different (extended, limited and omitted) extents of ENI. Minimum doses and volumes of LNS receiving 40 Gy or more (V40) were compared for omitted vs. limited+ extended ENI and limited vs. extended ENI.

RESULTS

For omission of the ENI the minimum doses and V40 for particular LNS were significantly lower than for patients treated with ENI. For the limited ENI group, the minimum doses for LNS 5, 6 lower parts of 3A and 3P (not included in the elective area) did not differ significantly from doses given to respective LNS for extended ENI group. When the V40 values for extended and limited ENI were compared, no significant differences were seen for any LNS, except for group 1/2R, 1/2L.

CONCLUSIONS

Incidental irradiation of untreated LNS seems play a part in case of limited ENI, but not in cases without ENI. For subclinical disease the delineation of uninvolved LNS 5, 6, and lower parts of 3A, 3P may be not necessary, because these stations receive the substantial part of irradiation incidentally, if LNS 4R, 4L, 7, and ipsilateral hilum are included in the elective area while this is not case for stations 1 and 2.

Empirically-based estimates for the burden of subclinical metastases

PURPOSE

To describe the frequency distribution for the number of residual subclinical metastatic tumor cells after removal of the primary cancer.

MATERIALS AND METHODS

Previously obtained autopsy, surgical pathological and laboratory data were used to characterize the size and number distributions for hematogenous and lymphatic metastases. Monte Carlo simulations were used to estimate the numbers of residual tumor cells based upon the assumption of a lognormal distribution for the sizes of metastases and Poisson, Poisson negative binomial, or negative binomial distributed numbers of metastases (corresponding to lymphatic metastases within individuals, hematogenous metastases within individuals, and lymphatic metastases within populations, respectively).

RESULTS

In each of the scenarios the resultant distribution for the numbers of subclinical tumor cells was unimodal and positively skewed, with a tail extending to the higher numbers of metastases. When plotted with equal sized counting bins and according the logarithm of the number of tumor cells, the distributions showed deviations from the normal form no greater than several percentage points--a result considered acceptable given the variabilities inherent to metastasis data.

CONCLUSIONS

The distribution for the number of residual subclinical metastases may be extrapolated from data and models derived from the size and number distributions for metastases. In the absence of a closed form description for this distribution, the lognormal distribution could provide a crude, but practical, approximation for cases limited to occult microscopic residual disease. These analyses will facilitate the definition of the dose-response for the adjuvant therapy of subclinical metastases.

The tolerance and efficacy of preoperative chemoradiotherapy followed by gastrectomy in operable gastric cancer, a phase II study

The aim of study was to assess the tolerance and effectiveness of preoperative chemoradiotherapy in the group of 40 patients with operable gastric cancer. The therapy was well tolerated. We observed the high rate of pathological response and R0 resections, low rate of local recurrence and high percent of 2-year survival.

The concurrent chemoradiation paradigm—general principles

During the past 20 years, the advent of neoadjuvant, primary, and adjuvant concurrent chemoradiotherapy has improved cancer care dramatically. Significant contributions have been made by technological improvements in radiotherapy, as well as by the introduction of novel chemotherapy agents and dosing schedules. This article will review the rationale for the use of concurrent chemoradiotherapy for treating malignancies. The molecular basis and mechanisms of action of combining classic cytotoxic agents (e.g. platinum-containing drugs, taxanes, etc.) and novel agents (e.g. tirapazamine, EGFR inhibitors and other targeted agents) with radiotherapy will be examined. This article is part one of two articles. In the subsequent article, the general principles outlined here will be applied to head and neck cancer, in which the impact of concurrent chemoradiotherapy is particularly evident.

Innovative strategies for image-guided proton treatment of prostate cancer

Proton beam therapy has a proven track record of treating non-metastatic prostate cancer with excellent disease-free survival results when using homogeneous doses between 75 and 82 CGE (Cobalt Gray Equivalent) to the prostate target volume. In clinically organ-confined prostate cancer, it may be possible, in principle, to further improve outcomes by reducing the margins of the high-dose planning target volume to the gross tumor volume and by covering the clinical target volume with a dose sufficient to control microscopic extensions of the tumor. This would allow further dose escalation without increasing the risk of acute and late effects. In this paper, we undertake a careful review of existing histopathological data that support this view and discuss technical possibilities to this approach utilizing the highly conformal characteristics of proton beams and combining them with modern 4D imaging and treatment techniques.

A pilot study of accelerated preoperative hyperfractionated pelvic irradiation with or without low-dose preoperative prophylactic liver irradiation in patients with locally advanced rectal cancer

BACKGROUND AND PURPOSE

To evaluate the feasibility of low-dose preoperative prophylactic liver irradiation (PLI) combined with preoperative accelerated hyperfractionated pelvic irradiation (HART) in patients with locally advanced rectal cancer.

PATIENTS AND METHODS

Between 1999 and 2003 62 patients were enrolled: 38 (61%) received HART and 24 (39%) HART+PLI. The pelvis was irradiated twice a day, with a minimal interfraction interval of 6h: the total dose of 42 Gy was given in 1.5 Gy per fractions over 18 days. The PLI (14 Gy in 10 daily fractions of 1.4 Gy) was given simultaneously with the morning fraction of HART. Twenty patients (32%), including 7 in PLI group, received 5-Fu based postoperative chemotherapy.

RESULTS

In general, acute normal tissue reactions appeared tolerable irrespectively of PLI. Six to twelve months after completion of combined therapy the mean ALAT levels in patients treated with HART alone (25 pts), HART+chemotherapy (13 pts), HART+PLI (17 pts), and HART+PLI+chemotherapy (7 pts) were 15, 21, 26 and 55 IU/l, respectively. A mild increase of ALAT levels observed in the HART+PLI+chemotherapy sub-group was non-symptomatic. Three-year actuarial loco-regional control rate in a group of 62 patients was 94%. None of the patients who received PLI developed metastases during the follow-up, compared to 10 out of 38 patients (26%) with no PLI. A difference in metastases-free survival in favor of HART+PLI can be, however, attributed to selection of patients for PLI who were in better general health and stage of disease than those treated with HART.

CONCLUSIONS

Further use of PLI may be limited due to asymptomatic, but detectable biochemical changes of liver function when PLI is sequentially combined with chemotherapy. HART, on the other hand, provides acceptable rate of local control, and is well tolerated, also when combined with postoperative chemotherapy.

Optimal treatment of intermediate-risk prostate carcinoma with radiotherapy

The clinical heterogeneity of intermediate-risk prostate carcinoma presents a challenge to urologic oncology in terms of prognosis and management. There is controversy regarding whether patients with intermediate-risk prostate carcinoma should be treated with dose-escalated external beam radiotherapy (EBRT) (e.g., doses > 74 gray [Gy]), or conventional-dose EBRT (e.g., doses < 74 Gy) combined with androgen deprivation (AD). Data for this review were identified through searches for articles in MEDLINE and in conference proceedings, indexed from 1966 to 2004. Currently, the intermediate-risk prostate carcinoma grouping is defined on the basis of prostate-specific antigen (PSA), tumor classification (T classification), and Gleason score. Emerging evidence suggests that additional prognostic information may be derived from the percentage of positive core needle biopsies at the time of diagnosis and/or from the pretreatment PSA doubling time. Novel prognostic biomarkers include protein expression relating to cell cycle control, cell death, DNA repair, and intracellular signal transduction. Preclinical data support dose escalation or combined AD with radiation as a means to increase prostate carcinoma cell kill. There is Level I evidence that patients with intermediate-risk prostate carcinoma benefit from dose-escalated EBRT or AD plus conventional-dose EBRT. However, clinical evidence is lacking to support the uniform use of AD plus dose-escalated EBRT. Patients in the intermediate-risk group should be entered into well designed, randomized clinical trials of dose-escalated EBRT and AD with sufficient power to address biochemical failure and cause-specific survival endpoints. These studies should be stratified by novel prognostic markers and accompanied by strong translational endpoints to address clinical heterogeneity and to allow for individualized treatment.