Time factor in postoperative radiotherapy: a multivariate locoregional control analysis in 868 patients

PURPOSE

To study locoregional tumor control in postoperative radiotherapy (PRT) for head-and-neck cancer in relation to the position and duration of treatment gaps, duration of the interval surgery-radiotherapy, and to the other potentially prognostic variables.

METHODS AND MATERIALS

The retrospective study included 868 patients with cancer of the larynx, oral cavity, oropharynx, and hypopharynx treated in Gliwice between 1980 and 1997. Mean total radiation dose, dose per fraction, overall radiation treatment time (OTT), and the interval surgery-PRT were 62.8 Gy, 2.1 Gy, 45 days, and 63 days, respectively. No interruptions during PRT (except for weekend breaks) appeared in 30% of patients, whereas 19% had more than 5 days of gap. The actuarial locoregional recurrence-free survival (RFS) has been examined using multivariate Cox regression model, and the ultimate locoregional tumor control probability using a logistic model.

RESULTS

Increased duration of treatment gaps, positive resection margins, pathologically proven metastases to the neck nodes, and extralaryngeal site of cancer were significantly related to a decrease in RFS. The duration of time interval surgery-PRT appeared, by contrast, only borderline significant for RFS. The relative risk of locoregional recurrence was approximately the same for the gaps in days 1-21 as for the "late" gaps (days >21), except in a subgroup of patients with positive clinical margins. The logistic analysis revealed a significant time-related displacement of the dose-response curves for PRT. The detriment from the protraction of OTT appeared to be larger than the benefit from the equivalent shortening of OTT.

CONCLUSIONS

Although the conclusions from this study must be regarded as only hypothesis-generating, we assume that a highly significant adverse influence of radiation treatment gaps on the rate of tumor control is consistent with rapid repopulation of cancer clonogenes during PRT. Lack of significant effect of the position of gaps on locoregional tumor control after radical surgery may suggest that a lag time for the onset of repopulation in PRT is short. A less likely explanation is that the total amount of regeneration during OTT is the same, regardless of the timing of the gap, even if all the repopulation occurred late. The magnitude of the detriment in tumor control from prolonged interval surgery-PRT indicates that repopulation of cancer cells between surgery and radiotherapy is not as fast as between the fractions of radiotherapy.

Randomized clinical trial on accelerated 7 days per week fractionation in radiotherapy for head and neck cancer. Preliminary report on acute toxicity

PURPOSE

Toxicity of an accelerated 7 days per week fractionation schedule (arm A) was evaluated and compared with a conventional 5 days per week treatment (arm B) in a randomized trial.

MATERIALS AND METHODS

Forty-four patients with squamous cell carcinoma of the head and neck in stage T2-4Nzero-1Mzero were included in the study. Total dose and dose per fraction of 2.0 Gy given once-a-day at 24 h intervals were the same in both arms of the trial. The only difference was the overall treatment time being 5 weeks in arm A and 7 weeks in arm B.

RESULTS

Analysis of severe mucosal reactions shows significant difference between arm A and B, with regard to both maximum score and duration of severe mucositis. Confluent mucositis (score > 15 according to the Dische system) lasting longer than 3 weeks developed in 48% of patients in arm A and only in 5% in arm B. In group A seven (30%) late effects (osteo- and soft tissue necrosis) occurred during 7-12 month follow-up with two reactions (10%) in group B being suspected as late effects. There was significant association between acute reactions and late effects in arm A, suggesting that the late effects are consequential.

CONCLUSION

The high incidence of severe acute reactions and consequential late effects suggests that the accelerated treatment in arm A (using daily fractions of 2.0 Gy, 7 days per week) gives unacceptable toxicity.

Dose-response relationship for prophylactic cranial irradiation in small cell lung cancer

PURPOSE

To determine the dose-response relationship for prophylactic cranial irradiation (PCI) in small cell lung cancer, to quantify the growth kinetics of subclinical metastases, and to determine the influence of time-delay in initiating PCI on its utility.

METHODS AND MATERIALS

Published reports of brain relapse rates in small cell lung cancer with and without PCI were collected. The reduction in brain relapse rate as a function of radiation dose was analyzed. The time interval between treatment of the primary tumor and the initiation of PCI was analyzed as a factor potentially influencing dose-response.

RESULTS

A shallow dose-response curve without any threshold in the dose intercept was demonstrated for control of subclinical brain metastases in "early PCI" (delay between initiation of treatment for primary tumor and PCI less than 60 days). By contrast "late PCI" (delay over 60 days) was associated with a significant displacement of the dose intercept. Doses over 30-35 Gy in 2-Gy fractions did not result in a further reduction in brain relapse rate, but there were too few high-dose studies to draw any definite conclusion.

CONCLUSIONS

The nearly linear dose-response relationship for reduction in brain relapses demonstrated for "early PCI" in the range of doses from zero up to 35 Gy given in 2-Gy fractions supports the model of a fairly logarithmically uniform distribution of metastatic cell number within a series of patients. When PCI is delayed, a significant threshold in dose-response was observed, consistent with a fast growth rate of untreated subclinical brain metastases from small cell lung cancer. The exact shape and locations of dose-response curves is not well established by this retrospective analysis of diverse data. A high probability of eliminating brain relapses following PCI requires a dose of about 30-35 Gy in 2-Gy fractions. Control rates in brain can be enhanced if PCI is applied early.

Continuous accelerated 7-days-a-week radiotherapy for head-and-neck cancer: long-term results of phase III clinical trial

PURPOSE

To update 5-year results of a previously published study on special 7-days-a-week fractionation continuous accelerated irradiation (CAIR) for head-and-neck cancer patients.

METHODS AND MATERIALS

One hundred patients with squamous cell carcinoma of head and neck in Stage T(2-4)N(0-1)M(0) were randomized between two definitive radiation treatments: accelerated fractionation 7 days a week including weekends (CAIR) and conventional 5 days a week (control). Hence the overall treatment time was 2 weeks shorter in CAIR.

RESULTS

Five-year local tumor control was 75% in the CAIR group and 33% in the control arm (p < 0.00004). Tumor-cure benefit corresponded with significant improvement in disease-free survival and overall survival rates. Confluent mucositis was the main acute toxicity, with the incidence significantly higher in CAIR patients than in control (respectively, 94% vs. 53%). When 2.0-Gy fractions were used, radiation necrosis developed in 5 patients (22%) in the CAIR group as a consequential late effect (CLE), but when fraction size was reduced to 1.8 Gy no more CLE occurred. Actuarial 5-year morbidity-free survival rate was similar for both treatments.

CONCLUSIONS

Selected head-and-neck cancer patients could be treated very effectively with 7-days-a-week radiation schedule with no compromise of total dose and with slight 10% reduction of fraction dose (2 Gy-1.8 Gy), which article gives 1 week reduction of overall treatment time compared with standard 70 Gy in 35 fractions over 47-49 days. Although this report is based on the relatively small group of patients, its results have encouraged us to use CAIR fractionation in a standard radiation treatment for moderately advanced head-and-neck cancer patients.

Radiation dose response for subclinical metastases

The development of adjuvant therapies for subclinical metastases has been empiric. Decades of experience showed that 45 to 50 Gy resulted in high control rates for subclinical lymph node involvement.1 By analogy with the response of macroscopic tumors, in which doses below a threshold yield no benefit, it was commonly believed that doses lower than 40 to 50 Gy would not be useful in elective treatment of subclinical disease. Biological phenomena, such as presumed metastatic tumor cell burden and growth rate of micrometastases, which could guide the oncologist, had little or no role in the empirical development of adjuvant cytotoxic therapies. In this article, some assumptions regarding the biology of subclinical metastases are discussed and examined in the light of treatment responses reported from clinical experience. In particular, the importance of early initiation of adjuvant therapy can be appreciated as well as the significant reductions in the incidence of metastases that can be achieved even when doses less than 45 to 50 Gy have to be accepted if necessitated by normal tissue tolerance.

Rapid growth of microscopic rectal cancer as a determinant of response to preoperative radiation therapy

PURPOSE

To quantify the dose-time fractionation factors in preoperative radiation therapy for microscopic pelvic deposits of rectal cancer. This provides a biologic basis for understanding and improving the results of adjuvant therapies for this disease.

METHODS

The reduction in incidence of pelvic relapses as a function of radiation dose and overall treatment time was determined from the literature. The displacement of dose-response curves to higher doses reflects the growth during radiation treatment of subclinical pelvic deposits which are beyond the future surgical margins.

RESULTS

Dose-response curves are steep if the effect of overall duration of radiation therapy is accounted for. The time-related displacement of these steep dose-response curves is consistent with a median doubling time for malignant clonogenic cells of about 4 or 5 days, much faster than the growth rate of the average primary tumor at diagnosis. This rapid growth is evident within the first few days of irradiation, implying that the natural growth rate of these microscopic deposits if fast, and/or that an acceleration of growth follows initiation of radiation injury with a very short lag time.

CONCLUSION

Subclinical pelvic deposits of rectal cancer grow rapidly during preoperative radiation therapy with an adverse influence on the rate of pelvic tumor control from protracting the duration of adjuvant treatment. Low doses only offer clinically relevant reduction in risk of pelvic relapses if the overall radiation treatment time is short. For a given overall treatment duration there is a relatively steep dose-response curve, predicting that significant improvements in tumor control are possible.

Clinical radiobiology of stage T2-T3 bladder cancer

PURPOSE

To evaluate the relationship between total radiation dose and overall treatment time (OTT) with the treatment outcome, with adjustment for selected clinical factors, in patients with Stage T2-T3 bladder cancer treated with curative radiotherapy (RT).

METHODS AND MATERIALS

The analysis was based on 480 patients with Stage T2-T3 bladder cancer who were treated at the Center of Oncology in Gliwice between 1975 and 1995. The mean total radiation dose was 65.5 Gy, and the mean OTT was 51 days. In 261 patients (54%), planned and unplanned gaps occurred during RT. Four fractionation schedules were used: (1) conventional fractionation (once daily, 1.8-2.5 Gy/fraction); (2) protracted fractionation (pelvic RT, once daily, 1.6-1.7 Gy/fraction, boost RT, once daily, 2.0 Gy/fraction); (3) accelerated hyperfractionated boost (pelvic RT, once daily, 2.0 Gy/fraction; boost RT, twice daily, 1.3-1.4 Gy/fraction); and (4) accelerated hyperfractionation (pelvic and boost RT, twice daily, 1.2-1.5 Gy/fraction). In all fractionation schedules, the total radiation dose was similar (average 65.5 Gy), but the OTT was different (mean 53 days for conventional fractionation, 62 days for protracted fractionation, 45 days for accelerated hyperfractionated boost, and 41 days for accelerated hyperfractionation). A Cox proportional hazard model and maximum likelihood logistic model were used to evaluate the relationship between the treatment-related parameters (total radiation dose, dose per fraction, and OTT) and clinical factors (clinical T stage, hemoglobin level and bladder capacity before RT) and treatment outcome.

RESULTS

With a median follow-up of 76 months, the actuarial 5-year local control rate was 47%, and the overall survival rate was 40%. The logistic analysis, which included the total dose, OTT, and T stage, revealed that all of these factors were significantly related to tumor control probability (p = 0.021 for total radiation dose, p = 0.038 for OTT, and p = 0.00068 for T stage). A multivariate Cox model, which included the treatment-related parameters and other clinical factors, revealed that the hemoglobin level and bladder capacity before RT and T-stage were statistically significant factors determining local control and overall survival. The total radiation dose was of borderline statistical significance for overall survival (p = 0.087), and OTT did not reach statistical significance.

CONCLUSION

The results of our study showed that the treatment outcome after RT for bladder cancer depends mainly on clinical factors: hemoglobin level and bladder capacity before RT, and clinical T stage. An increase in the total radiation dose seemed to be associated with a better treatment outcome. The effect of the OTT was difficult to define, because it was influenced by other prognostic factors.

The erythropoietin-receptor pathway modulates survival of cancer cells

Anemia in cancer patients is associated with reduced quality of life and local failure after radiation treatment. However, the use of erythropoietin to correct cancer anemia and to improve radiation efficacy was disappointing. Erythropoietin-receptor signaling mainly acts via activation of STAT 5, but also crossactivates the antiapoptotic transcription factor NF-kappaB. This causes neuroprotection against oxidative stress and implies radioprotection. In order to investigate possible radioprotective effects of erythropoietin-receptor signaling, we used an in vitro model system employing HeLa TetOff cells, stably transfected with an expression vector for the erythropoietin-receptor gene. Using electrophoretic mobility shift assays, we could demonstrate strong activation of NF-kappaB by erythropoietin-receptor signaling in HeLa cells. Activation of NF-kappaB did not require degradation of IkappaBalpha and was not prevented by proteasome inhibition. Furthermore, stimulation with erythropoietin resulted in a 50% increased clonogenicity of erythropoietin-receptor-expressing cells but did not alter radiation sensitivity itself. As most human tumors express erythropoietin receptor, we advocate a restricted use erythropoietin to patients suffering from erythropoietin-receptor-expressing cancers.

PTEN as a prognostic and predictive marker in postoperative radiotherapy for squamous cell cancer of the head and neck

Background

Tumor suppressor PTEN is known to control a variety of processes related to cell survival, proliferation, and growth. PTEN expression is considered as a prognostic factor in some human neoplasms like breast, prostate, and thyroid cancer.

Methodology/Principal Findings

In this study we analyzed the influence of PTEN expression on the outcome of a randomized clinical trial of conventional versus 7-days-a-week postoperative radiotherapy for squamous cell cancer of the head and neck. The patients with cancer of the oral cavity, oropharynx, and larynx were randomized to receive 63 Gy in fractions of 1.8 Gy given 5 days a week (CF) or 7 days a week (p-CAIR). Out of 279 patients enrolled in the study, 147 paraffin blocks were available for an immunohistochemical assessment of PTEN. To evaluate the prognostic value of PTEN expression and the effect of fractionation relative to PTEN, the data on the outcome of a randomized clinical trial were analyzed. Tumors with a high intensity of PTEN staining had significant gain in the loco-regional control (LRC) from p-CAIR (5-year LRC 92.7% vs. 70.8%, for p-CAIR vs. CF, p = 0.016, RR = 0.26). By contrast, tumors with low intensity of PTEN did not gain from p-CAIR (5-year LRC 56.2% vs. 47.2%, p = 0.49, RR = 0.94). The intensity of PTEN highly affected the LRC in a whole group of 147 patients (5-year LRC 80.9% vs. 52.3% for high vs. low PTEN, p = 0.0007, RR = 0.32). In multivariate Cox analysis, including neck node involvement, EGFR, nm23, Ki-67, p53, cyclin D1, tumor site and margins, PTEN remained an independent predictor of LRC (RR = 2.8 p = 0.004).

Conclusions/Significance

These results suggest that PTEN may serve as a potent prognostic and predictive marker in postoperative radiotherapy for high-risk squamous cell cancer of the head and neck.

Moderately Low Alpha/Beta Ratio for Rectal Cancer May Best Explain the Outcome of Three Fractionation Schedules of Preoperative Radiotherapy

PURPOSE

To estimate the alpha/beta ratio for rectal cancer according to the outcome of three fractionation schedules of preoperative radiotherapy.

METHODS AND MATERIALS

Between 1996 and 2002, 168 patients with locally advanced rectal cancer were treated as follows: 53 patients received 25 Gy in 5 Gy per fraction, 45 received 30 Gy in 3.0 Gy per fraction, and 70 were treated with accelerated hyperfractionation (42 Gy, 1.5 Gy per fraction, given twice daily). No patients received concurrent chemotherapy. The clinical characteristics of the groups were comparable. Surgery was performed shortly after radiotherapy. Crude data on locoregional tumor control were fitted directly using a linear-quadratic model, and the actuarial data were analyzed using Cox model.

RESULTS

A linear-quadratic model provided an alpha estimate of 0.339 (SE 0.115) and beta estimate of 0.067 (SE 0.027), which resulted in an alpha/beta ratio of 5.06 Gy (95% confidence interval -0.1 to 10.3). In all three schemes the overall radiation treatment time was short, which limits the rationales for incorporating time effect into the model. If, however, time was incorporated the alpha/beta ratio was 11.1 Gy and the dose increment required to compensate for repopulation was 0.15 Gy/day. The actuarial analysis provided similar alpha/beta estimates.

CONCLUSION

Although because of the retrospective character of the study, nonrandomized selection of fractionation schedule, and uncontrolled quality of surgery the present results can be regarded as hypothesis generating only, the control rates obtained in the pelvis are consistent with a moderately low alpha/beta ratio for rectal cancer.

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.

Impact of HPV infection on the clinical outcome of p-CAIR trial in head and neck cancer

The purpose of the study was to analyse the influence of HPV infection on the outcome of a randomized clinical trial of conventional (CF) versus 7-days-a-week postoperative radiotherapy (p-CAIR) for squamous cell cancer of the head and neck (SCCHN). Between 2001 and 2004, 279 patients with high-risk SCC of the larynx or cancer of the oral cavity/oropharynx were randomized to receive 63 Gy in fractions of 1.8 Gy given 5 days a week or 7 days a week (Radiother Oncol 87:155-163, 2008). The presence of HPV DNA in 131 archival paraffin blocks was assessed with multiplex quantitative real-time PCR using five consensus primers for the conservative L1 region and molecular beacon probes targeting 14 high-risk HPV subtypes. Following the RT-PCR procedure, we could determine the presence and type of HPV16, HPV18 and the other 12 less frequent oncogenic subtypes. Out of 131 samples, 9 were positive for HPV infection (6.9%), all of them with HPV16 subtype. None of the 65 laryngeal tumours was HPV positive. The 5-year LRC in HPV-positive patients was 100%, compared to 58% in the HPV-negative group (p = 0.02, log-rank test). Amongst 122 patients with HPV-negative tumours, 5-year LRC was 50.3% in p-CF versus 65.2 in p-CAIR (p = 0.37). HPV infection was associated with low expression of EGFR and cyclin D. This study demonstrates a favourable outcome for HPV-positive patients with SCCHN treated with postoperative radiotherapy. While considering the small number of HPV+ tumours, the data set can be considered as hypothesis generating only, the outcome raises new questions on the necessity of aggressive postoperative treatment in HPV+ patients.

Tumor volume and growth kinetics in hypothalamic-chiasmatic pediatric low grade gliomas

Pediatric low grade gliomas evidence a tendency towards quiescent growth, thus complicating the clinical management of nonresected tumors whose clinical behavior may be difficult to predict. We decided to explore the hypothesis of possible correlation in pediatric low grade glioma between tumor volume and growth rate. We identified 6 children with hypothalamic chiasmatic lesions. Five of these patients were treated only with biopsy and 1 with repeated partial tumor resection. All of 6 patients had 10-15 sequential brain MRI over a time span of 3-8 years. Tumor volume was determined using Sigma Scan Image software. The results were analyzed utilizing two equations for modeling tumor growth: exponential and Gompertz. In 4 patients whose tumor volume was approximately 80-100 cm(3) at the time of diagnosis, slow spontaneous partial regression was observed. In the other patients deceleratory or exponential tumor growth was volume-dependent. Our results suggest that growth of pediatric low grade glioma decelerates as tumor becomes large and that the Gompertz model for tumor growth is useful for understanding the growth kinetics of pediatric low grade glioma.

Predicting the effect of accelerated fractionation in postoperative radiotherapy for head and neck cancer based on molecular marker profiles: data from a randomized clinical trial

PURPOSE

To determine the prognostic and predictive values of molecular marker expression profiles based on data from a randomized clinical trial of postoperative conventional fractionation (p-CF) therapy versus 7-day-per-week postoperative continuous accelerated irradiation (p-CAIR) therapy for squamous cell cancer of the head and neck.

METHODS AND MATERIALS

Tumor samples from 148 patients (72 p-CF and 76 p-CAIR patients) were available for molecular studies. Immunohistochemistry was used to assess levels of EGFR, nm23, Ki-67, p-53, and cyclin D1 expression. To evaluate the effect of fractionation relative to the expression profiles, data for locoregional tumor control (LRC) were analyzed using the Cox proportional hazard regression model. Survival curves were compared using the Cox f test.

RESULTS

Patients who had tumors with low Ki-67, low p-53, and high EGFR expression levels and oral cavity/oropharyngeal primary cancer sites tended to benefit from p-CAIR. A joint score for the gain in LRC from p-CAIR based of these features was used to separate the patients into two groups: those who benefited significantly from p-CAIR with respect to LRC (n = 49 patients; 5-year LRC of 28% vs. 68%; p = 0.01) and those who did not benefit from p-CAIR (n = 99 patients; 5-year LRC of 72% vs. 66%; p = 0.38). The nm23 expression level appeared useful as a prognostic factor but not as a predictor of fractionation effect.

CONCLUSIONS

These results support the studies that demonstrate the potential of molecular profiles to predict the benefit from accelerated radiotherapy. The molecular profile that favored accelerated treatment (low Ki-67, low p-53, and high EGFR expression) was in a good accordance with results provided by other investigators. Combining individual predictors in a joint score may improve their predictive potential.

International consensus on radiotherapy in metastatic non-small cell lung cancer

Background

Lung cancer is the leading cause of cancer-related death worldwide, with non-small cell lung cancer (NSCLC) accounting for most cases. While radiotherapy has historically served as a palliative modality in metastatic NSCLC, considerable advances in its technology and the continuous development of cutting-edge therapeutic agents, such as targeted therapy and immune checkpoint inhibitors (ICIs), are increasing its role in the multi-disciplinary management of the disease.

Methods

International radiotherapy experts were convened to consider and reach consensuses on the clinical utilities of radiotherapy in metastatic NSCLC, with the aim to provide patient-focused, up to date, evidence-based, recommendations to assist cancer specialists in the management of patients with metastatic NSCLC worldwide.

Results

Timely radiotherapy can offer rapid symptom alleviation and allow subsequent aggressive treatment approaches in patients with heavy tumor burden and/or oncologic emergencies. In addition, appropriate incorporation of radiotherapy as concurrent, consolidation, or salvage therapy makes it possible to achieve long-term survival, or even cure, for patients with oligo-metastatic disease. Cranial radiotherapy plays an important role in the management of brain metastasis, potentially augmenting the response and prolonging survival associated with targeted agents and ICIs. However, key questions remain, such as the appropriate choice of radiation techniques, optimal sequence of systemic therapies and radiotherapy, and optimal patient selection for such combination strategies. Although a strong rationale for combining radiotherapy and ICIs exists, its optimal parameters in this setting remain to be established.

Conclusions

In the modern era, radiotherapy serves not only as a palliative tool in metastatic NSCLC, but also plays active roles in patients with oligo-focal disease, CNS metastasis and receiving ICIs.

Randomized clinical trial on continuous 7-days-a-week postoperative radiotherapy for high-risk squamous cell head-and-neck cancer: a report on acute normal tissue reactions

BACKGROUND AND PURPOSE

To analyse acute mucosal reactions in patients treated with continuous accelerated postoperative irradiation (p-CAIR) compared to conventionally fractionated postoperative radiotherapy (p-CF).

PATIENTS AND METHODS

The patients were randomly assigned to receive 63 Gy in 1.8 Gy fractions 7-days-a-week given over a period of 5 weeks (n=88), or 63 Gy in 1.8 Gy fractions given 5-days-a-week over 7 weeks (n=87). It represents 65% of an overall trial size. Acute mucosal reactions were scored using modified Dische system. Polychotomous logistic regression was used to estimate the influence of the selected variables on maximum grade of mucositis, and percent of the body weight loss during radiotherapy.

RESULTS

The average maximum Dische score and percent of the patients with confluent mucositis were higher in patients treated with p-CAIR, compared to p-CF (13.3 vs. 10.8 and 54 vs. 27%). Polychotomous logistic regression analysis revealed that fractionation scheme and tumour site have significantly influenced maximum Dische score. Tumour site (laryngeal vs. other) had even stronger influence on maximum Dische score than fractionation scheme. The average residual Dische score 8 weeks after radiotherapy was higher in p-CAIR compared to p-CF (2.1 vs. 1.4), and was, most frequently, related to persistent mucosal erythema (70 vs. 57% of pts.). No severe consequential toxicity of radiotherapy was observed, so far, in the trial.

CONCLUSIONS

While the incidence, intensity and duration of mucosal reactions was higher in p-CAIR than in p-CF the accelerated treatment can be considered tolerable with respect to acute toxicity. In both arms of the trial slight or moderate mucosal erythema was the most frequent acute side effect, which did not completely subside within 8 weeks after irradiation.

Time factor and treatment strategies in subclinical disease

Rational biological development of treatment strategies for subclinical metastases has lagged behind such efforts with primary cancers: most adjuvant therapies for subclinical disease have been developed empirically, based on clinical observation. This paper reviews recent studies that point to rapid growth of subclinical disease. The effect of rapid growth of occult metastases and undetectable extensions of primary cancer is to increase the radiation dose necessary for their elimination if treatment duration is extended. This increase may be evident even when changes are made to short courses of treatment, consistent with no lag time between the start of treatment and rapid growth or regrowth of subclinical tumour deposits. This provides a strong rationale for avoiding gaps or delays in adjuvant treatments and suggest that accelerated regimens of radiation or chemoradiation may be advantageous in the treatment of subclinical disease provided that the total dose can be maintained or not greatly reduced from those used conventionally. Conversely, an escalation of total dose with a concomitant increase in overall treatment duration may not result in improved control rates because the rapid growth of small clonogen deposits might counterbalance the effect of the higher dose.

The effect of heterogeneity in tumor cell kinetics on radiation dose-response. An exploratory investigation of a plateau effect

PURPOSE

To investigate the effect of heterogeneity in tumor cell kinetics on radiation dose-response curves for a population of patients.

MATERIALS AND METHODS

A series of exploratory calculations have been performed using an improved geometric-stochastic model of tumor cure.

RESULTS

Radiation therapy dose-response curves may plateau, or nearly so, at tumor control levels well below 100%, if a proportion of tumors would grow sufficiently fast to counterbalance the effect of fractionated radiotherapy. If the model assumptions of doubling time heterogeneity are correct, the difference between a short and protracted radiation regimen would be not only in the position and steepness of the radiation dose-response curve, but also in the level of the predicted plateau.

CONCLUSIONS

For a given rate of dose accumulation, the one-sided flattening in dose-response curves at high doses is predicted from the modeling, and determined by the proportion of most radioresistant and rapidly growing tumors. This shows that empirical models of tumor control probability which assume a symmetric sigmoid relationship from 0 to 100% have apparent limitations, seemingly not well acknowledged in the literature.

Alpha/beta (α/β) ratio for prostate cancer derived from external beam radiotherapy and brachytherapy boost

OBJECTIVE

There is disagreement regarding the value of the α/β ratio for prostate cancer. Androgen deprivation therapy (ADT) may dominate the effects of dose fractionation on prostate-specific antigen (PSA) response and confound estimates of the α/β ratio. We estimate this ratio from combined data on external beam radiation therapy (EBRT) and brachytherapy (BT)-treated patients, providing a range of doses per fraction, while accounting for the effects of ADT.

METHODS

We analyse data on 289 patients with local prostate cancer treated with EBRT (2 Gy per fraction) or EBRT plus one or two BT boosts of 10 Gy each. The timing of ADT was heterogeneous. We develop statistical models to estimate the α/β ratio based upon PSA measurements at 1 year as a surrogate for the surviving fraction of cancer cells as well as combined biochemical + clinical recurrence-free survival (bcRFS), controlling for ADT.

RESULTS

For the PSA-based end point, the α/β ratio estimate is 7.7 Gy [95% confidence interval (CI): 4.1 to 12.5]. Based on the bcRFS end point, the estimate is 18.0 Gy (95% CI: 8.2 to ∞).

CONCLUSION

Our model-based estimates of the α/β ratio, which account for the effects of ADT and other important confounders, are higher than some previous estimates.

ADVANCES IN KNOWLEDGE

Although dose inhomogeneities and other limitations may limit the scope of our findings, the data suggest caution regarding the assumptions of the α/β ratio for prostate cancer in some clinical environments.

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.

Combination of immunotherapy and radiotherapy in the treatment of brain metastases from non-small cell lung cancer

It was commonly assumed in the past that blood-brain barrier could efficiently prohibit penetration of large peptide molecules, such as monoclonal antibodies, including programmed death-1 (PD-1)/programmed death-ligand 1 (PD-L1) inhibitors. This belief has been recently revised by studies that demonstrate the presence of functional lymphatic vessels lining the dural sinuses. Furthermore, the activated circulating T cells have been shown to cross the blood-brain barrier. Such observations created strong rationale for attempts of immunotherapy for patients with brain metastases, used either alone or in combination with radiotherapy. The expected benefit from immunotherapy particularly refers to patients without targetable “driver” mutations who are not considered as candidates for novel targeted therapies. Current inference on efficacy and safety of combination of immunotherapy and radiotherapy in the treatment of brain metastases from non-small cell lung cancer (NSCLC) origins, in most, from the retrospective studies. The existing data suggest that use of immune checkpoint inhibitors (ICIs) with brain radiotherapy improves patients outcome, compared to brain radiotherapy alone. The available data also suggest that concurrent use of ICI and stereotactic radiation therapy (SRT) for brain metastases from NSCLC is tolerable and appears more effective than sequential combination of radiotherapy and ICI. Use of steroids appeared detrimental. Since a dependence between the risk of adverse events and type of ICI therapy as well as tumor pathology was found, further studies are required to establish optimal dosage, selection of drugs and sequence of ICI and brain radiotherapy in patients with brain metastases from NSCLC.

The prognostic value of hemoglobin concentration in postoperative radiotherapy of 835 patients with laryngeal cancer

PURPOSE

To investigate the prognostic value of hemoglobin (Hb) concentration in patients with laryngeal cancer treated with postoperative radiotherapy (pRT).

METHODS AND MATERIALS

The records of 835 patients who underwent pRT between 1980 and 2003 were reviewed. Most patients (526 of 835 patients; 63%) were in advanced clinical stages (T3-T4) and 371 of 835 patients (44%) were node positive. Total laryngectomy had been performed in 676 of 835 patients (81%). Median Hb concentration before (Hb0) and after pRT (Hb1) was the same (13.3 g/dl). However, individual differences between Hb1 and Hb0 (dHb) varied within a broad range (-8.8; 5.0 g/dl). Univariate and multivariate analyses were performed to identify variables significantly associated with locoregional control (LRC), metastases-free survival, and overall survival.

RESULTS

Patients with dHb greater than 0 had significantly improved 5-year LRC compared with those with dHb of 0 or less (80% vs. 72%, p = 0.01). Conversely, when categorized, neither Hb0 nor Hb1 had a significant influence on LRC. In multivariate analysis, dHb remained a prognostic factor for LRC (p = 0.01) among the other variables, which included overall radiation treatment time and nodal status. None of the Hb-related variables significantly influenced metastases-free or overall survival.

CONCLUSION

Individual change in Hb concentration during the course of pRT (dHb) rather than Hb level before or after pRT appeared as an independent prognostic factor for LRC in this set of patients.

Gene expression from bronchoscopy obtained tumour samples as a predictor of outcome in advanced inoperable lung cancer

Background

Several studies have shown the prognostic and predictive potential of molecular markers in combined therapy for lung cancer. Most of them referred, however, to operable early stage NSCLC. The aim of the present study is to correlate the expression of multiple mRNA markers in bronchoscopy obtained cancer specimens with clinical outcome of advanced lung cancer.

Methods

Bronchoscopy cancer specimens were taken from 123 patients with radiological diagnosis of advanced lung tumor. Out of 123 patients 50 were diagnosed with squamous cell cancer, 17 with adenocarcinoma, 12 with NOS, 32 with SCLC and one with large cell neuroendocrinal cancer. In 11 patients other tumours were diagnosed. The group was heterogeneous with respect to clinical stage, performance of the patients and treatment. Quantitative real time PCR was carried out by ABI 7900 HT machine, with Universal Probe Library (Roche) fluorescent probes. The genes selected for the analysis were ERCC1, EGFR, BRCA1, CSF1, CA9, DUSP6, STAT1, ERBB3, MMD, FN1, and CDKN1B.

Results

More than 50 ng of RNA (the amount considered sufficient for the analysis) was isolated in 82 out of 112 lung cancer specimens (73%), including 60/80 (75.0%) of NSCLC specimens and 22/32 (68,7%) of SCLC samples. The highest Cohen’s κ coefficient for discrimination between small cell, squamous cell and adenocarcinoma was found for CDKN1B, CSF and EGFR1 (κ = 0.177, p = 0.0041). A multivariate Cox regression model has shown a significant impact of clinical stage (p<0.001, RR = 4.19), ERCC1 (p = 0.01, RR = 0.43) and CA9 (p = 0.03, RR = 2.11) expression on overall survival in a group of 60 patients with NSCLC.

Conclusion

These results show the feasibility of multiple gene expression analysis in bronchoscopy obtained cancer specimens as prognostic markers in radiotherapy and chemotherapy for advanced lung cancer. A limiting factor was relatively high proportion of samples from which sufficient amount of RNA could not be isolated.

A nomogram model based on peripheral blood lymphocyte subsets to assess the prognosis of non-small cell lung cancer patients treated with immune checkpoint inhibitors

Background

The primary aim of this study was to investigate the prognostic value of peripheral blood lymphocyte subsets in non-small cell lung cancer (NSCLC) patients treated with immune checkpoint inhibitors (ICIs).

Methods

From 2018 to 2019, 82 patients diagnosed with stage IIIB–IV NSCLC at Zhejiang Cancer Hospital were recruited for this study. Peripheral blood lymphocyte subsets of NSCLC patients were analyzed using flow cytometry before and after ICI treatment. The relationship between the percentage of peripheral blood lymphocyte subsets, clinicopathological features, progression-free survival (PFS), and overall survival (OS) was identified by correlation heat map, Kaplan-Meier curve, log-rank test, and Cox regression analysis.

Results

The CD4/CD8 ratio and the percentage of B cells was decreased after ICI treatment. Furthermore, the percentage of CD3⁺ T cells, natural killer (NK) cells, and natural killer T (NKT) cells before ICI treatment was associated with brain metastases, the proportion of CD3⁺CD4⁺ T cells before ICI treatment was related to epidermal growth factor receptor (EGFR) status, the CD4/CD8 ratio before ICI treatment was correlated to pathology, the ratio of B cells before ICI treatment was related to therapeutic regimen, and the percentage of NKT cells before ICI treatment was associated with use of radiotherapy. Furthermore, univariate survival analysis revealed that low percentage of B cells forecasted a poor OS for NSCLC patients with ICI treatment. In addition, the nomogram developed by percentages of peripheral blood lymphocyte subsets could determine survival probability and survival time of NSCLC patients with immunotherapy.

Conclusions

ICI treatment induced changes in the percentage of peripheral blood lymphocyte subsets, which had prognostic value for brain metastases, radiotherapy, EGFR status, pathology, and therapeutic regimen, along with prognostic value, for NSCLC patients treated with ICIs.