Significance and therapeutic implications of tumor regression following radiotherapy in patients treated for squamous cell carcinoma of the oropharynx and pharyngolarynx

Identifying the prognostic value of MRI-based tumor response and predicting the risk of radio-resistance in re-radiotherapy for locally recurrent nasopharyngeal carcinoma

OBJECTIVE

To investigate the prognostic value of tumor response (TR) for locoregionally recurrent nasopharyngeal carcinoma (lrNPC) patients at the end of re-radiotherapy (re-RT) and develop a risk score model to predict patient's radiosensitivity to re-RT.

MATERIALS AND METHODS

A total of 594 patients with lrNPC from 2010 to 2020 were retrospectively reviewed as the total cohort. Among these, 310 patients with complete first-line treatment data were reviewed as a secondary cohort. Overall survival (OS) was the primary endpoint. Locoregional control (LRC) was the secondary endpoint. Multivariate Cox analysis was performed to investigate the prognostic value of TR at the end of re-RT (rTR). A risk score model for predicting rTR was obtained by logistic regression analysis, and its effectiveness was compared using receiver operating characteristic (ROC) analysis.

RESULTS

Patients with complete response (CR) to rTR had higher 5-year OS and LRC rate than non-CR patients in both the total and secondary cohort. rTR was an independent prognostic factor for OS (P=0.002) and LRC (P=0.008). We developed a risk score model including four significant risk factors (relapse T stage, relapse gross tumor volume, time to recurrence, and initial TR). The area under the curve of the risk score model was 0.73 (95% CI: 0.678 to 0.780), which was significantly higher than that of each variable alone. Patients with the highest risk scores may be insensitive to re-RT and had a residual tumor risk of 89.9% after rRT.

CONCLUSION

rTR was an independent prognostic factor for OS and LRC in lrNPC patients. We developed a risk score model for predicting patients' sensitivity to re-RT to screen for radiosensitive patients. This can serve as a treatment decision-making tool for clinicians.

Longitudinal characterization of the tumoral microbiome during radiotherapy in HPV-associated oropharynx cancer

PURPOSE

To describe the baseline and serial tumor microbiome in HPV-associated oropharynx cancer (OPC) over the course of radiotherapy (RT).

METHODS

Patients with newly diagnosed HPV-associated OPC treated with definitive radiotherapy +/- concurrent chemotherapy were enrolled in this prospective study. Using 16S rRNA gene sequencing, dynamic changes in the tumor site microbiome during RT were investigated. Surface tumor samples were obtained before RT and at week 1, 3 and 5 of RT. Radiological primary tumor response at mid-treatment was categorized as complete (CR) or partial (PR).

RESULTS

Ten patients were enrolled, but 9 patients were included in the final analysis. Mean age was 62 years (range: 51-71). As per AJCC 8th Ed, 56%, 22% and 22% of patients had stage I, II and III, respectively. At 4-weeks, 6 patients had CR and 3 patients had PR; at follow-up imaging post treatment, all patients had CR. The baseline diversity of the tumoral versus buccal microbiome was not statistically different. For the entire cohort, alpha diversity was significantly decreased over the course of treatment (p = 0.04). There was a significant alteration in the bacterial community within the first week of radiation. Baseline tumor alpha diversity of patients with CR was significantly higher than those with PR (p = 0.03). While patients with CR had significant reduction in diversity over the course of radiation (p = 0.01), the diversity remained unchanged in patients with PR. Patients with history of smoking had significantly increased abundance of  Kingella (0.05) and lower abundance of Stomatobaculum (p = 0.03) compared to never smokers.

CONCLUSIONS

The tumor microbiome of HPV-associated OPC exhibits reduced alpha diversity and altered taxa abundance over the course of radiotherapy. The baseline bacterial profiles of smokers vs. non-smokers were inherently different. Baseline tumor alpha diversity of patients with CR was higher than patients with PR, suggesting that the microbiome deserves further investigation as a biomarker of radiation response.

Magnetic Resonance-based Response Assessment and Dose Adaptation in Human Papilloma Virus Positive Tumors of the Oropharynx treated with Radiotherapy (MR-ADAPTOR): An R-IDEAL stage 2a-2b/Bayesian phase II trial

BACKGROUND

Current standard radiotherapy for oropharynx cancer (OPC) is associated with high rates of severe toxicities, shown to adversely impact patients' quality of life. Given excellent outcomes of human papilloma virus (HPV)-associated OPC and long-term survival of these typically young patients, treatment de-intensification aimed at improving survivorship while maintaining excellent disease control is now a central concern. The recent implementation of magnetic resonance image - guided radiotherapy (MRgRT) systems allows for individual tumor response assessment during treatment and offers possibility of personalized dose-reduction. In this 2-stage Bayesian phase II study, we propose to examine weekly radiotherapy dose-adaptation based on magnetic resonance imaging (MRI) evaluated tumor response. Individual patient's plan will be designed to optimize dose reduction to organs at risk and minimize locoregional failure probability based on serial MRI during RT. Our primary aim is to assess the non-inferiority of MRgRT dose adaptation for patients with low risk HPV-associated OPC compared to historical control, as measured by Bayesian posterior probability of locoregional control (LRC).

METHODS

Patients with T1-2 N0-2b (as per AJCC 7th Edition) HPV-positive OPC, with lymph node <3 cm and <10 pack-year smoking history planned for curative radiotherapy alone to a dose of 70 Gy in 33 fractions will be eligible. All patients will undergo pre-treatment MRI and at least weekly intra-treatment MRI. Patients undergoing MRgRT will have weekly adaptation of high dose planning target volume based on gross tumor volume response. The stage 1 of this study will enroll 15 patients to MRgRT dose adaptation. If LRC at 6 months with MRgRT dose adaptation is found sufficiently safe as per the Bayesian model, stage 2 of the protocol will expand enrollment to an additional 60 patients, randomized to either MRgRT or standard IMRT.

DISCUSSION

Multiple methods for safe treatment de-escalation in patients with HPV-positive OPC are currently being studied. By leveraging the ability of advanced MRI techniques to visualize tumor and soft tissues through the course of treatment, this protocol proposes a workflow for safe personalized radiation dose-reduction in good responders with radiosensitive tumors, while ensuring tumoricidal dose to more radioresistant tumors. MRgRT dose adaptation could translate in reduced long term radiation toxicities and improved survivorship while maintaining excellent LRC outcomes in favorable OPC.

TRIAL REGISTRATION

ClinicalTrials.gov ID: NCT03224000; Registration date: 07/21/2017.

Feasibility of concomitant cisplatin with hypofractionated radiotherapy for locally advanced head and neck squamous cell carcinoma

Background

The evolution of radiotherapy over recent decades has reintroduced the hypofractionation for many tumor sites with similar outcomes to those of conventional fractionated radiotherapy. The use of hypofractionation in locally advanced head and neck cancer (LAHNC) has been already used, however, its use has been restricted to only a few countries. The aim of this trial was to evaluate the safety and feasibility of moderate hypofractionated radiotherapy (HYP-RT) with concomitant cisplatin (CDDP).

Methods

This single-arm trial was designed to evaluate the safety and feasibility of HYP-RT with concomitant CDDP in LAHNC. Stage III and IV patients withnonmetastatic disease were enrolled. Patients were submitted to intensity modulatedradiation therapy, which comprised 55 Gy/20 fractions to the gross tumor and44–48 Gy/20 fractions to the areas of subclinical disease. Concomitant CDDPconsisted of 4 weekly cycles of 35 mg/m2. The primary endpoints were the treatment completion rate and acute toxicity.

Results

Twenty patients were enrolled from January 2015 to September 2016, and 12 (60%) were classified as unresectable. All patients completed the total dose of radiotherapy, and 19 patients (95%) received at least 3 of 4 cycles of chemotherapy. The median overall treatment time was 29 days (27–34). Grade 4 toxicity was reported twice (1 fatigue and 1 lymphopenia). The rates of grade 3 dermatitis and mucositis were 30% and 40%, respectively, with spontaneous resolution. Nasogastric tubes were offered to 15 patients (75%) during treatment; 4 patients (20%) needed feeding tubes after 2 months, and only 1 patient needed a feeding tube after 12 months.

Conclusion

HYP-RT with concomitant CDDP was considered feasible for LAHNC, and the rate of acute toxicity was comparable to that of standard concomitant chemoradiation. A feeding tube was necessary for most patients during treatment. Further investigation of this strategy is warranted.

Trial registration

ClinicalTrials, NCT03194061. Registered 21 Jun 2017 – Retrospectively registered.

Prognostic value of gross tumor regression and plasma Epstein Barr Virus DNA levels at the end of intensity-modulated radiation therapy in patients with nasopharyngeal carcinoma

PURPOSE

To assess gross tumor regression and plasma Epstein-Barr virus (EBV)-DNA levels at the end of intensity-modulated radiation therapy (IMRT) and its prognostic impact on patients with nasopharyngeal carcinoma (NPC).

PARTICIPANTS AND METHODS

In total, 397 patients with non-metastatic, histologically confirmed NPC were retrospectively examined. All patients underwent magnetic resonance imaging of the nasopharynx and neck, and plasma EBV DNA assays before treatment and at the end of IMRT.

RESULTS

The estimated 5-year loco-regional, local and regional relapse-free survival rates for patients with complete response (CR) and non-CR of the total tumor, primary tumor and metastatic lymph nodes at the end of IMRT were 94.9% vs. 85.8%, 96.6% vs. 87.3%, and 98.7% vs. 89.8%, respectively (P < 0.05). The estimated 5-year loco-regional relapse-free survival (LRRFS) rates for patients with persistent tumor with and without boost irradiation were 95.3% vs. 83%, respectively (P = 0.034). The estimated 5-year overall survival (OS), failure-free survival (FFS) and distant metastasis-free survival (DMFS) rates for patients with negative and positive plasma EBV DNA at the end of IMRT were 83.1% vs. 50.3%, 81.5% vs. 49.3%, and 87.6% vs. 61.5%, respectively (P < 0.001). Multivariate analyses indicated that regression of the total tumor and boost irradiation was an independent predictor of LRRFS, and plasma EBV DNA levels were independent predictors of OS, FFS and DMFS.

CONCLUSIONS

Gross tumor regression and plasma EBV DNA levels at the end of IMRT served as predictors of poor prognosis for patients with NPC. The patients with persistent tumor and/or positive plasma EBV DNA might require timely strengthening treatment.

Primary tumor regression speed after radiotherapy and its prognostic significance in nasopharyngeal carcinoma: a retrospective study

BACKGROUND

To observe the primary tumor (PT) regression speed after radiotherapy (RT) in nasopharyngeal carcinoma (NPC) and evaluate its prognostic significance.

METHODS

One hundred and eighty-eight consecutive newly diagnosed NPC patients were reviewed retrospectively. All patients underwent magnetic resonance imaging and fiberscope examination of the nasopharynx before RT, during RT when the accumulated dose was 46-50 Gy, at the end of RT, and 3-4 months after RT.

RESULTS

Of 188 patients, 40.4% had complete response of PT (CRPT), 44.7% had partial response of PT (PRPT), and 14.9% had stable disease of PT (SDPT) at the end of RT. The 5-year overall survival (OS) rates for patients with CRPT, PRPT, and SDPT at the end of RT were 84.0%, 70.7%, and 44.3%, respectively (P < 0.001, hazard ratio [HR] = 2.177, 95% confidence interval [CI] = 1.480-3.202). The 5-year failure-free survival (FFS) and distant metastasis-free survival (DMFS) rates also differed significantly (87.8% vs. 74.3% vs. 52.7%, P = 0.001, HR = 2.148, 95% CI, 1.384-3.333; 91.7% vs. 84.7% vs. 66.1%, P = 0.004, HR = 2.252, 95% CI = 1.296-3.912). The 5-year local relapse-free survival (LRFS) rates were not significantly different (95.8% vs. 86.0% vs. 81.8%, P = 0.137, HR = 1.975, 95% CI, 0.976-3.995). By multivariate analyses, the PT regression speed at the end of RT was the only independent prognostic factor of OS, FFS, and DMFS (P < 0.001, P = 0.001, and P = 0.004, respectively). The 5-year FFS rates for patients with CRPT during RT and CRPT only at the end of RT were 80.2% and 97.1%, respectively (P = 0.033). For patients with persistent PT at the end of RT, the 5-year LRFS rates of patients without and with boost irradiation were 87.1% and 84.6%, respectively (P = 0.812).

CONCLUSIONS

PT regression speed at the end of RT was an independent prognostic factor of OS, FFS, and DMFS in NPC patients. Immediate strengthening treatment may be provided to patients with poor tumor regression at the end of RT.

Influence of [18F] fluorodeoxyglucose positron emission tomography on salvage treatment decision making for locally persistent nasopharyngeal carcinoma

PURPOSE

The purpose of this study was to evaluate the role of [18F] fluorodeoxyglucose positron emission tomography (FDG-PET) in influencing salvage treatment decision making for locally persistent nasopharyngeal carcinoma (NPC).

METHODS AND MATERIALS

A total of 33 NPC patients with histologic persistence at nasopharynx 1 to 6 weeks after a full course of radiotherapy underwent both computed tomography (CT) and FDG-PET/CT simulation at the same treatment position. The salvage treatment decisions, with regard to the decision to offer salvage treatment and the definition of gross tumor volume (GTV), were made before knowledge of the FDG-PET findings. Subsequently the salvage treatment decisions were made again based on the FDG-PET findings and compared with the pre-FDG-PET decisions.

RESULTS

All 33 patients were referred for salvage treatment in the pre-FDG-PET decision. After knowledge of the FDG-PET results, the decision to offer salvage treatment was withdrawn in 4 of 33 patients (12.1%), as no abnormal uptake of FDG was found at nasopharynx. Spontaneous remission was observed in repeat biopsies and no local recurrence was found in these 4 cases. For the remaining 29 patients, GTV based on FDG-PET was smaller than GTV based on CT in 24 (82.8%) cases and was greater in 5 (17.2%) cases, respectively. The target volume had to be significantly modified in 9 of 29 patients (31%), as GTV based on FDG-PET images failed to be enclosed by the treated volume in the salvage treatment plan performed based on GTV based on CT simulation images.

CONCLUSION

Use of FDG-PET was found to influence the salvage treatment decision making for locally persistent NPC by identifying patients who were not likely to benefit from additional treatment and by improving accuracy of GTV definition in salvage treatment planning.

PET-CT vs contrast-enhanced CT: What is the role for each after chemoradiation for advanced oropharyngeal cancer?

PURPOSE

The aim of our study was to assess the utility of positron emission tomography (PET) and 2 fluoro-2-deoxy-D-glucose coupled with neck CT compared with contrast-enhanced CT in predicting persistent cancer either at the primary site or cervical lymphatics in patients with oropharyngeal cancer treated with concurrent chemoradiation

METHODS

Thirty consecutive patients underwent clinical examination, PET-CT, and contrast-enhanced CT to assess response after the completion of the treatment. The outcome variable was positive tissue diagnosis or negative disease at 6 months. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy were calculated for the primary site as well as cervical disease.

RESULTS

Contrast-enhanced CT alone showed the best accuracy in detecting disease at the primary site after treatment (85.7%). Accuracy in evaluating residual tumor in the cervical lymphatics for contrast-enhanced CT and PET-CT was 59.3% and 74.1%, respectively. For evaluating the neck, PET-CT and contrast-enhanced CT demonstrated 100% NPV, but the PPV was 36.3% and 26.6%, respectively.

CONCLUSIONS

In this preliminary study, PET-CT seems to be superior to contrast-enhanced CT in predicting persistent disease in the neck after chemoradiation for oropharyngeal or unknown primary cancer, but not at the primary site. However, the possibility of a false-positive result in the neck remains high, and thus overtreatment may result. Even more concerning are the false-negative results. Larger, prospective studies will be important in defining the role of PET-CT in obviating the need for salvage neck dissections after chemoradiation.

Current use of 18F-Fluorodeoxyglucose Positron Emission Tomography and Combined Positron Emission Tomography and Computed Tomography in Squamous Cell Carcinoma of the Head and Neck

The history and physical examination, computed tomography (CT) and magnetic resonance imaging are the cornerstones for identifying new and recurrent cancers of the head and neck. The advent of positron emission tomography (PET) and combined PET/CT imaging technology is a promising development. These modalities have the potential to help stage patients presenting with head and neck cancer, identify responses to nonsurgical therapy, and allow earlier detection of recurrence in the hope of improving survival. The following paper provides a brief history of PET and PET/CT imaging. The current PET and PET/CT literature for squamous cell carcinoma of the head and neck is reviewed, and specific recommendations for its use are provided.

Survival Impact of Planned Restaging and Early Surgical Salvage Following Definitive Chemoradiation for Locally Advanced Squamous Cell Carcinomas of the Oropharynx and Hypopharynx

OBJECTIVES

Patients who have received definitive radiation therapy (RT) for a nonlaryngeal T3/4 head and neck squamous cell carcinoma have a limited opportunity for post-RT surgical salvage. The authors reviewed the practice of planned post-RT restaging to determine its impact on the success of early surgical salvage.

METHODS

A retrospective review was performed for patients with resectable T3/4 cancers of the oropharynx and hypopharynx treated with RT +/- chemotherapy who underwent planned restaging clinically, radiographically (CT or MRI), and by direct laryngoscopy with biopsy at 4 to 8 weeks post-RT. Chemotherapy was given as induction, concurrently, or both. Neck dissection was performed at time of restaging in patients with primary tumor control and initial N2/N3 neck disease or persistent lymphadenopathy.

RESULTS

A total of 54 patients had a median follow-up of 34.7 months (range, 7.6-97.8 months). Forty-two patients (78.8%) achieved a complete response (CR) at the primary site immediately after RT. Six developed late local failure at 9 to 61 months, of whom 2 were successfully salvaged. The ultimate 2-year local control among patients with initial CR was 94.8%. The 2-year organ preservation, disease-free survival, and overall survival (OS) rates were was 92.5%, 87%, and 90%, respectively. Twelve patients did not achieve initial CR. Two patients with bulky stage IV disease had unresectable cancers. Ten underwent immediate surgical salvage and 7 achieved local control (1 of whom developed distant metastases) whereas 3 had continued local failure. For patients without initial CR, the 2-year ultimate local control rate was 46.7% and OS was 46.8%. For all patients, overall 2-year local control, organ preservation, and OS rates were 85.6%, 75.6%, and 81.8% respectively. The rate of local failure-free organ preservation was 71.5%.

CONCLUSION

For patients with T3/4 resectable nonlaryngeal head and neck cancers, planned clinical, radiographic, and pathologic restaging at 1 to 2 months after definitive RT provides the opportunity for early surgical salvage in those who fail at the primary site. This practice produces improved overall local control and survival rates compared with the literature reports for delayed attempted salvage with timing based on the findings of routine postradiation clinical surveillance. Future efforts may focus on the improved selection of patients who would be most likely to require early surgical intervention.

Three-dimensional conformal radiotherapy versus intracavitary brachytherapy for salvage treatment of locally persistent nasopharyngeal carcinoma

PURPOSE

To compare the outcomes of three-dimensional conformal radiotherapy (3D-CRT) and intracavitary brachytherapy (ICBT) as salvage treatment for locally persistent nasopharyngeal carcinoma.

METHODS AND MATERIALS

Between March 1994 and November 2001, a total of 117 patients with locally persistent nasopharyngeal carcinoma received salvage treatment for 2-8 weeks (median, 4 weeks) after a full course of conventional external beam RT. Of the 117 patients, 54 were salvaged with 3D-CRT (3D group) and 63 with ICBT (BT group). No statistically significant differences were found in the patient characteristics between the two groups (p >0.05). In the 3D group, the planning target volume for 3D-CRT was defined as the persistent disease plus a 5-mm margin; three to seven static conformal coplanar or noncoplanar portals were delivered for each fraction. The median salvage dose was 24 Gy (range, 18-38 Gy), with fraction size of 2.0 Gy/d. In the BT group, a median salvage dose of 20 Gy (range, 15-30 Gy) was delivered with a (192)Ir source, at 5 Gy/fraction, twice weekly. The brachytherapy dose was prescribed at a distance of 1 cm from the center of the surface as defined by the sources, irrespective of the extent of persistent disease. The actuarial rates of survival were estimated using the Kaplan-Meier method. Potential differences in the actuarial outcomes between groups were evaluated using the Mantel log-rank test. Multivariate analyses were performed with the Cox regression proportional hazards model.

RESULTS

The 5-year actuarial rates of overall survival, disease-specific survival, and local failure-free survival for the 3D group and BT group were 64.50% vs. 55.78% (p = 0.33), 70.03% vs. 59.56% (p = 0.11), and 88.93% vs. 76.28% (p = 0.07), respectively. Subgroup analysis showed that the 5-year actuarial local failure-free survival rate of patients with initially diagnosed T3-T4 disease for the 3D group and BT group was 84.01% vs. 60.50% (p = 0.03). The incidence of Grade 3-4 late complications was comparable between the two groups. Multivariate analyses performed in the whole group showed that T stage at initial diagnosis and the salvage technique (3D-CRT or ICBT) were the statistically significant, independent prognostic factors for local failure-free survival (p = 0.00 and p = 0.02, respectively).

CONCLUSION

3D-CRT seemed to provide better local control than ICBT as a salvage treatment for locally persistent nasopharyngeal carcinoma, especially in patients with initially diagnosed T3-T4 disease. CT/MRI evaluation of the extent of persistent disease is recommended for technique selection of salvage RT. Patients should be cautioned about the potentially increased complications. The optional time for salvage treatment remains controversial.

F-18-fluoro-deoxy-glucose positron-emission tomography scanning in detection of local recurrence after radiotherapy for laryngeal/ pharyngeal cancer

BACKGROUND

The objective of this investigation was to determine whether F18-fluoro-deoxy-glucose (FDG) positron-emission tomography (PET) could differentiate between local recurrence and late radiation effects after radiotherapy for laryngeal/pharyngeal cancer.

METHODS

In a prospective study of 75 patients (67 larynx, eight oro/hypopharynx), 160 laryngoscopies and 109 FDG PET scans were performed on the head and neck region. The mean follow-up time after the first FDG PET scan was 23 months (minimum 1 year).

RESULTS

Local recurrence was diagnosed in 37 patients: 19 after the first biopsy and 18 after follow-up biopsies. For all of the negative initial FDG scans (27), the biopsies that were taken at the same time were negative and no recurrence was seen for at least 1 year. The first FDG scan was a true positive in 34 of 48 patients. In 12 of the 14 patients with false-positive results, FDG scans were repeated; a decreased FDG uptake was found in 9 of the 12. The sensitivity and specificity of the first scan were respectively 92% and 63%; including subsequent FDG scans, the rates were 97% and 82%, respectively.

CONCLUSIONS

When a local recurrence is suspected after radiotherapy for cancer of the larynx/pharynx, an FDG PET scan should be the first diagnostic step. No biopsy is needed if the scan is negative. If the scan is positive and the biopsy negative, a decreased FDG uptake measured in a follow-up scan indicates that a local recurrence is unlikely.

Implications of quantitative tumor and nodal regression rates for nasopharyngeal carcinomas after 45 Gy of radiotherapy

PURPOSE

To quantitatively investigate the clinical implications of tumor regression rate (TRR-45) and nodal regression rate (NRR-45) of nasopharyngeal carcinomas (NPC) after receiving 45 Gy of radiotherapy (RT). The values, predictive values, and associated factors of TRR-45 and NRR-45 in NPC are analyzed.

METHODS AND MATERIALS

One hundred one patients with newly diagnosed NPC and who were curatively treated by RT alone were included in the study. Tumor volume and nodal volume before treatment and after 45 Gy were obtained from computed tomographic (CT) scans performed at those times and calculated with the assistance of a computer-based imaging analyzing system. TRR-45 (NRR-45) was defined as the ratio of reduced tumor (nodal) volume after 45 Gy to the initial tumor (nodal) volume. TRR-45 (NRR-45) values were stratified into three groups of slow (below 50%), moderate (between 50% and 75%), and rapid (above 75%) change. After conventional RT with 45 Gy, conformal RT for primary tumors was boosted to 70.2-72 Gy for T1-2 tumors, and 75.6-81 Gy for T3-T4 tumors. RT for residual neck masses was boosted by electron beam to 61-75 Gy.

RESULTS

The mean value of TRR-45 for all patients was lower than that of NRR-45 for the 78 patients with metastatic neck nodes (70% +/- 4.8% vs. 81% +/- 5%, p = 0.003). The 3-year actuarial neck control rate was better than the primary tumor control rate with statistical significance (98% vs. 85%, p = 0.009). No significant statistical differences concerning local control probability, nodal control probability, or survival rate were found among patients with slow, moderate, or rapid TRR-45 or NRR-45. T-stage was the only significant prognostic factor for locoregional control after multivariate analysis. Tumor volume and T-stage were found to have a statistically significant negative correlation with TRR-45. No associated factor was found to be significantly correlated with NRR-45.

CONCLUSION

Slow regression rates of the primary tumor or neck nodes in NPC after receiving 45 Gy of irradiation do not mean ultimately poor radiocurability, but may merely imply slow clearance of the cells damaged during irradiation. The different radiobiological behaviors of the regression rates during treatment, ultimate control probabilities, or associated factors for regression rates of NPC between primary tumors and neck nodes need to be further investigated.

Organ preservation by transoral laser microsurgery in piriform sinus carcinoma

OBJECTIVE

To determine the effectiveness of organ-preserving CO2 laser microsurgery for the treatment of piriform sinus carcinoma.

METHODS

A retrospective review of 129 previously untreated patients undergoing CO2 laser microsurgery for the treatment of squamous cell carcinomas of the piriform sinus from 1981 to December 1996 was undertaken. The intention was complete tumor removal by preserving functionally important structures of the larynx. Distribution of tumors (Union Internationale Contre le Cancer/American Joint Committee on Cancer, 1992) was 24 cases with pT1, 74 with pT2, 17 with pT3, and 14 with pT4 disease. Node status was positive in 68% of patients. Seventy-five percent of patients had stage III or IV disease. Forty-two percent of the patients were treated solely with surgery, and 58% had surgery and postoperative radiotherapy. The median follow-up interval was 44 months.

RESULTS

Eighty-seven percent of patients were controlled locally. Neck recurrences occurred in 14.0% of patients, metachronous distant metastases with locoregional control in 6.2%, and second primary tumors in 18.6%. Twenty percent of patients died of TNM-related deaths. The 5-year overall Kaplan-Meier survival rate was 71% for stages I and II and 47% for stages III and IV disease; the 5-year recurrence-free survival rates were 95% and 69%, respectively.

CONCLUSION

A comparatively low local recurrence rate, a high recurrence-free survival rate, and the avoidance of laryngectomy favor function-preserving surgery of piriform sinus carcinomas.

Salvage brachytherapy for patients with locally persistent nasopharyngeal carcinoma

PURPOSE

Locally persistent nasopharyngeal carcinoma (NPC) carries an increased risk of local failure if additional treatment is not given. This study was conducted to evaluate the outcomes of patients with locally persistent NPC as treated by high-dose-rate (HDR) intracavitary brachytherapy, and to explore whether routine brachytherapy boost could improve the local control.

METHODS AND MATERIALS

Eighty-seven patients with locally persistent NPC treated during 1990-1998 with HDR intracavitary brachytherapy were retrospectively analyzed. Fibreoptic nasopharyngoscopy was performed 3-6 weeks after completion of the primary external radiation therapy (ERT). Biopsies were only taken from suspicious areas. Those with complete regression of local disease were put on observation. Eighty-seven patients were shown to have persistent viable disease at a median time of 6 weeks post-RT. The distribution according to Ho's staging system at initial diagnosis was as follows: Stage I-8, II-33, III-41, IV-5; T1-19, T2-48, T3-20; N0-32, N1-22, N2-28, N3-5. CT scan for restaging was not performed after the documentation of persistent disease. Our policy was to treat all patients with persistent disease with brachytherapy irrespective of the extent of disease just prior to brachytherapy. They were treated with HDR intracavitary brachytherapy, with either cobalt sources or an iridium source, giving 22.5-24 Gy in 3 weekly sessions in all but 4 patients. This dose was prescribed at a distance of 1.5 cm from the center of the surface as defined by the sources in the first six patients and subsequently reduced to 1 cm for the others. Twelve patients were treated with neoadjuvant chemotherapy. To compare the efficacy of brachytherapy, another 383 consecutive nonmetastatic patients, treated with curative intent by ERT, during the years 1990-1993, were evaluated. Multivariate analysis was performed using the Cox regression proportional hazards model.

RESULTS

The 5-year actuarial local failure-free survival (LFFS) rates and disease-specific survival rates for the brachytherapy group and ERT group were 85% and 76.6% (p = 0.15), and 72% and 67.8% (p = 0.2), respectively. The corresponding 5-year actuarial LFFS rates for T1, T2, and T3 disease were 94.7%, 88.2%, 67.4%, and 84.1%, 79.8%, 62.6%. In assessing the local control, only the T staging was significant on multivariate analysis (p = 0.0004). Other parameters such as age, sex, and persistence of disease (giving brachytherapy) were all nonsignificant. Complications were comparable between the two groups. In the persistent group, the local failure rates of the patients treated with and without neoadjuvant chemotherapy were 17% (2/12) and 13% (10/75) respectively. When analyzed according to different brachytherapy sources, the 5-year LFFS rates of the T1, T2, and T3 patients treated with iridium and cobalt sources were 100% vs. 85.7 (p = 0.19), 93.6% vs. 70% (p = 0.04), and 67.7% vs. 60% (p = 0.72). The difference was statistically significant for the T2 groups. When early T-stage (T1 and T2) patients were grouped together for analysis, the iridium group again showed a statistically significant improvement in 5-year LFFS rate when it was compared with the cobalt group (95.3% vs. 76.5%, p = 0.03) and the ERT alone group (95.3% vs. 81.5%, p = 0.03). The improvement of local control is attributed to a higher nasopharyngeal mucosal dose that is achieved by using small-size flexible applicators with an iridium source. It is interesting to note that the 5-year LFFS rates for the ERT alone group (T1: 84.1%, T2: 79.8%, T3: 62.6%) are comparable to the corresponding rates of the cobalt group. This information supports our speculation that an adequate booster treatment could compensate for inadequate primary treatment. The prognosis of patients with locally recurrent NPC is grave. Maximizing the local control is therefore crucial for the survival of the patients. (ABSTRACT TRUNCATED)

The predictive value of tumor regression rates during chemoradiation therapy in patients with advanced head and neck squamous cell carcinoma

OBJECTIVE

The value of tumor regression rates in predicting survival outcome during chemoradiation therapy was prospectively evaluated.

METHODS AND MATERIALS

Sixty-two patients diagnosed with locally advanced stage III/IV unresectable head and neck squamous cell carcinoma underwent weekly clinical and endoscopic serial assessment of primary and nodal tumor sizes during chemoradiation therapy between July 1993 and September 1995. Chemoradiation therapy consisted of protocol treatment using supradose intra-arterial targeted cisplatin (SIT-P) at 150 mg/m2 four times at weekly intervals along with intravenous sodium thiosulfate at 9 g/m2 and concurrent conventionally fractionated radiotherapy at 1.8 to 2.0 Gy/fraction (fx) to a total dose of 68 to 74 Gy. Tumor reduction was serially measured as a percentage of the original pretreatment size at weekly intervals by the same team of surgical and radiation oncologists. Correlations were then made between tumor regression rates and survival.

RESULTS

Complete or near complete regression of disease during chemoradiation therapy as compared with nonresponsive/partially responsive disease was associated with better survival outcome (P = 0.001 and P = 0.013, respectively). Among patients exhibiting complete or near complete regression of disease, rapid tumor reduction (median = 4.2 weeks) was associated with inferior survival outcome when compared with slower disease regression (median = 6.4 weeks, P = 0.007).

CONCLUSIONS

Our findings fail to support the "traditional" hypothesis that rapid tumor regression during treatment is predictive of an improved survival outcome. Treatment strategies that alter ongoing therapy based upon initial tumor regression rates should be avoided.

The response of tumours with Gompertzian growth characteristics to fractionated radiotherapy

Proliferation of tumour cells during radiotherapy may be a significant factor determining response to treatment. In previous work based on the linear-quadratic (LQ) model, tumour cell proliferation was assumed to be independent of both tumour size and the temporal structure of treatment. This paper examines a form of tumour cell proliferation that is exponential at small tumour sizes and Gompertzian at larger sizes. This is integrated with the LQ description of tumour cell sterilization. It is assumed that exposure to therapeutic radiation changes the state of tumour cells from viable to doomed. Doomed cells are assumed to be lost from the tumour mass with exponential kinetics. Six parameters are used to describe tumour response. Three of these are the standard 'LQ+time' (alpha, beta, Tpot) parameters. Two additional parameters are required to describe the shape of the tumour growth/regrowth curve (VG, Vmax). The sixth parameter (Ts) represents the rate of loss of doomed cells from the tumour. The model may be used to describe the effects of radiation therapy, both in terms of cure response (clonogenic cell sterilization) and also remission response (tumour regression and regrowth). An important feature of the model is that it enables the effects of temporally non-uniform treatments to be described. Preliminary modelling studies suggest that it may be possible to manipulate the temporal structures of fractionation schedules to increase the duration of remission at the expense of the probability of cure.

Clearance of parenchymal tumors following radiotherapy: analysis of hepatocellular carcinomas treated by proton beams

Clearance of a parenchymal tumor following radiotherapy was determined by using follow-up CT scans of 18 hepatocellular carcinoma tumors treated with focused proton beams. Regression analysis of the daily decrement (DD) and the diameter (D) of a tumor mass in each CT observation interval, DD = a*Db, showed that the exponent b was 3.0 or larger in early periods and 2.0 or smaller in late periods. This suggests that the clearance depends initially on the tumor volume, subsequently on the tumor surface area, and then it becomes much more moderate, possibly due to radiation damage to the parenchymal tissues.

Disease-specific survival and locoregional control in tonsillar carcinoma

In a nationwide survey on oropharyngeal carcinoma in the Netherlands (1986-1990), 380 patients with a tonsillar carcinoma were retrospectively studied. The records of 268 (71%) men and 112 (29%) women with a median age of 59 yr (range 31-91), who had squamous cell carcinoma (272 patients, 98%) or undifferentiated carcinoma (8 patients, 2%) were reviewed with respect to treatment, disease-specific survival and locoregional control. Distribution by stage according to the UICC'92 system was: 27 patients (7%) stage I, 59 (15%) stage II, 99 (26%) stage III, 182 (48%) stage IV and 13 patients (3%) unknown stage. Using a previously reported revised staging system the following distribution was obtained: 118 patients (31%) stage I, 120 (31%) stage II, 67 (18%) stage III, 54 (14%) stage IV and 21 patients (6%) with an unknown stage. Treatment consisted of radiotherapy alone in 231 patients (61%), surgery and radiotherapy in 101 (27%), surgery alone in 30 (8%), chemotherapy in 5 (2%) and 13 patients (3%) did not receive any treatment. At 5-yr the overall survival was 32%, the disease-specific survival 42% and the locoregional control 61%. In patients treated with radiotherapy alone the disease-specific survival was 39%, for surgery and radiotherapy 53% and for surgery alone 83%. The disease-specific survival according to UICC'92 stage was 71% in stage I, 59% in II, 50% in III and 32% in stage IV (P < 0.0001). In the revised staging the survival figures were 63% in stage I, 43% in II, 31% in III and 9% in IV (P < 0.0001). The two staging systems appeared to be comparable in prognostic discrimination; the clinical relevance of the revised stage might, however, be slightly superior to the UICC'92 version. The difference in results after radiotherapy alone and surgery + radiotherapy remained significant, also after adjusting for stage (P < 0.0001).

Cell kinetics and tumor regression during radiotherapy in head and neck squamous-cell carcinomas

Head and neck squamous-cell carcinoma (HN-SCC) patient management is mainly based on TNM classification and needs be improved by considering other potentially useful prognostic factors. We examined the pre-radiotherapy tumor potential doubling time (Tpot) evaluated after in vivo infusion of bromodeoxyuridine and flow-cytometric analysis and the early clinical tumor regression after 40 Gy (40 Gy-TR). Tpot values and clinical 40 Gy-TR classes (minor and major) were available for 82 HN-SCC patients. Radiation therapy completion was done either with 1 dose per day (conventional regimen) or 2 doses per day (accelerated regimen). Local control was also available for follow-up times above 4 years. We found that major 40 Gy-TR was strongly correlated with fast tumor growth, characterized by Tpot values below 5 days, and that patients with major 40 Gy-TR showed better local control than those with minor 40 Gy-TR, independently from the radiotherapy regimen type. We also found that treatment completion with accelerated radiotherapy gave better local control for patients with major 40 Gy-TR and fast tumor growth than conventional radiotherapy. Multivariate analysis, performed on all patients, assigned an independent prognostic value to Tpot, tumor classification and 40 Gy-TR.

Early tumour response and treatment toxicity after hyperfractionated radiotherapy in nasopharyngeal carcinoma

The aim of the present study was to undertake a planned interim analysis of a prospective randomized trial comparing the tumour response and the acute and subacute complications of hyperfractionated radiotherapy and conventional radiotherapy in non-metastatic nasopharyngeal carcinoma (NPC). 100 patients with newly diagnosed non-metastatic NPC were randomized to receive either conventional radiotherapy (Arm I) or hyperfractionated radiotherapy (Arm II). Stratification was done according to the T-Stage (modified Ho's T-Stage classification). The biological effective dose (10 Gy) to the primary and the upper cervical lymphatics were 75.0 and 73.1 for Arm I and 84.4 and 77.2 for Arm II, respectively. Hyperfractionated radiotherapy was associated with significant mucositis which is of higher grade than conventional radiotherapy (p = 0.0001), but the duration of mucositis was similar between the two Arms and all study patients completed radiotherapy on schedule without interruption of radiotherapy. Early survival and tumour recurrence rates were comparable between the Arms. The preliminary results indicate that the hyperfractionated radiotherapy has excellent patient compliance in Chinese patients, with acceptable acute and subacute toxicities and the local and regional complete tumour response rates being comparable with conventional radiotherapy. The significance of the time required after start of radiotherapy to achieve a complete tumour response is discussed.

Impact of biological clearance on tumor radioresponsiveness

PURPOSE

To determine the capacity of biological clearance in tumor regression following radiotherapy by using metastatic brain tumors as a clinical model in which mechanical clearance is negligible.

METHODS AND MATERIALS

Thirty-eight tumors (19 nonsmall cell lung cancer, 11 small cell lung cancer, and 8 nonlung cancer) in 23 patients were followed with computed tomography (CT) scans over 3 months or more following initiation of radiotherapy, with doses ranging between 34 and 66 Gy. The tumor regression rate (RR; mm3/day), which represented the capacity of biological clearance, was calculated for each CT observation period. The complete response (CR) rate was calculated. The relationship between RR and tumor diameter was determined with regression analysis in conjunction with the pattern of contrast enhancement and the type of primary disease. The change of the RR also was examined.

RESULTS

The CR rate was 60.5% for the total group; it was lower for ring-enhanced tumors (41.7%) than diffusely enhanced tumors (69.2%), which included mostly small cell lung cancer metastases. The RR correlated significantly with the tumor diameter (D), with a regression curve of exponential function (RR = 0.035 *D2.5). The RR varied widely and was rather large until 40 days following initiation of radiotherapy, especially for the subgroups of diffusely enhanced tumors and the small cell lung cancer tumors, and became rather constant thereafter.

CONCLUSION

A tumor diameter exponent in the regression curve of smaller than 3.0 indicates that the larger the tumor volume is, the smaller the capacity of biological clearance. The capacity of biological clearance also is dependent on vascularity and cellularity of the tumor components expressed by the pattern of contrast enhancement.

Head and neck cancer

This synthesis of the literature on radiotherapy for head and neck cancer is based on 424 scientific articles, including 3 meta-analyses, 38 randomized studies, 45 prospective studies, and 246 retrospective studies. These studies involve 79174 patients. The literature review shows that radiotherapy, either alone or in combination with surgery, plays an essential role in treating head and neck cancers. When tumors are localized, many tumor patients can be cured by radiotherapy alone and thereby maintain full organ function (1, 2). Current technical advancements in radiotherapy offer the potential for better local tumor control with lower morbidity (3). This, however, will require more sophisticated dose planning resources. To further improve treatment results for advanced tumors, other fractionation schedules, mainly hyperfractionation, should be introduced (5). This mainly increases the demands on staff resources for radiotherapy. The combination of radiotherapy and chemotherapy should be subjected to further controlled studies involving a sufficiently large number of patients (4, 5). Interstitial treatment (in the hands of experienced radiotherapists) yields good results for selected cancers. The method should be more generally accessible in Sweden. Intraoperative radiotherapy should be targeted for further study and development.

In vitro uptake of bromodeoxyuridine by human nasopharyngeal carcinoma (NPC) and its relation to clinical findings

A cell kinetic study of 27 newly diagnosed patients with nasopharyngeal carcinoma (NPC) using the in vitro bromodeoxyuridine (BrdU) technique was performed. The results were reproducible as demonstrated by three independent sections performed on each patient. No correlation between BrdU labelling index (LI) and Ho's clinical staging was found. A higher LI was associated with the development of distant metastases (P = 0.057). Statistically significant correlation was found between low LI and longer duration required to achieve complete remission in the primary site of disease (P = 0.026). This study suggests a potential role for in vitro BrdU labelling index as a prognosticator for NPC prior to treatment.

Prognostic value of tumor regression during radiotherapy for head and neck cancer: a prospective study

OBJECTIVE

Prospective evaluation of tumor regression during external irradiation for head and neck squamous cell carcinomas and its association with long-term local control.

METHODS AND MATERIALS

Two hundred twenty-eight patients with histologically confirmed squamous cell carcinoma [oral cavity: 59 (26%), oropharynx: 65 (29%), hypopharynx: 37 (16%), larynx: 67 (29%)] were included between January 1986 and December 1990. Curative intent external irradiation delivered 65-70 Gy over a period of 7 weeks (five 2 Gy fractions per week). Tumor regression was evaluated clinically and endoscopically every week.

RESULTS

Tumor regression, assessed at 2 weeks, was as follows: no response: 62 (30%), 25% response: 121 (59%); 50% response: 23 (11%). At 5 weeks, 9 (4%) patients showed 0-25% regression, 75 (33%) showed 50% regression, 115 (50%) showed 75% regression, and 29 (13%) showed complete regression. Median follow-up was 79 months (range: 6-96 months). The local control probability was 68% (62-74%) at 2 years, 65% (59-70%) at 5 years. Univariate analysis showed that, at 2 weeks, local control was significantly different between the nonresponders and the patients with 25% or greater response (p < 0.025) and that, at the fifth week, local control was very different between the major responders (75 and 100%) and the minor responders (0-50%) (p < 0.0001). Multivariate analysis (Cox Proportional Hazards Model) showed that the probability of local relapse was significantly and independently increased for minor regression at 5 weeks [Relative risk (RR) of failure was 2.3 (1.4-3.7)], for nonlaryngeal tumors [RR: 2.4 (1.3-4.5)], and for Stage T3-T4 [RR:2.4 (1.4-4)]. Three prognostic groups can, therefore, be proposed: 1) low risk of recurrence when regression > or = 75% and laryngeal tumor or T1-T2 tumors in other sites: 106 (46.5%) patients, 2-year local control probability: 84% (77-92%); 2) high risk of recurrence: regression < or = 50% and T3-T4 nonlaryngeal tumors: 44 (19%) patients, 2-year local control probability: 27% (13-41%); 3) intermediate risk of recurrence: 78 (34.5%) patients, 2-year local control probability: 69% (58-80%).

CONCLUSION

The present study suggests that tumor regression during external radiotherapy is an independent predictive factor of local control in head and neck carcinomas.

The importance of correct stage grouping in oncology. Results of a nationwide study of oropharyngeal carcinoma in The Netherlands

BACKGROUND

In the frame of a nationwide study of oropharyngeal carcinoma in the Netherlands (1986-1990), the current International Union Against Cancer 1992/American Joint Committee on Cancer 1988 staging system was evaluated with respect to patient distribution and prognostic value.

METHODS

Data related to epidemiology, treatment and survival from 640 patients referred for primary treatment were analyzed. Staging was first evaluated in a proportional-hazard regression analysis controlled for these data. Next, all possible combinations of T, N, and M were tested in a stepwise backward elimination model until all remaining indicator variables had a P value of less than 0.05. New stages were defined, based on the coefficients of the remaining indicator variables.

RESULTS

The revised stages revealed two advantages compared with the UICC 1992/AJCC 1988 version: a more balanced distribution of patients (31% in Stage I, 31% in Stage II, 18% in Stage III, 14% in Stage IV, and 5% unknown in the revised staging system versus 7% in Stage I, 17% in Stage II, 24% in Stage III, 50% in Stage IV, and 2% unknown in the UICC 1992/AJCC 1988 staging system), and an improved prognostic discrimination for the disease specific survival (5-year results in the revised staging were 67% in Stage I, 42% in Stage II, 28% in Stage III, and 11% in Stage IV, versus 68% in Stage I, 64% in Stage II, 44% in Stage III and 27% in Stage IV in UICC 1992/AJCC 1988).

CONCLUSION

Improvements in the current staging system in patient distribution in the stages in prognostic discrimination is feasible by regrouping the T, N, and M but without redefining the categories themselves.

Radiotherapy of tonsillar and base of the tongue carcinoma. Prediction of local control

119 patients with squamous cell carcinoma of the tonsillar region (68) and the base of the tongue (51), who received external radiotherapy with curative intent between 1966 and 1984, are analysed with respect to overall treatment results, local tumour control and prognostic factors. Radiation doses were equivalent to 60-70 Gy in 6-7 weeks, with a mean fraction dose of 2.4 Gy on the cobalt 60 equipment and 2 Gy on the linear accelerator. Significant differences were found between both oropharyngeal subsites. Three-year overall survival was 57% in tonsillar carcinoma and 38% in base of the tongue (P = 0.006); disease-specific survival was 70% and 47%, respectively (P = 0.005); and local control rates were 82% and 61% (P = 0.02). Late damage to normal tissues, like persistent dysphagia and osteomyelitis, were seen in 11% of patients. Patients with large tumours in the tongue based developed significantly more complications (P = 0.04). T-stage and tumour subsite predicted local control independently before start of the treatment (P = 0.02 in both cases). A significant nonlinear correlation between Normalised Total Dose (using an alpha/beta ratio of 15 Gy) and local control rate was found (P = 0.006), the middle range having the worst prognosis. The size of radiation field and overall treatment time did not correlate with local control in either site. Response at the end of radiotherapy and 6 weeks later have additional prognostic value for local control, irrespective of the initial stage or subsite (P = 0.004 and < 0.001, respectively).

T3 laryngeal cancer: a retrospective study of the Dutch Head and Neck Oncology Cooperative Group: study design and general results

511 Patients with T3 N0-3 M0 squamous cell carcinoma of the larynx, treated in the Netherlands from 1975 until 1984, were retrospectively analysed. Four different treatment policies were followed: primary surgery, planned combination of radiotherapy and surgery, primary radical radiotherapy, and selective radiotherapy. General results are presented. Local control rate was 72%. Regional control rate was 90% for clinically N0 patients and 78% for clinically N+ patients. Salvage therapy was overall successful in 38%. Surgical salvage for local radiation failures (with regional relapse) was successful in 69%, and for regional failures (without local relapse) in 46%. Ultimate locoregional control was 78% and, due to 8% distant metastases, 5-year actuarial corrected survival was 70%. Prognosis did not improve over the years. Corrected survival was independently correlated with tumour extension, involvement of neck nodes and treatment strategy. Corrected survival was similar for primary radiotherapy and primary surgery, but significantly better for planned combined therapy. Multiple primary tumours occurred significantly more often in male (19.5%) than in female patients (7.3%) (P = 0.05), the bronchus being most commonly affected. Cumulative actuarial risk for metachronous tumour was 15% after 5 years and 30% after 10 years so prevention and early detection of these second tumours may play the most important role in improving overall survival rates in the future.

Concomitant boost technique using accelerated superfractionated radiation therapy for advanced squamous cell carcinoma of the head and neck

Of 142 patients irradiated for American Joint Committee on Cancer Stage III or IV head and neck carcinoma, 100 patients were eligible for analysis with a minimum follow-up of 12 months. In one group, 50 patients were treated with conventional once-a-day (QD) fractionation to doses in excess of 6600 cGy. The other 50 patients were treated prospectively with accelerated superfractionated radiation therapy using a concomitant boost twice-a-day schedule (BID). Patients received conventional fractionation (180 cGy/fraction) combined with a boost field of 160 cGy/fraction BID after a 4-hour to 6-hour interval 3 days per week during part of their treatment course. After 3 years, locoregional tumor control was 62% in the BID group versus 33% in the QD group (P = 0.003). Disease-free survival was 60% and 30%, respectively, for the BID and QD groups (P = 0.002), and adjusted survival was 66% and 38%, respectively, for the BID and QD groups (P = 0.03). Overall survival approached statistical significance in favor of the BID group (P = 0.06). Complete tumor responses were observed in 63% of patients treated in the BID group 1 to 3 months after completion of radiation therapy. Of these, 84% remain free of local recurrence. Of the 19 patients with persistent disease 1 to 3 months after treatment, 47% remain locally controlled. Superfractionated accelerated radiation therapy produced superior local control and disease-free and adjusted survival rates relative to a group of patients treated QD.