Clinical Implementation of "Plan of the Day" Strategy in Definitive Radiation Therapy of Cervical Cancer: Online Adaptation to Address the Challenge of Organ Filling Reproducibility

PURPOSE

Definitive pelvic intensity modulated radiation therapy (IMRT) in cervical cancer is susceptible to geographic miss due to daily positional and volumetric variations in target and organs at risk. Hence, despite evidence of reduced acute and late treatment-related toxicities, implementation of image-guided IMRT (IG-IMRT) with a reasonable safety margin to encompass organ motion is challenging.

METHODS AND MATERIALS

In this prospective, nonrandomized phase 2 study, patients with cervical cancer International Federation of Gynecology and Obstetrics (2009) stage IB2-IIIB between the ages of 18 and 65 years were treated with definitive pelvic chemoradiotherapy with a prespecified organ (bladder and rectum) filling protocol. Reproducibility of organ filling was assessed along with the implementation of daily comprehensive adaptive image-guided radiotherapy (IGRT), with a library of 3 IMRT (volumetric modulated arc therapy) plans with incremental expansions of clinical target volume (CTV) to planning target volume (PTV) (primary) margins (small, 0.7 cm; adequate, 1 cm; and large, 1.5 cm) and a backup motion robust 3-dimensional conformal radiotherapy plan; the appropriate plan is chosen based on pretreatment cone beam computed tomography (CBCT) ("plan of the day" approach).

RESULTS

Fifty patients with a median age of 49 years (IQR, 45-56 years) received definitive radiation therapy (45-46 Gy in 23-25 fractions to pelvis, with simultaneous integrated boost to gross nodes in 15 patients) with the aforementioned IGRT protocol. In the analysis of 1171 CBCT images (in 1184 treatment sessions), the mean planning computed tomography (CT) and CBCT bladder volumes were 417 and 373 cc, respectively. Significant interfractional variation in bladder volume was noted with a mean absolute dispersion of 29.5% with respect to planning CT; significant influential random factors were postchemotherapy sessions (P ≤ .001), pre-CBCT protocol duration (P = .001), and grades of chemotherapy induced nausea vomiting (P = .001). Significantly higher variation in bladder filling was noted in patients with older age (P = .014) and larger planning CT bladder volume (P ≤ .001). Time trend analysis of fraction-wise bladder volume revealed an absolute systemic reduction of 16.3% in bladder volume means from the first to the fifth week. Variation in rectal diameter was much less pronounced, with 19.2% mean dispersion and without any significant factors affecting it. Although in 19% and 2% of sessions large IMRT PTV and 3-dimensional conformal radiotherapy were necessary to cover the primary target, respectively, reduction in treated volume was possible in 43% of sessions with small PTV selection instead of standard adequate PTV (36% sessions). Plan of the day selection had a moderate to strong correlation with nonabsolute dispersion of bladder filling (Spearman ρ =0.4; P = .001) and a weak (but significant) correlation with grades of acute toxicities. The planned protocol was well tolerated with no radiation-induced local grade 3 toxicity.

CONCLUSIONS

Interfractional variation in organ filling (especially bladder) is inevitable despite fixed pretreatment protocol in definitive settings (intact cervix). Despite the logistical challenges, adaptive IGRT in the form of plan of the day based on incremental CTV-to-PTV margins is a relatively simple and feasible strategy to minimize geometric uncertainties in radical IG-IMRT of cervical cancer.

Correlation of Hematological Parameters With Clinical Outcomes in Cervical Cancer Patients Treated With Radical Radio(chemo)therapy: A Retrospective Study

PURPOSE

Variations in the levels of systemic inflammatory biomarker levels have been linked with outcomes in various malignancies including cervical cancer. In this study, we investigated prognostic implications of pretreatment hematological factors/indices in locally advanced cervical cancers treated with radical radio(chemo)therapy.

METHODS AND MATERIALS

Electronic medical records of 1051 patients with cervical cancer of FIGO (International Federation of Gynecology and Obstetrics) stage IB2-IVA treated in various prospective trials at our institute between 2003 and 2017 were reviewed. All clinical parameters such as age (dichotomized at the median), stage (IB2-IIB vs III-IVA), histologic type (squamous vs others), and hematological parameters (hemoglobin, platelets, absolute neutrophil count, absolute lymphocyte count, absolute monocyte count) were recorded. Neutrophil-to-lymphocyte ratio, platelet-to-lymphocyte ratio (PLR), lymphocyte-to-monocyte ratio (LMR), and prognostic nutritional index (PNI; defined as 10 × albumin concentration [g/dL] + 0.005 × total lymphocyte count [μL]) were calculated. Univariate and multivariate (Cox regression) analyses were performed to evaluate these factors with disease-free survival (DFS) and overall survival (OS).

RESULTS

With a median follow-up of 69 months, the 5-year DFS and OS were 65% and 69%, respectively. On multivariate analysis, FIGO stage (hazard ratio [HR], 1.9; P = .000) and PLR (HR, 1.002; P = .008) significantly affected DFS while FIGO stage (HR, 1.804; P = .000), LMR (HR, 0.92; P = .018), PNI (HR, 0.96; P = .013), and PLR (HR, 1.002; P = .006) significantly affected OS. Apart from FIGO stage, PLR significantly affected both DFS and OS. This correlation of hematological parameters is stronger in stage IIIB cervical cancer.

CONCLUSIONS

Hematological indices, including PNI, PLR, and LMR, can serve as reliable prognostic indicators for patients with cervical cancer. By incorporating these indices into routine assessment and monitoring, clinicians can better stratify patients, personalize treatment plans, and more accurately predict outcomes, ultimately improving patient care and management.

Reirradiation with advanced brachytherapy techniques in recurrent GYN cancers

PURPOSE

To evaluate clinical outcomes of recurrent gynaecological cancers treated with reirradiation (reRT) using advanced brachytherapy (BT) technique.

METHODS AND MATERIALS

Seventy-six women who underwent reRT with BT for gynaecological cancers at our institute between January 2000 and December 2019 were analysed to determine patient, disease and treatment characteristics and clinical outcomes. Descriptive analysis was used for demographics, and the Kaplan Meir method was used for survival analysis.

RESULTS

Median age at recurrence was 55 years (Range: 35-73). Forty-three patients had recurrent cervical cancer with intact uterus, and 33 had recurrent vault/vaginal cancers post adjuvant RT. Eight patients received EBRT prior to BT (Range: 30-50Gy). Twenty-two patients (28.9%) received salvage chemotherapy before consideration of brachytherapy. Brachytherapy application was done using MUPIT in 38, Vienna applicator in 20, Syed Neblett in 8, central vaginal cylinder in 3, multicatheter intravaginal applicator in 2, tandem-ovoids in 4 and Houdek applicator in 1 patient. Median cumulative EQD2 for all courses of radiation was 108 Gy (IQR 92-123 Gy). At median follow up of 39 months, local control (LC), progression-free survival (PFS) and Overall survival (OS) at 2-years was 60%, 56.3%, and 72.9 respectively. Patients who had recurrences beyond 2 years had significantly better OS compared to early recurrences. Patients who received BT doses >40 Gy had a higher LC and PFS. Grade 3 to 4 late rectal toxicity was seen in 10 (13%), bladder toxicity in 6 (8%) and vaginal fibrosis in 24 (31%) patients.

CONCLUSION

The use of advanced BT approach in reirradiation setting is a feasible and safe option in treatment of post-treatment recurrent cervical, endometrial, and vaginal cancers.

Early Results of Extreme Hypofractionation Using Stereotactic Body Radiation Therapy for High-risk, Very High-risk and Node-positive Prostate Cancer

AIMS

Stereotactic body radiotherapy (SBRT) in low- and intermediate-risk prostate cancer has shown encouraging results. However, its use in high-risk patients is limited due to lack of data regarding adequate radiotherapy dose, need for pelvic nodal treatment and androgen deprivation therapy. Herein we report our experience of SBRT in this subgroup.

MATERIALS AND METHODS

Analysis of a prospectively maintained database of 68 consecutive patients of the National Comprehensive Cancer Network (NCCN) high-risk, very high-risk and node-positive adenocarcinoma prostate treated with SBRT was undertaken. All patients were treated with rotational intensity-modulated radiotherapy with daily image guidance. The dose delivered to the prostate and gross node was 35-37.5 Gy in 5 alternate day fractions. Node-positive patients received 25 Gy to pelvic nodal regions until the common iliac nodes. Treatment was delivered in 7-10 days. All patients received long-term androgen deprivation therapy (79% medical and 21% surgical).

RESULTS

Most patients (65%) had a Gleason score ≥ 8. The median prostate-specific antigen was 42. Twenty patients were high risk (30%), 11 (16%) very high risk and 37 (54%) node positive. No acute Radiation Therapy Oncology Group grade ≥ 3 genitourinary or gastrointestinal toxicity was noted. Acute grade 2 genitourinary and gastrointestinal toxicity were 12% and 3%, respectively. Late grade 3 genitourinary and gastrointestinal toxicity was 3% and 0%, respectively. There was no increase in acute or late gastrointestinal toxicity with prophylactic pelvic nodal radiotherapy. Prior transurethral resection of prostate (n = 11) did not increase toxicity. At a median follow-up of 18 months, 97% patients were alive and 94% were biochemically controlled.

CONCLUSION

SBRT is safe in the treatment of high-risk, very high-risk and node-positive prostate cancer, even with prophylactic pelvic radiotherapy or prior transurethral resection of prostate. Longer follow-up is required to determine efficacy.