Impact of adjuvant treatments on survival in Korean patients with WHO grade II gliomas: KNOG 15-02 and KROG 16-04 intergroup study

Congress of Neurological Surgeons systematic review and evidence-based guidelines for the role of chemotherapy in newly diagnosed WHO Grade II diffuse glioma in adults: update

Questions and recommendations from the prior version of these guidelines without changeTarget populationAdult patients (older than 18 years of age) with newly diagnosed World Health Organization (WHO) Grade II gliomas (Oligodendroglioma, astrocytoma, mixed oligoastrocytoma).QuestionIs there a role for chemotherapy as adjuvant therapy of choice in treatment of patients with newly diagnosed low-grade gliomas?RecommendationLevel III: Chemotherapy is recommended as a treatment option to postpone the use of radiotherapy, to slow tumor growth and to improve progression free survival (PFS), overall survival (OS) and clinical symptoms in adult patients with newly diagnosed LGG.QuestionWho are the patients with newly diagnosed LGG that would benefit the most from chemotherapy?RecommendationLevel III: Chemotherapy is recommended as an optional component alone or in combination with radiation as the initial adjuvant therapy for all patients who cannot undergo gross total resection (GTR) of a newly diagnosed LGG. Patients with residual tumor >1 cm on post-operative MRI, presenting diameter of 4 cm or older than 40 years of age should be considered for adjuvant therapy as well.QuestionAre there tumor markers that can predict which patients can benefit the most from initial treatment with chemotherapy?RecommendationLevel III: The addition of chemotherapy to standard RT is recommended in LGG patients that carry IDH mutation. In addition, temozolomide (TMZ) is recommended as a treatment option to slow tumor growth in patients who harbor the 1p/19q co-deletion.QuestionHow soon should the chemotherapy be started once the diagnosis of LGG is confirmed?RecommendationThere is insufficient evidence to make a definitive recommendation on the timing of starting chemotherapy after surgical/pathological diagnosis of LGG has been made. However, using the 12 weeks mark as the latest timeframe to start adjuvant chemotherapy is suggested. It is recommended that patients be enrolled in properly designed clinical trials to assess the timing of chemotherapy initiation once diagnosis is confirmed for this target population.QuestionWhat chemotherapeutic agents should be used for treatment of newly diagnosed LGG?RecommendationThere is insufficient evidence to make a recommendation of one particular regimen. Enrollment of subjects in properly designed trials comparing the efficacy of these or other agents is recommended so as to determine which of these regimens is superior.QuestionWhat is the optimal duration and dosing of chemotherapy as initial treatment for LGG?RecommendationInsufficient evidence exists regarding the duration of any specific cytotoxic drug regimen for treatment of newly diagnosed LGG. Enrollment of subjects in properly designed clinical investigations assessing the optimal duration of this therapy is recommended.QuestionShould chemotherapy be given alone or in conjunction with RT as initial therapy for LGG?RecommendationInsufficient evidence exists to make recommendations in this regard. Hence, enrollment of patients in properly designed clinical trials assessing the difference between chemotherapy alone, RT alone or a combination of them is recommended.QuestionShould chemotherapy be given in addition to other type of adjuvant therapy to patients with newly diagnosed LGG?RecommendationLevel II: It is recommended that chemotherapy be added to the RT in patients with unfavorable LGG to improve their progression free survival.Updated Question and Recommendations from the Prior Version of These GuidelinesQuestionIn adult patients with pathologically confirmed WHO Grade II diffuse glioma does chemotherapy alone, combined with radiation therapy or after radiation therapy compared to radiotherapy alone result in better overall survival, progression free survival, local control, fewer complications, neurocognitive preservation, and quality of life?RecommendationLevel I: It is recommended that chemotherapy (PCV) be added to radiation therapy (RT) in all patients with newly diagnosed high-risk WHO Grade II diffuse glioma (Patients younger than 40 unable to get gross total resection and older than 40 regardless of the degree of resection) to improve their overall survival.

LEVEL II

It is recommended that chemotherapy be added to radiation therapy in all patients with newly diagnosed high-risk WHO Grade II diffuse glioma to improve overall survival without a decline in neurocognitive function.

LEVEL III

It is suggested that chemotherapy (temozolomide) be added to RT in all patients with newly diagnosed high-risk WHO Grade II diffuse glioma to improve progression free survival and overall survival.

LEVEL III

It is suggested that chemotherapy alone should be considered in patients with newly diagnosed WHO Grade II diffuse glioma in cases with 1p/19q co-deletion.New questions and recommendationsTarget populationThese recommendations apply to adult patients diagnosed with WHO Grade II diffuse glioma.QuestionIn adult patients with newly diagnosed WHO grade II diffuse glioma does administration of chemotherapy prior to surgical resection improve extent of resection, provide longer progression free survival and overall survival when compared to chemotherapy alone?RecommendationLevel III: Neo-adjuvant temozolomide may be used in patients with WHO Grade II diffuse gliomas deemed unsafe for resection due to infiltration of eloquent areas or with large contralateral extension as an initial step to improve the extent of resection.There is insufficient evidence to support a recommendation regarding the ability of chemotherapy provided prior to surgical resection to improve progression free survival (PFS) and overall survival (OS).QuestionIn adult patients with newly diagnosed WHO grade II diffuse glioma does the administration of temozolomide increase the rate of malignant transformation when compared to no chemotherapy or other chemotherapy regimens?RecommendationThere is insufficient evidence to support a recommendation against the use of temozolomide for WHO Grade II diffuse gliomas due to concern over increasing the rate of malignant transformation.QuestionIn adult patients with newly diagnosed WHO grade II diffuse glioma does administration of multi-agent chemotherapy improve progression free survival and overall survival when compared to administration of single-agent chemotherapy?RecommendationThere is insufficient evidence to support a recommendation for or against the use of multi-agent chemotherapy to improve progression free survival and overall survival when compared to administration of single-agent chemotherapy in patients with newly diagnosed WHO Grade II diffuse glioma.

A systematic review and meta-analysis informing the role of adjuvant radiotherapy (RT) in Grade 2 and 3 oligodendroglioma

BACKGROUND AND PURPOSE

Evidence and clinical guidelines support the use of adjuvant RT in high-risk low-grade gliomas. However, patients with oligodendroglioma have a more indolent disease course and delaying or avoiding RT is often considered to reduce treatment-related toxicities. As the optimal adjuvant management for oligodendroglioma is unclear, we aimed to assess the effect of adjuvant RT on overall survival (OS) and progression-free survival (PFS).

METHODS

MEDLINE, EMBASE, CENTRAL and CINAHL were searched from January 1990 to February 2023 for studies comparing adjuvant RT versus no adjuvant RT for patients with oligodendroglioma.

RESULTS

This review found 17 eligible studies including 14 comparative retrospective studies and 3 randomized controlled trials. Using random-effects model, the results suggested that adjuvant RT improved OS by 28 % (HR 0.72, 95 % CI (0.56-0.93), I2 = 86 %), and PFS by 48 % (HR 0.52, (95 % CI 0.40-0.66), I2 = 48 %) compared to patients without adjuvant RT. Subgroup analysis showed that upfront adjuvant RT improved OS and PFS compared to salvage RT. There were no significant differences in OS and PFS between adjuvant RT versus adjuvant chemotherapy. There was improvement in PFS but not OS for adjuvant chemoradiotherapy versus adjuvant chemotherapy alone. Adjuvant RT improved OS in WHO Grade 3 but not WHO Grade 2 oligodendroglioma.

CONCLUSION

Overall, adjuvant RT improved OS and PFS in patients with oligodendroglioma. In patients with low-risk features (e.g. Grade 2, gross total resection), alternative approaches and individualization of management such as adjuvant chemotherapy alone may be reasonable considering the lack of survival benefit. Future efforts should prospectively investigate these treatment regimens on molecularly-classified oligodendroglioma patients (defined by presence of IDH mutation and 1p/19q co-deletion), balancing between maximizing survival outcomes and reducing RT-related toxicities.

Malignant Progression of Diffuse Low-grade Gliomas: A Systematic Review and Meta-analysis on Incidence and Related Factors

Malignant progression of diffuse low-grade glioma (LGG) is a critical event affecting patient survival; however, the incidence and related factors have been inconsistent in literature. According to the PRISMA guidelines, we systematically reviewed articles from 2009, meta-analyzed the incidence of malignant progression, and clarified factors related to the transformation. Forty-one articles were included in this study (n = 7,122; n, number of patients). We identified two definitions of malignant progression: histologically proven (Htrans) and clinically defined (Ctrans). The malignant progression rate curves of Htrans and Ctrans were almost in parallel when constructed from the results of meta-regression by the mean follow-up time. The true transformation rate was supposed to lie between the two curves, approximately 40% at the 10-year mean follow-up. Risk of malignant progression was evaluated using hazard ratio (HR). Pooled HRs were significantly higher in tumors with a larger pre- and postoperative tumor volume, lower degree of resection, and notable preoperative contrast enhancement on magnetic resonance imaging than in others. Oligodendroglial histology and IDH mutation (IDHm) with 1p/19q codeletion (Codel) also significantly reduced the HRs. Using Kaplan-Meier curves from eight studies with molecular data, we extracted data and calculated the 10-year malignant progression-free survival (10yMPFS). The 10yMPFS in patients with IDHm without Codel was 30.4% (95% confidence interval [95% CI]: 22.2-39.0) in Htrans and 38.3% (95% CI: 32.3-44.3) in Ctrans, and that with IDHm with Codel was 71.7% (95% CI: 61.7-79.5) in Htrans and 62.5% (95% CI: 55.9-68.5) in Ctrans. The effect of adjuvant radiotherapy or chemotherapy could not be determined.

The Korean Society for Neuro-Oncology (KSNO) Guideline for WHO Grade II Cerebral Gliomas in Adults: Version 2019.01

BACKGROUND

There was no practical guideline for the management of patients with central nervous system tumor in Korea for many years. Thus, the Korean Society for Neuro-Oncology (KSNO), a multidisciplinary academic society, has developed the guideline for glioblastoma. Subsequently, the KSNO guideline for World Health Organization (WHO) grade II cerebral glioma in adults is established.

METHODS

The Working Group was composed of 35 multidisciplinary medical experts in Korea. References were identified by searching PubMed, MEDLINE, EMBASE, and Cochrane CENTRAL databases using specific and sensitive keywords as well as combinations of keywords regarding diffuse astrocytoma and oligodendroglioma of brain in adults.

RESULTS

Whenever radiological feature suggests lower grade glioma, the maximal safe resection if feasible is recommended globally. After molecular and histological examinations, patients with diffuse astrocytoma, isocitrate dehydrogenase (IDH)-wildtype without molecular feature of glioblastoma should be primarily treated by standard brain radiotherapy and adjuvant temozolomide chemotherapy (Level III) while those with molecular feature of glioblastoma should be treated following the protocol for glioblastomas. In terms of patients with diffuse astrocytoma, IDH-mutant and oligodendroglioma (IDH-mutant and 1p19q codeletion), standard brain radiotherapy and adjuvant PCV (procarbazine+lomustine+vincristine) combination chemotherapy should be considered primarily for the high-risk group while observation with regular follow up should be considered for the low-risk group.

CONCLUSION

The KSNO's guideline recommends that WHO grade II gliomas should be treated by maximal safe resection, if feasible, followed by radiotherapy and/or chemotherapy according to molecular and histological features of tumors and clinical characteristics of patients.