GOG 99

GOG 99

A phase III trial of surgery with or without adjunctive external pelvic radiation therapy in intermediate risk endometrial adenocarcinoma: a Gynecologic Oncology Group study

Pubmed

Hypothesis:
Addition of external beam radiation to postoperative therapy in intermediate risk endometrial cancer improves recurrence free survival

Site: Endometrium

Study population:
Inclusion: Derived from GOG 33

  • Intermediate Group: Any myometrial invasion with any grade and negative lymph node involvement i.e ([FIGO] stage IB, IC, IIA (occult), and IIB [occult]) – 5-year recurrence rate of 20 – 25%
  • Lymph node – Sampling/debulking if suspicious; Full lymphadenectomy if no enlarged or suspicious nodes
  • Revised during the course of study to enroll only “high intermediate risk” group : Expected 25% recurrence risk:
GOG 99 High Intermediate risk Group. Also used in GOG 249
    -  Age
    -  G2-3 tumor
    -  LVI
    -  Outer 1/3 myometrial invasion

1) >70 yrs old with only 1 other risk factor
2) >50 yrs old with 2 risk factors
3) any age with 3 risk factors

Excluded: High risk pathologies i.e. Clear cell and Papillary Serous, laparoscopic surgery excluded.

Experimental arm:
190 patients: External beam radiation 50.4 Gy given in 28 fractions. No Vag brachytherapy

Standard Arm:
202 patients: No additional therapy after surgery

Outcomes: Experimental arm vs. Standard arm (OR and p-values)

  • Primary Outcome (Recurrence Free @ 24 months) – 3% vs. 12% (OR – 0.42, p=0.007)
  • Secondary Outcome (Overall Survival @ 48 months) – 92% vs. 86% (OR – 0.86, p = 0.557)
  • Local Recurrences – 1.6% vs. 8.9% (p = ss)
  • Significantly Different Toxicity (Grade 2 or greater):
    • Hematologic: 7.4% vs 2.5% (p = ss)
    • GI : 34% vs. 2.5% (p = ss)

Conclusions:

  • Radiation reduced local recurrences but did not improve overall survival
  • Many deaths in the study were not endometrial cancer specific, therefore study underpowered to detect difference in overall survival even if it existed.
  • HIR group (132 total patients) : Defined above
    • Reduction in Hazard of isolated recurrence (RH: 0.37)
    • Reduction in Distant metastatic recurrence related to RT (RH: 0.46)
  • 2/3rd of recurrences and 2/3rd of cancer deaths in this group.
  • HIR – 19% improvement in cumulative recurrence at 24 months compared to no adjuvant therapy group vs LIR group 4% improvement compared to no adjuvant therapy group.

This study was the basis of GOG 249 selection criteria.


PORTEC 3

Pubmed

Study Summary by: Dr. Kevin McCool

Title: Adjuvant chemoradiotherapy versus radiotherapy alone for women with high-risk endometrial cancer (PORTEC-3): final results of an international, open-label, multicentre, randomized, phase 3 trial

Hypothesis: To investigate the benefit of adjuvant chemotherapy during and after radiotherapy (chemoradiotherapy) versus pelvic radiotherapy alone for women with high-risk endometrial cancer.

Standard Arm: EBRT (48.6 Gy in 1.8 Gy fractions)

Experimental Arm: EBRT (48.6 Gy) Chemotherapy (Cisplatin 50 mg/m2 in weeks 1 and 4 during RT followed by 4 cycles of Carboplatin AUC5 and Paclitaxel 175 mg/m2)

Design: Open-label, randomized, multi-center (UK, Australia, Italy, Canada, France)Inclusion Criteria:
– Endometrioid:

  • Stage IA Grade 3 with with LVSI

  • Stage IB Grade 3

  • Any Stage II or  III.

  • Serous or Clear Cell: Stage IA (with invasion), IB, II, III

Exclusion Criteria (outside of usual): Carcinosarcoma, prior malignancy within 10 years, prior radiotherapy, hormonal therapy, chemotherapy, bulky cervical involvement with radical hysterectomy, residual macroscopic disease

Primary Endpoint: Co-primary endpoints were failure-free survival (FFS) and overall survival (OS)

Outcomes: ChemoRT vs. RT alone (HR and p-value)

  • OS: 81.8% vs.76.6% [HR 0.76 (p=0.109)]
  • FFS: 75.5% vs. 68.6%[HR 0.71 (p=0.022) favoring chemotherapy RT]
  • Subgroup analysis: Stage III patients
    • 5 year FFS = 69.3% vs 58.0% (HR=0.66, p=0.031)
    • 5 year OS = 78.7% vs. 69.8% (HR=0.71, p=0.13)

Serious Adverse Events: ChemoRT vs. RT alone (p-value)

  • Any hematologic: 45% vs. 5% (p<0.0001)
  • GI: 14% vs. 5% (p<0.0001)
  • Neuropathy: 7% vs. 0% (p<0.0001)
  • At 12 months no significant difference in any grade 3 toxicity

Conclusions:

  • Improvement in FFS with the addition of chemotherapy. OS unchanged
  • Significant improvement in FFS
  • Most benefit in patients with stage III
  • Age is a significant predictor on risk adjustment. Patients above 70 benefit from chemoradiation (however toxicity discussion is warranted)